Evaluation of genetic variability and interrelationships among M3 and M4 maize inbred lines in Kenya

Abstract

The present study was conducted at Jomo Kenyatta University of Agriculture and Technology, Juja to assess the agronomic performance of mutant maize lines of 39 filial generation 3 (M3) and filial generation 4 (M4) maize lines and a check variety among agro-morphological traits with their association with grain yield. Data on various agro-morphological characters were recorded using morphological descriptors for maize and analyzed using Genstat Release 14.1. Data was also subjected to XLSTAT 2014 and DARwin 6.0.12 software for principal and cluster analyses. Results obtained differed significantly in herbicide tolerance days for both M3 and M4 (p≤0.01). However, plant height, maturity days, flag leaf length and width, grains ear-1, ear length, ear diameter and grain yield plant-1 differed significantly in M3 and M4 lines (p≤0.05).\xa0 Grain yield plant-1 showed a strong significant positive correlation with anthesis days, plant height, grains ear-1 and ear diameter and length but negatively correlated with days to pollen shedding, tasseling, maturity and tolerance in M3 while flag leaf width, harvestable and total ears plant-1 showed positive and significant correlation but negatively correlated with tolerance days in M4. Principal component analysis showed variations among mutated maize lines in M3 and M4 with first seven principal components (PC) indicating that the first six PCs explained 78.69% and first six PCs contributing 71.28% respectively of the total variation. Cluster analysis showed three clusters and seven sub-clusters indicating differences in morphological diversity among the M3 inbred lines and two clusters with cluster one of hybrid 513 and three sub-clusters in cluster two of hybrid 520. Plant height, flowering days and ear length were crucial phenological traits determining grain yield among herbicide tolerant lines showing significant variability that could be considered in hybridization and development of herbicide tolerant hybrid genotypes in future maize breeding programmes.