Abstract:Plant height is one of the important agronomic traits and controlled by a consequence interacting among the genetic factors, the endogenous hormones and external environment. In common wheat, plant height is recognized as a quantitative trait modulated by multiple genes that are found on 21 chromosomes. Several molecular markers associating with plant height are available for marker-assisted breeding. The important progress on determining the genetic factors, genetic localization and gene isolation, regulation mechanism and marker assisted selection have been achieved. This paper summarizes the factors that contribute to wheat plant height, as well as the achievements on genetic localization, gene cloning, allelic mining, marker-assisted wheat breeding, followed by the prospective on future focuses in wheat.

Abstract:miR397 is one of the conserved miRNAs in plants. In different plants, the miR397 family is mostly composed of one to three members. Through regulating the laccase gene and other genes, miR397 is widely involved in regulating plant growth, development, and stress responses, thus affecting important economic traits such as seed yield and fruit quality. Therefore, as a target gene of molecular breeding, miR397 has great application potential in plant genetic improvement. In this article, the distribution of miR397 in plants, the identification of target genes of miR397, and the regulating roles of miR397 in plant growth, development, and stress responses were reviewed, and the problems that remain to be solved are pointed out, which provides a reference for the application of miR397 in plant genetic improvement.

Abstract:Brassica napus had been cultivated in China since 1930s, but the Chinese modern cultivars represented a narrow genetic basis. In order to enrich the genetic diversity in gene pool, distant hybridizations with relative species have been conducted. This paper summarizes recent advances on distant hybridization in Brassica napus with other Cruciferae plants. These novel germplasm resources showing early maturation, yellow seed or disease resistance, have been generated by inter-species hybridization in genus Brassica. The elite alleles on traits of drought resistance, cold resistance or milky white flower, which were identified from other genus, have been introgressed into Brassica napus. We further proposed the focus on distant hybridization in Brassica napus in future.

Abstract:Fusarium wilt is one of the important diseases in common bean production in China. This article reviews the progress on classification of the pathogen causing Fusarium wilt and its infection cycle, control measures, germplasm resource identification and the genetic analysis for resistance. However, the understanding on Fusarium wilt is largely limited. For example, the resistance germplasm resource and genetic genes are scarce, and the molecular mechanism of genetic resistance is blank. To achieve the resistance breeding against Fusarium wilt, there is a demand to identify the resistance germplasm resource, explore the resistance genes or allelic variants, as well as decipher the molecular mechanism of genetic resistance in common bean.

Abstract:Solanaceae crops are economically important, but they are not suitable to be cultivated in high density and consume a large amount of water and fertilizer for their large plants. It has been well known that phytohormones play an important role in regulating plant height via modulating cell division and cell elongation. Accordingly, mining dwarf genes and creating dwarf germplasm have been the important base for improvement of plant architecture in Solanaceae crops. Here we firstly summarized the biological function of the phytohormones modulating plant height, furthermore emphasized the mechanism of hormone-related dwarf mutation in Solanaceae crops. Finially proposed a simple and efficient strategy of gene mining and utilization by modern molecular biological technique based on dwarf mutant.

Abstract:Drought stress can induce autophagy in plant cells，and plants can remove some harmful substances through autophagy，with the result of increasing their drought resistance. In this study，droughtresistant wheat cultivars Pingmai 189 and Luohan 6 Hao，and drought-vulnerable wheat cultivars Linmai 2 Hao and Shannong Youmai 3 Hao were used as materials. It was found that under drought stress the expression of autophagy-related genes 6 and 8（ATG6，ATG8，autophagy related gene 6/8），the formation of ATG8-PE（phosphatidylethanolamine）and the number of autophagic vacuoles increased slowly in the drought-tolerant cultivars，but increased sharply first and then decreased in the drought-vulnerable cultivars，as detected through the use of lysosome fluorescence probe，Western blot，transmission electron microscope and other molecular biological techniques. The slow yet long-lasting autophagy response of the drought resistant wheat to drought stress slowed down the speed of the seedling wilting，while the fast yet short lasting autophagy response of the drought-vulnerable wheat to drought stress speeded up the seedling wilting. This study provides a theoretical basis for further elucidating the molecular mechanism of drought resistance，screening drought-resistant wheat germplasm resources and breeding new drought-resistant wheat

Abstract:In order to study the genetic diversity and the genetic background of quinoa (Chenopodium quinoa Willd.) germplasms distributed in China, molecular markers research was carried out based on 163 quinoa accessions and 3 djulis (Chenopodium formosanum Koidz.) accessions by using 66 simple repeat sequence (SSR) markers, to analyze the polymorphism and inter-species relationship. According to the data, a total of 327 alleles were amplified from 66 SSR markers, with an average of 5.031 alleles per marker. The mean values of observed and expected heterozygosity were 0.387 and 0.588, respectively, while the mean values of the polymorphism information index was 0.524. The method of UPGMA clustered all the accessions into three groups. Group I included 3 djulis accessions only. Group II included 103 accessions, most of which were derived from USDA-NPGS and Chilean types. Group III included 60 accessions, most of which were derived from Bolivian and Peru types. The quinoa population was divided into two groups by population structure analysis and principal component analysis, and there was gene exchange between the two groups. The results indicate that there is a clear distinction between Bolivian, Peru accessions and American, Chilean accessions in genetic information, and the genetic relationship of the accessions from Qinghai and Yunnan are closer to Andean highland type, while the accessions from Hebei and Shanxi are closer to Chilean lowland type. Djulis is a native plant in Taiwan.

Abstract:Lodging affects the production and transportation of photosynthetic products, molding and germination of seed, which aggravates the occurrence of diseases and insect pests, and reduces the quality and yield of grains. Usually, lodging resistance is influenced by plant height, stem structure and cultivation conditions. ‘Yuenong Simiao’, a main rice variety with good quality, has strong lodging resistance and can adapt to simplified cultivation pattern. However, the main factors of lodging resistance are still unclear. In this research, the plant height, breaking-resistant strength of individual plant and of basal internode, and the stem structure of rice ‘Yuenong Simiao’, ‘Xiangya Xiangzhan’, and the F2 population of ‘Yuenong Simiao’ × ‘Xiangya Xiangzhan’ were analyzed. The results showed that the shorter basal internode, the thicker wall and the higher substantiality of the stem were the important structural basis of lodging resistance of ‘Yuenong Simiao’ in comparison to ‘Xiangya Xiangzhan’. In the F2 populations, internode resistance, internode length, internode diameter, and stem wall thickness of N2 internode may be controlled by QTLs. The lodging resistance was weakly correlated with plant height and panicle length, but significantly positively correlated with stem diameter and wall thickness, and negatively correlated with internode length. The lodging resistance is mainly depended on the internode length, thickness and wall thickness. This study provides an important basis for revealing the internal factors of lodging resistance of rice ‘Yuenong Simiao’.

Abstract:Identification of new heat tolerant rice germplasm and breeding of new heat tolerant varieties are important for lessening the impacts of heat stress on rice production. Our previous study showed that rice 9311 was heat sensitive, while rice SDWG005 from Africa was heat tolerant. In this study, leaf morphology, microstructure and other physiological indexes of 9311 and SDWG005 were observed, tested and analyzed during or after 5 consecutive days treatment of high temperature stress (42℃/28℃, 12 h/12 h). The results showed that there were no significant changes in leaf morphology and microstructure, MDA content and superoxide dismutase content of SDWG005 at most time points of high temperature stress as compared with normal growth, and the content of soluble sugar and leaf proline increased significantly, whereas the leaves of 9311 were wilting after high temperature stress, the content of malondialdehyde and proline increased significantly or extremely significantly, the soluble sugar did not change significantly, and the activity of superoxide dismutase decreased significantly. The high temperature stress had no significant effect on photosynthesis of SDWG005 seedlings, but inhibited the photosynthesis of 9311 seedlings significantly. The chlorophyll content of SDWG005 and 9311 increased significantly or extremely significantly at some time points, and the biomass accumulation of SDWG005 increased under high temperature stress. The morphological and physiological basis of heat tolerance of SDWG005 is discussed in the present study, which will be helpful for breeding rice varieties with high heat tolerance using SDWG005 in future.

Abstract:In order to provide reference for germplasm enhancement and variety improvement, the phenotypic diversity of 434 sorghum germplasms with different origins were analyzed. The results showed that sorghum germplasms used in this study presented abundant phenotypic variations at multiple traits. The diversity indices (H') of panicle type, panicle shape and leaf disease were 1.0454, 0.9244 and 1.1718, respectively. The moderate H' at plant height, main panicle length, 1000-grain weight, ear stem length and kernel weight per panicle was found with 2.0463, 2.0259, 2.0093, 1.9807 and 1.9210, respectively. The positive correlation between plant height with main panicle length and growth period was observed, while a negative correlation was detected between plant height and kernel weight per panicle. Cluster analysis suggested three sub-groups from 434 sorghum germplasm accessions, including: Cluster I, which contain elite lines suitable for forage or energy; Cluster II, in which germplasm materials are considerably used for cultivating processing sorghum; Cluster III, in which valuable source for grain sorghum germplasm enhancement and cross breeding are present.

Abstract:In this study, 23 qualitative traits and 15 agronomic and quality quantitative traits of 239 soybean germplasm resources introduced from abroad were evaluated. Elite germplasms were screened to provide reference for soybean germplasm innovation and breeding in southern China. The results showed that those soybean germplasms represented abundant genetic diversity. The Simpson diversity index of 23 quality traits ranged from 0 to 0.672. The mature pod color diversity index was the highest, and the stem shape and pod shape diversity indexes were 0. The variation coefficients of the 15 agronomic and quality traits ranged from 4.85% to 83.73%, and the Simpson diversity index ranged from 0.6406 to 0.8526. The number of nodes on main stem diversity index was the highest, and the pod width diversity index was the lowest. The variation coefficient of bottom pod height was the highest, and the variation coefficients of crude fat content, pod length, growth duration and crude protein content were < 10%. The crude protein content was concentrated in the range of 40.01% to 45.00%, while the crude fat content was concentrated in the range of 18.01% to 20.00%. The crude protein content was only positively correlated with the bottom pod height, and the improvement of growth duration, stem diameter, seed number per plant, seed weight per plant, 100-seed weight, pod length and pod width was beneficial to the increase of crude fat content. The top 5 principal components, from top downwards, were the yield component factor, the seed and pod factor, the plant height factor, the quality factor, and the growth period factor; their cumulative contribution reached 84.419%. From those soybean germplasm resources, 14 with high crude protein content, 6 with high crude fat content, and 2 with very large seed were screened.

Abstract:Agronomic traits of 276 rice bean (Vigna umbellata) germplasm resources were evaluated in Beijing and Hainan, to provide information for new gene mining and utilization. The results showed that rice bean germplasm resources had obvious sensitivity to light and temperature. Among the 276 rice bean germplasms, 188 could flower and set seed in Beijing, while 271 could flower and set seed in Hainan. Young stems of most of the rice beans were purple (91.7%). The seeds were mainly yellow (44.9%) or red (33.0%). A large part of the germplasms were twining in Beijing (93.1%) but semi-twining in Hainan (64.9%). Comparative analysis of quantitative traits showed that the growth period, number of branches on the main stem, and 100-seed weight were greater in Beijing than in Hainan, while pod length and number of seeds per pod were in reverse. The average coefficient of variation for each trait of the rice beans growing in the two locations, in decreasing order, was number of branches on main stem (25.84%), 100-seed weight (25.34%), pod length (16.78%), number of seeds per pod (14.23%), and growth period (9.35%). The growth period and the number of branches on main stem of the same germplasm resources were less in lower latitude than in the higher latitude, while the length of pod, the number of seeds per pod and the 100-seed weight were not notably correlated with the geographical locations. Finally, 47 elite germplasms with early maturity, erect stems, long pod, or large seed were selected. The present study would provide information for further study on new gene mining and their application in breeding.

Abstract:In this study, the genetic diversity of 288 domestic and foreign pea germplasm resources were analyzed by SSR technique, which provided a basis for comprehensive evaluation of domestic and foreign pea germplasm resources and the utilization of elite genes. The results showed that 153 alleles were amplified by 24 pairs of SSR primers, with an average of 6.38 alleles per primer. Among them, the effective alleles accounted for 37.48%, the Shannon’s index averaged 0.9432, and the polymorphism information content (PIC) of the tested primers was 0.4331. The genetic diversity index of Asian pea germplasm was 0.4638, while that of Africa was 0.3480. This indicated that the genetic variation of pea germplasm resources in Asia was the most abundant, while that in Africa was relatively narrow. The intercontinental cluster analysis showed that there were obvious regional distribution rules among the pea germplasm resources in Asia, Europe, America, Oceania, Africa and the Russian Federation, which could be divided into two groups. In group I, there were two subgroups. The genetic distance between Europe and America was the closest (0.922), followed by Asia and Africa (1.425), and the genetic distance between Oceania and other continents was the longest at 2.958. These pea germplasm resources with high genetic diversity could provide rich genetic materials for breeding and cultivar improvement.

Abstract:Under the frame of the Third National Survey and Collection of Crop Germplasm Resources, we carried out systematic investigation of vegetable germplasm from 27 selected counties, cities or districts in Jiangxi Province of China. A total of 62 amaranth germplasm accessions were collected, followed by the genetic diversity at five quality-related traits and seven quantitative traits. There were significant genetic diversity at the phenotypic traits present in local amaranth germplasm resource. The leaf type and fresh weight at the quality-related and quantitative traits represented highest values (1.627 and 2.082) on the genetic diversity, respectively. The germplasm accessions were classified into four sub-groups, including sub-group II among which the germplasm resource showed divided leaf, leaf hypertrophy and higher yield per plant. The yield per plant was detected showing significant positive correlation with three traits plant height, leaf mass as well as root and stem weight. Finally, six amaranth varieties with excellent performance (i.e. high yield and short growth period) were identified thus providing valuable resources with commercial interests in breeding for new amaranth varieties.

Abstract:Four eggplant inbred lines with different colors in flower，peel and flesh were used as experimental materials，which were crossed in three hybrid combinations and through backcrossing and selfing produced six generation populations，for the study of the genetic relationships among eggplant flower color，peel color and flesh color，the aim of this study was to enrich the genetic research on peel color and flesh color of eggplant，and to provide theoretical basis for the breeding of new eggplant varieties. The results indicated that the flower color was controlled by a pair of genes，with purple fully dominant to white. The peel color was controlled by two pairs of dominant genes with overlapping effect，and the purple gene had dominant epistatic effect. Peel purple was dominant to green，and the purple gene of eggplant peel color inhibited the expression of the green gene. The flesh color was controlled by a pair of genes，with green-white fully dominant to white. There was the gene interaction effect in the inheritance of eggplant peel color and flesh color. The green-white gene controlling eggplant flesh had an epistatic effect on the white gene controlling eggplant peel，the inheritance of eggplant flower color and peel color were not completely linked，the crossing-over value of white flower with green peel and purple flower with purple peel being 20.5%，and the crossing-over value of white flower with white peel and purple flower with purple peel being 34.6%，the flower color and flesh color of eggplant were in accordance with the independent genetic law in the process of hybrid inheritance，and there was no linkage relationship.

Abstract:The quality of grass cloth for clothing is limited by the raw material ramie used for making the cloth. The evaluation and selection of excellent resources of ramie varieties are the basis for the production of high quality grass cloth materials. In this study, 30 ramie varieties (germplasms) were used as experimental materials, and Liuyangjigubai and Ribenzhaohecunma were used as controls. By comparing the diameter and strength of individual fibers, 14 ramie varieties were found to be superior to the controls. Difference analysis, correlation analysis, principal component analysis and cluster analysis were carried out on 8 indexes of the 30 ramie varieties and CK1. Significant differences among the varieties, and among some of the indexes were found. The 30 varieties and CK1 could be divided into 3 categories, and the number of evaluation indexes could be simplified to 6. The varieties better than the control CK1, selected by the method of membership function analysis, were Dayonghuangkema (No. 18),including Gema (No. 11)and Lechanghuangpizhu(No. 3).

Abstract:The reduction of chromosome number in plant somatic cells is a rare phenomenon. In this study, the tetraploid scion, chimeric scion, and diploid rootstock of the same wild germplasm of Hevea brasiliensis were used to analyze the position effect of tetraploid cell proportion in chimeras by flow cytometry, and the origins of tetraploid and chimeric identified by SSR markers. The results showed that the proportion of tetraploid cells in the chimera plants decreased to 65.58% in the seventh leaf layer from 80.50% in the first leaf layer. The 32 bands amplified by 18 pairs of primers were identical in the tetraploid and chimera, and there were 28 different bands compared with 28 bands of the diploid rootstock, indicating that the chimera was derived from the spontaneous somatic ploidy reduction of tetraploid. The peak ratio of two alleles in one of the 18 loci was 3:1, indicating that the tetraploid germplasm was not an autotetraploid produced by chromosome doubling of somatic cells, but an allotetraploid derived from sexual polyploidization of the 2n egg and 2n pollen. This study discovered and proved the phenomenon of ploidy reduction of an allotetraploid in Hevea brasiliensis.

Abstract:Wheat is globally one of the most important grain crops. Raising its yield and quality is of great significance in ensuring food security and human health. Fusarium head blight (FHB) may seriously destabilize and lower the yield and quality of wheat. Wild relatives of wheat are considered important effective sources to explore for FHB resistance. In this study, thirty-one germplasm accessions of Roegneria kamoji Ohwi from China and abroad were tested for FHB resistance over two years under field conditions, by deployment of two infection methods of spore spraying method and single flower instillation. The results showed that R. kamoji had moderate anti-invasion, excellent anti-expansibility, good overall resistance performance, diversified disease-resistance ability, and a few of the populations had both excellent anti-invasion and anti-expansion abilities. Among the 31 accessions, 4 were resistant (R, accounting for 12.90%), 22 were moderately resistant (MR, accounting for 70.97%) and 5 were moderately susceptible (MS, accounting for 16.13%). The accessions 88-89 282 (collected from Haba River, Xinjiang), Pr 87-88 353 (Ya’an, Sichuan), Pr 87-88 352 (Ya’an, Sichuan) and 88-89 304 (Kyoto, Japan) were identified as elite resources resistant to FHB from our two-years experiments, and they may be used for transference of FHB resistance to wheat for cultivar improvement.

Abstract:In this study, we investigated the phenotypic diversity of 26 characters of five main natural populations of Calanthe arcuata distributed at the north and south slopes on the main peak of the Qinling Mountains in China. The statistical methods used included Shannon-Wiener index, nested variance analysis, coefficient of variation analysis, principal component analysis (PCA), correlation analysis and cluster analysis. The results showed that: 22 phenotypic traits had rich coefficient of variation of 10.95% ~ 46.05% within and among the populations in C. arcuata, and the intra-population variation was greater than the inter-population variation. The petal color in this study had a relatively higher diversity index (1.12) among the four quality traits, indicating that the percentage of petal color varied greatly. The average coefficient of variation of leaf length-to-width ratio was the largest, and that of the middle sepal width was the smallest. The PCA analysis indicated that the length of middle sepal, width of middle sepal, length of the lateral sepal, width of synsepal, width of leaves and number of flowers were the main sources of phenotypic variation. The correlation of phenotypic traits was mainly concentrated among the flowers, and highly correlated with the altitude among the geographical factors. The five populations are clustered into two groups, with the Dadian (DD) population, which was at a much higher altitude than the other four populations, clustered in a branch of itself, and the 22 phenotypic traits were clustered in R into three groups. This study provides a theoretical basis for the strategy of in-situ conservation of the wild populations and for establishment of germplasm bank, breeding, development and utilization of these plants.

Abstract:EST-SSR molecular markers were used to identify the hybrids of two F1 crosses, which was derived from the variety ‘Fuding Dabaicha’ and ‘Anhui 1’ as the female parent and ‘Baojing Huangjincha 1’ as the male parent, followed by a genetic diversity. The results showed that 41 (85.42%) of 48 progenies from Fuding Dabaicha were identified to be true F1 hybrids, while among 35 strains (79.55%) of 44 plants from Anhui 1 were true hybrids. Genetic analysis using 17 pairs of SSR primers revealed 41 alleles in the two hybrid populations with an average of 2.82 (Fuding Dabaicha) and 2.71 (Anhui 1). No significant difference on the genetic diversity parameters of the two hybrid F1 populations were detected. The mean values of Nei, He, Ho, I were 0.56, 0.78, 0.43, 0.93 (Fuding Dabaicha) and 0.55, 0.75, 0.43, 0.90 (Anhui 1), respectively. The variation range of genetic similarity coefficient in F1 hybrid of Fuding Dabaicha × Baojing Huangjincha 1 and Anhui 1 × Baojing Huangjincha 1 was between 0.44~0.90 and 0.48~0.95 respectively. The cluster analysis using UPGMA showed that two hybrid populations were divided into three groups when the similarity coefficient was 0.60 and 0.64 respectively. The progenies were clustered together and represented a higher genetic similarity with respective female parents than the male parent. Collectively, this study reported an example on the genetic classification of tea hybrids using EST-SSR markers.

Abstract:This study attempted to establish a high-throughput and rapid method using SSR markers, in order to clarify the mustard varieties (Brassica juncea L.) released from China. Sixteen representative mustard varieties were used to screen SSR primers showing polymorphism. Out of 432 pairs of tested primers, 84 were detected with higher polymorphism and good repeatability, and they were subjected for synthesizing the fluorescent-labeled primers. We further genotyped 96 varieties with updated versions of primers using gene analyzer. Based on the amplification stability, the readability of peaks, polymorphism and chromosome location, etc., 25 SSR markers were finally qualified. We further provided the solution using reference varieties to eliminate genotyping errors caused by different experimental batches or platforms. By taking use of these markers from six groups according to the fluorescence color and amplification fragment size, a SSR-based mustard variety identification system has been established. The DNA database containing the fingerprinting information of 189 mustard varieties was generated showing a total of 175 allelic variants with an average of 7 allelic variants per primer. The gene diversity index was variable from 0.239 to 0.870, with an average of 0.555, while the polymorphism was observed between 0.23 and 0.86, with an average of 0.493. Collectively, this study established a mustard variety clarification method by taking use of 25 SSR markers on the capillary electrophoresis genotyping platform, which might be useful in rapid authenticity identification, genetic diversity analysis and similar varieties selection in DUS test in mustard.

Abstract:MYB transcription factors are one of the largest transcription factor families in higher plants, and they are involved in the regulation of a variety of plant life activities. Recent studies have shown that MYB transcription factors play a regulatory role in various stages of flower development and different parts of flower organs. In order to study the role of MYB transcription factor involved in ear development in wheat (Triticum aestivum L.), we isolated the TaMYB35 gene by taking advantage of the latest wheat genome data and the sequence homolog with the Arabidopsis thaliana AtMYB35 gene, which allowed identifying three copies TaMYB35A, TaMYB35B and TaMYB35D. Sequence analysis showed that TaMYB35A, TaMYB35B and TaMYB35D contained complete open reading frames of 924bp, 927bp and 927bp, respectively, encoding for 307, 308 and 308 amino acids, respectively. All the three members contained two MYB domains at the N-terminus, which are the feature of the R2R3-MYB transcription factor in the MYB gene family. Phylogenetic analysis showed that TaMYB35A was grouped with the orthologue of Triticum dicoccum, independent of a phylogenetic cluster where TaMYB35B and TaMYB35D were resided. TaMYB35A, TaMYB35B and TaMYB35D were found with higher transcripts in stamens, less in spikelets (excluding stamens) and no detectable transcripts in other tissues. Moreover, a significant difference in the expression of TaMYB35A was observed in samples harvested at sterile and fertile environments. Thus, this study clarified transcriptional characteristics of TaMYB35 in the development of wheat anthers, which thus provided insight for deciphering the molecular basis in wheat breeding with two-line hybrid strategy.

Abstract:Grain weight (GW) is one of key factors contributing the wheat yield. In wheat, breeding for higher GW becomes an important target. In this study, a population of 198 RILs crossed by C615 and Yangmai13 (YM13) was constructed, followed by genotyping with 90K SNP array and quantifying thousand grain weight at four environmental conditions. By using the genome-wide association scanning (GWAS), QTGW.yaas-1BL derived from C615 was detected in one environment at 12.90 cM on 1BL, which accounted for 3.07% of the phenotypic variances and 0.78 of the additive effect. The second locus QTGW.yaas-6AL derived from Yangmai13 was verified at four environments between 112.70 cM~116.00 cM on 6AL, accounting for 7.63%~10.55% of the phenotypic variances and 1.46~1.51 of the additive effect. Genotyping with functional KASP (Kompetitive allele-specific PCR) markers associating with the grain weight revealed six higher grain weight alleles commonly detected in C615 and YM13, and three alleles that are polymorphic between parents. Collectively, the new grain weight QTL identified will lay the foundation for the genetic studies of grain weight in YM13 and in breeding for high-yielding wheat cultivars.

Abstract:The Wx gene，which controls the synthesis of amylose in rice endosperm，is the major gene that determines rice eating and cooking quality（ECQ）. It can significantly improve rice ECQ by moderately reducing amylose content（AC）of endosperm. Editing the C-terminal of Wx encoded GBSSI enzyme to fine-tune its enzyme activity and grain AC is expected to further improve rice ECQ. By analyzing the functional domain of GBSSI through bioinformatics websites，two target sites，T1 and T2（located in the 12th and 13th exons of the Wx gene，respectively），were subjected for CRISPR/Cas9-medicated editing. The homozygous mutants were validated by PCR and Sanger sequencing，followed by quantifying the apparent amylose content，gel-permation chromatography，western blot and qRT-PCR. A total of 8 homozygous lines，C1-C8，with retained major domains of GBSSI were obtained. Among which，the 518-550/551 codons were shifted in the predicted protein in C2 and C3 lines and the predicted protein in C1，C4-C8 were shifted after codon 551，517 or 518. The apparent amylose content of C1-C8 was significantly reduced from 16.79% to 4.44%-3.69%，but significantly higher than that of near-isogenic line（NIL）carrying the conventional wx allele（AAC=2.92%）. GPC results showed that there was no amylose synthesis in the selected mutants，but their chain length distribution of Ap2 was longer than that in NIL wx. The qRT-PCR and western blot suggested no significant difference on transcript of Wx gene but obvious reduction of GBSSI accumulation in the developing seeds in mutants. No GBSSI accumulation was detected in all the homozygous lines except for C2 and C3. As a result，this study generated glutinous rice lines with fine-tuned starch fine structure to conventional glutinous rice by CRISPR strategy，and provided evidence of the 518-551 amino acids on the formation of GBSSI enzyme activity. These results provide a reference for further analyzing the structure of GBSSI protein to achieve its precise editing.

Abstract:In order to further improve the efficiency of maize composite population, four synthetic populations were crossed to four testers including Cpop.15, Cpop.16, W9706 and Si144 adopting NCII genetic design. The 16 crosses and one check hybrid Zhengdan958 were evaluated in Xinxiang of Henan province and Jinan of Shandong province to analyze the effect of introgression of different germplasm into maize composite population. The results showed an increase of grain yield in Cpop.15 and Cpop.16 after the introgression of different germplasm. The synthetic population CP15-2 exhibited short silking date, low plant height, low moisture at harvest and high grain yield, and good general combining ability (GCA) for day to silking and grain yield. The cross CP15-2 ×Cpop.15 showed better performance than the synthetic population Cpop.15 for day to silking, low moisture at harvest and grain yield, and low specific combining ability (SCA) effect and heteosis. Therefore, the synthetic population CP15-2 can be used as a new elite germplasm to improve the growth period, moisture at harvest and yield of the composite population Cpop.15.

Abstract:Heterosis utilization is one of the effective means to raise the crop yield. With the rise of the third generation of "intelligent sterility hybrid breeding technology", nuclear sterility gene has been widely used in crop cross breeding. In soybean, ms6 as an important gene of nuclear sterility has been widely used in recurrent selection breeding, but it is rarely reported in hybridization breeding. In this study, 12 dCAPS markers were developed using SNP mutation site of soybean ms6 gene. Three dCAPS markers ms6-dCAPS-1, ms6-CAPS-2 and ms6-CAPS-3 were identified by restriction endonuclease digestion. Further verification showed that the ms6-dCAPS-3 marker was stable and reproducible. After restriction endonuclease Hind III digestion, the amplified products could accurately distinguish homozygous fertile, heterozygous fertile and homozygous sterile single strains in the isolated population of ms6 offspring. This provides an effective technical support for the application of nuclear sterile gene ms6 in hybrid soybean breeding.

Abstract:Soybean (Glycine max (L.) Merr.) is one of the important grain and oil crops in China, and vegetable soybean is a nutrition-rich vegetable crop. However, few InDel markers are known for convenient use in soybean. In this study, 18 soybeans were tested for resequencing analysis, with InDel loci mined on the basis of the resequencing datasets, and the effectivity and application value of the InDel markers validated. After strict screening, 17,977 highly polymorphic InDel loci with Insert/Delete of 13-50 bp suitable for agarose gel electrophoresis detection were obtained. There were from 505 to 1355 InDel markers on each chromosome, and the average distribution density was 12.60-35.76 InDel/Mb across the chromosomes. Among the 73 InDel markers randomly selected for effectivity validation in 18 soybeans, 43 (56.16%) of the InDel markers showed polymorphism. Of those 73 InDel markers, 25 polymorphic InDel markers were used for genetic diversity analysis in 192 soybeans (including 64 vegetable soybeans, 65 spring soybeans, 36 summer soybeans, 19 landraces and 8 wild soybeans). The polymorphic information content (PIC) for each InDel marker was between 0.17 and 0.46 with an average of 0.35, and the 192 soybeans were classified into 24 groups with the different types in different groups. Among them, the vegetable soybeans were mainly classified into the 3# group with the genetic similarity coefficient of 0.66 and a few vegetable soybeans were classified into the 1# group with the genetic similarity coefficient of 0.71, which suggested that the genetic background of vegetable soybeans in China are relatively narrow, and we should select soybean lines with small genetic similarity coefficient as parents for breeding in future to enrich the genetic background. The 25 polymorphic InDel markers were also used to verify the F1 from 13 hybrid combinations, which agreed with the phenotypic identification, indicating the usefulness of the InDel markers developed for F1 identification. Taken together, the polymorphic InDel markers developed in this study will be widely used in genetic diversity analysis, hybrid identification, genetic linkage map construction, gene mapping and molecular marker assisted selection breeding in soybean.

Abstract:In order to reveal the molecular mechanism of heat shock on ovule expansion, the global transcriptional profiles using RNA-seq were revealed based on the unfertilized ovules of watermelon under heat shock treatment. Total RNAs were extracted from the unfertilized ovules at 0 hour (A1), 4 hour (A3), 8 hour (A5), 12 hour (A7) and 24 hour (A8) post heat shock at 37℃, and then subjected for RNA-seq. Overall, 10093 differentially expressed genes (DEGs) were detected in the four pair-wise comparison groups (A3 to A1, A5 to A1, A7 to A1 and A8 to A1), including 4645 DEGs that were commonly detected at four comparisons. The cluster analysis of DEGs showed that the transcriptional reprograming of unfertilized ovules occurred after heat shock at 37℃ for 4 h, implying that the earlier response upon heat shock treatment. GO analysis showed that DEGs were mainly annotated in cell processes, cell parts and organelles, suggesting that heat shock may increase the activity of ovule cells. KEGG analysis revealed enrichments in amino acid metabolism, carbohydrate and sugar metabolism, plant hormone signal transduction and MAPK signaling pathway, which raises a putative impact on the development of unfertilized ovule. In addition, it was found that changes in the expression of DEGs related to heat shock proteins, plant hormones and embryo development under heat stress may be important in inducing unfertilized ovule development, which provides preliminary insights for future unlocking the molecular mechanism of heat shock development of unfertilized ovules in watermelon.

Abstract:In the present study, wide hybridization was performed between ‘Whenzhou turnip’ (Brassica rapa L. em. Matzg.，2n=20, AA) and ‘purple kohlrabi’ (B. oleracea L. var. caulorapa DC, 2n=18, CC) by hand emasculation following tissue culture for hybrid seeds. A total of 2 hybrids were obtained through bud pollination and ovary culture, and 19 asexual seedlings were obtained through expanding propagation. Morphological analysis, cytological observation and RAPD molecular analysis identified the two strains as true hybrids of ‘Wenzhou turnip’ × ‘purple kohlrabi’, and then the novel allotetraploid rutabagas germplasm was obtained by chromosome doubling (AACC, 2n=38). The two hybrid lines were separated by stem color, and their root and stem were enlarged, but the degree was lower than that of the parents. The floral organs of allotetraploid were larger, anthers developed normally, and the pollen viabilities was higher. The new germplasm of allotetraploid rutabagas was obtained in present studies, which expanded the genetic background of rutabagas germplasm resources to a certain extent and laid a foundation for the research on the origin and evolution, genetic improvement, production and promotion of rutabagas.

Abstract:Self-incompatibility is an important way for plants to avoid inbreeding and thus to maintain excellent species. Japanese apricot is a kind of typical gametophyte self-incompatibility (GSI) species. In this study, AS-PCR (Allele Specific PCR) technique and sequencing were used to analyze and identify S-RNase genotypes and SFB genotypes of 11 cultivars. First, primer pairs Pru-C2 and PCE-R, SFB-C1F and Pm-Vb were designed according to the conservative region of the S-RNase gene and SFB gene of Japanese apricot. Then, the genomic DNA was used as a template for AS-PCR amplification and PCR products sequenced directly. After sequences comparison and analysis, the S-RNase genotype and SFB genotype of 11 Japanese apricot cultivars were ‘Ruantiaohongmei’ of S13S14 and F-box2/SFB14, ‘Xiaoyezhugan’ of S3S33 and SFB51/SFB53, ‘Zhonghong’ of S3S24 and SFB2/SFB24, ‘Qingjia915’ of S3S15 and SFB2/SFB43, ‘Meilinhong’ of S1S37 and SFB1/SFB24, ‘Chifenghongmei’ of S14S38 and SFB12/SFB49, ‘Dalongmei’of S20S30 and SFB7/SFB41, ‘Hongguangmei’ of S3S33 and SFB24/SFB55, ‘Nannongfengyu’ of S3S5 and SFB31/SFB43, ‘Nannongfengjiao’ of S3S6 and SFB2/SFB47, ‘Nannonglongxia’ of S15S37 and SFB41/SFB43. Further analysis of the obtained S-RNase gene and SFB gene sequence showed that in addition to the known S-RNase gene and SFB gene, and two unregistered S-RNase genes of S37-RNase and S38-RNase, and five unregistered new SFB genes SFB47, SFB49, SFB51, SFB53 and SFB55 were also identified. Their sequences have been registered in the GenBank database, the accession numbers were MT950061 and MT950062, MW186463, MW186465, MW186467, MW186469 and MW186471, respectively. The research results provide a basis for the allocation of pollination trees for Japanese apricot production and cultivation and the improvement of breeding efficiency.