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.

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.

Genetic control of agronomically important traits of pepper fruits analyzed by Hayman's partial diallel cross scheme.

Pepper species of the genus Capsicum have been cultivated over centuries, producing both pungent and sweet fruit; the pungency is caused by alkaloids called capsaicinoids. Among the five cultivated species, Capsicum chinense is one of the most popular, being native to the Amazon basin. This species is characterized by a wide variety of fruit sizes, shapes and colors, with different capsaicinoid content. In addition, fruits are rich in vitamins A and C. Despite the importance of this plant as a spice and its medicinal uses, research on its genetic variability and potential for breeding programs is still incipient. We investigated the genetic control of some traits through diallel analysis with the objective of introgressing these traits into cultivated varieties. For the diallel analysis, the progeny of crosses between peppers with pungent and sweet fruits, together with the parents, were grown in pots under greenhouse conditions. The fruits were harvested and analyzed for the traits total fresh fruit mass, total dry fruit mass, percentage dry matter, total soluble solids, vitamin C content, fruit pungency, and number of seeds per fruit. Genetic variability was detected for all traits. In the diallel analysis, the additive-dominant model was considered to be adequate for total fresh fruit mass, percentage dry matter, total soluble solids, and vitamin C content. Additive genetic effects and dominance were found for all traits; consequently, breeding for improvement of these fruit traits would be viable.

Genetic diversity of Capsicum chinensis (Solanaceae) accessions based on molecular markers and morphological and agronomic traits.

We estimated the genetic diversity of 49 accessions of the hot pepper species Capsicum chinensis through analyses of 12 physicochemical traits of the fruit, eight multi-categorical variables, and with 32 RAPD primers. Data from the physicochemical traits were submitted to analysis of variance to estimate the genetic parameters, and their means were clustered by the Scott-Knott test. The matrices from the individual and combined distance were estimated by multivariate analyses before applying Tocher's optimization method. All physicochemical traits were examined for genetic variability by analysis of variance. The responses of these traits showed more contribution from genetic than from environmental factors, except the percentage of dry biomass, content of soluble solids and vitamin C level. Total capsaicin had the greatest genetic divergence. Nine clusters were formed from the quantitative data based on the generalized distance of Mahalanobis, using Tocher's method; four were formed from the multi-categorical data using the Cole-Rodgers coefficient, and eight were formed from the molecular data using the Nei and Li coefficient. The accessions were distributed into 14 groups using Tocher's method, and no significant correlation between pungency and origin was detected. Uni- and multivariate analyses permitted the identification of marked genetic diversity and fruit attributes capable of being improved through breeding programs.

Effect of hydrocooling, packaging, and cold storage on the post-harvest quality of peppermint (Mentha piperita L. ) / Efeito do hidroresfriamento e embalagem sobre hortelã-pimenta fresca armazenada em temperatura ambiente e ambiente refrigerado

ABSTRACT The purpose of this study was to assess the effects of hydrocooling and polyethylene terephthalate (PET) perforated and non-perforated packaging on post-harvest quality of peppermint (Mentha piperita L.) leaves stored at 5 and 25ºC. The experiments were conducted using a subdivided parcel layout in a completely randomized design with four replicates. Each parcel used a 2x3 layout (two hydrocooling treatments and three packaging treatments) with subparcels for storage time. The shelf life, chlorophyll content, mass loss (ML), relative water content (RWC), total soluble sugars (TSS), reducing sugars (Red), non-reducing sugars (NRed) and starch of the leaves were determined. Cold storage increased the shelf life of the peppermint by up to 64 times (>15 days). Hydrocooling increased the RWC of the leaves. Plastic packaging was effective in maintaining the RWC. Unperforated packages more effectively prevented ML in the peppermint leaves and prevented the leaves from wilting for a longer period of time. The chlorophyll content of the leaves varied according to the treatment. The soluble sugars and starch levels varied according to RWC. Hydrocooling with the use of non-perforated plastic packages was the most effective method for maintaining the postharvest quality of the peppermint.

RESUMO O trabalho objetivou avaliar os efeitos do hidroresfriamento e da embalagem de politereftalato de etileno (PET) perfurada e não perfurada na qualidade pós-colheita de folhas de hortelã pimenta (Mentha piperita L.) armazenadas em temperatura ambiente e sob refrigeração. Os experimentos foram instalados seguindo o esquema de parcela subdividida, tendo na parcela o esquema fatorial 2x2 (dois tratamentos envolvendo hidroresfriamento e dois tratamentos envolvendo embalagens) e nas subparcelas os tempos de armazenamento no delineamento inteiramente casualizado com quatro repetições. Foi determinada a vida de prateleira, os teores de clorofila, a perda de massa fresca (PM), o teor relativo de água (TRA), os teores de açúcares solúveis totais (AST), redutores (RED), não redutores (NRED) e amido das folhas. O armazenamento refrigerado aumentou em até 64 vezes (>15 dias) a vida de prateleira de hortelã-pimenta. O hidroresfriamento aumentou o TRA das folhas. A embalagem plástica foi efetiva no aumento da vida de prateleira de hortelã-pimenta sendo eficiente na manutenção dos TRA das folhas. A embalagem não perfurada foi mais eficiente na prevenção da PM. O teor de clorofila das folhas variou de acordo com o tratamento. AST, RED, NRED e amido variaram de acordo com TRA nas folhas. O hidroresfriamento juntamente com utilização de embalagem não perfurada foi o método mais eficiente na manutenção da qualidade pós-colheita de hortelã-pimenta.