Estimativas de parâmetros genéticos para pigmentos foliares e caracteres agronômicos em diferentes populações de alface.

Abstract

The growing market for leaves of lettuce (Lactuca sativa L.) processed in Brazil has aroused new opportunities, including the search for cultivars that combine agronomic caracteristics and functional. However, the lack of knowledge of the genetic parameters and the type of gene action that govern these characteristics result in difficulties to obtain genotypes that meet this demand. The objective of this study was to determine the type of gene action involved with the contents of clorophyll and agronomic characteristics in lettuce. The research was conducted at the Experimental Station of Vegetables of the Federal University of Uberlândia (UFU), Monte Carmelo Campus, Minas Gerais. To perform the crosses and obtaining the generations P1, P2, F1, F2, BC1 and BC2 genotypes were used for the UFU-Albina#2, UFU-Albina#3, UFU-Lisa124#2#1, UFU-Crespa199#1#1 and UFU-Lisa217#5#2 as parents.. The generations were evaluated for three characteristics (number of leaf , diameter of plants and chlorophyll content). The parameters were estimated; genetic variance, environmental, phenotypic, additive, dominance in F2, heritability in the broad sense, heritability in the narrower sense, average degree of dominance based on averages, number of genes, measure the deviations of dominance , measurement of additive effects, measurement of all interactions of the additive x additive type, the measure of all interactions of the type additive x dominant and measure of all interactions of the dominant type x dominant. Among the three characteristics evaluated the chlorophyll content was the most influenced by the environment. The plant diameter of plant presented the highest heritability in the narrow sense to the intersection UFU-Lisa-124#2#1 x UFU-Albina#3 (82.1%). The number of genes for the number of leaves varied from inconclusive until a minimum of 9 genes. It is concluded that the gene interactions for number of leaves were shown to be of type partinal dominance. It is suggested that the characteristics assessed are polygenic nature or oligogenic.