Resistência à mancha-bacteriana e características agronômicas de linhas recombinadas de Capsicum annuum L.

Abstract

RESUMOO objetivo deste trabalho foi avaliar a reação à mancha-bacteriana (RMB) e o desempenho agronômico de 18 linhas recombinadas, provenientes do cruzamento entre um pimentão suscetível (UENF 1421) e uma pimenta resistente (UENF 1381). Para RMB, seis plantas de cada genótipo foram conduzidas em casa de vegetação, e inoculadas com suspensão bacteriana na concentração de 10 5 ufc mL -1 . A avaliação foi realizada por dois métodos: a escala de notas, variando entre 1 (resistente) e 5 (suscetível) e pela área abaixo da curva de progresso da doença. Para o desempenho agronômico, foi instalado um experimento em campo, conduzido em blocos ao acaso, onde se avaliou a produção e padrão de frutos, arquitetura da planta e a presença de capsaicina. Os dados foram submetidos à análise de variância, agrupando-se as médias pelo teste Scott Knott e foram estimados os parâmetros genéticos. Cinco linhas foram resistentes à mancha-bacteriana. Destacaram-se as linhas pungentes 8 e 13, por seu número e massa média de frutos de formato cônico; a linha 11, pelo formato do fruto e porte anão foi indicada para utilização como ornamental. A linha 1, não-pungente, destacou-se, pelo formato cônico e por frutos de 13 gramas. Palavras-chave:Desempenho agronômico, parâmetros genéticos, pimenta, pimentão, Xanthomonas euvesicatoria Bacterial spot resistance and agronomic characteristic in Capsicum annuum recombinant inbred lines ABSTRACTThe aim of this work was to evaluate the bacterial spot resistance and the agronomic performance of 18 recombinant lines from crosses between a susceptible sweet pepper (UENF 1421) and a resistant chili pepper (UENF 1381). For bacterial spot resistance, six plants of each line were grown under greenhouse conditions and inoculated with a bacterial suspension in a 10 5 cfu mL -1 concentration. The evaluation were done using two methods: a rate scale, from 1 (resistant) to 5 (susceptible) and calculating area under progress disease curve. The agronomic performance estimate, an experiment was carried out in randomized block design, which evaluated the pattern and production of fruit, plant architecture and the presence of capsaicin. The data were submitted to analysis of variance, Scott Knott test of mean clustering and genetic parameters were estimated. Five lines were resistant to BS. Lines 8 and 13, had higher yield of pungent fruits in a conical shape. Line 11 has a potential considering ornamental purposes, since it has a small size of the plant. Line 1, is a non-pungent type, by its conical shape and fruit of 13 grams.

Phenotypic and genotypic variation among Capsicum annuum recombinant inbred lines resistant to bacterial spot

“…In RILs 1, 2, and 6 and the cultivar 'Casca Dura Ikeda', capsaicin was absent (Table 2). These data agree with those obtained by Moreira (2008). Capsaicin, an alkaloid that confers pungency in the fruits of some Capsicum spp, is produced in the placenta and released when the fruit is physically damaged (Moreira et al, 2006).…”

“…RILs evaluated in this study were originally derived from crosses between accessions UENF 1381 and UENF 1421, and thus far, the selection made in the advanced generations of this bi-parental cross are considered to have several agronomic attributes and resistance to BS (Moreira, 2008;Riva-Souza et al, 2009;Moreira et al, 2009Moreira et al, , 2010. Thus, the presence of different phenotypic expressions in the descriptors evaluated shows the variability of the RILs, even those aiming for selection for specific traits, as well as the efficiency of these descriptors in the differentiation of RILs.…”

Inheritance of bacterial spot resistance in Capsicum annuum var. annuum

“…From the scoring scale, the results showed that all P 1 parent plants reached an incidence of 100%, i.e., all plants were susceptible ( Figure 4A). These findings corroborate those reported in preceding studies such as Moreira et al (2013aMoreira et al ( , 2015. Moreover, P 2 had its resistance confirmed ( Figure 4B), as already observed by Moreira et al (2010Moreira et al ( , 2013b and Pimenta et al (2016).…”

“…It confirms this genotype resistance since the smaller the affected area, the more resistant is a genotype (Table 1). Riva-Souza et al (2009) and Moreira et al (2015), evaluating plants at the same time, also confirmed resistance by lower means for the same resistant parent, which were 15.67 and 15.5, respectively. Likewise, Demosthenes and Bentes (2011), evaluating resistance to bacterial wilt in of Capsicum accessions, reported plants with lower AUDPC, being classified as resistant.…”

“…Genetic control of bacterial spot resistance in sweet peppers has been the focus of studies seeking for resistance sources and resistant cultivars abroad and in Brazil (Cook and Stall, 1982;Jones et al, 2002;Riva et al, 2004;Riva-Souza et al, 2007;Stall et al, 2009;Vallejos et al 2010;Moreira et al, 2015).…”