Physiological response of three large-seeded soybean genotypes under drought and waterlogged stress conditions

Abstract

This study aims to determine the physiological response of large-seeded soybean genotypes on the effect of drought and waterlogged stress conditions. The method used in this study was an experimental method by conducting the experiment in the greenhouse of the Faculty of Agriculture, University of Mataram using polybags for drought and plastic buckets for waterlogged stresses. The experiment was carried out from April to November 2020, arranged with Split Plot Design with four replicates and two factors, i.e. stress conditions (S0 = normal, no stress, S1 = drought stress, and S2 = waterlogged (saturated water) stress) as the main plots, and soybean genotypes (G1 = KH-1, G2 = Argomulyo, and G3 = Grobogan) as the subplots. Variables observed includes: root/shoot ratio, root length, number of nodules, nodule weight, proline content, leaf chlorophyll content (chlorophyll a, b, total, a/b ratio), relative water content, stomata behavior (stomata open, close, open/close ratio). Data were analyzed with analysis of variance (ANOVA) and LSD at 5% level of significance using CoStat for Windows. The results showed that: a) The physiological responses of the three large-seeded soybean genotypes were more influenced by stress factors than the genotype factors especially on proline and chlorophyll b contents, number of stomata opened and clossed, and root/shoot dry weight ratio. b) The highest proline content and the number of stomata clossed occured under drought stress, while the number of stomata opened, the stomata opened/clossed ratio, the chlorophyll b content of KH-1 and the ratio of root/shoot of Argomulyo were the highest under waterlogged stress condition.