Screening for yield-related agronomic traits in a panel of locally conserved common bean (Phaseolus vulgaris L.) accessions

Abstract

Characterization and conservation of germplasm is a critical step toward the genetic improvement of the crop. This study assessed variation in 257 common bean genotypes which included 207 accessions obtained the National Gene Bank of Kenya, 33 accessions from Kenya Agricultural and Livestock Research Organization (KALRO), 13 landraces collected from farmers' fields and four commercial varieties for various agronomic traits. The experiments were laid out in a randomized complete block design with three replicates at Jomo Kenyatta University of Agriculture and Technology (Kenya) for four seasons between 2019 and 2020. Significant differences (P≤0.05) existed among the common bean accessions for all traits studied. Seed yield ranged from 220.6 to 4641.9 kg/ha (KNB0106) among the accessions with a mean of 1267.0 kg/ha. Significant (P ≤0.05) positive correlation was recorded for days to flowering and days to maturity (0.73), while 100-seed weight had a significantly negative correlation with the number of pods per plant (-0.66) and the number of seeds per pod (-0.65). High (>20%) broadsense heritability was recorded for 100-seed weight (89.0%), days to flowering (76.8%), and grain yield (60.5%). Nineteen accessions that combined early maturity and high-yielding traits were identified. On average, higher seed yields were recorded for large-seeded and climbing genotypes compared to smallseeded and bush types. Common bean accessions characterized can be exploited in breeding programs.