Response of peanut genotypes to mid-season moisture stress: phenological, morpho-physiological, and yield traits

Nine peanut genotypes were evaluated in two seasons under irrigated and simulated mid-season drought conditions to investigate the influence of water stress on some phenological, morpho-physiological, and yield traits. Analysis of variance revealed significant genotypic differences for all the traits studied. Water saturation deficit and epicuticular wax load increased in response to water stress and age of the crop, while specific leaf area decreased with water stress and age of the crop. In general, correlations of water saturation deficit (WSD), epicuticular wax load (EWL), and specific leaf area (SLA) with yield traits were fairly weak. WSD in the early stage under irrigated conditions was found to be positively associated with pod yield under water stress; EWL in the early stage was negatively associated with harvest index (HI) under stress. Although significant and negative correlations of SLA were found only when it was recorded in the early stage under stress and the later stage under irrigated conditions with HI and pod yield (PY), both under irrigated conditions, the trends of its associations showed that SLA had rather weak and negative correlations with PY and HI both under irrigated and stress conditions. Genotypes that accumulated flowers sooner after initiation showed less yield reduction. The negative association between HI under stress and its reduction deems HI under moisture stress an important criterion of selection for drought tolerance in peanut.