Genetic Gain for Adzuki Bean Beetle (Callosobruchus chinensis L.) Resistance in Ethiopian Chickpea (Cicer arietinum L.) Genotypes

Abstract

Chickpea (Cicer arietinum L.) is attacked by a number of insect pests, including the adzuki bean beetle (Callosobruchus chinensis L.). Genetic gains from selection to infestation by adzuki bean beetle were studied using 130 chickpea genotypes in 2009/2010. The test was conducted under ambient condition in the Entomology Laboratory of Holetta, Ambo and Debre Zeit, using RCBD in 3 replications. Data on infestation and seed damage levels were recorded and subjected to statistical analysis. Differences among the genotypes were mostly significant. Seed related traits generally exhibited larger heritable variations than insect related traits. The t-test revealed effective selection for almost all traits. Broad sense heritability varied from 43-76% and 0.20-11.00% for seed and insect related traits, respectively. The corresponding expected genetic gain ranged from 28-42% and 0.01-6.00% in the same order. Significant positive correlations were found among seed weight loss and three component characters, i.e. number of eggs, adults emerged and seed size. Number of uninfested seeds (%) and percent seed coat weight showed strong negative correlations with seed weight loss. Selection of genotypes could improve resistance to the beetle in this gene pool, but with a compromise for seed quality. A search for more suitable sources of variability and selection criteria would be  advisable with the adoption of molecular plant breeding tools for better selection efficiency and effectiveness.

Keywords: Broad Sense Heritability; Chickpea; Correlation Coefficient; Genetic Gain