Abstract:Pear is the second largest deciduous fruit tree in China. In recent years, many important advances in China have been made in the evaluation and exploitation of pear germplasm resources, unlocking the mechanism of genetic development and breeding of characteristic cultivars. The main achievements contained: (1) defining 13 species of oriental pear originated in China, of which five belong to primary species including Pyrus callryana Dene, P. koehnei Schneid, P. betulaefolia Bunge, P. pyrifolia Burm and P. ussuriensis Max, while three species composing of P. bretshneideri Rehd., P. serrulata Rehd. and P. phaeocarpa Rehd. are hybrids; (2)Breakthrough progress in breeding for high-quality early-maturing pear cultivars. The proportion of early, middle and late ripening pear cultivars were 20:28:52 in 2006 (relative to 7:23:70 in 1994), and the early ripening pear cultivars accounted for nearly 50% in the past 10 years. (3) Korla pear is an indispensable germplasm for pear quality breeding because of its strong hereditary ability ofhigh quality and storage tolerance. Complex genetic background and abundant genetic diversity are the key factors for parent selection in pear quality breeding. (4) Breeding and popularization of high-quality and late-maturing pear cultivars is the key to satisfy the annual supply of high-quality pear market, boost consumer confidence and promote the efficient development of pear industry in China. In view of the current status, two subjects are suggested in the future researches, including: (1) Constantly breeding for elite pear cultivars that represent high-quality, storage-tolerant and extremely late maturity, in order to meet the diversified demands in market; (2) unlocking the development mechanism of quality traits from transcription, translation and modification, by taking use of the modern molecular biology technologies, which might provide the theoretical basis for pear quality breeding.

Abstract:Apple is a globally-popular fruit and the apple tree serves as the largest deciduous fruit tree species in China. This review article summarizes the recent important acheivements in apple, comprising of the origin and evolution of cultivated apple, the genetic diversity and core germplasm of Malus sieversii in Xinjiang, the genetic and developmental mechanism of quality-related traits, the breeding of characteristic and diversified varieties such as white-fleshed, red-fleshed and functional apples as well as the research and development of efficient production technology. In view of the complexity in functional apple breeding and the long-process in achieving the economical value, a system ‘Four-Quality’ is proposed, which refers Quality formation, Quality breeding, Quality varieties and Quality maintenance. Furthermore, a “Seven-in-one” system for research, development and promotion of scientific and technological achievements is suggested, which includes independent promotion, multiple licenses, exclusive transfer, integrated demonstration, network media, technical training and popular articles. Based on the current status on research, two subjects are suggested as the following: (1) deciphering the development mechanism of quality traits from transcription, translation and modification, by deployment of the modern molecular biology technologies, with the aim of theoretical supports in breeding for high-quality; (2) strengthening the breeding for high-quality，storage-resistant, late-maturing white meat apples and new varieties with high-flavonoid at different ripening stages, in order to meet the diversified needs in market and increase the farmers’ incomes.

Abstract:The genus Fagopyrum Mill. is an important crop which can be used as food, forage and medicine. China is the largest producer of tartary buckwheat and the world’s diversity center of buckwheat., while the southwest China is internationally recognized as the original-land of buckwheat. The crop germplasm are fundamental materials for production, cultivar development and biotechnology research, which is of great importance and potential values. Since the 1980s, Chinese researchers has collected more than 3000 cultivated germplasm resources, of which more than 2200 are preserved in the long-term bank. The extremely abundant and rich diversified germplasm resources have spread all around the world after the natural evolution, artificial cultivation and introduction. This review summarized the common buckwheat and tartary buckwheat distribution,,collection and preservation, as well as the identification and evaluation of agronomic characters and nutritional quality of germplasm resource in recent 40 years. Meanwhile, this paper introduced the progress of collection and evaluation of buckwheat germplasm resources in other countries and organizations, which may provide the reference for the protection and rational utilization of these precious germplasm resources. What’s more,, we summarized the wild buckwheat species (including varietas and subspecies) and their distribution status, including their main characteristics and variation, and summed up the research about development and utilization of different species. Except for a few species, such as F. cymosum, most of wild buckwheat resources were widely distributed in the southwest of China, and mainly inhabited in the Yunnan-Guizhou-Sichuan border area. Finally, the study discussed the insufficiency and expectation in exploitation of buckwheat germplasm resources, and put following suggestions for the future researches:(1)Continuously improve the evaluation and quality identification of the buckwheat germplasm resources, and establish a comprehensive, systematic and quantitative evaluation system for the agronomic traits, nutrient components, processing quality, taste quality. (2)To promote buckwheat industry development healthily, orderly and quickly, developing the potential crop distribution and economic value of buckwheat and accelerating the breeding based on original and introduced germplasms . (3) More attention should be paid to the problems in the deterioration of living environment of wild buckwheat. Especially the living environment of some wild species(F. statice, F. gilesii, F. crispatofolium and F. hailuogouense) get worse, and the area scatters narrower. It is urgent to intensify the rescue investigation, collection and protection of wild resources.(4) Making further analysis on the functions of key genes and regulatory genes in the biosynthesis pathway of buckwheat flavonoids, especially rutin, and the mechanism of molecular regulatory network at the molecular level.

Abstract:Waterlilies (Nymphaea) play an increasingly important role in water garden, water purification and ecological construction. This paper reviews the advances on studies of germplasm resources, breeding objectives, breeding techniques and achievements. (1) The genetic diversity of waterlilies in China is constitutively increasing. Only five species were originally found in China, which accounted for only 10% of global water lily species. Nowadays, over 30 exotic species and 400 cultivars have been conserved, in which the flowering biology has been studied. (2) The modern breeding aimed at the selection of colorful cultivars before 2009, while breeding for hardy waterlilies with blue-purple flower colors by inter-subgenera crosses has been thereafter conducted. However, this international breeding steps of waterlilies didn’t meet to the demand in domestic market. (3) Application of advanced breeding methods. The cross combinations have moved from intraspecific, interspecific to inter-subgeneric. The hybridizing technology without emasculation of waterlily has been invented and the efficiency of hybridization has been improved. The inheritance of some characteristics in waterlilies was analyzed. Some new techniques such as physical and chemical mutagenesis, ploidy breeding and transgenic breeding have been applied to the breeding of waterlilies. (4) Over past 20 years, Chinese breeders have released 205 new varieties including 18 nationally-approved cultivars and 187 internationally-registered cultivars. Especially, these four varieties, composing of ‘Hong Yanyan’, ‘Lan Jian’, 'Tian Ci' and 'Detective Erika', have been approved by winning six awards in the International New Waterlily Competition.

Abstract:Alkali stress, including layers of sresses such as ion toxicity, osmotic stress and extraneous high pH (pH >8.5) injury, is a major abiotic stress that seriously endangers the growth and development of plants and the yield and quality of crops. With the continuous expansion of salinized land in China, the ecological system balance is increasingly seriously damaged. Compared with salt stress, the current understanding of alkali stress is relatively superficial, and the adaptation mechanism of plant alkali stress is even less well understood. Therefore, it is of great practical significance to understand and master the adaptive mechanism of alkali stress and plant response to alkali stress, to explore alkali-resistant germplasm resources for future improving ecological environment, and to cultivate alkali-resistant crop varieties for improving saline-alkali land. Based on the domestic and international progress recently, this paper briefly describes the definition and difference of salt and alkali stress. Morphological changes of different organs and organelles under alkali stress are summarized. The physiological adaptation mechanism of plants to alkali stress through cell metabolism, chemical synthesis and accumulation, and scavenging of reactive oxygen species is described. In addition, the molecular adaptation mechanisms of plants in response to alkali stress are indicated with three aspects: cloning and functional identification of alkali-tolerant genes, utilization of transcriptome technology to explore alkali-tolerant candidate genes, and plant alkali-tolerant mediated by Ca2+ signal system. It is pointed out that although many of candidate genes related to alkali resistance were obtained, fewer genes are actually cloned and explored with functional mechanism. Meanwhile, the research prospect of Multi-Omics which mainly focuses on modification omics in alkali tolerance mechanism of plants are prospected, in order to further provide theoretical basis for exploring new alkali resistance genes and unlocking the functional mechanism.

Abstract:Based on 2,256 common wheat reference varieties for DUS test in China, a DNA profile database was established to assist in distinctness test. We first analyzed the DNA profiles of 96 reference varieties using 81 fluorescently labeled SSR markers. A total of 731 alleles were detected with the number of alleles varying between 3 and 16 and the PIC values from 0.24 to 0.82. A DNA profile database consiting of 2256 wheat reference varieties was constructed using 42 fluorescently labeled SSR markers. A total of 148,493 datapoint were included with a missing rate of less than 5%. The genetic and genotypic datasets of 176 wheat varieties were collected and analyzed. The genetic similarities between the non-distinct candidate varieties and their most similar vairieties were above 90%. The candidate varieties with a genetic similarity of over 80% are assumed to be similar varieties, which are suggested to be further investigated for phenotypic variations in the field.

Abstract:Thinopyrum elongatum (Host) D. R. Dewey as one of relatives of wheat, harboring genes resistance to strip rust and Fusarium head blight and tolerance to salinity for wheat improvement, could be used for wheat genetic improvement. To understand the effects of chromosome 1Ee on wheat agronomical and quality-related traits, wheat-Th. elongatum chromosome disomic substitution line 1Ee(1A) from common wheat cultivar Chinese spring was analyzed in multiple environments. In relative to the Chinese Spring, the substitution line showed the reduction of the length and width of wheat flag leaf, the length and width of kernels, no. of spikelets per spike, no. of kernels per spike and thousand kernel weight. However, the length of spikes (P < 0.05) was significantly increased. Regarding to the quality-related traits, the substitution line displayed the increases of the dough max peak height and band width of 8 min, but no differences of the grain protein content, SDS sedimentation, wet gluten content, gluten index and peak height time were observed. In addition, 17 COS markers specific to chromosome 1Ee were developed in this study. All in all, chromosome 1Ee can improve wheat grain quality traits, but it has negative effects on yield related traits. And the developed markers specific for chromosome 1Ee might be used for developing wheat-Thinopyrum chromosome short segment lines carrying Glu-Ee1 by reducing the chromosomal linkage drag.

Abstract:This study aims to evaluate the phenotypic diversity and the characteristics of 129 maize landraces, which were collected from Chongqing. By performing a two-year field trial, we evaluated the phenotypic variation and calculated the diversity index, i.e. Shannon-Weaver index. All these 129 landraces were subjected for cluster analysis with Ward method based on Euclidean distance of these resources. The phenotypic performance of all 31 traits were significantly positively correlated between two years, and the Shannon-Weaver diversity indices of 16 traits were more than 2.0. The diversity index of plant height exhibited the highest, 2.07 and 2.08 respectively in the year of 2017 and 2018. By clustering, the maize landraces collected from Chongqing were divided into 3 groups, i.e. Group I, early-maturing small-grain genotype, Group II, early-maturing flint genotype with middle stem, and Group III, medium-maturing genotype with high stem. Group I was mainly consisted of waxy resources that collected from middle altitude regions, Group II mainly contained early-maturing white flint resources from middle and high altitude mountains. And Group III mainly contained medium-maturing genotypes with high stem and larger ears that collected from middle to low altitude regions. In summary, maize landraces collected from Chongqing possess and exhibit three distinctive groups, the phenotypic characterization of which provided informative references for the germplasm protection and future mining and utilization of maize resources for maize breeding particularly in Chongqing.

Abstract:Excellent inbred line serves as foundation in commercial breeding. Combining ability is an important index to evaluate the heritability and breeding value of inbred lines. By analyzing 182 hybridized combinations that derived from 14 inbred lines from home and abroad following complete diallel crossing, we analyzed the kernel dehydration related traits combining ability in maize. The results indicated that: (1) significant differences on kernel dehydration rate, kernel moisture content, husk number and husk area among different inbred lines, which were environment-dependent; (2) through combining ability analysis, we found that Zheng12, Zheng645, PHR55 and LH202 as parents can easily mate combinations with rapid kernel dehydration or low kernel moisture content at mature, especially Zheng12 × LH202; (3) The phenotypic value of 182 hybridized combinations for kernel dehydration related traits were all respectively significantly positive related with the sum of their parents general combining ability. The results might provide useful resources or theoretical basis for the genetic improvement of maize varieties which are suitable for mechanical harvesting.

Abstract:Soybean mosaic virus SC3 is main prevalent strain of Mosaic virus in huang-huai river and the middle and lower reaches of Yangtze river that causes the yield loss of soybean (Glycine max. ).The resistance of 217 soybean germplasms to SC3 were studied by the method of indoor inoculation identification and by investigating the influence of SC3 on the agronomic and quality traits of different disease-resistant varieties after field inoculation with SC3.It provided data support for the production and application of soybean varieties resistant to Mosaic virus disease and resistant parents for breeding resistant varieties.Virus resistance of 217 soybean germplasm were identified by using artificial inoculation SC3 method in the greenhouse during 2012-2014 years.According to the analysis results, 30 materials (10 disease-resistant varieties, 10 moderately susceptible varieties, and 10 highly susceptible varieties) of different disease resistance varieties were randomly selected. The effects of SC3 on yield - related and quality traits of different varieties were studied by the field inoculation identification in 2013-2014 years on the field..The identification results of 217 soybean germplasms SC3 showed that the disease-resistant varieties of the first class, include 4 symptomless varieties, accounted for 1.84%. Two varieties with high resistance, accounting for 0.92%; 35 varieties with moderate resistance, accounting for 16.13%. In the second class, 92 varieties were moerate susceptible, accounting for 42.40%. The third type of highly susceptible varieties, including 3 susceptible varieties, accounted for 1.38%; 81 varieties were highly susceptible, accounting for 37.33%. SC3 had different effects on the seed weight per plant, plant height, number of nodes on main stem, protein content and oil content of different resistant varieties. The seed weight, plant height, number of nodes on main stem, protein content and oil content of the resistant varieties in the first group were not significantly decreased. The seed weight per plant, number of nodes on main stem, protein content and oil content of the susceptible varieties in the second class did not decrease significantly, and the plant height of the susceptible varieties decreased to different degrees due to the differences of varieties. The seed weight per plant, plant height, number of nodes on main stem, protein content and oil content of the third type of highly susceptible varieties decreased significantly.The studies have shown that SC3 has different effects on the agronomic and quality traits of different resistant varieties, as well as on the agronomic and quality traits of the same disease-resistant varieties. SC3 has no significant influence on most agronomic and quality traits of disease resistant and moderately susceptible varieties, which are suitable for resistance breeding as breeding materials.

Abstract:The high temperature (HT) stress caused by global climate change has seriously affected the growth and development of soybean. In recent years, high temperature became one of the important factors leading to the decline of soybean yield and quality in Huanghuaihai. This study attended to identify the HT resistance germplasm resources and establish a scientific method for evaluating the HT tolerance. By taking use of 35 soybean varieties that were collected from the Huanghuaihai ecological and the Chinese soybean micro-core germplasm resources, we determined the phenotypic variation at flowering stage via the field artificial warming (44 .1 ± 1.47 ℃). Based on the comprehensive physiological and biochemical traits related to the HT stress, we constructed a set of HT resistance evaluation standards for soybean with pollen vigor (pollen germination rate) as the main indicator, and used this standard to screen for HT soybean germplasm resources. The results found that compared with the natural environment in the field, the pollen germination rate, the number of pods per plant and the number of effective branches after HT stress showed a significant decrease, while the relative conductivity increased significantly. According to the HT resistance coefficient significant responding to HT stress traits, the principal component and membership function were standardized and analyzed and estimated the comprehensive evaluation value (C) of soybean response to HT stress and clustered analysis based on C value. Finally, the HT resistance of soybean varieties classified into 5 types (I, sensitive type; II, strong sensitive; III, medium; IV, tolerance; V, strong tolerance). The grading standard is basically consistent with the field phenotype identification, indicating that the method can be used for the screening and identification of soybean HT resistance germplasm resources, and two HT resistant soybean varieties (Jidou 21 and Nannong 34) are initially screened for further research, which laid method and material basis on breeding for HT resistant new varieties and HT resistance molecular mechanism.

Abstract:In this study, we analyzed the phenotypic variation of seven agronomic traits and five fiber quality traits were analyzed in 270 cotton germplasm resources. We expected to identify the upland cotton germplasm materials suitable for trait improvement, particularly interested in the Yellow River Basin and the selection of parents in future breeding work. Twelve agronomic traits showed different levels of genetic variation (boll number per plant, 24.2%; first branch length, 17.5%; first branch position, 14.1%; boll weight, 13.3%; micronaire value, 11.1%; plant height, 11.0%; lint percentage, 10.9%; fruit branch number per plant, 9.6%; fiber strength, 8.6%; upper half mean length, 6.3%; elongation ratio, 2.0%; and regularity degree, 1.6%). The upper half mean length positively correlated with plant height, and negatively correlated with micronaire value; the lint percentage positively correlated with either plant height or fiber strength, and negatively correlated with fruit branch number per plant; the micronaire value positively correlated with the elongation ratio; and the boll number per plant positively correlated with the first branch position. The cumulative contribution of the top four principal factors reached 67.358% in the principal component analysis. The first principal factor was mainly related to fiber quality; the second was mainly related to boll number per plant and first branch length; the third was mainly related to fruit branch number per plant; and the fourth was mainly related to first fruit branch number per plant position. Cluster analysis classified 270 cotton germplasms into six groups. Therefore, the cotton resources of the first cluster can be used as materials to improve the upper half mean length and fiber strength of cotton. SIMIAN 2, NANDANBADIDAHUA, EKANGMIAN8, and Qik can be used as materials for improving cotton yield; LIAO113, JUNMIAN1, LIAOYANGLVRONGMIAN, and BAO2367 can be used to improve the cotton micronaire value; and SHANSANYUAN78-782 can be used to improve the cotton type. Thus, this work provided a theoretical basis for cotton breeding by pyramiding these elite traits during breeding to cultivate new varieties and strains.

Abstract:Mutants are excellent genetic materials for revealing molecular mechanisms of important genes. In this research, the cotton seeds were mutagenized by different concentrations of EMS solution (0%, 0.2%, 0.5%, 1.0% and 1.5%) and processing duration (4 h, 8 h, 10 h and 12 h), respectively, in order to optimize the reaction condition for EMS mutagenesis in upland cotton. Then, the effect of different EMS concentrations and treatment duration on germination rate and growth of sprouted cotton seeds was analyzed and the morphological characters of M2 and M3 generation were identified. The results showed that 1.0% EMS for 10 h was optimal for Lu6269 mutagenesis. The seed germination rate was about 49%, and the half lethal concentration is 1.0%. To obtain abundant mutants, approximated 10000 seeds of Lu6269 were treated with 1.0% EMS for 10h. A fiber abnormal mutant (the fiber non-fluffy in the development of maturation, sfm-1) was found in the M2 generation, and this phenotype was inherited by observing M3 generation seeds. This mutant showed a large cavity between the embryo and the seed coat, a weak and small embryo as well as decreased unearthing of seeds. Taken together, by establishing the EMS mutagenesis system of G. hirsutum cv Lu6269, we obtained sfm-1, a stable mutant for abnormal seed and fiber development, which served as the material foundation for fiber development, seed germination and function genome research in cotton.

Abstract:In order to shed light the transcriptional reprograming of wheat upon Puccinia triticina infection, the wheat near isogenic line TcLr26 (incompatible, resistance) and its recurrent parent Thatcher (Tc) (compatible, susceptibility) were inoculated by physiological race 260, and then harvested for RNA-seq analysis using HiSeq^TM2000 high-throughput sequencing technology. The assembled transcripts were subjected to analyze COG, GO and KEGG classification and functional annotation, pathway annotation and in silico prediction of coding genes. Total 87,291 Unigenes were obtained after de novo assembly, with an average length of 866 bp. The functional clustering analysis revealed 25 COG classifications, 55 GO functional subclasses and 128 KEGG paths. By analyzing the differentially expressed genes (DEGs) between compatible and incompatible combinations, a total of 4,037 up-regulated and 1,949 down-regulated Unigenes were identified at 8 h, and 2,122 up-regulated and 3,248 down-regulated Unigenes were identified at 24 h. The genes, which residue to the calcium signaling pathway, active oxygen burst and SA signaling pathway, were found to be differentially expressed at different time point. The DEGs at 8h and 24h after inoculation were assumed to be closely related to the induction of basic defense response and Lr26-mediated HR defense response, respectively. Taken together, the generated datasets would be useful for further analysis and evaluation of wheat resistance related genes against Puccinia triticina.

Abstract:Cultivated barley (Hordeum vulgare L. ssp. vulgare) is one of oldest domesticated crops and four most important cereal species. In addition to end-use for animal feeding, malting and human diets using barley grains, the straw of cultivated barley serves as a silage grass for animals in some parts of barley cultivation areas (e.g. Tibet). In order to identify elite barley resources in future breeding for silage barley varieties, this study analyzed the phenotypic variation 102 barley germplasm accessions from National Crop Genebank of China in Chongqing, south-west part of China. We determined the phenotypic variation on 15 traits and conducted statistical analysis using Shannon-Weaver Index, correlation analysis, cluster analysis and PCA analysis. These results suggested that the Shannon-Weaver Index (H’) ranged from 0.729 to 0.957. The higher phenotypic variation was detected on leaf yellowing at heading and filling stages, plant lodging and 1000-grain weight, but the narrowed diversity was found on grain width and plant height. In addition, we found that the phenotypic diversity of winter barley ecological region (0.721) was slightly higher than that of southwest and Tibet Plateau region (0.706). Four subpopulations were clarified by clustering analysis, being consistent with the geographic origins of tested materials. Moreover, a number of barley germplasm resources, which showed high plant height, lodging resistance, large leaves, staying green of old leaves, were identified. These elite barley germplasms might become useful potentially in breeding for silage barley varieties in areas of Chongqing, China.

Abstract:Pea sprouts is a kind of traditional vegetable in China. Therefore, it is of great significance to screen vegetable pea varieties (lines) with high nutritional quality for cultivation and breeding of pea sprouts. In this study, seven main nutritional quality traits in sprouts of 97 pea varieties (lines) with different genetic origins, were measured to explore the characteristics of nutritional quality in different genotypes of Pisum sativum. The comprehensive evaluation of several nutritional quality traits in pea sprouts, including soluble protein, vitamin C, starch, cellulose, soluble sugar, water content and so on, was performed according to genetic diversity index, frequency distribution, correlation analysis, the average membership function and cluster analysis. The results showed that the variation coefficient of the quality traits of the tested cultivars ranged from 2.80% to 38.64%, among them, the variation coefficient of cellulose content was the largest (38.64%). Also, the genetic diversity index ranged from 2.02 to 2.94, showing extensive genetic variation. According to the results of comprehensive evaluation based on the average membership function method, the top 5 varieties were Aoyin 3, Korean sweet crispy pea, SWU-6, Improved Yongshengzhenbao, and B-61. Cluster analysis was carried out based on characteristics of nutritional quality that the tested cultivars were roughly divided into three groups at the Euclidean distance D = 18.480. There are 35 varieties in Group I, 26 varieties in Group II and 36 varieties in Group III. In conclusion, the seven quality traits of 97 peas sprouts showed extensive genetic variation and abundant genetic diversity, and the 5 pea varieties with higher nutritional quality were distributed in different groups. And the results can be used as reference for breeding and genetic study of new pea cultivars with tender tip.

Abstract:Studies of the genetic relationship could provide reference for the excellent germplasm innovation and new varieties breeding. Within this study, we investigated the genetic diversity by SSR markers using capillary electrophoresis fluorescence detection technology, in 187 accessions that include cauliflower, broccoli, Roman cauliflower, landraces and wild species. A total of 313 alleles were amplified from 30 pairs of SSR primers, with an average of 10.43. According to the curd phenotypic characters of the materials, these genotypes were composed of four subgroups: cauliflower (subgroup 1, P1-81), broccoli (subgroup 2, P82-147), Roman cauliflower (subgroup 3, P148-154), wild and local species (subgroup 4, P155-187). The narrowed genetic diversity was observed among subgroups 1, 2 and 3, except subgroup 4 that showed abundant diversity. The phylogenetic tree and population structure analysis assigned these genotypes into three groups. Cauliflower (G1) and broccoli (G2) were grouped independently, while Roman cauliflower together with wild species and landraces assembled the third group (G3).

Abstract:Breeding for tetraploid hybrids has become an optimal strategy in grape breeding. In the present study, we deployed 20 morphological traits and 25 simple sequence repeat (SSR) markers to access the genetic diversity of 278 genotypes. These materials contained four grape varieties (Muscat Hamburg, tetraploid Muscat Hamburg, Kyoho and Hybrid F1 Jumei by crossing of Kyoho and tetraploid Muscat Hamburg) and 274 individuals from Jumei's F2 population. The morphological variation analysis revealed the average Shannon information index and the average Nei's genetic diversity index of 1.14 and 0.62, respectively. The coefficient of variation of 14 traits was higher than 20% and significant correlations were found among some characteristics. Prostrate hairs density of lower side of young leaf was significantly positively correlated with Hairs density on internode of shoot (r=0.203) and Prostrate hairs density of lower side of mature leaf (r=0.128). By principal component analysis (PCA) and cluster analysis, the morphological traits showed eight principal components (PC1-PC8) explained approximately 60.99% of the total variance of the 278 genotypes, and the first three major PCs contributed to approximately 30.08%. The two-dimensional graph of PC1 and PC2 directly reflected the similarity between the phenotype of F2 population and its parents. The cluster analysis of 278 materials based on 20 morphological traits resulted in four main groups. Further genetic variation and diversity evaluation in 278 grapes materials was done using 25 SSR markers. 127 bands totally were generated by 25 SSR markers using PCR amplifcation, including 52 polymorphic fragments. SSR analysis indicated, in the population, the average polymorphism information content (PIC) value was 0.26, the average Nei's genetic diversity index was 0.32, and the average Shannon information index was 0.49. The result showed that these SSR markers were able to distinguish genetic variation among genotypes. The SSR cluster analysis based on UPGMA illustrated that the similarity coeffcient ranged from 0.38 to 1.00 and cluster analysis in 0. 47 similarity coeffcient can divide 278 grapes genotypes accessions into five groups These results based 20 morphological traits and 25 SSR markers would be valuable for genetic diversity analysis and helpful in breeding selection. PCA and clustering analysis revealed that most of tetraploid F2 individuals were similar to Jumei (F1). The remaining individuals showed genetic differentiation with their parents, and they served as good materials for future selection and breeding for new tetraploid grape varieties.

Abstract:The rice varities harboring Wx-mp genotype generally results in 10% of amylose, which brings elite eating quality (e.g soft and elastic) favorited by consumers in Yangtze River Region, China. In order to identify Wx-mp carrying rice germplasm in future breeding, a functional marker associating to Wx-mp has been developed. By tests in 242 japonica rice materials collected from southern China, twenty-six germplasms were found carrying Wx-mp gene. Out of that, 25 varieties or breeding materials were collected from Jiangsu, the others from Shanghai. By validation using Sanger sequencing, this newly-developed marker proved 100% accuracy within 26 samples. Furthermore, average content of amylose was 9.2%, with a range of 3.3%. The rice cultivar Nanjing 505 with the lowest amylose content was 7.3, while cv. Nanjing 46 showed a highest amylose content of 10.6%. Thus, by deployment of the new functional marker, this study unlocked the distribution of Wx-mp carrying cultivars that were was mainly found in Jiangsu and shanghai Province.

Abstract:In order to identify the resistance and leaf rust resistance genes of 12 wheat cultivars from Hebei province, we conducted tests for leaf rust resistance using 20 Puccinia triticina pathotypes at the seedling stage of 12 wheat cultivars (lines) as well as 37 cultivars (lines), which are the resistant donors with known leaf rust resistance genes. Meanwhile, marker-assisted identification using 11 molecular markers closely linked were performed. In order to identify the adult plant leaf rust resistance, , the diseases severity of the tested materials was investigated by field trails in 2014-2015 and 2015-2016 cropping seasons at Zhoukou, Henan Province and Baoding, Hebei Province. Four leaf rust resistance genes including Lr1, Lr26, LrB and Lr46, were detected in 12 wheat cultivars (lines), and eight cultivars (lines) may carry Lr26. These cultivars Shixin 618, Gaoyou 2018 and Ji 5265 may carry Lr1, LrB, Lr46 respectively. As indicated by field identification in two field growing seasons, Shixin 733, Gaoyou 2018 and Shiyou 17 showed slow delayed establishment of leaf rust disease symptom rusting, and they can be used as the resistance donors for breeding.

Abstract:The CCT (CO, COL, and TOC1) family genes are widely involved in the regulation of florescence, and play an important role in plant growth and development. In this study, 57 maize CCT genes, designated ZmCCT, were identified by search for sequence homolog in publicly available databases. The structure, amino acid characteristics, chromosome location and gene evolution of ZmCCT genes were analyzed by bioinformatics approaches, and the CCT gene families of other species were compared and analyzed. The ZmCCT family members were found to be unevenly distributed on chromosomes. For instance, 11 ZmCCT members were found on chromosome 5, while only three were found on chromosomes 3, 7 and 10. The ZmCCT gene family has relatively conserved structures, comprising of commonly-present CCT DNA domain, one α-helix and three β-folds, as well as DNA motifs that are only found a few of genes. The phylogenetic analysis of CCT proteins suggested nine phylogenetic branches, and the ZmCCT genes was grouped with these of Setaria italica and Brachypodium distachyon. Thus, this study provided a reference for further revealing the functional mechanism of CCT family genes in maize.

Abstract:Plant E3 ubiquitin ligase plays an important role against abiotic stresses such as high salt and drought. In this study, we isolated soybean E3 ubiquitin ligase gene GmAIRP1, which contained a full length coding sequence of 642 bp, encoding for 213 amino acids. Protein domain analysis indicated that GmAIRP1 carried a typical RING-finger domain. By phylogenetic tree analysis, GmAIRP1 was found to be closely related with MtAIRP1. The expression of GmAIRP1 turned to be elevated under salt, drought or ABA stresses, particularly at 1h or 3h post treatments. By transforming GmAIRP1 into tobacco, the transgenic tobacco grew better than the wild type after 21 days of high salt and drought stress, implying an elevated stress tolerance. Furthermore, we analyzed the physiological indicators, including POD and CAT activities that were elevated in transgenic plants than that of the control, and the MDA content that was constantly lower in transgenic plants. Taken together, these results indicated that GmAIRP1 acts as a positive regulator in plant responding to high salt and drought stress, possibly by activating antioxidant enzyme activity and increasing accumulation of osmotic adjustment substances.

Abstract:NAC transcription factors are involved in plant abiotic stress response and play important roles for improving plant drought and salt tolerance. Taking advantage of established agrobacterium-mediated transformation platform using the potato cultivar "Atlantic", we generated the transgenic potatoes by expressing Haloxylon ammodendron HaNAC1, and conducted tests for drought resistance with PEG-6000 simulated drought treatment. By analyzing the contents of endogenous hormones, these results showed significant increased content of auxin (IAA, IBA), cytokinin (IP, cZ), jasmonic acid (MEJA, JA-ILE), salicylic acid (MESA), gibberellin (GA3) in three transgenic potato lines if compare to the receptor line (p<0.01, p<0.05). The content of abscisic acid (ABA) was significantly lower than the receptor line. By analyzing the transcriptional level using quantitative PCR analysis, several stress-tolerant genes including NCED1, ERD11, RD29A, DREB2A, LEA3 and KIN1 showed the modified expression in HaNAC1 overexpressing plants to the receptors (p<0.01, p<0.05). Taken together, our results suggested that increased drought resistance by expressing HaNAC1 is associated with the different expression of stress-related genes and hormone content, thus providing a theoretical basis for further molecular mechanism analysis of HaNAC1 response to drought stress.

Abstract:In this study, an association analysis of pepper (Capsicum annuum Linnaeus) resistance to Phytophthora capsici Leonian was performed in a pepper core collection of 194 C. annuum Linnaeus materials. By taking use of 58 pair of SSR markers, 178 allelic variations were detected. The average shannon index, polymorphism information content (PIC) and gene diversity were 0.6732, 0.3859 and 0.4400, respectively, implying a high level of polymorphism within the diversity panel. The structure analysis suggested two sub-populations, correlating with the difference on levels of resistance. Twelve of 58 SSR loci were found to be associated with disease index, with an explanation of 2.98%-16.05% of the phenotypic variance. Fifteen SSR loci were identified to be associated with diseased plant rate, which could explain 2.95%-21.29% of the phenotypic variance. The locus explaining the largest phenotypic variance was assigned to chromosome 7, and the other loci with minor effects were found on chromosome 2, 3, 7, 8, 9 and 11. Furthermore, which indicates the materials in this study probably contain novel P. capsici Leonian resistant alleles. The alleles with the largest minor effects in each associated locus were elite alleles for P. capsici Leonian resistance, including CM0005c, ge35-141pmH0135Cd, Hpms1-139c, etc. Based on these elite alleles, a series of excellent carrier materials were explored, including germplasm 171, 55, 161, 65, 132, 128, 91, 106, 125, 127, 169, etc. Taken together, the resistant alleles and carrier materials explored in this study provided valuable natural resources in marker-assisted selection breeding for P. capsici Leonian resistance varieties in the future.

Abstract:NAC transcription factors are one of plant-specific transcription factors that participate in the regulation of plant growth and development as well as the responses to environmental stress. In relative to the in-depth study of NAC transcription factors in model plants Arabidopsis and rice, there are few related studies on NAC transcription factors in apple. In this study, to explore the role of NAC transcription factors in growth and development, as well as biotic and abiotic stress response of apple (Malus×domestica Borkh.), full-length coding sequences of 13 MdNAC genes were isolated by search for sequence homolog and RT-PCR. The obtained cDNA sequences were used as queries in BLAST P searches against NCBI. The open reading frame (ORF) and amino acid sequence were analyzed by DNAMAN 6.0, and phylogenetic tree was constructed by MEGA 6 software. The conserved domains were predicted by Pfam 26.0 and Conserved Domains in NCBI. CELLO v.2.5, PSORT and SoftBerry ProtComp 9.0 were used for predicting subcellular location. As a result, thirteen MdNAC cDNAs from ‘Zihong Fuji’ were obtained (designated MdNAC40-45, MdNAC47-53, with GenBank accession No. MG099877-MG099882, MG099884-MG099890), with sizes of open reading frame (ORF) of 639 - 1830 bp. By phylogenetic analyses, MdNAC41 was assigned to AtNAC3 group, MdNAC40, MdNAC42-43 and MdNAC45-53 were NAM group, and MdNAC44 was belonged to VND group. The subcellular localization prediction suggested that MdNAC40-45, MdNAC47-50 and MdNAC52-53 were in the nucleus, while MdNAC51 was located in the cytoplasm or nucleus. The results from array analysis indicated that thirteen MdNAC genes were expressed in all examined tissues with various transcript abundance. RNA-seq data showed that the expression levels of MdNAC43, MdNAC45, MdNAC47, MdNAC49 and MdNAC51 were induced in response to AAAP infection. qRT-PCR results showed that, under 150 mmol/L NaCl treatment, the transcription levels of MdNAC45, MdNAC47 and MdNAC52 were induced, whereas the transcription levels of MdNAC40, MdNAC48 and MdNAC51 were down-regulated in ‘Gala’ tissue culture seedlings under 300 mmol/L mannitol treatment, the transcription level of MdNAC50 was induced, while the transcription level of MdNAC41 was down-regulated. These results indicated that 13 MdNAC genes were expressed in all examined tissues, and these genes were inducible under AAAP infection, NaCl or mannitol treatment with different degrees. Taken together, these results laid a theoretical foundation to further study the mechanism of NAC transcription factor in the regulation of apple growth, development and stress responses.

Abstract:Camellia sinensis var. assamica (Assam type), which served as special germplasm resource, were widely distributed and cultivated in geographical and ecological environments of the Yun-nan province. Due to redundant phenotypic variations, these materials become of importance in studies of tea evolution and breeding. The cultivar (cv.) Mengku-dayecha (MK tea) is a national sexual variety originated from Meng-ku town, Shuang-jiang County of Yun-nan province, and this genotype shows the characteristics of strong bud, leaf fertility and tenderness. MK tea becomes popular and is widely cultivated in the western and southern tea -producing counties of Yun-nan province. Within this study, 235 germplasm resources of MK tea plants, which were collected from Shuang-jiang county of Yun-nan province, were subjected to evaluate genetic diversity and genetic relationships among individuals, construct molecular fingerprints, select suitable core marker combinations, analyse population genetic structure. The results showed that: the polymorphism of each SSR marker had detected in the candidate samples. The alleles of markers ranged from 2 to 7 with mean value 3.84, and Ho ranged from 0.18 to 0.74 with mean value 0.47; the genotyping combinations by 25 SSR loci had confirmed to accurately identify each sample and each of them had been given a unique fingerprint. Indeed, 8 core SSR loci were successfully screened out as a simplified combination which had only 8.1 e-5 to 7.7 e-3 probability to appear the same genotype combination in the sample group; 235 samples collected from 11 regions were divided into 5 sub-populations (R, G, Y, Pi, Pu) and 3 groups (Pu + Y, R+G, Pi + Y) based on genetic structure analysis. Taken together, we proposed that R sub-population in ML and BD area was likely derived from the south area (NL), while group Pu + Y and group Pi + Y highly associated and originated from Y population. Notably, the genetic components of Pu and Pi populations assumed to be caused by the migration of tea resources in Dong-guo area.

Abstract:In this study, hybrids of the interspecific cross between Gossypium barbadense L. and Gossypium hirsutum L. are employed as materials. The introgression line-to-line plants were crossed to break the undesirable linkage for breeding this semi-okra cotton germplasm which is called the ZKY-1. To provide theoretical data for further deploying the new germplasm ZKY-1 in breeding program, the agronomical character, fiber properties, physiological, biochemical and genetic characteristics of the semi-okra germplasm were evaluated. The result showed that the yield of ZKY-1 is slightly lower than the wide-cultivated control upland cotton varieties CCRI49. ZKY-1 showed the improved fiber properties, with the fiber length of 34.5 mm and the breaking tenacity of 38.4 cN·tex-1. The hereditary capacity for fiber quality of ZKY-1 was high, while the derived hybrids with various upland cotton varieties show a relatively strong mid-parent heterosis, for instance, on the fiber length and fiber breaking tenacity, except that few combinations showed significant transgressive heterosis. The leaf lobe index of ZKY-1 was 0.75±0.01, indicating a semi-okra leaf type. The leaf type of the F1 hybrid between ZKY-1 and normal leaf-type G.hirsutum L. is intermediate form and its F2 offspring showed the segregation on this character. The Chi-Square test indicated that the semi-okra trait was controlled by a dominant gene. Besides, the plant height, first fruit node, numbers of fruiting branches, germination rate and germination potential are all higher than the parent CCRI49. No significant difference in the net photosynthetic rate between the ZKY-1 and the CCRI49 at the square stage and boll stage was observed, although the ZKY-1 was significantly lower than the CCRI49 at the flowering stage. For the total content of chlorophyll, no significant difference between ZKY-1 and CCRI49 was detected at the square and flowering stage. But at the boll stage, the total content of chlorophyll in ZKY-1 was significantly higher than the CCRI49. In addition, ZKY-1 showed significantly higher SOD and POD activities relative to CCRI49 at the square stage and the flowering stage. No significant difference was found in the content of MDA. At the boll stage, ZKY-1 exhibited the lower POD activity, but significantly higher MDA content if compared to CCRI49. Taken together, ZKY-1 exhibited stable inheritance on semi-okra and excellent fiber quality, which can serve as an excellent germplasm resource for improving fiber properties and breeding high photosynthetic efficiency varieties.

Abstract:By employment of karyological and taxonomic techniques, we determined the karyotype of three species in genus of Silene (Caryophyllaceae) from the Qinghai-Tibet Plateau. The asymmetry index (AI) and polyploidy level were discussed. We made a clustering analysis for karyotype from four species (three species in this study and one species from previous study). The results indicated that: S. dawoensis was diplophyte with a karyotype formula of 2n = 2x = 24 = 20m + 2sm + 2st (asymmetry: 2A, AI: 3.09); S. indica was tetraploid with a karyotype formula of 2n = 4x = 48 = 48m (asymmetry: 1B, AI: 0.88); S. huguettiae was hexaploid with its karyotype formula of 2n = 6x = 72 = 72m (asymmetry: 1A, AI: 0.82). Furthermore, S. dawoensis has the highest value of AI and asymmetry coefficient among three species. Based on results of previous studies, we can speculate that the chromosome numbers of 2n = 24 should be a main character in Silene. The chromosome numbers and karyotype of three species of Silene provided first insights, which supplemented the plant cytological data of Qinghai-Tibet Plateau and cytological classification information for Silene. Taken together, this study will provide basis on illuminating the phylogenetic relationship of Caryophyllaceae in this region.

Abstract:Melon is a very important economically horticultural crop around the world. At present, andromonoecy is a widespread sexual system in traditional cultivar melon carrying both male and bisexual flowers, and andromonoecious maternal lines necessitate laborious hand emasculation for F1 hybrid seed production. Thus, gynoecious without emasculation will save labor cost and greatly?improve?the efficiency?of?hybrid?seed production, with?significant mean on improving the purity of hybrid seeds. Gynoecious melon plants are commonly genotypically designated as AAgg, and the phenotype-dependent selection of g recessive allele for breeding new gynoecious is slow and time-consuming. To accelerate the breeding of elite gynoecious lines, development of molecular markers linked to g allele might greatly contribute to the molecular marker assisted selection breeding. In this study, an allele-specific maker for g gene, g-FR, was developed based on a Gyno-hAT transposon on downstream of CmWIP1 locus. The sex phenotype and genotype of 141 F2 plants derived from hermaphrodite B15 and andromonoecious 054 was co-segregated based g-FR analysis. And the result was verified by two tightly linked molecular marker C5-9 and C5-10, which suggested that the accuracy of genotypic analysis of g-FR almost reaches to 100.0% in F2 population. Furthermore, we tested this newly-developed marker in genotyping of thirty-six melon accessions, and identified two bisexual genotypes B15 and B18. Taken together, these results will greatly facilitate the utilization of g gene in melon gynoecious breeding programs by marker-assisted selection.

Abstract:Selenocysteine methyltransferase (SMT) is a key enzyme of selenium metabolism pathway in plants and plays important roles in accumulating for selenium in plants. To investigate the function of SMT in Dioscorea Esculenta (Lour) Brukill, the full-length cDNA was cloned from Dioscorea Esculenta (Lour) Brukill Ds148 using reverse transcription-PCR (RT-PCR) technique. This gene was named DsSMT with a GeneBank accession number MH046782. The full-length open reading frame (OFR) of DsSMT was 1038bp that encoded 345 amino acids. The predicted molecular weight is 37.24 kD with the hypothetical isoelectric point of 5.01. DsSMT was highly conserved and grouped with the homologous proteins from Phoenix dactylifera and Ananas comosus. Wolf Psort protection indicated that DsSMT protein was located in cytoplasm. Real-time quantitative PCR (RT-qPCR) analysis revealed the transcripts of DsSMT in different tissues of Dioscorea Esculenta (Lour) Brukill, including roots, stems, leaves, tubers and the peel of tubers. The levels of DsSMT were different among different tissues, and the level was the highest in roots and mature period during the process of Dioscorea Esculenta (Lour) Brukill development, respectively. Furthermore, the expression level of DsSMT was obviously down-regulated during the enlargemental period, and then increased during the mature period. These results isolated the coding sequence of DsSMT gene and unlocked its expressional profiles, which provided a base in future study of molecular regulation mechanism on selenium metabolism in Dioscorea Esculenta (Lour) Brukill.