Abstract:
Common bean is an important food and cash crop, but its seed yield productivity is constrained by the soil phosphorus
(soil-P) deficiency among other factors. This study was implemented to determine variability of root traits and seed size of
14 bean genotypes, and identify genotypes with tolerance to low soil-P. A pot experiment was laid out in split-plot design
with two replicates. Highly significant (P<0.01) mean square differences were observed among the genotypes and the
genotype×soil-P interactions for all the root traits and seed size. Genotypes BFS-29, USRM-20 and SEF-15 all of Meso-American origin had the lowest values for seed size reduction rate and low fertility susceptibility index and were, therefore,
considered tolerant to low soil-P. Cumulatively PC-1 and PC-2 accounted for about 99% of the total variability and were both
highly correlated with Hypocotyl Root Length (HRL). PC-2 was also highly correlated with basal root whorl number, basal
root growth angle, basal root length and tap root diameter. Quadrant-3 comprised of genotypes USRM-20, SEF-15, BFS-29
and SAB-560 that were tolerant to low soil-P and were characterized with longer basal roots, large tap root diameter, and
high seed size. The tolerant genotypes need to be tested on a large scale, conserved and could be utilized in bean improvement programs for low soil-P tolerance.
