Association Analysis of Morpho-physiological Traits for Breeding Drought Tolerant Maize (Zea mays L.)

摘要

Drought is the universal abiotic stress condition, which limit maize production in different parts of the world. Occasionally it is unpredictable in terms of time and intensity, and can affects crops at different stages. The productivity of maize in India is low as compared to the temperate countries partly because of the moisture stress at critical growth stages, especially at flowering. It is expected that while breeding for drought tolerance genetic gains would be more rapid and predictable if desired morphological and physiological attributes could be identified. In the present study, an attempt was made to study the association of grain yield with various morpho-physiological traits under drought stress using 87 strains (60 hybrids, 23 parents and 4 checks) derived by line × tester mating design (20×3) conducted at two different moisture regimes (ⅰ) Optimum moisture at critical stages (E1), (ⅱ) Terminal moisture stress at flowering stage (E2). In stressed environment grain yield, plant height, ear height, ears per plant, 100 seed weight and harvest index showed 32.8%, 7.5%, 8.7%, 2.8%, 10.6% and 21.2% reduction respectively as compared to normal moisture. Plant height, ear height and 100-seed weight exhibited positive and significant associations at both the moisture conditions. Grain yield per plant manifested significant positive correlation with ears per plant, harvest index, 100-seed weight and tassel score in both the environments. Physiological characters like ASI, leaf rolling, desiccation tolerance (% injury) and chlorophyll stability index exhibited negative association with grain yield in E2 suggesting lower magnitude of these parameters are linked to higher grain yield under drought.