Response of field pea genotypes to the infestation of Adzuki bean beetle (Callosobruchus chinensis L.) under different soil fertility regimes and locations in Ethiopia.

Field pea (Pisum sativum L.) is an important source of protein and income for smallholder farmers in Ethiopia. But recently, it has faced challenges due to a storage pest, the Adzuki bean beetle, Callosobruchus Chinensis (L.) (Coleoptera: Bruchidae). The response of 80 field pea genotypes managed under different soil fertility levels was evaluated under no-choice conditions for this pest infestation in the laboratory with a randomized complete block design with three replications at two locations during 2017/18. Except for thousand seed weight and percentage of seed coat weight of seeds, combined ANOVA at the two locations showed a highly significant difference (p = 0.01) for the following traits: number of eggs, date of adult emergency, number of adults, adult recovery, mean number of holes per seed, percentage of seed damage and susceptibility index. However, all traits values showed highly significant variations among genotypes. When genotypes were grown with neither rhizobium nor phosphorus, rhizobium only, and rhizobium and phosphorus, the lowest and highest values ranges of genotypic coefficient of variation (GCV) and phenotypic coefficient of variation (PCV) were observed for trait susceptibility index and thousand seed weight. Except for the percentage of seed weight loss, percentage of seed coat, thousand seed weight, and number of holes per seed, PCV was consistently higher than the corresponding GCV for more traits at each fertility level. We found moderate to high genetic advance as a percentage of mean and high heritability coupled with high genetic advance over percent mean for the traits thousand seed weight and proportion of seed coat weight across all fertility levels. Small-seeded field pea, Pisum var. abyssinicum genotypes fpcoll-1/07, fpcoll-2/07, fpcoll-21/07 and fpcoll-43/07 were moderately resistant, while the levels of the pea variety Adi were consistently more susceptible to Adzuki bean beetle than the other genotypes at all fertility levels. [ABSTRACT FROM AUTHOR]