Adaptabilidade e estabilidade de genótipos de berinjela sob diferentes níveis de sombreamento

Abstract

Eggplant is an olericole of the Solanaceae family, originating in regions of tropical and subtropical climate. Its fruits develop well at temperatures around 25-35 ° C and relative humidity of 80%, therefore, in the Northeast, its cultivation is recommended throughout the year. Average temperatures above 32 °C accelerate fruit ripening, while temperatures above 35 °C, for prolonged periods, make pollen formation unfeasible, preventing full, mature fertilization in defective fruits, often not viable for the consumption. For eggplant producers in protected environments, one of the strategies to avoid losses and obtain the highest productive performance of each genotype is manipulation and optimization of the environment. For example, shading using meshes, this is a tool applied in the cultivation of vegetables, in an attempt to mitigate the effects of temperature and excessive radiation on plants. However, when the solar radiation is very low, due to excessive shading of the crop or the occurrence of consecutive cloudy days, a significant increase in the rate of flower abortion. Given this, it is clear that the environment can intensify or impair the productive potential of the genotypes. This is because there is an interaction between the genotype and the environment at all times. Considering the behavior of genotypes in different environments, it is possible to evaluate them by two phenomena: adaptability and stability. Therefore, the present study aimed to estimate the adaptability and stability of eggplant genotypes under different types of shading and times of the year using the REML / BLUP method. The experiments were conducted in two seasons (May-October / 2019 and November / 2019-April / 2020) in greenhouses with three types of shading: 1) Without cover; 2) Covering with 130 micron diffuser film and 3) Covering with black top and side screen with 50% shading. The combination of the two factors (Shading type x Time of year) gave rise to the six environments evaluated (E1-SC, E1-PD, E1-TS, E2-SC, E2-PD and E2-TS). In all locations, 12 eggplant genotypes were evaluated, with four replications and the experimental plot consisting of four plants. Four characters were evaluated: Fruit Catch Index (IPF), Number of fruits per plant (NF), Average fruit production per plant in g (PP) and In vitro pollen grain germination (GPIV). To assess the adaptability and stability of eggplant genotypes, statistical analyzes and the estimation of genetic parameters were carried out based on mixed models of the REML / BLUP type, using the SELEGEN software and the statistical model 51. According to the results obtained, there were agreement between the PRVG (Relative Performance of Genotypic Values), MHVG (Harmonic Average of Genotypic Values) and MHPRVG (Harmonic Average of Relative Performance of Genetic Values) methods for the characters PP, NF and GPIV, indicating that such methods have a high degree of agreement in the ordering of the materials. Therefore, the 135x60, 135x51, 135x141, CNPH 109, 109x60 and 109x141 genotypes highlighted by the MHPRVG method can be used for cultivation in various environments, with different genotype x environment interactions