Understanding genetics and the gene interactions involved in the expression of certain characteristics becomes a determining factor for better exploration of its use. The development of breeding programs that combine one or more desirable trait into a single cultivar is directly impacted by this lack of knowledge of the genetic bases involved. The objective of the present study was to estimate the genetic parameters involved in pigment expression and agronomic characteristics in lettuce. Parental evaluations of lettuce, P1 (green) and P2 (purple) parental generations, the segregating generations F1 and F2, and the backcrosses Bc1 and Bc2 originating from the UFU-Crespa199#1#1 x UFU-Albina#2 crossing were evaluated. The chlorophyll and anthocyanin contents, number of leaves and plant diameter were evaluated. The study was conducted by testing all generations and the estimates obtained by averages and variances. Indications of polygenic or oligogenic inheritance were verified by the characteristic number of leaves, plant diameter, and anthocyanin content. The complete and additive-dominant models satisfactorily explained the performance of the variables, except the anthocyanin content.

ABSTRACT:The objective was to evaluate the genetic variability among pepper accessions al the physical and chemical characteristics of fruit. Pepper accesses are from the Germplasm Bank at the Federal University of UberlandiaMonte Carmelo Campus (Universidade Federal de Uberlândia-UFU, Campus Monte Carmelo, MG, Brazil). The experiment was conducted from November 2013 to March 2014 at UFU's Experimental Station on the Monte Carmelo campus, MG, Brazil. The statistical design consisted of randomized blocks with 47 treatments and four replications. Multivariate analyzes were performed for quantitative traits in 47 pepper access by principal component analysis. Means were compared by Scott-Knott test (α = 0.05). Mature fruits were collected 120 days after transplant and used to determine titratable acidity (TA), total soluble solids (SS), pH and SS/TA. There was genetic variability among accessions. The 47 accessions showed high soluble solids content of 9.08 ° Brix, acidity of 0.22, pH of 5.50 and an SS/TA ratio of 33.8. This last characteristic is of great importance in the food processing industry. UFU accession 28 has high levels of SS and TA and is therefore a candidate for Pepper breeding programs that target the needs of the food processing industry.

The lack of knowledge of the genetic parameters and the type of gene action results in difficulties to obtain varieties that combine agronomic and functional characteristics. The objective of this study was to determine the type of gene action associated with the contents of chlorophyll and agronomic characteristics in lettuce populations. The research was conducted at the Experimental Station of Vegetables, Monte Carmelo, Brazil. To perform the crosses and obtain the generations P1, P2, F1, F2, Bc1 and Bc2 the genotypes UFU-Albina#2, UFU-Albina#3, UFU-Lisa124#2#1, UFU-Crespa199#1#1 and UFU-Lisa217#5#2 were used as parents. The generations were evaluated for three characteristics: number of leaves, plant diameter and chlorophyll content. The parameters: genetic, phenotypic, environmental and additive variance, the dominance in F2, heritability in the broad and narrow-sense, the average degree of dominance based on averages, number of genes, the measure of the dominance deviations, additive effects and all interactions of ‘additive x additive’, ‘additive x dominant’ and ‘dominant x dominant’ type, were evaluated. Chlorophyll content was the most influenced by the environment. Plant diameter had the highest narrow-sense heritability for the cross UFU-Lisa-124#2#1 x UFU-Albina#3 (82.1%). The number of genes for the number of leaves varied from inconclusive to a minimum of 9 genes. The gene interactions for number of leaves were of overdominance type, while for plant diameter and for chlorophyll content the gene interactions were of partial dominance. The characteristics are suggested as being of polygenic or oligogenic nature.

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.