Genetic variability, heritability and genetic gain for quantitative traits in South African sorghum genotypes

Abstract

Sorghum is one of the most important cereal crops grown in the world for human consumption, animal feed and bio-energy. The objective of the study was to estimate the genetic variability, heritability and genetic gain of some agro-physiological traits of 98 sorghum accessions in South Africa. The studies were conducted at Makhathini in KwaZulu-Natal and Burgershall in Mpumalanga provinces. The experiments were laid out in an alpha lattice design replicated twice. The plant height, panicle length, panicle width and panicle exsertion, rachis number, panicle weight, thousand seed weight, and grain yield per panicle were recorded. The data were subjected to analysis of variance using generalised linear model and means were separated using Duncan Multiple Range Test. Coefficients of variation were also determined. There were significant differences among the traits measured. Plant height was significant and positively associated with panicle length (r =0.139), panicle width (r = 0.127) and panicle weight (r = 0.1457). Panicle exsertion was highly significant and negatively correlated with all other traits except with plant height. The Principal Component analysis revealed three most important PCs contributing a total variation of 92.36%. The PC1, PC2, and PC3 contributed 42.53, 34.65 and 15.18%, respectively. Low, medium and high estimates of broad sense heritability were found in different plant characters under study. Highest heritability estimates were found in plant height, thousand seed weight, panicle length and rachis number. Values of genetic advance ranged between 0.39 to 17655.04 and the genetic gain (of the mean percent) ranged from 3.27 to 372.52. Greater magnitude of broad sense heritability coupled with higher genetic advance in traits studied provided the evidence that these were under the control of additive genetic effects indicating that selection in the germplasm should lead to a fast improvement of the traits.