Heritability of Drought Resistance.pdfVIP

CROP SCIENCE, VOL. 48, NOVEMBER–DECEMBER 2008 2245 RESEARCH Drought is the major abiotic constraint aff ecting peanut (Ara-chis hypogaea L.) productivity and quality worldwide. Two- thirds of the global production occurs in rain-fed regions of the semi-arid tropics where rainfall is generally erratic and insuffi cient, causing unpredictable drought stress, the most important constraint for peanut production (Wright and Nageswara Rao, 1994; Reddy et al., 2003). Even peanut grown under irrigation may experience drought because of limited water supply or because irrigation water is applied in amounts at frequencies less than optimal for plant growth. Improving water access and management are practically diffi cult since water is a scarce resource. Therefore, breeding for drought resistance is an important strategy in alleviating the prob- lem and off ers the best long-term solution. Selection of segregating populations under stress conditions has been a standard approach for developing cultivars with improved stress tolerance. While direct selection for yield under stressed conditions can be eff ec- tive, the limitations of this approach are high resource investment and poor repeatability of the results due to the large genotype × Heritability of Drought Resistance Traits and Correlation of Drought Resistance and Agronomic Traits in Peanut P. Songsri, S. Jogloy,* T. Kesmala, N. Vorasoot, C. Akkasaeng, A. Patanothai, and C. C. Holbrook ABSTRACT Inheritance of traits is important for develop- ing effective breeding schemes for improving desired traits. The aims of this study were to esti- mate the heritabilities (h2) of drought resistance traits and the genotypic (rG) and phenotypic (rP) correlations between drought resistance traits and agronomic traits, and to examine the rela- tionships between drought resistance traits under stressed and nonstressed conditions. The 140 lines in the F4:7 and F4:8 generations from four peanut (Arachis hypogae