Effect of seed phosphorus concentration on nodulation and growth of three common bean cultivars

An experiment was conducted in the greenhouse to evaluate the effects of se ed phosphorus (P) concentration on growth, nodulation, and nitrogen (N) and P accumulation of three common bean (Phaseolus vulgaris L.) cultivars. See ds were produced under low or high soil P levels, and soaked, or not, in 20 0 mM KH2PO4 solution. The experiment had a 3x3x2x2 factorial block design: three cultivars (ICA Col 10103, Carioca and Honduras 35), three levels of a pplied P (15, 30 and 45 mg P kg(-1) soil), two native seed P concentrations , and two seed soaking treatments. Plants were harvested at flowering. Soak ed seeds increased the number, dry mass and P content of nodules, but did n ot affect plant growth. Plants originated from seeds with high native P con centration presented higher shoot dry mass and nodule number and mass at ev ery soil P level, and were less responsive to increased soil P supply, than plants from low seed P. In plants from seeds with high P, soil P levels di d not alter significantly root dry mass, while in plants from seeds with lo w P bean cultivars expressed wider differences in root dry mass. The genoty pic variability of nodulation was influenced by soil P levels and seed P co ncentration. Both higher soil or seed P supply enhanced N and P accumulatio n in shoots. These results indicate that a high seed P concentration produc es plants less dependent on soil P supply, and can enhance nodulation and N , fixation of common bean. Seed P supply affected the cultivar performance, and should be considered in evaluation of bean genotypes.