Heritability and correlates of maize yield (Zea mays L.) under varying drought conditions
The study was undertaken to estimate broad-sense heritability and correlations between grain yields and other traits in maize under non-stress, intermediate stress and severe drought stress conditions. Fifty six genotypes were evaluated in a simple lattice design with two replications during the 2012/13 dry season at Institute for Agricultural Research farm Samaru (11o11'N; 07o38'E) in the Northern Guinea savannah of Nigeria. The results showed high (>60%) heritability estimates for all the traits studied except number of ears per plant under non-stress and intermediate stress that showed low (<30%) and moderate (30-60%) heritability of 33.33% and 50.00%, respectively, while leaf senescence under intermediate stress showed moderate heritability of 57.14%. The heritability of anthesis-silking interval (ASI), plant height, ear height, leaf senescence, and number of ears per plant increased with increasing drought stress, whereas, that of days to 50% tasseling, days to 50% silking and grain yield decreased with increasing drought stress. Correlation analysis revealed that days to 50% tasseling and silking under non-stress, ASI and leaf senescence under severe stress exhibited negative and significant correlations with grain yield. The correlations between grain yield and plant height, ear height under non-stress, intermediate and severe stress conditions, respectively and number of ears per plant under severe stress were positive and significant. Traits that had high heritability and positive correlation with grain yield may be considered as important traits in selection programmes aimed at maize yield improvement and the breeder may consider these traits as main selection criteria.
Keywords: Drought, Maize, Heritability, Correlation and Traits