CARACTERIZAÇÃO DE CULTIVARES DE Passiflora edulis Sims. EM DOIS NÍVEIS DE ADUBAÇÃO FOSFATADA EM RIO VERDE-GO: PARÂMETROS AGRONÔMICOS, GENÉTICOS E FISIOLÓGICOS

Abstract

Brazil is considered the world's largest producer of passion fruit and its cultivation is justified by the rapid economic return. However, inadequate management and the lack of cultivars with good agronomic characteristics lead to yields below the crop potential. Phosphorus (P) is one of the mineral elements that most limit crop productivity. The selection of genotypes with greater efficiency in the absorption, translocation and use of this element can contribute to increase the crop productivity. In this context, this study aimed to evaluate genetic parameters, agronomic performance and to compare the morphophysiological and biochemical responses in cultivars of passion fruit cultivated under conditions of high and low phosphate fertilization in southwest Goiás, in field conditions. The present work is structured in two chapters. Chapter I aimed to evaluate the genetic parameters estimation for agronomic and physiological variables in sour passion fruit under conditions of low and high phosphate fertilization. Five cultivars of passion fruit were evaluated. The statistical design used was the randomized blocks, with three replications and an experimental plot consisting of three plants. The treatments were allocated in two environments. In environment I (low phosphorus), 50% of the recommended dose was applied according to the soil analysis; 30 g P2O5 per pit. In environment II (high phosphorus) 100% more of the recommended dose was applied; 120 g P2O5 per hole. The following variables were evaluated: total productivity; average fruit weight; fruits longitudinal diameter; fruit transverse diameter; bark mass; shell thickness; pulp mass; soluble solids; titratable acidity; hydrogen potential; luminosity; Chroma: saturation (C); hue angle: hue (hab); maximum flow of energy retained by a PSII reaction center (TRo/RC); transpiratory rate (E); Photosynthetic rate (A); stomatal conductance (gs); chlorophyll a (Chl a); chlorophyll b (Chl b) and total chlorophyll (Chl a + b). The following parameters were estimated: Vg: genotypic variance; Vint: variance of the genotype x environment interaction; Ve: residual variance; h2mc: Heritability of the genotype average, assuming complete survival; Acclon: accuracy of genotype selection, assuming no loss of plots. rgloc: Genotypes correlation between performance in different environments; CVgi%: genotypic variation coefficient and CVe%: residual variation coefficient. The genetic values were estimated using the Software Selegen, using the REML/BLUP procedure. Estimates of genetic parameters by REML. The MF characteristic presented average heritability estimates of 0.58 and 0.79 in the low and high P environments, respectively, whereas the E characteristic presented values of 0.40 and 0.91 respectively in each environment. The high values for this parameter indicate that most of the observed phenotypic variation is due to genetic causes, which is of interest for studies with this purpose. The genetic parameters estimates for the agronomic and physiological variables revealed the possibility of success in the characterization of superior genetic materials of passion fruit for the region in question. The doses previously selected in chapter 1 were used in the study in chapter 2, which aimed to evaluate physiological variables and agronomic characteristics of passion fruit genotypes (hybrids and open pollinated cultivar) under contrasting conditions of soil P content. The experiment was carried out under the same conditions described above. No differences were observed between the environments under study. This study allows us to suggest that cultivars of passion fruit can be grown satisfactorily under conditions of low P availability.