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
Wu T.,Chinese Academy of Agricultural Sciences |
Sun S.,Chinese Academy of Agricultural Sciences |
Wang C.,Chinese Academy of Agricultural Sciences |
Lu W.,Heihe Branch of Heilongjiang Academy of Agricultural science |
And 13 more authors.
Crop Science | Year: 2015
The first soybean [Glycine max (L.) Merr.] breeding program in China was established in the northeast in 1913. A trend analysis of widely grown cultivars across Chinese soybean breeding history may provide a better perspective on the genetic progress in soybean. The objective of the current study was to assess the genetic change of 15 phenological, yield, and agronomic traits on widely grown cultivars in northeast China. Sixty-four soybean cultivars representing a span of 84 yr (1923–2007) of release were included. The field experiments were conducted at three sites in each region during 2009, 2010, and 2011, and the annual genetic changes were obtained by regression analysis. The results showed that the yield gain in widely grown cultivars of different regions ranged from 6 to 16 kg ha-1 yr-1 due to improvements in different yield components in the last nine decades. In addition, modern cultivars demonstrated more upright plant architecture, fewer branches, shorter height, higher lodging resistance, and earlier flowering than obsolete cultivars. However, changes were insignificant in the height of the bottom pod and the node number. The changing rates of yield and phenological traits across these decades were constant, while that of agronomic traits were discontinuous. Days to flowering, branch number, and lodging score were more responsive to environments in new cultivars than in old cultivars. In conclusion, these findings indicate a substantial improvement in the yield, agronomic, and phenological traits resulted from long-term genetic breeding. This study also provides insight into developing new strategies for soybean genetic improvement in China and worldwide. © Crop Science Society of America. All rights reserved. Source
Jia H.,Institute of Crop Science |
Jia H.,Heihe Branch of Heilongjiang Academy of Agricultural science |
Jiang B.,Institute of Crop Science |
Wu C.,Institute of Crop Science |
And 5 more authors.
PLoS ONE | Year: 2014
Background: With the migration of human beings, advances of agricultural sciences, evolution of planting patterns and global warming, soybeans have expanded to both tropical and high-latitude cold regions (HCRs). Unlike other regions, HCRs have much more significant and diverse photoperiods and temperature conditions over seasons or across latitudes, and HCR soybeans released there show rich diversity in maturity traits. However, HCR soybeans have not been as well classified into maturity groups (MGs) as other places. Therefore, it is necessary to identify MGs in HCRs and to genotype the maturity loci. Methods: Local varieties were collected from the northern part of Northeast China and the far-eastern region of Russia. Maturity group reference (MGR) soybeans of MGs MG000, MG00, and MG0 were used as references during field experiments. Both local varieties and MGR soybeans were planted for two years (2010-2011) in Heihe (N 50μ159, E 127μ279, H 168.5 m), China. The days to VE (emergence), R1 (beginning bloom) and R7 (beginning maturity) were recorded and statistically analyzed. Furthermore, some varieties were further genotyped at four molecularly-identified maturity loci E1, E2, E3 and E4. Results: The HCR varieties were classified into MG0 or even more early-maturing. In Heihe, some varieties matured much earlier than MG000, which is the most early-maturing known MG, and clustered into a separate group. We designated the group as MG0000, following the convention of MGs. HCR soybeans had relatively stable days to beginning bloom from emergence. The HCR varieties diversified into genotypes of E1, E2, E3 and E4. These loci had different effects on maturity. Conclusion: HCRs diversify early-maturing MGs of soybean. MG0000, a new MG that matures much earlier than known MGs, was developed. HCR soybean breeding should focus more on shortening post-flowering reproductive growth. E1, E2, E3, and E4 function differentially. © 2014 Jia et al. Source