Dry matter and grain production of two Brazilian bean genotypes in response to phosphorus nutrition
The amount of absorbed phosphorus directly impacts on the growth and grain yield of common bean plants. We evaluated dry matter production at different growth stages and grain yield of common bean genotypes in response to phosphorus availability in a nutrient solution and examined possible associations between these characters. The experiment was carried out in a greenhouse, using a completely randomized design in sub-sub-divided plots. The main plots consisted of five phosphorus concentrations (0.5; 0.9; 1.3; 1.9 and 2.3 mmol.L-1) supplied to plants in a nutrient solution in the growth medium. The sub-plots were composed of two common bean genotypes (Pérola and IPR88 Uirapurú, which are commonly used in Rio Grande do Sul state) and the sub-sub-plots by two growing seasons (fall-winter and spring-summer). In the initial stages, at the first trifoliate leaf and flowering stages, the highest dry mass production occurred in the leaves. As the plants developed, they produced more dry matter in the pods during the pod filling stage, and later in grains, at the maturation stage. Phosphorus concentrations in the nutrient solution between 1.33 and 1.84 mmol.L-1 provided the greatest mass of beans at podfilling and at maturation, the largest number of grains and the greatest grain yield in the two genotypes. The characters dry mass of the leaves, stems and pods in pod filling, dry mass of grains at maturity, number of grains and number of pods are promising for indirect selection criteria.