Abstract:
【Objective】 Soybean (
Glycine max L.) originated from China, which was an important crop for grain, oil and forage. Drought stress inhibits soybean germination potential, germination rate, and germination index, leading to missing seedlings in the field. The elite soybean germplasms were screened in the hope of providing material basis for drought-tolerant breeding and molecular mechanism analysis.
【Methods】 218 soybean accessions, provided by National Central Asian Characteristic Crop Germplasm Resources Medium-term Gene Bank (Urumqi), were employed and five drought tolerance index, including relative germination potential, relative germination rate, relative germination index, promptness index, and damage rate were identified under 15% PEG stress. Furthermore, soybean drought tolerance was evaluated by membership function method and clustering analysis.
【Results】 The soybean germination rate, germination potential, and germination index declined to different degrees under 15% PEG stress. The ranges of the relative germination potential, relative germination rate, relative germination index, promptness index, and damage rate were 0.04-1.00, 0.41-1.00, 0.09-0.63, 0.03-1.92, and 0-58.63%, respectively. Correlation analysis showed that the relative germination potential, relative germination rate, relative germination index, and promptness index were positively correlated with each other and negatively correlated with damage rate. Furthermore, based on membership function values, 218 soybean accessions were classified into four groups: Group I, Group II, Group III and Group IV. From Group I, ten drought-tolerant germplasm were selected including No.10294, Dongnong 60, PI475810, No.3226 and FtC039. Moreover, a mathematical model (
D=0
.382-0
.429
DR+0
.209
RGP+0
.106
PI+0
.238
RGI) was established by stepwise regression analysis, which might be used to quickly evaluate and predict the drought tolerance of soybean germplasm during germination.
【Conclusion】 From 218 soybean accessions, ten drought-resistant varieties are screened, including No.10294, Dongnong60, PI475810, No.3226, FtC039, JiangJinQingPiDou, FtC005, Uzbekskaja-2, Union and FtC054.