The Effects of Midseason and Terminal Drought Stress on Morphological, Physiological and Seed Yield Attributes in Groundnut (Arachis hypogaea L.) for Malawian Genotypes

Abstract

Groundnuts (Arachis hypogaea L.), is the world’s 13th most important food crop, 4th most important source of edible oil and 3rd most important source of vegetable protein. Although, groundnut considered as a profitable venture, its production in African countries such as Malawi where it is grown at small-scale level with less application of modern technologies, still farmers are experiencing a sharp decline in yield. The decline in productivity is caused by several factors where drought due to inadequate and highly variable rainfall has been reported as the major causing factors of low groundnuts productivity. Therefore, developing groundnuts enhanced with drought stress is an inevitable strategy to serve the livelihood of the farmers. Current study aimed to determine the level of drought tolerance among segregating population using agronomical and physiological traits and to identify the effects of drought stress on water use efficiency (WUE) traits. Twenty-five genotypes from the International Crop Research for Semi-Arid Tropics (ICRISAT) were evaluated under glasshouse and field condition at three different levels of drought regimes in a glasshouse and one level at field condition making four drought treatments. The data collected after stress imposition were grain yield (GY), hundred seed weight (HSW), shelling percentage (SHP), SPAD chlorophyll meter reading (SCMR), specific leaf area (SLA) and relative water content (RWC). Drought tolerance index (DTI) and percentage yield reduction (PYR) were calculated to determine the effects of drought on water use efficiency (WUE) traits and performance of the genotypes. Drought treatments affected all traits studied and the magnitude varied significantly where the effects was more severe on 60 days after planting (DAP) followed by 90 DAP and later RD and watered condition. Genotypes also showed different degrees of tolerance where 8 genotypes with high yield and favourable adaptive traits for breeding were selected.