Aspectos fisiológicos e rentabilidade de híbridos de maracujazeiro-amarelo, cultivados sob taxas de reposição hídrica.

Abstract

Water is limiting factor for irrigated agricultural activities in semiarid area in view that plants growth, physiology and production are affected by water deficit or excessive moisture, which can reflect as a negative factor in the profitability of agricultural activity. Therefore, aimed evaluated with this work, the influence of different replacement rates ETo on physiological aspects and profitability of yellow passion fruit hybrids cultivated at the Sertão of Paraíba. The experiment was realized at the Campus IV of the State University of Paraíba, at the Catolé do Rocha-PB, which was arranged in blocks design with five replications and three plants per plot, on in factorial 4x2, being tested four ETo replacement rates (33, 66, 100 and 133%) and two yellow passion fruit hybrids ("BRS Sol do Cerrado" and "BRS Gigante Amarelo"). The variables studied were: absolute and relative growth rate of stem diameter, main of secondary and tertiary branch, stomatal conductance (gs), transpiration (E), carbon internai concentration (Ci), photosynthesis (A), water use efficiency (A/T), instantaneous carboxylation efficiency (A/C\), chlorophyll fluorescence, pulp and juice yield, longitudinal and transverse fruits diameter, mass and fruit number, total productivity and profitability. So much hybrids as water leveis affect the rates of growth, with the highest growth rate productive branches obtained in "BRS Sun Cerrado" between 70 and 100% ETo. Ci and A/T were affected only by hybrids, and the best results obtained with the "BRS Sol do Cerrado". E only was influenced by irrigation depth. Gs, A and A/Ci were influenced both by hybrids as by replacement rates ETo. On the hybrid "BRS Sol do Cerrado" the best results were obtained for gas exchange. The photochemical efficiency was not affected by water deficit and hybrids. With respect to quality, only juice yield and longitudinal fruit diameter were affected by hybrid factor, in BRS "Gigante Amarelo" obtained higher juice yield and "BRS Sol do Cerrado" the largest longitudinal diameter, the other variables (Pulp yield, longitudinal diameter and fruit mass) were not influenced by water deficit and hybrids. In water depths between 100 and 133% ETo in "BRS Sol do Cerrado", was obtained higher amounts of fruits produced per plant. The total yield was influenced by two factors, the maximum yield of 22.8 and 28.1 Mg ha"1 were obtained with the corresponding depth 100 and 133% ETo for "BRS Gigante Amarelo" and "BRS Sol do Cerrado", respectively.The treatments applied no possible prejudice, but the best economic performance was observed when the genotype "BRS Sol do Cerrado" was irrigated with 133% ETo. So the "BRS Sol Cerrado" as "BRS Gigante Amarelo" can be cultivated at the paraiban Setão area with ETo replacement rate of 100%, without compromising the vegetation performance, productive, qualitative, physiological and economic of the culture.