Phenotyping RIL Population to Identify Water Deficit Tolerant Lines in Groundnut (Arachis hypogaea L.)

Background: Genotype sensitivity to mid-season drought suggests the possibility of identifying genotypes with high yield potential and low sensitivity to mid-season droughts. The overall objective of the present research was to select genotypes with high tolerance to mid-season moisture stress. This effort includes assessing the variation of physiological and productive traits among RIL population lines, assessing the range of correlation for physiological and productive traits across two seasons and identifying a set of contrasting material under drought stress conditions. Methods: To assess the recombinant inbred lines (RIL) under moisture stress, we screened RIL population of groundnut with 432 lines and parents under mid-season drought stress conditions in rabi for two years. During the drought stress period, soil moisture content (SMC) and temperatures were measured. SPAD chlorophyll meter reading (SCMR), specific leaf area (SLA), relative water content (RWC), visual wilting rate (VWR) and canopy temperature (CT) were recorded at the end of the stress period. Pod yield per plant (PYPP), kernel yield per plant (KYPP) and shelling percent (SP) were recorded at harvest. Result: Physiological traits and yield attributes varied significantly among the RIL population. The Genotype by Trait biplot (GT biplot) revealed that the yield attributes showed a positive association with RWC, SCMR and a negative association with SLA, VWR and CT. The inbred lines were classified as visually healthy with high physiological and high or moderate yield traits; visually wilting with low physiological and low yield traits under a drought environment. The identified superior and inferior lines werefurther utilized to analyze genomic regions and genes for drought tolerance in groundnut.