Analyzing the Variability in Maize (Zea mays L.) Genotypes Using Principal Component Analysis under Varied Ecosystems

Abstract

Maize is a cereal cross-pollinated crop which belongs to the family poaceae. It is grown over a wider range of environment than any other cereal crop. The present study was conducted to study genetic variability using principal component analysis. Twenty maize genotypes were used in the study. Ten characters viz., plant height, ear height, days to 50 % tasselling, days to 50 % silking, ASI, cob length, number of rows per cob, hundred seed weight, shelling percentage and yield were recorded for the study. In the PCA, four principal components exhibited eigen value more than 1.0 exhibiting 84.54 percent of the variability for the characters under irrigated conditions. The PC1 negative loadings for the flowering traits, viz., days to 50 % silking (-0.3886), ASI (-0.3233) and days to 50 % tasselling (-0.2972) and positive loadings with higher contribution from cob length (0.4033), no of rows per cob (0.3480) followed by shelling percentage were observed. Positive loadings were exhibited by days to tasselling (0.4780), plant height (0.4670) and hundred seed weight (0.4518) in PC2. In PC3 positive loadings for the characters viz., number of rows per cob (0.5338), ASI (0.5226) and cob length (0.3299) and negative loadings for the traits grain yield (-0.3815), ear height (-0.2658) and plant height (-0.2437) and in PC4 positive loadings for plant height (0.4953), ear height (0.2546) and negative loadings were shown by days to grain yield (-0.6632), shelling percentage (-0.3751), ASI (-0.2369) and 50 % silking (-0.0648) were observed. In rainfed conditions, the two principal components had eigen value of more than 1. Under normal irrigated condition,  PC1 and PC2  had eigen value of 5.689 and 1.6439. Plant height (0.3866), cob length (0.3726), number of rows per cob (0.3551), shelling % (0.3196), grain yield (0.2941), and hundred seed weight (0.2847) contributed positively to PC1. PC 2 had highest positive contributions from days to 50 % tasselling (0.5676), days to 50 % silking (0.5249), shelling % (0.3885), hundred seed weight (0.3763) and grain yield (0.2007). Negative loadings were shown by ear height (-0.1356) and plant height (-0.0093). Positive loadings were contributed by days to 50 % tasselling (0.5676), Days to 50 % silking, shelling percentage (0.3885) and hundred grain weight (0.3763).