Yield formation in Nicaraguan landraces of common bean compared to bred cultivars

Abstract

Dry matter accumulation and its partitioning to different plant components were studied in six common bean populations (two bred cultivars and four landraces) with different yield potentials. The hypothesis that yield was correlated with leaf area or mass and also with leaf area duration was tested. Leaf area and total above-ground dry matter were sampled weekly between 13 and 62 days after planting (DAP). Yield, yield components and seed yield rate were measured at the final harvest. No differences in total above-ground dry matter were observed among populations up to 62 DAP. Bred cultivars had significantly larger leaf areas than the landraces at the last harvest. Landraces initially partitioned more dry matter to reproductive organs but this was not reflected in higher yields. Temporary differences in growth rate and rate of pod formation were observed among the populations. Landraces, with one exception, tended to grow faster at early stages, and they also reached their maximum number of pods per plant earlier than the bred cultivars. Bred cultivars yielded more than all but one of the landraces. In general, yield was positively correlated with the total number of pods per plant, which in turn was well correlated with leaf area and mass. It was concluded that an increase in leaf area duration and a balanced development of reproductive organs v. other plant components are important traits in conferring improvement in yield of common bean.