Screening of adaptive cultivars and identification of QTNs associated
with flowering time and related traits of diverse soybean cultivars
grown in low-latitude, high-altitude regions
Abstract
Soybean ( Glycine max [L.] Merr.) has been grown in diverse
environments in a wide range of latitudes in the world. However, the
adaptation of soybean to low-latitude, high-altitude environments
characterized by short day and low temperature is still in its early
stages. To understand the genetic basis of adaptation in this region, we
conducted cultivar screening in low-latitude, high-altitude mountainous
regions and carried out genome-wide association studies (GWAS) using 200
diverse soybean cultivars spanning maturity groups 000 to VIII.
Evaluation of flowering time (DTF), maturity time (DTM), and other
agronomic traits including node number on main stem (NNM), plant height
(PH), effective number of pods per plant (EPN) and 100-seed weight (HGW)
were performed in Bamei with the altitude of 3460 m (30°29’4”N and
101°28’50”E) and Xianshui with the altitude of 2946 m (30°57’48”N and
101°9’26”E), in Daofu county, Sichuan province, southwest China, in 2019
and 2023, respectively. We screened 5 MG I-II adapted cultivars for
Bamei and 17 MG II-V cultivars, for Xianshui, exhibiting late flowering
and maturity, along with tall plant height, and high number of nodes and
pods per plant. The allelic combinations E1/e2-ns/e3-tr/E4 and
E1/e2-ns/E3/E4, and only E1/e2-ns/E3/E4 predominated in
the adaptive cultivars in Bamei and Xianshui, respectively. Thus, the
cultivars adaptive to low-latitude and high-altitude regions are
featured with relatively late flowering and maturing in MG I-V mostly
from mid- and low-latitude region with allelic combination mostly of
E1/e2-ns/E3/E4. Additionally, our results revealed 9, 6, and 2
genomic regions significantly associated with DTF, NNM and PH,
respectively, with two of these genomic regions having QTNs
significantly associated with both DTF and PH. Most significant QTNs of
the genomic regions associated with DTF were located near previously
identified quantitative trait loci, and their alternative loci caused
significant differences in flowering time. Furthermore, 7 genomic
regions were located near homologs of Arabidopsis flowering time genes
FD-1, bZIP29, SEC, PA2, PIE1, FY, IAA31, AS1 and MBD9.
Non-synonymous mutations within the candidate genes
Glyma.09g112200 ( GmPIE1) , Glyma.13g198200 (
GmFY) and Glyma.17g042800 ( GmIAA31) were found to
cause later flowering and taller plant height in both environments.
Collection of adaptive cultivars, molecular markers, and candidate genes
identified in this study holds substantial promise within the realm of
soybean adaptation in low-latitude and high-altitude regions.