Differential Responses of Dry Bean Genotypes to N and P Fertilization of a Central American Soil1

Abstract

AbstractIncorporation of nutrient use efficiency into existing cultivars may be necessary if advances in crop yields are to be maintained while supplies of fertilizer elements are decreasing. To do this we must have some knowledge of the amount of variability present in a species for nutrient‐use efficiency. The objective of this work is to report the diversity present among genotypes of dry beans (Phaseolus vulgaris L.) for nutrient use efficiency. For the purposes of this manuscript, nutrient use efficiency is defined as the ability of a genotype to produce above average yields under low soil fertility conditions and to possess the capacity to produce higher yields when additional nutrients are supplied.Differential responses of 124 genotypes of dry bean to two levels of soil fertility (N ‐f‐ P) were evaluated under greenhouse conditions. Significant differences among genotypes were observed at each level of fertility. Overall, the high fertility level significantly increased seed yield/plant (W), pods/plant (X), seeds/pod (Y), and single seed weight (Z), whereas genotypes responded differentially to added fertilizer for W, X, Y, and Z. The number of pods/plant (X) exerted a predominant influence on yields at both the low and high fertility levels. The main effect of the high fertility level was to enhance the role of X and Z in influencing seed yield/plant.Although the response of a genotype to an increased fertility level could not be predicted from knowledge of its performance at a lower fertility level, genotypic responses values realized under high fertility conditions could be predicted reasonably well from their corresponding high fertility means.Response was not specific to either improved or unimproved lines. We infer from our data that genotypes of beans have unique genetic properties that regulate their responses.