Trocas gasosas em híbridos de maracujá-amarelo no semiárido

Abstract

The agronomic characterization and exploration of the genetic variability of the genus Passiflora reveal virtuous genetic resources in species subjected to the environmental conditions of the Semiarid, with contributions to the genetic improvement of a crop of great socioeconomic value. The objective of this work was to evaluate the vegetative and physiological characteristics of fifteen yellow passion fruit hybrids in semi-arid conditions. The experiment was conducted at IF Baiano – Campus Guanambi, BA. The 15 treatments, 10 genotypes: H09-10; GP09-02; H09-02; H09-14; H09-07; H09-09; FOP09; GP09-03; H09-30; FOP08, from the Active Germplasm Bank of the Genetic Improvement Program of Embrapa Cassava and Fruit Culture, and five commercial hybrids: FB200; FB300; BRS SC; BRGA; BRS Rubi, were arranged in a randomized block experimental design, with three replications and five useful plants per plot. Vegetative characters were measured in full vegetative development, only 90 days after transplanting (DAT) as many plants senesced, affected by Fusariosis, compromising the number of repetitions and making assessments at other phenological stages impossible. Meanwhile, gas exchange was evaluated at 90 DAT, at 08:00 and 14:00, and at 300 DAT, at 08:00, 10:00, 12:00, 14:00 and 16:00, without compromising the loss of plants due to Fusariosis, as the replications were performed on the same surviving specimens within treatments. The H09-10 hybrid showed earlier flowering, was physiologically more efficient in the morning, closed the stomata in the afternoon and restricted transpiration, in addition to exhibiting lower leaf temperature, higher photosynthesis rates and water use efficiency. Gas exchange and photosynthesis, at 300 DAT, varied between hybrids and times, and was greater in the morning, while transpiration was greater in the afternoon. The reduction in carboxylation efficiency is related to the action of non-stomatal factors. The gas exchange variables of the genotypes are directly correlated with the photosynthetically active radiation incident on the leaf.