Early assessment of drought tolerance in oil palm D × P progenies using growth and physiological characters in seedling stage

Abstract Drought is a major constraint to oil palm plantation in many regions relying on rainfall. One strategy to overcome this problem is to develop drought-tolerant cultivars through screening and selection. Drought tolerance assessment based on growth and physiological traits provides an alternative approach for rapid screening especially in tree crops. The aims of this study were to determine the contribution of some growth and physiological parameters to drought response variation in oil palm seedling and to use those parameters to evaluate relative drought stress tolerance in tenera oil palm progenies. Eight D × P progenies were grown under well-watered, moderate and severe stressed conditions for a total of 6 months. Data on growth traits, maximum quantum yield (Fv/Fm), SPAD value and proline content were recorded. Principal component analysis (PCA) on studied traits revealed that PC1 and PC2 explained 74.57 and 76.80% of total variance in moderate and severe drought treatments, respectively. Major contributions towards the variation of control and drought-treated plants were identified and appeared to be growth traits in moderate drought stress and growth trait plus proline content in severe drought stress. According to drought tolerance index, PCA analysis and ranking method using integrated PCA values, PSU-106 and PSU-206 were identified to be relatively high tolerant to severe drought stress, while PSU-106, PSU-128, PSU-206 and PSU-208 were tolerant to moderate drought stress. Field validation of D × P progenies selected as drought tolerance is recommended to establish this indirect selection approach in oil palm breeding programme.