Physiological and colorimetric phenotyping in obtaining genetic gains by indirect selection in Capsicum

Fenotipagem fisiológica e colorimétrica na obtenção de ganhos genéticos por seleção indireta em Capsicum

For the development, growth and reproduction of plants, light is one of the most important environmental factors. This work presents the characterization of accessions of three Capsicum species from the germplasm bank of the Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF) Campos dos Goytacazes, Rio de Janeiro, Brazil, in terms of physicochemical traits of ripe fruits, and the influence of light and temperature on leaf reflectance indices. Eleven accessions were grown under shade and direct sun conditions at UENF. The experimental design used randomized blocks in a simple genotype x environment factorial with three replications. Three ripe fruits were collected from each plant for physicochemical phenotyping. Fruit color and total soluble solids (TSS) content were assessed using colorimetry and digital refractometry, respectively. Leaf reflectance indices were obtained during the fruiting stage in the three accessions. The data were subjected to analysis of variance and Scott-Knott and Tukey tests. Canonical correlation analysis was used to estimate existing relationships between colorimetric and physiological traits. Fruits were graded into seven color categories using a colorimeter: red, dark red, light yellow, pale yellow-orange, orange, orange with purple spots, and brown. Significant variability in TSS was recorded (5.59 to 13.04 ºBrix). Normalized Difference Vegetation Index (NDVI) and Water Band Index (WBI) traits co-associated at high magnitude with colorimetric traits, thus offering an alternative for indirect selection promoting genetic gains in Capsicum.

Keywords:
spectral reflectance; genetic resources; abiotic stress; plant breeding