Combining ability in sweet pepper for resistance to powdery mildew

Abstract

With the increase of the production of pepper in protected environment, pathogens began to cause serious damages to producers such as Leveillula taurica (Lév.) Arn., fungus that causes powdery mildew. The systemic fungicides have not shown very satisfactory results. Thus, considering that protected cropping of pepper in Brazil is significant and growing, the incorporation of genes that confer resistance to powdery mildew is important for the maintenance of this cropping system. In this research, carried out in 2007 in Campinas, São Paulo State, Brazil, the agronomic performance and resistance to powdery mildew was determined by triple hybrids of sweet pepper through general and specific combining ability of their parents. For agronomic performance of the triple hybrid, it was evaluated the weight length and width average of the fruit, length and width ratio of the fruit and wall thickness. For severity of powdery mildew a scale of scores from 1 to 5 was used. For statistical and genetic analysis, it was adopted Griffing's method two, model I, adapted for partial diallel. The experimental design was completely randomized blocks, with 17 treatments, including ten experimental hybrids and seven parents, eight replications and four plants per plot. The additive effects were greater than the non-additive effects for all agronomic characters; 'P36-R' and 'Platero' were highlighted as good combiners; 'Quantum-R x HV-12', 'Rubia x HV-12' and 'P36-R x HV-12' presented the best specific combining ability; the mean square of the specific combining ability for the severity of the disease was significant indicating the importance of genes with dominant and epistatic effect; triple hybrids obtained by crosses with 'Quantum-R' and 'Rubia-R' had negative general combining ability and the best reactions to powdery mildew.

Combining ability and gene action of hot pepper (Capsicum annuum L.) genotypes in Southern Ethiopia

“…Parents with various gca effects are combined to produce crosses varying in sca effects. This result is consistent with the findings reported by some researchers (Lohithaswa et al, 2000;Marchesan et al, 2009).…”

Estimation of genetic merit of diallel hybrids of sweet pepper by mixed models

“…The current strategy to develop superior cultivars has been based on the obtention of hybrids that prove their quality and superior traits in terms of the performance of genitor line. Nevertheless, this strategy can also be used to form a populationbase, that is, the selection of the best lines or crosses of double or triple hybrids, according to the estimates of general and specific combining ability (MARCHESAN et al, 2009).…”

Melhoramento genético de pimenta do tipo Jalapeño (>i<Capsicum annuum>/i< L.)

“…Os objetivos dos melhoristas devem estar alinhados às demandas da indústria e do consumidor in natura quanto às características qualitativas do fruto (Rego et al, 2011). Dessa forma, deve-se dar atenção aos estudos genéticos dos caracteres morfoagronômicos, como forma de avaliar o potencial genético dos genitores, de produzir descendentes melhores e de aumentar a eficiência dos métodos de melhoramento Fehr, 1987;Cruz & Regazzi, 1994;Marchesan, 2009;Gonçalves et al, 2011).…”