Assessment of Genetic Variability and Character Associations in Maize (Zea mays L.) Inbred Lines
Vijay Anjana *
Department of Genetics and Plant Breeding, Faculty of Agriculture Science and Technology, AKS University, Satna (M.P.) India.
Brindaban Singh
Department of Genetics and Plant Breeding, Faculty of Agriculture Science and Technology, AKS University, Satna (M.P.) India.
Ayodhya Prasad Pandey
Department of Genetics and Plant Breeding, Faculty of Agriculture Science and Technology, AKS University, Satna (M.P.) India.
Ankit Kumar Bhagat
Department of Genetics and Plant Breeding, Faculty of Agriculture Science and Technology, AKS University, Satna (M.P.) India.
Suhel Mehandi
Department of Genetics and Plant Breeding, School of Agriculture, Lovely Professional University, Jalandhar, Punjab, India.
*Author to whom correspondence should be addressed.
Abstract
This study was undertaken to quantify the extent of genetic variability, characterise trait associations, and partition the direct and indirect effects of yield components on grain yield in maize (Zea mays L.). Thirty inbred lines were evaluated for sixteen quantitative characters in a randomised block design replicated three times. Analysis of variance detected highly significant differences among the inbred lines for every character, confirming a broad base of genetic variability in the material. The phenotypic coefficient of variation (PCV; 4.13–117.97%) exceeded the genotypic coefficient (GCV; 4.13–115.89%) only marginally for all traits, both being high for cob length (115.89, 117.97), days to 50% pollen shed (43.70, 43.73), flag leaf length (26.22, 26.24) and flag leaf width (24.65, 26.37). Broad-sense heritability was consistently high (72.61–99.86%), and the combination of high heritability with high genetic advance as per cent of mean—recorded for cob length (91.53%, 242.70%), days to 50% pollen shed (99.54%, 89.97%), flag leaf length (92.65%, 53.98%), tassel length (88.16%, 34.70%) and cob diameter (92.59%, 31.87%)—points to predominantly additive gene action and to the effectiveness of straightforward selection for these traits; because the estimates derive from a single season and location, however, they require confirmation across multiple environments. Grain yield per plant was significantly and positively correlated, at both the genotypic and phenotypic levels, with cob weight, test weight, number of cobs per plant, cob compact index, cob length and shelling percentage, the corresponding genotypic correlations being 0.581**, 0.562**, 0.523**, 0.512**, 0.472** and 0.448*. Path coefficient analysis interpreted in light of the strong intercorrelation among yield components (genotypic residual effect 0.2561) identified cob length (0.459), cob weight (0.412), shelling percentage (0.354) and cob compact index (0.276) as the traits with the highest positive direct effects on grain yield. These traits are accordingly proposed as reliable selection criteria for improving grain yield in maize.
Keywords: Maize, genetic variability, correlation, path coefficient