Abstract:Crop domestication has laid the fundamental basis of agricultural initiation and human civilization. Taking advantage of recent achievements on studies of crop domestication, this article reviewed the characterization of major domesticated-associated morphological traits, identification of important genomic segments, and isolation of domestication genes as well as the global spreading of cultivated crops post domestication. Furthermore, the advances on theoretical principals and fundamental methodologies as well current research focuses have been reviewed, and the future perspectives have been proposed.

Abstract:Landraces, which serve as important resources for germplasm innovation, are playing important roles in current and future breeding. In this review, the research achievements of landraces are summarized from the aspect of genetic diversity, application value of breeding, and methods of innovation and utilization. Prospects for future research and utilization of landraces have been made from the aspect of development trend, existing problem, and development directions.

Abstract:The superior and/or novel alleles (even rare alleles) for a particular trait are often detectable in crop germplasm resources. Exploration and application of allelic variations in crop genetic improvement is one of the tasks in the field of germplasm resources. Allele mining, which is an important tool in deciphering the genetic diversity, the origin and evolution, the molecular mechanism of important agriculture traits as well as germplasm innovation, etc., is the cornerstone of crop breeding by molecular design. There is a great demand on development of high-throughput, efficient allelic mining approaches, in order to accelerate the discovery of excellent alleles and their application in future crop improvement. For this purpose, here we review the major methods of the allelic discovery and propose the research priorities and focuses.

Abstract:Full-length transcriptome sequencing (Iso-Seq) is a technique method by deployment of the third generation sequencing (TGS) technology to obtain the full length sequence of mRNA. With the development of TGS technology which is represented by single molecule real-time (SMRT) sequencing, is becoming more and more mature, and it’s application advantages in genome and transcript de novo sequencing, full-length transcriptome sequencing technology has been widely used in animals, plants and microorganisms, and produced a large number of related data. In this paper, the principle of Iso-Seq technology and the applications of full-length transcriptome sequencing in model and non-model plants are reviewed, which aims to provide reference in analysis of full-length transcripts in plants.

Abstract:The PRRs family gene, which serves as a major component of the core clock of the circadian clock, plays important role in inhibiting the plant flowering, and manipulating ABA-dependent stress resistance and the accumulation of plant biomass. This article reviews the structural characteristics of the PRRs family genes, the photoperiod regulation model and its responses under stress treatments, in order to provide a theoretical reference for further study of the function of PRRs family genes and the cultivation of high-quality and broad-suit crop varieties.

Abstract:In order to elucidate the genetic diversity and population structure of superior rice species resources in the three gorges reservoir area, this study used 25 pairs of SSR polymorphism molecular markers to analyze the genetic diversity and population structure of 81 superior rice species resources, which were collected from different geographical sources and types in the three gorges reservoir area. The results showed that the above markers could effectively identify the level of genetic diversity of the tested materials. A total of 56 alleles were detected, and the number of alleles detected at each locus was 2~ 5, with an average of 2.44; The number of effective alleles varied from 1.077 to 2.582, with an average of 1.757; the polymorphism information (PIC) ranged from 0.069 to 0.539, with an average of 0.332; the Shannon index ranged from0. 158 to 1.017, with an average of 0.625; and the Nei's gene diversity index ranged from 0.071 to 0.665, with an average of 0.407. Further analysis showed that the average effective allele number of landrace was higher than that of cultivars, while the average allele number and Shannon index of cultivars were higher than that of landrace. However both of them are very similar in terms of gene diversity index, polymorphic information content and expected heterozygosity. By the cluster analysis, population structure analysis and principal coordinate analysis, the tested materials were roughly assigned to two groups. The regional law of the aggregation of various groups was not obvious, and the clustering relationship of varieties was relatively complex. The results of molecular variance analysis showed that the variation between populations was the same as that between varieties, and the variation between populations and varieties was the source of variation.

Abstract:Pythium stalk rot is a serious disease that threats the maize production. Exploration of the resistance maize germplasm resources to this disease will benefit for noval genes mining and the determination of heterosis patterns. Within this study, fourteen molecular markers linked to eight stalk rot resistance genes were used for genotyping 196 resistant maize germplasm accessions. Moreover, 42 polymorphic SSR makers were adopted in genetic diversity analysis of 54 selected resistant maize lines. A total of 128 resistance marker genotypes were identified with the eight functional markers. Out of 196 accessions, 191 exhibited one or more of fragments being identical with these of Qi319, X178 or 1145. No fragments were detected in five germplasm accessions (Yue61, Zheng653, Chi L136, Bai53, and 18--14), suggsting that these five germplasm might harbor other maize stalk rot resistance gene(s). By deployment of 42 SSR primers, 119 alleles were amplified in 54 selected lines, with polymorphic site percentage (PPB) of 99.17%. The average number of alleles (Na), effective number of alleles (Ne), Nei's gene diversity (H), and Shannon’s information index (I) were 2.86, 1.7070, 0.3999, and 0.5884, respectively. The value of polymorphism information content (PIC) for each marker varied from 0.2061 to 0.7844, with an average of 0.5527. The UPGMA analysis classified 54 inbred lines into 2 groups and 6 subgroups with relatively high genetic diversity, including Lüda red cob (LRC), BSSS, Tang si ping tou (TSPT), PA, PB and Lancaster. Taken together, the results revealed variable resources with resistance to stalk rot in six heterosis groups, among which the most resistance germplasms were found in PA subgroup.

Abstract:Unlocking disease resistance to exotic maize germplasm is the basis and premise for the fully utilization of germplasm and breeding ofresistant varieties. In this study, resistance evaluation of 149 American inbred lines to maize stalk rots induced by four different pathogens, including Fusarium graminearum, F. verticillioides, F. proliferatum and Pythium aristosporum, were conducted by artificial inoculation in continuous two years from 2017 to 2018. And, 30 resistant materials and six backbone inbred lines were selected for genetic diversity analysis. The results showed that among the 149 American inbred lines, 62, 44, 41, and 54 materials exhibited moderate resistance (MR) or higher resistance levels to maize stalk rots caused by F. graminearum, F. verticillioides, F. proliferatum and P. aristosporum, respectively. There were 23 inbred lines showing high resistance (HR) for all four stalk rots, 32 inbred lines showing MR or higher resistance levels for all four stalk rots, and 27 inbred lines showing HR for three Fusarium stalk rots. Among the tested materials, 88 inbred lines showed the same level of resistance to all four stalk rots, 61 inbred lines had different resistance to all four stalk rots. Twenty polymorphic primers were screened, and 5~11 alleles were detected with each primer, and the average allelic variation was 7.7. Thirty-six materials were divided into 6 groups by cluster analysis, Among them, 2FACC, J8608 and Huangzaosi were separately clustered into three groups, and the other inbred lines were divided into three groups, each group consisting of 26, 5 and 2 inbred lines, and the first group was further divided into three subgroups. The results of this study clarified the differences in resistance of exotic American inbred lines to maize stalk rot caused by different pathogens, and provided a reference for the selection of resistant sources in resistance breeding.

Abstract:Fagopyrum cymosum is a perennial herb of the family Polygonaceae, which has a very high medicinal value because its swollen stems are rich in flavonoids. Wild Fagopyrum cymosum is widely distributed in China, especially in southwestern areas such as Yunnan, Guizhou, Sichuan. Our research group conducted a 20-day study in Yunnan and collected wild Fagopyrum cymosum resources from 14 different regions in Lijiang, Dali and Kunming. There were some differences in the plant or fruit morphology of wild golden buckwheat in different regions, which may be related to the geographical environment and climatic conditions. The contents of total flavonoids, rutin and quercetin in the swollen stems of wild golden buckwheat were measured by spectrophotometry and high performance liquid chromatography (HPLC). Results showed that the flavonoid contents of the swollen stems from different regions were remarkably different. Using ITS and matK molecular markers, genetic diversity and genetic relationship analysis were carried out, and it was found that the classification had a significant relationship with regional altitude.

Abstract:Shiwandashan Mountain in Guangxi is an important area with abundant biodiversity. Surveying the diversity of Crop Germplasm Resources in this area is of great significance in protection and exploration of local crop germplasm/gene resources. By use of 181 germplasm resources, which were collected in a frame of the Third National Survey and Collection Action on Crop, the clarification of species, geographic distribution and biodiversity were investigated. These germplasm accessions were clarified in 48 species, 39 genera and 22 families. That included 78 feeding grain crops, 53 industrial crops, 39 vegetables and 11 fruit trees, including 146 local landraces and 35 wild accessions. Due to the unbalanced industrial development and adjustment of modern crop planting structure, the distribution and biodiversity of crop germplasm resource in Shiwandashan Mountain are constantly decreasing and many excellent germplasm resources are rarely found. These findings suggested a strategy on ectopic conservation and original habitat protection, which might promote the sustainable utilization of local excellent germplasm resources valuable for Rural Revitalization and economic construction.

Abstract:Ecological immigration may produce significant impacts on the traditional edible plants resources and knowledge for using them by the local communities. In this study, semi-structure interviews, voucher specimen collection and identification, and Jaccard index quantitative analysis were deployed for surveying the utilization of traditional edible plants and their related knowledge in the ecological immigrant villages and their traceable villages in Hongsipu District of Ningxia Autonomous Region. The results showed that: (1) 106 traditional edible plants were found in the six survey villages, including 17 species in eight families for traditional food crops, 44 species in 16 families for traditional cultivated fruits and vegetables, and 45 species of wild edible plants belonging to 22 families. The traditional edible plants in the immigrant villages are decreasing if compared to those of the traceabile villages. (2) The immigrants to Hongsipu from different sources of forest area, loess hilly area and semi-arid desertification area, are different in their knowledge in traditionally using the edible plants. The smaller the difference between the immigrants' immigration location and the traceable ecological environment, the higher the retention of traditional edible plant knowledge. (3) Traditional edible plants retained by immigrants in three different types of areas are closely related to traditional food culture. Traditional culture plays an important role in promoting the conservation of farmer germplasm resources. In this study, the similarities and differences in the resources of traditional edible plants in different villages is deeply discussed, the quantitative research of traditional edible plants is explored, and suggestions for the protection and inheritance of traditional edible plant knowledge of ecological immigrants are presented. Thus, the research results can provide a reference being valuable for regional biodiversity management and sustainable development.

Abstract:To clarify the distribution status of Pi-ta, Pi-b, Pi54, Pikm genes and their effects on the resistance of rice blast in Huang-Huai-Hai Region, 88 rice varieties collected from this region were detected using the functional markers that specifically target to the four genes. The genetic frequency of Pib+Pi54 was 60.2% within this collection..In parallel, this collection was subjected to test for resistance by natural infection and artificial injection in 2016 and 2017. 87.5% and 77.3% of varieties were susceptible in two years, respectively. This result suggested that the effects of resistant genes were declined. Four genes or gene combinations (Pi-ta, Pi-ta+Pi-b, Pi-ta+Pi-b+Pi54 and Pi-ta+Pi-b+Pi54+Pikm) are applicable in the rice-breeding, due to the resistance to rice blast but with low distribution in the tested varieties. Taken together, the results raised a positive strategy for breeding rice cultivars with rice blast-resistance.

Abstract:In the present study, 113 peanut varieties in Northern China and 40 key breeding parental lines were subjected for molecular genotyping, by using 57 SSR markers and 6 AhTEtransposable element markers which come from 3964 candidate primers. Out of 267 detected alleles, 209 alleles showed polymorphisms with the polymorphic ratio of 78.28% . The PIC of all the primers ranged from 0.0754 to 0.9217 with an average of 0.713 4. Subsequently, when GS (genetic similarity coefficient) = 0.62, the cluster analysis partitioned two groups including I (including 2 sub-groups, GS=0.6786) and II (including 13 sub-groups, GS=0.7674). When GS was 0.98 9, a total of 153 peanut cultivars were separated by 63 core primer pairs, and a DNA fingerprint database was established. By tracing the source of varieties, Fuhuasheng, Shitouqi, and Muyangdazhanyang as main backbone parents of peanut cultivars in Northern China, were dissected by calculating the genetic contribution value and the number of derived varieties of the backbone parents. Among them, the genetic contribution of Fuhuasheng was the largest (18.26% ), and the most derivative species (75 cultivars), while the ratio of derivatives in Henan, Hebei and Shandong provinces were 65.12 %, 70.83 %, and 72.73 %, respectively. The ratio of derivatives was positively correlated with the genetic contribution value. Thus, this study will provide a theoretical basis on the molecular identification of peanut cultivars (lines) in Northern China, which might be valuable on the guidance of classifying peanut pedigree.

Abstract:The phenotype of reciprocal-crossing F1 was affected by cytoplasmic genome. Interestingly, no reproductive isolation was detected using Cucurbita maxima x Cucurbita moschata, but the sterility was observed using C. moschata x C. maxima (reciprocal cross). This phenomenon restricted the research on cytoplasm genetic effect of reciprocal-crossing in C. moschata and C. maxima as well as the transformation progress of cytoplasmic genome in C. moschata. In this study, MO (C. moschata, inbred line with disease resistance) and MA (C. maxima, core parent line) were selected to make inter-specific crosses. The immature embryo of MO×MA was cultured and the suitable cultural period, sterilizing procedure and culture medium were selected. The hybrid reliability of 6 regenerated plants (E0) was identified by co-dominant SSR markers. The results showed that the suitable cultural period of the immature embryo of MO×MA was 25 days post pollination. Under the lab condition, the immature embryos were removed from seeds carefully and soaked using 2% NaClO for 5 min to remove the endotesta. Then the embryos were moved into super-clean worktable, surface sterilized in 75% (v/v) ethanol for 30s, followed by immersion in 2% NaClO for 5 min, and rinsed with sterile distilled water 3 times. This sterilization pipeline showed the lowest contamination rate (39%), highest germination rate (24%) and convenient operation. The immature embryos on the No.8 culture medium (MS + 3.0 mg/L 6-BA + 0.5 mg/L 2,4-D + 0.2 mg/L NAA + 20g/L sugar + 0.68% agar) resulted in the highest embryos germination rate of 25%. The effect of 3-day initial incubation in dark on the MO×MA immature embryo culture was also tested, but no visible difference was detected. By marker-assisted identification using 23 and 8 co-dominant SSR markers, these six E0 regenerations of MO×MA were the real hybrid and could be used for further cytoplasm genome transfer of C. moschata.

Abstract:In recent years, the new varieties breeding of common bean has been developing rapidly, and the number of new varieties and applications for Plant Variety Protection (PVP) has been increasing. In order to protect the legitimate rights and interests of breeders, regulate the seed market and improve the efficiency of the seed market supervision, this study intends to establish common bean identification system based on a set of SSR molecular markers. Firstly, 12 common bean varieties with different origins and botanical morphology were selected, and 120 SSR markers with high polymorphism and clear bands were screened by polyacrylamide gel electrophoresis. Then, 33 SSR core markers with even distribution, high polymorphism and stable peak pattern were obtained in 96 common bean varieties by fluorescence capillary electrophoresis. On this basis, the core markers were grouped according to the length of amplified fragments and the color of fluorescent markers, and reference varieties were set to correct the errors between different experimental batches and platforms. A variety identification system based on SSR markers was thus established. Meanwhile, a fingerprint database was constructed for 161 common beans for which plant variety protection was applied or which are protected varieties or dominant varieties or landraces. 140 varieties can be distinguished by the set of core markers, and the average genetic similarity coefficient is 0.33, showing a high genetic diversity of those varieties. 21 varieties that are not distinguished share high similarities in terms of origin, parentage and botanical characters, but they could still be recognized by some traits. The result indicates that the set of core markers are effective in aiding screening of similar varieties. The identification system of common bean based on SSR molecular markers established in this study will provide strong support for variety identification and for assisting selection of similar varieties in DUS tests.

Abstract:Safflower (Carthamus tinotorius L.), which serves as an important oil crop, contains higher content of the unsaturated fatty acids. Forty-eight SSR markers were used to unlock the genetic diversity and the population structure of 74 safflower germplasm resources from 27 countries. The association analysis using the general linear model (GLM) and the mixed linear model (MLM) was conducted to identify the molecular markers associated with oil-related traits. The results showed that the polymorphism information content (PIC) value ranged from 0.0632 to 0.3750, with an average of 0.2937, and the genetic diversity index ranged from 0.0653 to 0.5000, with an average of 0.3700. The cluster analysis using UPGMA assigned 74 safflowers into 3 groups, including 7, 52 and 15 genotypes, respectively. The population structure analysis suggested three subgroups consisting of 7, 55 and 12 genotypes, respectively. At a significant level of p < 0.05, 18 markers associated with oil-related traits were detected by either GLM or MLM models, which explained the phenotypic variation with a range of 5.42 % to 20.69 % and 4.35 % to 20.69 %, respectively. Out of that, twenty eighteen markers, except for Ct589 and Ct178, were detected by both approaches. Taken together, this study suggested an abundant genetic diversity and revealed several markers associating with oil-related traits, which provided the marker resource in future breeding for high-oil content safflower.

Abstract:The rice cultivars Ningnong black carp and high indica rice exhibited low and high content on γ-aminobutyric acid, respectively. Both genotypes were deployed for generating a F2 population that comprises of 216 individual plants. By taking use of 130 polymorphic SSR markers, a linkage map was produced with an length of 2406.9 cM. Each linkage group expands from 129.5 to 360.7 cM, and a mean distance between markers was 18.5 cM. The QTL mapping positioning study showed that seven QTL loci controlling the γ-aminobutyric acid content were found on chromosomes 8 and 9, respectively. The contribution rate of qGABA8-2, qGABA8-3, qGABA9-1 was 10%, 11% and 9%, respectively. The composite interval mapping was performed on three QTL sites with large contribution rate. When LRS was 25.6, a QTL qGABA8 was initially found at RM342-RM515 in an interval of 326Kb. The confidence interval was further delimited to 180 kb by using the InDel marker G121. Therefore, the accumulated results of this study might be useful in further gene isolation and marker-assisted screening for the genotypes with the enriched amino butyric acid.

Abstract:In flowering plants, 14-3-3 protein plays an important regulatory role in plant growth and development. In this experiment, a 14-3-3 protein family gene Lb14-3-3c was cloned from the anther of Ningqi No.1 by reverse transcription PCR (RT-PCR). The expression characteristics of Lb14-3-3c gene in different stages of anther development were analyzed by real-time PCR. The plant over-expression vector pCambia1305.1-35s-Lb14-3-3c(+) of Lb14-3-3c gene and plant inhibition were constructed. The vectors were transformed into Agrobacterium GV3101 by freeze-thaw method, and then transformed into Astragalus membranaceus by Agrobacterium-mediated transformation. The expression of Lb14-3-3c gene in positive transformed seedlings and leaf starch content were analyzed. Bioinformatics analysis showed that the complete open reading frame (ORF) of Lb14-3-3c gene is 777bp long and has a conserved domain of 14-3-3 protein family. The molecular weight of the protein is 64.14 kD and the isoelectric point is 4.95. The grade structure is mainly α-helix. The amino acid sequence has a similarity to tobacco 14-3-3c-1 of 90.04%. The protein encoded by Lb14-3-3c gene is on the same branch of tomato as the phylogenetic tree, and has the closest relationship. Real-time PCR analysis showed that the gene was expressed in all organs of the sputum, and the expression was highest in the stamens. It is expressed in all stages of anther development and has the highest expression during microspore mother cell. The exogenous gene Lb14-3-3c was successfully loaded into the plant expression vector containing the strong promoter CaMV35s, and the plant overexpression vector of the gene was transformed into potato. Five transgenic plants were identified by phenotypic observation and PCR positive identification. The growth rate of transgenic plants was better than that of wild-type plants. The content of wild-type and transgenic starch in seedling stage was similar. The starch content of transgenic potato in potato and mature stage was higher than that in wild type. This study provides a reference for the further study of Lb14-3-3c gene regulation of starch supply during the development of anthers, and provides a demonstration of the function of Lb14-3-3c gene during plant development and molecular genetic improvement.

Abstract:The cultivated soybean varieties are moderate tolerant under salt stress, but soil salinization seriously threats thesoybean yield and quality. Characterization of the salt-tolerant genes might be suitable for the genetic improvement of salt tolerance. In eukaryotes, transcription factor IIIC (TFIIIC) generally interacts with transcription factor IIIB (TFIIIB) on RNA polymerase III to regulate tRNA gene transcription, which in turn affects protein synthesis. In our previous study, we found that TFIIIC was up-regulated in soybean root under salt stress. However, the gene function of GmTFIIIC remains unknown under high salinity stress. In this study, we characterized the GmTFIIIC function in transgenic complex, in which the GmTFIIIC over-expression was conducted by transforming the soybean hairy roots. The results showed that the Na+/K+ of roots and shoots in the GmTFIIIC overexpression complex were lower than that in the vacant control complex. While the relative content of chlorophyll and water in leaves was higher, and the content of H2O2 and O2- was lower than that of the vacant control complex, which indicates that the salt tolerance in transgenic complex is enhanced by GmTFIIIC overexpression. Thus, the results might contribute to a better understanding of the molecular mechanism of GmTFIIIC in responding to salt stress.

Abstract:MYB transcription factors are widely involved in the regulation of plant growth and development, and they also play important roles in secondary metabolism. In our previous study, the transcription factor TrMYB308 related to flavonoid synthesis was identified by RNA-Seq in V-type purple white clover. Based on these results, the coding sequence (CDS) of TrMYB308 gene was cloned with a length of 921bp, encoding for 306 amino acid residues. Subcellular localization analysis indicated that TrMYB308 was localized to the nucleus. Multiple sequence alignment and phylogenetic analysis indicated that TrMYB308 protein belongs to a typical R2R3-MYB transcription factor subfamily and shows sequence close similarity to TaMYB308 from Trifolium pretense and MtMYB308 from Medicago sativa. Expression analyses revealed that the transcripts of TrMYB3 were detected in all tissues and inducible under JA treatment. Heterologous expression of TrMYB308 in tartary buckwheat hairy root resulted in significant transcriptional elevation of flavonoid metabolic pathway key enzyme genes (FtF3H, FtFLS). Consistently, the content of total flavonoids in transgenic roots was significantly increased if compared to that of the non-transgenic roots. Hence, we speculated that TrMYB308 is involved in the regulation of secondary metabolic biosynthesis of flavonoids. These results provided a theoretical foundation for the genetic improvement of flavonoid content in buckwheat.

Abstract:Huanglv group germplasm is an important landrace and exhibits well adaption in China. Great effort had been taken in the improvement and innovation of Huanggai and Lvdahonggu germplasm by enriching favorable alleles or introducing exotic germplasm decent since 1980s and 1990s, which contributed a lot for maize hybrids breeding in our country. Mechanical grain harvesting is the inevitable trend of maize production, therefore, it’s essential to improve agronomic traits that related Mechanical grain harvesting, for example moisture content, lodging resistance and stalk rot resistance. In this study, both male and female parental European early-maturing inbred lines, UH004F and UH004M (UH004F: male, Hard-gained maize; UH004M: female, Iodent maize), were used to purposefully improve the mechanical grain harvest related traits of Huanglv group germplasm, and finally we got some nearly homozygous inbred lines(named after Huanglv-European lines, HE lines) by modified pedigree selection and recurrent selection. The major research is: (1) The days to tasseling, days to silking and growth period decreased and exhibited considerable early-maturity. Anthesis-to-Silking Interval (ASI), Plant height, Tassel length, Internode length above ear, Ear length, Kernel length and Seed production rate showed an increasing trend. While Ear height, Stalk diameter, Kernel row number, Ear diameter, Cob diameter and Kernels weight per ear exhibited a reversed trend. Meanwhile, we observed that the introgressive lines perform well on lodging and conversion resistance. In terms of Hundred kernels weight, all the improved subgroups except Chang7-2 subgroup have lower moisture content compared with unimproved subgroups. The tassel branch number ranged from 6 to 9 and did not show an unique trend before and after improvement. (2) The introgression of 25% and 50% European early-maturing hard-grained male parent population and European early-maturing Iodent female parent population into the progeny lines of Huanglv Group showed a certain trend in most traits, which mainly manifested in the earlier Days to tasseling, days to silking and growth period; the increase of ASI value, the increase of Plant height,, the decrease of Ear height, the increase of Tassel length, the increase of Tassel branch number and Stalk diameter, the elongation of Internode length above ear. The trend of Lodging rate, Ear length, Kernel row number, Ear diameter, Cob diameter, Hundred kernels weight, Kernels weight per ear, and Moisture at harvest were improved. All the other traits mentioned above were further enhanced when 50% of the male parent population was introduced into European early-maturing hard grain germplasm, which indicated that the male parent population contained favorable alleles controlling mechanical grain harvest traits which were more suitable for innovative improvement of Huanglv population. The early-maturity European germplasm contained excellent alleles suitable for mechanical grain harvest. The visible achievements on improvement of mechanical grain harvest traits could provide theoretical guidance for subsequent large-scale breeding and application of Huanglv population.

Abstract:The ecological adaptability of rice varieties to the diverse environments is closely associated with the yield andlocal-adaptability. In order to identify the rice varieties with strong adaptability, 284 historic and modern rice varieties, which were collected from Heilongjiang, Jilin, Liaoning, Ningxia, Xinjiang of China and Japan, were deployed to clarify the phenotypic variations under multiple environmental conditions. Seven agronomic traits including days to heading, plant height, panicle length, panicles per plant, grains per panicle, seed setting rate and 1000-grain weight were determined at six identification sites (Shenyang, Beijing, Yinchuan, Linyi, Nanchang and Sanya). The phenotypic variations of these agronomic traits were visible at diverse locations. For instance, the phenotypic values were constantly decreased from Shenyang with higher latitude to Nanchang with lower latitude, but they were increased in Sanya winter environment. In relative to the varieties in years-I that were released before1960, the modern cultivars in years-IV (released after2000) showed the prolonged growth period, the reduction of plant height and panicle number, the elevation of grains per panicle, as well as no significant differences on seed setting rate and 1000-grain weight. Overall, the rice traits changed from multi-panicle type to large-panicle and heavy-panicle type. The genetic relationships among the varieties from Heilongjiang, Jilin and Japanwere relatively closer, while that between varieties from Liaoning and other regions including Heilongjiang, Jilin and Japan were relatively further. The genetic relationship between the varieties in years-II (released during 1960-1970's) and years-III (released during 1980-1990's) was relatively closer, followed by that between the varieties in years-II, years-III and years-I, and that between the varieties in years-IV and other years' were relatively further. Under multiple environmental conditions, the phenotypic values of 1000-grain weight, panicle length and panicle number were relatively stable, followed by days to heading, plant height, seed setting rate and grains per panicle. The stability parameter of days to heading was observed to be significantly positively correlated with that of plant height, panicle length and panicle number. The stability parameter of plant height was positively related to that of panicle length, grains per panicle and 1000-grain weight. The stability parameter of days to heading in varieties released over decades was variable (years-I >years-II >years-IV >years-III). An improved ecological adaptability was observed in the modern varieties, in contrast to the historical varieties that were released few decades ago. Twenty varieties (e.g. Liaojing 931, Liaojing 454) showed better local-adaptability under multiple environments, thus being valuable in breeding for new rice varieties with broad adaptability.

Abstract:Abstract: Soybean is an important source of vegetable protein, and innovation of high-protein soybean germplasm becomes of importance in breeding for elite soybean varieties and exploring the underlying mechanism. In order to obtain the high-protein soybean germplasm resources, the protein content of EMS mutagenized "Zp661" M2 population were measured following the NIR (Near-Infrared Reflectance) method, and the subsets of selected offspring lines were further investigated. The results showed that the protein content of 1971 M2 seeds ranged from 34.96% to 50.16% with an average of 42.97%, being 5.11% higher than wild type (40.88%). The protein content in 17.65% of tested M2 samples was higher than 45%. The mutants with high protein content showed a constant reduction in offspring lines in each of generations, whereas an increasing protein content was also observed in offspring lines of M2 mutants with low-protein content. Notably, we identified nine high protein M7 homozygous mutants (m1 ~ m9) with a mean of 48.17%, which were 16.94% higher than wild type (41.19%), with an increased 7.23% genetic gain. The mutants m1 to m7 were derived from sergeants of the M2 high-protein content mutant 20722 (47.21%), while m8 and m9 were derived from the M2 low protein content mutant 3442 (38.51%). Furthermore, that protein content in m2, m4 and m5 was found to be significantly positively correlated with 100-seed weight and single plant seed yield. Thus, the findings implied no negative correlation between protein content and yield production in some of mutants, and these germplasm resources might become valuable in future breeding for soybean varieties with simultaneous high-yield and high-quality.

Abstract:Lodging is one of the main problems affecting the maize production and extension. In this study, 181 maize inbred lines were used for determining 22 characters associating to lodging resistance. Statistical analysis using the correlation analysis, the principal component analysis, the cluster analysis, the stepwise discriminate analysis and the ridge regression analysis was deployed for data interpretation. The results of the correlation analysis showed that 22 characters existed in varying degrees of correlation. The first seven principal components explained 74.460% of the phenotypic variation with the contribution rates of 25.700%, 12.369%, 9.782%, 8.159%, 7.782%, 5.490% and 5.177%. Four categories were clustered in the 181 maize inbred lines at a genetic distance of 3.5. Among them, the first classⅠhas 35 inbred lines, the classⅡhas 47 inbred lines, the class Ⅲ has 49 inbred lines, the class Ⅳ has 50 inbred lines. The result of stepwise discriminant analysis showed that 175 maize inbred lines were correctly discriminated and the identification rate was 96.69%. Six maize inbred lines were incorrectly discriminated and the identification rate was 3.31%, which means that the result of cluster analysis is accurate and reliable. The hemicellulose content, rind penetrometer strength, third internode length, third internode diameter, ear height and area of total vascular bundles were selected and the regression model of lodging resistance of maize inbred line was established by using the ridge regression method. 35 inbred lines, such as AHU 24, e220 and 7026B, showed the highest lodging resistance. Thus, the results provided a reference of the maize lodging resistant germplasm resources, which become valuable in selection of elite germplasm resources in breeding for the lodging resistance hybrids.

Abstract:Polyploid breeding is an efficient method for breeding new varieties in rubber trees (Hevea brasiliensis Müll. Arg.). In order to reveal the genetic origin of 14 tetraploid lines, 25 simple sequence repeat markers were subjected for analyzing the diversity within this study. The leaf anatomy structure of diploid, triploid and tetraploid lines were analyzed using two section methods to evaluate the difference between ploidy. As a result, all 14 tetraploids are derived from the same clone or full siblings, and the diploid line Reyan73397 serves as one of the parental lines. The thickness of the leaves, upper epidermis, palisade tissue and sponge tissue between the diploid, triploid and tetraploid of the rubber tree was significantly different and increased with the increasing of the ploidy. The thickness of diploid, triploid and tetraploid fresh leaves are 122.63~195.68μm, 163.49~232.96μm, 169.16~239.30μm, and the thickness of the paraffin leaves are 110.04~161.18μm, 140.34~198.59μm and 136.78~240.95μm respectively. The demarcation of fresh leaf thickness of 177.81 μm or the paraffin wax thickness of 160.70 μm can be used to identify tetraploid from mixed population of diploid and tetraploid. The rank of Cell Tense Ratio and Palisade tissue /Spongy tissue ratio in different ploidy was as follows:triploid＞tetraploid ＞diploid, the rank of Spongy Ratio in different ploidy was as follows: diploid＞tetraploid＞ triploid. Takentogether, the findings derived from this study are valuable for clarifying the polyploidy resources and future breeding in polyploidy rubber trees.

Abstract:In this study, the core collection of cucumber germplasm accessions were used to evaluate low-temperature tolerance at seedling stage, and the candidate genes were identified via genome-wide association analysis. Two-mature-leaf seedling plants were exposed under low temperature conditions (12℃ or 19.3℃) for 14 days and 11 days, respectively. The classification of low-temperature tolerance was conducted based on the chilling injury index (CII) of cotyledons and true leaves. After treatments, the difference of seedlings was significant, and the coefficient of variation under two environmental conditions were 23.2% and 31.7%, respectively. These accessions were divided into four groups according to CII. Four accessions (CG45, CG61, CG88 and CG104) were shown to be tolerant under low-temperature stress. The genome-wide association mapping of low temperature tolerance identified four loci including gLTS1.1, gLTS3.1, gLTS4.1 and gLTS5.1 that were assigned to the chromosomes 1, 3, 4 and 5 respectively. Among them, the locus gLTS5.1 can be detected repeatedly. Thus, this work provided insight for identifying low-temperature tolerant cucumber germplasm and unlocking the functional genes in future.

Abstract:A calcium-dependent protein kinase gene (CDPK) was isolated from the Cypripedium macranthum roots using reverse transcription-PCR (RT-PCR) and rapid amplification of cDNA ends (RACE) techniques. The full-length fragment of CmCDPK gene was 2079 bp, with a complete open reading frame of 1491 bp, which encodes for 496 amino acids. CmCDPK was predicted to be a stable hydrophilic protein, possessing a typical and conserved serine/threonine protein kinase domain and a transmembrane structure domain. Secondary structure of CmCDPK is abundant in α-helices and random coils. By phylogenetic tree analysis, CmCDPK were clustered with CDPKs from Orchidaceae, such as Phalaenopsis equestris and Dendrobium catenatum. The fragment of interest was subsequently cloned into the pBI121 vector, which was verified by colony PCR, restriction enzyme digestion and Sanger sequencing. Taken together, this work isolated a CDPK gene from C. macranthum and generated the plant binary expression vector, which might provide the possibility for making transformation in tobacco and further illustrating the biological function of CmCDPK.

Abstract:Using the NPR1 gene family member’s protein sequences from Arabidopsis as query, MaNPR1 gene family members were identified in the banana A genome database, and these features using bioinformatics methods and the expression upon infection with Foc TR4 were further investigated. In total, 15 family members were identified, designated MaNPR1-MaNPR15. Physicochemical properties, conserved functional domain, essential amino acid residues and motif analysis results of MaNPR1 gene family are highly consistent with those of other species. The classification of phylogenetic tree, gene structure and functional domain suggested a functional specificity among members of the MaNPR1 gene family. The interspecific phylogenetic tree showed that the MaNPR1 gene family were divided into three subgroups, co-residing with respective Arabidopsis NPR1 members in each group. The predominant-cultivating banana variety ' Cavendish ' (Musa acuminata L.AAA group) was highly susceptible to fusarium wilt caused by Fusarium oxysporum f. sp. Cubense Tropical Race 4（Foc TR4）. By analyzing the transcriptome dataset from root transcriptome data of infected and un-infected Brazilian samples, eight differentially expressed MaNPR1 genes were identified, which were further tested by RT-qPCR in ‘Cavendish’ and the resistant variety ‘GCTCV-119’. Two members MaNPR4 and MaNPR11 showed an increasing transcriptional levels at time-points in ‘GCTCV-119’, in relative to the constant reduction in ‘Cavendish’. That indicated an involvement of MaNPR4 and MaNPR11 in responses to fusarium wilt. Taken together, this study raised a potential in breeding for fusarium wilt resistance banana by use of NPR1 genes.