Responses of rooting traits in peanut genotypes under pre-flowering drought stress

Abstract

The root is an important plant part contributing to peanut productivity under<br />water-limited conditions. Root volume, root surface area and root diameter may be<br />characters responding to pre-flowering drought (PFD) in peanut. The objectives of<br />this study were to investigate the responses to PFD for root surface area, root<br />volume and root diameter and to determine the inter-relationships among the<br />response of rooting traits and the response of yield. The experiment was conducted<br />under field conditions in the dry season 2007 and 2009. A split-plot experiment in<br />a randomized complete block design was used. The main plots were field capacity<br />(FC) and PFD and six peanut genotypes as the sub-plots. Root volume, root<br />diameter and root surface were measured by auger method at 25 days after<br />emergence (DAE), first seed (R5) and physiological maturity (R7). Total dry<br />weight and pod yield were measured at harvest. Root surface area of ICGV 98305<br />with increase in pod yield was greater in deeper soil layers under PFD compared to<br />FC treatment at both stress and recovery periods. Under PFD conditions, the<br />correlations between drought tolerance index (DTI) for root surface area at deeper<br />soil layer and DTI for pod yield in both seasons were positive and significant at<br />stress and recovery periods, but the correlations were not significant for root<br />diameter and root volume. The response of peanut for root surface area at deeper<br />soil layer contributed to pod yield. This finding could be useful for peanut<br />production in these drought conditions.<br />Keywords: Early season drought; Drought tolerance index; Root volume; Root<br />diameter; Root surface area.