Drought Stress Adaptive Responses of Six Short-Cycle Cowpea Varieties Grown in Togo.

Abstract:

Drought stress is a major hindrance to cowpea cultivation. Current climate fluctuations lead to sudden droughts, posing a real threat for this crop. This survey aimed to evaluate the effects of an induced water deficit in 6 short-cycle cowpea cultivars grown in Togo (Amélassiwa, Ketcheyi, Ketcheyi-Soukpelo, Malgbong-Bomoine, Siéloune, and TVX). The experimental device, under semi-controlled conditions, was a split plot (three repetitions, two treatments) with two interacting factors, varietal type and water regime. Plants in the flower initiation phase were subjected to a water deprivation of 30% of available water content (AWC) for 14 days. Plants used as control were irrigated at 70% of AWC. The fluctuations in growth parameters, total protein, proline, and malondialdehyde (MDA) levels, as well as yield variables, were determined, and the data were analysed through ANOVA, Tukey's HSD, and principal component analysis (PCA). The drought susceptibility index (DSI), was used to distinguish drought-tolerant from susceptible varieties. As a result, ANOVA revealed a significant effect (p 0.05). However, a negative correlation between both contents was noted with a significant interaction of the factors on proline levels. The first two dimensions of PCA revealed that varieties that exhibited higher yields were correlated with proline content. According to DSIs and PCA, the six varieties can be divided into three categories: susceptible varieties (Ketcheyi and Amélassiwa), medium-tolerant varieties (Siéloune, Malgbong-Bomoine, and TVX), and high-tolerant varieties (Ketcheyi-Soukpelo).