Authors
Yan, X.; Beebe, S.E.; Lynch, J.P.
Source
Crop Science, Volume 35, Issue 4, p.1094-1099 (1995)
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Abstract
Phosphorus deficiency is a primary constraint to common bean ( Phaseolus vulgaris ) production in the tropics. Bean genotypes differ in their P efficiency, defined as growth and yield in low P soil. The objectives of this study were to evaluate genetic variation in diverse bean germplasms for P efficiency in soil types with contrasting P chemistry and to assess possible relationships between dry matter distribution, P partitioning and yield. Experiments were conducted at two sites in Colombia, one an Andosol in which P availability is limited by allophane and recalcitrant organic matter and the other an Ultisol in which P availability is limited by Fe and Al oxides. Three levels of P fertilization were used. Twelve contrasting genotypes were evaluated for yield components, harvest index and P partitioning. Genotypes yielded differently under P stress. Andean germplasm was often higher yielding under P stress than Mesoamerican germplasm but less responsive to added P fertility. Genotypic rankings for P efficiency did not differ in the two soil types. Reproductive parameters such as harvest index, yield components and P allocation among plant parts at maturity were not related to P efficiency. It is concluded that (i) there is no evidence for specific adaptation to low P availability in volcanic or mineral soils in beans; (ii) Mesoamerican and Andean genotypes respond differently to P availability; and (iii) vegetative and reproductive responses to low P availability are not always correlated.
