Potencial de hibridação entre acessos de tomateiro para pré-melhoramento quanto à resistência à requeima

Abstract

Resumo -O objetivo deste trabalho foi avaliar genitores com potencial de hibridação para o pré-melhoramento do tomateiro (Solanum lycopersicum) quanto à resistência à requeima. Foram utilizados seis acessos de tomateiro (BGH-2102, BGH-2117, BGH-2127, BGH-2130, BGH-2332 e BGH-2343 como genitores resistentes e 15 híbridos F 1 originários destes genitores. Utilizou-se o delineamento de blocos ao acaso, com três repetições. As plantas foram inoculadas com uma mistura de esporângios de Phytophthora infestans, agente etiológico da requeima, na concentração de 5x10 3 esporângios mL -1 . A área abaixo da curva de progresso da doença foi utilizada para avaliar a resistência. Realizou-se a análise dialélica, tendo-se considerado o efeito de genótipos como fixo. Estimou-se a capacidade geral e específica de combinação dos acessos. O padrão de resistência dos genitores e da maioria dos F 1 foi o mesmo que o das testemunhas resistentes. Foram observados: variabilidade genética aditiva entre os genitores, predominância de efeitos gênicos não aditivos e desvios de dominância bidirecional no controle do caráter. A frequência de alelos favoráveis e divergentes para resistência à requeima é maior nos acessos BGH-2117, BGH-2127 e BGH-2343.Termos para indexação: Phytophthora infestans, Solanum lycopersicum, capacidade combinatória, fonte de resistência. Hybridization potential among tomato accessions for pre-breeding for resistance to late blightAbstract -The objective of this work was to evaluate parents with hybridization potential for pre-breeding of tomato (Solanum lycopersicum) for resistance to late blight. Six tomato accessions (BGH-2102, BGH-2117, BGH-2127, BGH-2130, BGH-2332, and BGH-2343) were used as resistant parents and 15 F 1 hybrids originated from these parents. The design was a randomized complete block with three replicates. The plants were inoculated with a mixture of Phytophthora infestans sporangia, the etiological agent of late blight, at a concentration of 5x10 3 sporangia mL -1 . The area under the disease progress curve was used to evaluate resistance. Diallelic analysis was performed, considering the effect of genotypes as fixed. The general and specific combining ability of the accessions was estimated. The resistance pattern of the parents and of most of the F 1 was the same as that of the resistant controls. The following were observed: additive genetic variability among the parents, predominance of nonadditive gene effects, and bidirectional dominance deviations in the control of the trait. The frequency of favorable and divergent alleles for late blight resistance is higher in the BGH-2117, BGH-2127, and BGH-2343 accessions.

Comparative Proteomics Reveals Set of Oxidative Stress and Thaumatin-Like Proteins Associated with Resistance to Late Blight of Tomato

“…Resistance source to the blight was identified in wild tomato species [32], however, when these genotypes were used in breeding programs, problems common to genetic trawling occur, because QTL's related to resistance against re-blight affect the characteristic morphoagronomics of interest [33]. An alternative to reverse this problem is to use resistance sources belonging to the same species that needs to be improved (S. lycopersicum), such as BGH-2127 access [7]. The differential characteristic of this genotype will provide faster recovery of the desired agronomic characteristics.…”

“…The experiment was conducted at the Federal University of Viçosa (UFV) in Viçosa, Minas Gerais, Brazil (20˚45'14''S, 42˚52'53''W, 648.74 m). The resistant genotype BGH-2127 access [7], conserved in the Gene Bank of Federal University of Viçosa, Minas Gerais State, Brazil, and susceptible cultivar Santa Clara [5], both belonging to the S. lycopersicum species, were evaluated. The plants were grown in a greenhouse in a completely randomized design with three replicates per genotype.…”

“…The access BGH-2127 conserved in the Gene Bank of the Federal University of Vicosa, Brazil used in this study belonged to the cultivated species Solanum lycopersicum and was highlighted for its resistant to late blight [7]. The differential characteristic of this species genotype enables its potential use in breeding programs to avoid the occurrence of common issues due to genetic drag when wild parents are crossed.…”

Tomato breeding for disease resistance

“…With this in mind, work to identify resistant germplasms within the cultivated species (S. lycopersicum) has been carried out, such as Fiorini et al (2010) and Laurindo et al (2016) identified in the Vegetable Germplasm Bank (VGB) of the Federal University of Viçosa (UFV) accesses with high levels of resistance to late blight, which presented reduced values of AUDPC (area under the disease progress curve).…”