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Jiang B.,Chinese Academy of Agricultural Sciences | Yue Y.,Chinese Academy of Agricultural Sciences | Yue Y.,Mudanjiang Branch of Heilongjiang Academy of Agricultural science | Gao Y.,Chinese Academy of Agricultural Sciences | And 6 more authors.
PLoS ONE | Year: 2013

Background:Soybean is a short-day crop of agricultural, ecological, and economic importance. The sensitive photoperiod responses significantly limit its breeding and adaptation. GmFT2a, a putative florigen gene with different transcription profiles in two cultivars (late-maturing Zigongdongdou and early-maturing Heihe 27) with different maturity profiles, is key to flowering and maturation. However, up to now, its role in the diverse patterns of maturation in soybeans has been poorly understood.Methods:Eighty varieties, including 19 wild accessions, covering 11 of all 13 maturity groups, were collected. They were planted in pots and maintained under different photoperiodicity conditions (SD, short day; LD, long day; and ND, natural day). The day to first flowering was recorded and the sensitivity to photoperiod was investigated. Polymorphisms in the GmFT2a coding sequence were explored by searching the known SNP database (NCBI dbSNP). The GmFT2a promoter regions were then cloned from these varieties and sequenced. Further polymorphism and association analyses were conducted.Results:These varieties varied greatly in time to first flowering under ND and exhibited a consecutive distribution of photoperiod sensitivity, which suggested that there is rich diversity in flowering time. Furthermore, although GmFT2a had only one known synonymous SNP in the coding sequence, there were 17 haplotypes of the GmFT2a promoter region, HT06 of which was extremely abundant. Further association analysis found some SNPs that might be associated with day to first flowering and photoperiod sensitivity.Conclusion:Although GmFT2a is a key flowering gene, GmFT2a polymorphism does not appear to be responsible for maturity diversity in soybean. © 2013 Jiang et al. Source

Liu D.,ShenYang Agricultural University | Liu D.,Mudanjiang Branch of Heilongjiang Academy of Agricultural science | Wang J.-Y.,ShenYang Agricultural University | Wang X.-X.,ShenYang Agricultural University | And 3 more authors.
Journal of Integrative Agriculture | Year: 2015

Abundant genetic diversity and rational population structure of germplasm benefit crop breeding greatly. To investigate genetic variation among geographically diverse set of japonica germplasm, we analyzed 233 japonica rice cultivars collected from Liaoning, Jilin and Heilongjiang provinces of China, which were released from 1970 to 2011 by using 62 simple sequence repeat (SSR) markers and 8 functional gene tags related to yield. A total of 195 alleles (Na) were detected with an average of 3.61 per locus, indicating a low level of genetic diversity level among all individuals. The genetic diversity of the cultivars from Jilin Province was the highest among the three geographic distribution zones. Moreover, the genetic diversity was increased slightly with the released period of cultivars from 1970 to 2011. The analysis of molecular variance (AMOVA) revealed that genetic differentiation was more diverse within the populations than that among the populations. The neighbor-joining (NJ) tree indicated that cultivar clusters based on geographic distribution represented three independent groups, among which the cluster of cultivars from Heilongjiang is distinctly different to the cluster of cultivars from Liaoning. For the examined functional genes, two or three allelic variations for each were detected, except for IPA1 and GW2, and most of elite genes had been introgressed in modern japonica rice varieties. These results provide a valuable evaluation for genetic backgrounds of current japonica rice and will be used directly for japonica rice breeding in future. © 2015 Chinese Academy of Agricultural Sciences. Source

Guo S.-J.,Shanxi Agricultural University | Yang K.-M.,Shanxi Agricultural University | Huo J.,Shanxi Agricultural University | Zhou Y.-H.,Shanxi Agricultural University | And 2 more authors.
Chinese Journal of Applied Ecology | Year: 2015

A drought-resistant soybean cultivar Jinda 70 and a drought-sensitive soybean cultivar Jindou 26 were taken as test materials. At the grain filling stage, the cultivars were subject to three water treatments including sufficient water supply, light drought stress, and severe drought stress by using pot experiments for research on influence of drought on leaf photosynthetic capacity and root growth of soybeans. The results showed that as the degree of drought stress was aggravated, all of the indices including leaf area, chlorophyll content, net photosynthetic rates (Pn), stomatal conductance (gs), transpiration rate (Tr), intercellular CO2 concentration (Ci), plant mass, plant height, seed yield, and harvest index in the two cultivars declined. The root length and root mass increased under light drought stress, and decreased under severe drought stress. Root-shoot ratio ascended as the degree of drought stress was aggravated. Under severe drought stress, the increase of root-shoot ratio of the drought-resistant soybean cultivar Jinda 70 was up to 135.7%, which was higher than the that (116.7%) of the drought-sensitive soybean cultivar Jindou 26. Simultaneously, leaf area and chlorophyll content in Jinda 70 were respectively 69.3% and 85.5% of those in the control, which were better than those of Jindou 26. gs and Pn of Jinda 70 respectively declined 67.9% and 77.9%, but still lower than those of Jindou 26. Therefore, the decline range of harvest index of Jinda 70 was 43.8%, which was lower than the range of 78.8% of Jindou 26. The Biplot revealed that under different dry treatments, there were significant positive correlations among the sixindexes including leaf area, chlorophyll content, Pn, gs, Tr, and Ci of the two cultivars. There were also significant positive correlations among the six indices including plant mass, plant height, root length, root mass, seed yield, and harvest index. Root-shoot ratio only had significant positive correlation with root mass and had significant negative correlations with other five indices. ©, 2015, Editorial Board of Chinese Journal of Applied Ecology. All right reserved. Source

Lu S.,Chinese Academy of Sciences | Lu S.,University of Chinese Academy of Sciences | Li Y.,Northeast Forestry University | Wang J.,Chinese Academy of Sciences | And 17 more authors.
Euphytica | Year: 2015

Flowering represents the transition from the vegetative to reproductive phase and plays an important role in many agronomic traits. For soybean, a short day (SD) induced and photoperiod-sensitive plant, delaying flowering time under SD environments is very important and has been used by breeders to increase yields and enhance plant adaptabilities at lower latitudes. The purpose of this study was to identify quantitative trait loci (QTLs) associated with flowering time, especially QTLs underlying the long juvenile (LJ) trait which delays flowering time under SD environments. A population of 91 recombinant inbred lines derived from a cross between AGS292 and K3 was used for map construction and QTL analysis. The map covered 2546.7 cM and included 52 new promoter-specific indel and 9 new exon-specific indel markers. The phenotypic days-to-flowering data were examined in nine environments, including four short-day (SD, low latitude) and five long-day photoperiod (LD, high latitude) environments. For the SD environments, six QTLs were detected. Five of them were associated with the LJ trait. Among the five LJ QTLs, four QTLs may be attributed to the known flowering time genes, including qFT-J-1 for FT5a locus, qFT-J-2 for the FT2a locus, qFT-O for the E2 locus and qFT-L for the E3 locus. This is the first report that the E2, E3, FT2a and FT5a loci may be associated with the LJ trait. Under the five LD environments, as expected, qFT-O for the E2 locus and qFT-L for the E3 locus were identified, suggesting that E2 and E3 loci are very important for soybean adaptation in LD photoperiod. Conjoint analysis of multiple environments identified nine additive QTLs and nine pairs of epistatic QTLs, among which most were involved in interactions with the environments. In total, five QTLs (qFT-B2-1, qFT-C1-1, qFT-K, qFT-D2 and qFT-F) were identified that may represent novel flowering time genes. This provides a fundamental foundation for future studies of flowering time in soybean using fine mapping, map-based cloning, and molecular-assisted breeding. © 2015 Springer Science+Business Media Dordrecht Source

Zhai H.,Chinese Academy of Sciences | Lu S.,Chinese Academy of Sciences | Lu S.,University of Chinese Academy of Sciences | Wang Y.,Jilin Agricultural University | And 12 more authors.
PLoS ONE | Year: 2014

The time to flowering and maturity are ecologically and agronomically important traits for soybean landrace and cultivar adaptation. As a typical short-day crop, long day conditions in the high-latitude regions require soybean cultivars with photoperiod insensitivity that can mature before frost. Although the molecular basis of four major E loci (E1 to E4) have been deciphered, it is not quite clear whether, or to what degree, genetic variation and the expression level of the four E genes are associated with the time to flowering and maturity of soybean cultivars. In this study, we genotyped 180 cultivars at E1 to E4 genes, meanwhile, the time to flowering and maturity of those cultivars were investigated at six geographic locations in China from 2011 to 2012 and further confirmed in 2013. The percentages of recessive alleles at E1, E2, E3 and E4 loci were 38.34%, 84.45%, 36.33%, and 7.20%, respectively. Statistical analysis showed that allelic variations at each of four loci had a significant effect on flowering time as well as maturity. We classified the 180 cultivars into eight genotypic groups based on allelic variations of the four major E loci. The genetic group of e1-nf representing dysfunctional alleles at the E1 locus flowered earliest in all the geographic locations. In contrast, cultivars in the E1E2E3E4 group originated from the southern areas flowered very late or did not flower before frost at high latitude locations. The transcriptional abundance of functional E1 gene was significantly associated with flowering time. However, the ranges of time to flowering and maturity were quite large within some genotypic groups, implying the presence of some other unknown genetic factors that are involved in control of flowering time or maturity. Known genes (e.g. E3 and E4) and other unknown factors may function, at least partially, through regulation of the expression of the E1 gene. © 2014 Zhai et al. Source

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