Assessment of Maize (Zea mays L.) Hybrids across Spacings for Variability, Trait Association and Path Analysis in North Eastern India

The present investigation was conducted with nine genotypes in randomized block design (RBD) during Rabi, 2019-20 across the spacings viz., 60 cm x 20 cm and 50 cm x 20 cm at the ICR farm, AAU, Jorhat. In pooled analysis of variance, the genotype mean square across spacing was significant to highly significant for all the traits except ears per plant. The mean square due to genotype x spacing was significant to highly significant for the traits days to 50% silk, ears per plant, leaf area index at 60 DAS (days after sowing), leaf area index at 90 DAS, harvest index and grain moisture. Each of the hybrids responded similarly from spacing to spacing for the traits viz., days to 50% pollen shed, days to 100% dry husk, anthesis-silking interval, plant height, ear length, ear diameter, kernel rows per ear, kernels per row, 100 kernel weight and grain yield per hectare. One or more hybrids responded differently in the two spacings for the traits viz., days to 50% silk, ear height, ears per plant, chlorophyll content, leaf area index 60 DAS, leaf area index 90 DAS, harvest index, grain moisture and grain yield per plant. High heritability coupled with high genetic advance was observed for plant height, ear height, kernels per row, chlorophyll content, leaf area index at 60 DAS, leaf area index at 90 DAS, harvest index, grain yield per plant and grain yield per hectare across spacing and it indicated the preponderant role of additive gene action for these traits. Significant genetic association of both grain yield per plant and grain yield per hectare with days to 50% pollen shed, days to 50% silk, day to 100% dry husk, kernels per row, leaf area index at 60 DAS and leaf area index at 90 DAS indicated that grain yield could be improved indirectly by selecting superior plants for easily heritable traits like days to 50% pollen shed, days to 50% silk and days to 100% dry husk across spacing. Genotypic path analysis revealed that the characters viz., days to 100% dry husk, days to 50% pollen shed, ear length and kernel rows per ear had the highest positive direct effects on grain yield per plant while days to 50% silk and kernels per row had the highest negative direct effect on grain yield per plant across spacing.