Characterization and genetic diversity of pepper (Capsicum spp) parents and interspecific hybrids.

Pepper species exhibit broad genetic diversity, which enables their use in breeding programs. The objective of this study was to characterize the diversity between the parents of different species and their interspecific hybrids using morphological and molecular markers. The parents of Capsicum annuum (UFPB-01 and -137), C. baccatum (UFPB-72), and C. chinense (UFPB-128) and their interspecific hybrids (01x128, 72x128, and 137x128) were used for morphological and molecular characterization. Fruit length and seed yield per fruit (SYF) traits showed the highest variability, and three groups were formed based on these data. CVg/CVe ratio values (>1.0) were calculated for leaf length (1.67) and SYF (5.34). The trait that most contributed to divergence was the largest fruit diameter (26.42%), and the trait that least contributed was pericarp thickness (0.33%), which was subject to being discarded. The 17 primers produced 58 polymorphic bands that enabled the estimation of genetic diversity between parents and hybrids, and these results confirmed the results of the morphological data analyses. The principal component analysis results also corroborated the morphological and random-amplified polymorphic DNA data, and three groups that contained the same individuals were identified. These results confirmed reports in the literature regarding the phylogenetic relationships of the species used as parents, which demonstrated that C. annuum was closer to C. chinense as compared to C. baccatum.

Genetic divergence of physiological-quality traits of seeds in a population of peppers.

Brazil has a great diversity of Capsicum peppers that can be used in breeding programs. The objective of this study was to evaluate genetic variation in traits related to the physiological quality of seeds of Capsicum annuum L. in a segregating F2 population and its parents. A total of 250 seeds produced by selfing in the F1 generation resulting from crosses between UFPB 77.3 and UFPB 76 were used, with 100 seeds of both parents used as additional controls, totaling 252 genotypes. The seeds were germinated in gerboxes containing substrate blotting paper moistened with distilled water. Germination and the following vigor tests were evaluated: first count, germination velocity index, and root and shoot lengths. Data were subjected to analysis of variance, and means were compared by Scott and Knott's method at 1% probability. Tocher's clustering based on Mahalanobis distance and canonical variable analysis with graphic dispersion of genotypes were performed, and genetic parameters were estimated. All variables were found to be significant by the F test (P ≤ 0.01) and showed high heritability and a CVg/CVe ratio higher than 1.0, indicating genetic differences among genotypes. Parents (genotypes 1 and 2) formed distinct groups in all clustering methods. Genotypes 3, 104, 153, and 232 were found to be the most divergent according to Tocher's clustering method, and this was mainly due to early germination, which was observed on day 14, and would therefore be selected. Understanding the phenotypic variability among these 252 genotypes will serve as a basis for continuing the breeding program within this family.

Epistasis and inheritance of plant habit and fruit quality traits in ornamental pepper (Capsicum annuum L.).

Two accessions of ornamental pepper Capsicum annuum L., differing in most of the characters studied, were crossed, resulting in the F1 generation, and the F2 generation was obtained through self-fertilization of the F1 generation. The backcross generations RC1 and RC2 were obtained through crossing between F1 and the parents P1 and P2, respectively. Morpho-agronomic characterization was performed based on the 19 quantitative descriptors of Capsicum. The data obtained were subjected to generation analysis, in which the means and additive variance (σa(2)), variance due to dominance deviation (σd(2)), phenotypic variance (σf(2)), genetic variance (σg(2)) and environmental variance (σm(2)) were calculated. For the full model, we estimated the mean effects of all possible homozygotes, additives, dominants, and epistatics: additive-additive, additive-dominant, and dominant-dominant. For the additive-dominant model, we estimated the additive effects, dominant effects and mean effects of possible homozygotes. The character fruit dry matter had the lowest value for broad sense heritability (0.42), and the highest values were found for fresh matter and fruit weight, 0.91 and 0.92, respectively. The lowest value for narrow sense heritability was for the minor fruit diameter character (0.33), and the highest values were found for seed yield per fruit and fresh matter, 0.87 and 0.84, respectively. The additive-dominant model explained only the variation found in plant height, canopy width, stem length, corolla diameter, leaf width, and pedicel length, but in the other characters, the epistatic effects showed significant values.

Combining ability for yield and fruit quality in the pepper Capsicum annuum.

The objective of this study was to determine the effects of the general and specific combining abilities (GCA and SCA, respectively) of 15 characteristics and to evaluate the most promising crosses and the reciprocal effect between the hybrids of six parents of the Capsicum annuum species. Six parents, belonging to the Horticultural Germplasm Bank of Centro de Ciências Agrárias of Universidade Federal da Paraíba, were crossed in complete diallel manner. The 30 hybrids generated and the parents were then analyzed in a completely randomized design with three replicates. The data were submitted to analysis of variance at 1% probability, and the means were grouped by the Scott-Knott test at 1% probability. The diallel analysis was performed according to the Griffing method, model I and fixed model. Both additive and non-additive effects influenced the hybrids' performance, as indicated by the GCA/SCA ratio. The non-additive effects, epistasis and/or dominance, played a more important role than the additive effects in pedicel length, pericarp thickness, fresh matter, dry matter content, seed yield per fruit, fruit yield per plant, days to fructification, and total soluble solids. The GCA effects were more important than the SCA effects in the fruit weight, fruit length and diameter, placenta length, yield, vitamin C, and titratable acidity characteristics. The results found here clearly show that ornamental pepper varieties can be developed through hybridization in breeding programs with C. annuum.