Gas exchange and leaf area requirement in tall ‘Prata’ banana

Abstract

The objective of this study was to evaluate the gas exchange and leaf area requirement for yield of six tall ‘Prata’ banana genotypes, under semi-arid conditions. The genotypes ‘Pacovan’ (AAB), ‘Pacovan Ken’ (AAAB), ‘Preciosa’ (AAAB), ‘Japira’ (AAAB), ‘PV79-34’ (AAAB) and ‘Garantida’ (AAAB) (four tetraploid hybrids and one triploid cultivar) were evaluated in two cycles, arranged in a completely randomized design in a factorial scheme, with five replicates and four usable plants per plot. For the physiological characteristics, a 6 x 12 x 2 factorial arrangement was adopted, with six genotypes, 12 evaluation periods and two reading times in each period, arranged in a completely randomized design. Of the 12 phytotechnical characteristics measured, seven were influenced by the interaction between the factors cultivar and cycle. Internal CO2 concentration, net photosynthesis rate, instantaneous water use efficiency, carboxylation efficiency and quantum efficiency of photosynthesis recorded in banana leaves are higher in the morning, favored by higher stomatal conductance and lower leaf temperature resulting from the meteorological conditions, while transpiration and intrinsic water use efficiency increase in the afternoon. The hybrid ‘PV79-34’ has higher yield and production efficiency per unit of leaf area, associated with high transpiration, compared to the tall ‘Prata’ banana cultivars.