Comparison Between Irrigation and Non-Irrigation In Bean Flowering Stage.

Bean (Phaseolus vulgaris L.) is widespread in the social and economic scene in Brazil, as well it is Brazilian population main dish, and it also helps small and medium farmers’ income. The hypothesis is that if the water supply is suppressed in just one of the four development stages of irrigated beans, the yield reduction would be lower than 20%, allowing water economy.    The objective of this study was to compare the performance of bean Carioca group IAC Alvorada yield components in all possible stage combinations (vegetative, grain filling and maturation), with and without irrigation suppression during the flowering stage. The statistical design was randomized blocks with eight treatments and eight replications, with data subjected to contrast analysis. Irrigation was conducted to increase the soil water content to the condition equivalent to soil field capacity.  Comparing  irrigation only at flowering stage and the treatment never irrigated there was a significant difference in total number of pods, size of pods, but no  significant difference in grain weight and yield parameters. Comparing irrigation at all stages and irrigation at vegetative / filling/maturation stages, all variables showed significant difference between treatments.  In the treatment with irrigation in the vegetative stage, the contrast occurred in all variables analyzed, except for pod size. For irrigation in grain filling stage it was found significant difference for the variables:  yield, total number of pods, total number of loci and average number of grains per pod. For Vegetative/Filling and Vegetative /Maturation treatments the contrast was significant in total number of pods, pod length, number of locules per pod, average number of grains per pod and crop yield. The yield variable showed that only those treatments which had irrigation at vegetative stage suffered significant difference with 1% of significance, showing a contrast between irrigated or not in the flowering stage. So, the flowering stage should be irrigated at the same time that the vegetative one.