Drought is a major limiting factor seriously influencing worldwide soybean production and its impact on yield, morphological and physiological traits depend on the timing it occurs and the intensity of water shortage. Only limited research has however been conducted on identifying the drought-tolerant genotypes at different growth stages (vegetative growth phase, reproductive growth phase and the whole growth phase) as well as evaluate the effectiveness and reliability of multiple phenotypic and yield-related characteristics in soybean. Two pot experiments and a 2-year field experiment were conducted to evaluate soybean drought tolerance at different growth stages. The membership function value of drought tolerance (MFVD) was used to identify drought-resistant cultivars during vegetative growth phase and reproductive growth stage; the relative drought index (RDI) of yield was used to assess drought-resistant cultivars during the whole growing period. In this study, regression models built based on MFVD indicated that the variation of drought tolerant coefficient (DC) of R/S, TRL, LAI and RSR could explain 73.70% of the total variation at vegetative growth phase. However, higher heritability only found in LAI and RSR, indicating the two traits could serve as reliable criteria for drought evaluation. Similarly, the DC of SPP, YPP, PH, PB, MSNN and STB could explain 94.30% of the total variation in MFVD according to stepwise multiple linear regression analyses at reproductive growth phase. Thus, these six traits were identified as indicators for screening drought resistance genotypes in soybean. In addition, correlation analysis revealed that the MFVD was significantly positively correlated with the DCRB, DCR/S, DCRSA, DCRSR and DCRBR at vegetative growth phase and DCYPP, DCSPP, DCRB, and DCPB at reproductive growth phase. This indicated that these traits were closely related to the drought resistance of plants. LD24, JD36 and TF31 of vegetative growth phase, and TD37 and LD26 of reproductive growth phase were identified with drought tolerant and highly drought tolerant, respectively. Moreover, 30 accessions with drought tolerance were screened in the field trial and could be applied for the drought resistance of other genotypes by cross-breeding.

中文翻译：

---

基于多性状和耐旱产量系数的隶属函数值筛选不同大豆耐旱基因型。


干旱是严重影响全球大豆生产的主要限制因素，其对产量、形态和生理性状的影响取决于干旱发生的时间和缺水的强度。然而，对于大豆不同生长阶段（营养生长阶段、生殖生长阶段和全生长阶段）的耐旱基因型的鉴定以及评估大豆多种表型和产量相关性状的有效性和可靠性的研究还很有限。 。通过两次盆栽试验和为期2年的大田试验，评价大豆不同生育阶段的耐旱性。利用耐旱隶属函数值（MFVD）鉴定营养生长期和生殖生长期的抗旱品种；采用产量相对干旱指数（RDI）来评价品种全生育期的抗旱能力。本研究基于MFVD建立的回归模型表明，R/S、TRL、LAI和RSR的耐旱系数(DC)的变化可以解释营养生长期总变化的73.70%。然而，仅 LAI 和 RSR 具有较高的遗传力，表明这两个性状可以作为干旱评估的可靠标准。同样，根据生殖生长阶段的逐步多元线性回归分析，SPP、YPP、PH、PB、MSNN 和 STB 的 DC 可以解释 MFVD 总变异的 94.30%。因此，这6个性状被确定为筛选大豆抗旱基因型的指标。 此外，相关分析显示，MFVD与营养生长期的DCRB、DCR/S、DCRSA、DCRSR、DCRBR以及生殖生长期的DCYPP、DCSPP、DCRB、DCPB呈显着正相关。这说明这些性状与植物的抗旱能力密切相关。营养生长期的LD24、JD36和TF31，生殖生长期的TD37和LD26分别被鉴定为耐旱和高度耐旱。此外，通过田间试验筛选出30个具有耐旱性的材料，可通过杂交育种应用于其他基因型的抗旱性。