STM Article Repository

Aims: To access the responses of 22 soybean genotypes under drought stress during the flowering stage of development.

Study Design: A completely randomized experimental design (CRD) was adopted in this study. Five seeds of each of the 22 soybean genotypes were planted in 12-liter (L) plastic buckets (with holes at the bottom) containing sandy loam soil. There was one genotype per pot with three replications. The setup was repeated to represent experimental (drought-stressed (DS) and control (well-watered (WW) groups.

Place and Duration of Study: Teaching and Research Farm of the School of Agriculture, College of Agriculture and Natural Sciences, University of Cape Coast, Cape Coast, Ghana in 2019.

Methodology: Twenty-one exotic soybean genotypes and a local variety were assessed for their responses to drought stress at the flowering stage of development using pot experiment in the greenhouse. One group (experimental) was exposed to drought stress by withholding water for 15 days whilst the other group (control) was watered regularly at three-day intervals. Data collected were the number of leaves, plant height, stem girth, leaf area, and number of flowers, at 5, 10, and 15 days after treatment (DAT) and relative leaf water content at 15 DAT. The number of days to permanent wilting of the genotypes was also recorded.

Results: Drought stress reduced the number of leaves and plant height significantly (P-values = 0.033, 0.000) and (P-values = 0.004, 0.000) at 10 and 15 days after drought treatment respectively. Also, stem girth, leaf area, and number of flowers were significantly reduced at all sampling dates (P-value = 0.002, 0.000, 0.000), (P-values = 0.004, 0.000, 0.000) and (P-values = 0.009, 0.000, 0.000) respectively. At 15 DAT, drought significantly (P < 0.001) reduced relative leaf water content. Genotypes TGX-1989-11F and TGX-1987-62F were the first and last to wilt at 7 days and 16 days after rewatering respectively.

Conclusion: The pot screening method revealed that the number of leaves, plant height, stem girth, leaf area, number of flowers, relative leaf water content, and days to permanent wilting differed significantly (P = 0.05) at 15 days of drought exposure.