Inheritance of pod cross-section in beans (Phaseolus vulgaris L.)

Summary

OSU 5062, a green bean line with a tendency for pods to become creasebacked (wider than deep) in cross-section, was crossed to near-round-podded cultivars ‘Oregon 83’ and ‘Slenderette’, oval-podded ‘Bountiful’, and flat-podded ‘Roma’, to further clarify the inheritance of pod cross-section. Differences among generations in pod cross-section index (PCS), calculated as pod width/depth, were small in the near-round x creaseback crosses (1.07 and 1.01 for ‘Oregon 83’ and ‘Slenderette’ versus 1.20 for OSU 5062). ‘Bountiful’ (0.63) and ‘Roma’ (0.50) differed to a greater extent from 5062. Generation means of individual plant PCS of the F₁ and F₂ were almost identical, were almost exactly intermediate between parents, and strongly supported additive inheritance. Backcross data generally supported additive inheritance, but in some cases indicated degrees of dominance of higher PCS. A generation means analysis indicated additive gene action, but deviations from an additive-dominance model were significant in each cross.