Capsicum species are very important in Brazil because of economic, cultural and biological factors, and the country is considered to be a diversity center for this genus. Collection and maintenance of the genetic diversity in Capsicum are important to avoid genetic erosion. Besides the identification of species, the characterization and evaluation of accessions maintained in gene banks are of fundamental importance. For this purpose, multivariate methods have become an important tool in the classification of conserved genotypes. The objectives of this study were: i) to identify and characterize accessions of the Capsicum spp collection and draw conclusions about the potential use of certain accessions in different production sectors; ii) to estimate the genetic divergence among accessions using the Ward-MLM procedure, and iii) to evaluate the efficiency of the analysis of continuous and categorical data using the Ward-MLM procedure. Fifty-six Capsicum spp accessions were evaluated based on 25 descriptors, 14 of which were morphological and 11 agronomic. Based on the qualitative descriptors, it was possible to identify all species and, together with the agronomic descriptors, genotypes could be indicated with potential for use in various production sectors. Five was determined as the ideal number of groups by the criteria pseudo-F and pseudo-t 2 . The Ward-MLM procedure allowed the differentiation of the species C. annuum, C. frutescens, C. baccatum, and C. chinense in separate groups. The Ward-MLM procedure showed some level of efficiency in clustering Capsicum species analyzing morphological and agronomic data simultaneously.
The Capsicum breeding has been developed with emphasis in bell pepper (Capsicum annuum) and few studies are available in other species, especially C. baccatum, which has potential use not only as disease resistance source but also in obtaining new genotypes suitable for farmers' production. In the present work, the combining ability of ten C. baccatum hybrids, along with their five parentals, were tested considering 12 agronomic traits. The hybrids were produced from a complete diallel without reciprocals and assessed in greenhouse conditions, in Campos dos Goytacazes, Rio de Janeiro state, Brazil, during the period July to December 2009. The experimental design was a randomized block with three replications and the following agronomic traits evaluated: canopy diameter (CD), plant height (PH), days to fructification (DF), number of fruits per plant (NFP), mean fruit weight (FW), dry fruit matter weight (FDM), dry matter content (DM), fruit length (FL), fruit diameter (FD), pulp thickness (PT), total soluble solids (TSS) and yield per plant (PP). Significant differences were observed only for general combining ability (GCA) in regard to PH, FW, FDM, DM, PT and TSS, indicating that additive effects were involved on the control of these characters. For CD, DF, NFP, FL, FD and PP, there was significance not only for GCA but also for specific combining ability (SCA) indicating that non-additive and additive effects were important in genetic control of these traits. The hybrids UENF 1629 X UENF 1732, UENF 1616 X UENF 1732 and UENF 1624 X UENF 1639 were considered superior because they have favorable agronomic traits.
O uso de germoplasma em programas de melhoramento está relacionado à disponibilidade de informações sobre os acessos contidos numa coleção ou banco. A caracterização e a divergência genética e fenotípica entre acessos de bancos de germoplasma têm sido determinadas, e várias espécies de hortaliças já foram objeto de estudos nessa área. Com o objetivo de quantificar a divergência fenotípica entre 29 acessos de Capsicum spp., com base em caracterização morfológica e agronômica, 37 descritores foram analisados utilizando-se técnicas de componentes principais, análise de agrupamento e variáveis multicategóricas. O experimento foi conduzido em condições de campo, em Campos dos Goytacazes, RJ, no período de março a dezembro de 2004. Os dados obtidos foram analisados utilizando-se os recursos computacionais do programa GENES. Os grupos formados pelos métodos de Tocher e do vizinho mais próximo foram parcialmente concordantes. A análise de variáveis multicategóricas foi eficiente na quantificação da divergência fenotípica.
The Pepper yellow mosaic virus (PepYMV) naturally infects chili and sweet pepper, as well as tomato plants in Brazil, leading to severe losses. This work reports the reaction to the PepYMV of 127 Capsicum spp. accessions, aiming at identifying resistance sources useful in breeding programs. The experiment was carried out in a completely randomized design, with eight replications, in greenhouse conditions. Plants were protected with an insect-proof screen to avoid virus dissemination by aphids. Leaves of Nicotiana debneyi infected with the PepYMV were used as the inoculum source. Plants were inoculated with three to four fully expanded leaves. A second inoculation was done 48 hours later to avoid escapes. Only the youngest fully expanded leaf was inoculated. Two plants were inoculated only with buffer, as negative control. Symptoms were visually scored using a rating scale ranging from 1 (assymptomatic plants) to 5 (severe mosaic and leaf area reduction). Nine accessions were found to be resistant based on visual evaluation. Their resistance was confirmed by ELISA. Two resistance accessions belong to the species C. baccatum var. pendulum, while the seven other were C. chinense. No resistant accessions were identified in C. annuum var. annuum, C. annuum var. glabriusculum, and C. frutescens.
Genetic divergence among tomato accessions using RAPD markers and its comparison with multicategoric descriptorsThe estimation of genetic variability in a germplasm bank is important not only for the conservation of the genetic resources, but also for applications in plant breeding. The genetic divergence among 78 tomato accessions was studied, based on 74 RAPD markers. Also, a correlation between the molecular profile and 27 morphological and agronomic data was performed. Cluster analysis (UPGMA), used to study the data, resulted in 13 groups that were correlated with five descriptors (growth habit, leaf type, fruit color, locule number, and fruit shape). Some groups had particularities, such as group IV that assembled accessions with pear shape fruits; group VII, that clustered accessions with bacterial wilt resistance, and group IX, that gathered accessions with potato leaf type. Bootstrap analysis revealed few consistent clusters. The results showed a positive and significant correlation between the matrixes generated out of qualitative and molecular data (t = 14.02). Mantel's correlation was highly significant, but with a low value (r = 0.39), which suggests that for a wise use of the germplasm bank accessions, both characterization, molecular and morphoagronomic, should be carried out.
Herança de caracteres relacionados à produção de frutos emAbstract -This work aimed to estimate genetic parameters related to the fruits production in a chilli pepper diallel (Capsicum baccatum var. pendulum). Five chilli pepper genitors were evaluated (UENF 1616, UENF 1624, UENF 1629, UENF 1639 and UENF 1732) and its respective hybrids F 1 , from a complete diallel without reciprocals. The experiment was carried out in a greenhouse covered with plastic film located in area from the consortium UENF/PESAGRO-RIO, Campos dos Goytacazes, RJ, from July/2009 to December/2009, in a randomized block design with three repetitions and nine plants by plot. The following agronomic traits were evaluated: canopy diameter (CD); plant height (PH); days for fruiting (DF); number of fruits by plant (NFP); fruit average-weight (FAW); fruit dry mass (FDM); dry matter (DM); fruit length (FL); fruit diameter (FD); fruit wall thickness (PT); total soluble solids (TSS); and yield per plant (PROD). Only the FAW, FDM and PROD had absence of significance concerning the three tests of sufficiency for the additive dominant model, indicating that there is homogeneity among the variances and co-variances and, consequently, lack of epistasis in the control of character. For the FAW and FDM traits, the additive genetic effects were the most important ones. Nevertheless, in the PROD the dominance effect was the most important. It was verified a partial dominance for FAW and FDM, and an over-dominance for PROD. The genitors UENF 1616 and UENF 1629 were the ones which had larger concentrations of favorable alleles for the three characteristics under study.
ABSTRACT. We investigated inheritance of resistance to Pepper yellow mosaic virus (PepYMV) in Capsicum baccatum var. pendulum accessions UENF 1616 (susceptible) crossed with UENF 1732 (resistant). Plants from generations P 1 , P 2 , F 1 , F 2 , BC 1:1 , and BC 1:2 were inoculated and the symptoms were evaluated for 25 days. Subsequently, an area under the disease progress curve was calculated and subjected to generation means analysis. Only the average and epistatic effects were significant. The broad and narrow sense heritability estimates were 35.52 and 21.79%, respectively. The estimate of the minimum number of genes that control resistance was 7, indicating that resistance is polygenic and complex. Thus, methods to produce segregant populations that advocate selection in more advanced generations would be the most appropriate to produce chili pepper cultivars resistant to PepYMV.
Ornamental use of Capsicum genus chili peppers has expanded due to easy seed propagation, short germination period, diversified fruit colors and harmony of potted plants. The ornamental plant sector requires cultivars adapted to different cultivation conditions in pots and gardens. Breeding programs can use heterosis and combining ability information, aiming to commercially explore hybrids or develop populations for lineage selection with desirable characteristics. However, the ornamental chili pepper field lacks studies with this data. In this study, combining ability of C. annuum accessions was determined for ornamental purposes and hybrid combinations were identified based on heterosis values. Fifteen hybrids were obtained from diallel crosses of six genotypes of C. annuum, from March to September 2014, under greenhouse conditions, grown in five-liter pots in experimental design of randomized blocks with 10 repetitions and one plant per plot. Morpho-agronomic characterization was conducted based on eight quantitative descriptors: plant height (before and after fruiting); canopy diameter; days to flourishing; days to fruiting; fruit length and diameter, and number of fruits per plant. Both additive and dominance effects play important role in controlling the studied characters, indicating hybrid exploitation as well as development of superior lineages from the progress of segregating generations. Negative heterosis values resulted in reduction in height, time for flourishing and fruiting, as well as fruit diameter and length, which are desirable for ornamental Capsicum breeding program. Considering an ideotype for ornamental chili pepper cultivars, the hybrids UENF 1626 x UENF 1750, UENF 1750 x UENF 2030 and UENF 1626 x UENF 2030 can be recommended for cultivation with ornamental purposes.
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