Research Article

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

Published: April 17, 2013
Genet. Mol. Res. 12 (2) : 1232-1242 DOI: 10.4238/2013.April.17.2

Abstract

A breeding program carried out under Brazilian growing conditions to obtain Capsicum annuum cultivars with disease resistance to bacterial spot (BS) produced 8 promising recombinant inbred lines (RILs). The present study aimed to characterize these RILs using phenotypic descriptors and molecular markers (inter-simple sequence repeat) and to confirm their resistance to BS. Twenty-two phenotypic descriptors and 15 inter-simple sequence repeat primers were used to characterize the RILs. The parent, UENF 1381, which is resistant to BS, and 'Casca Dura Ikeda', a traditional cultivar, were used as standards. Variability among genotypes was observed considering either binary or multicategorical characteristics, such as fruit length, fruit diameter, and fruit longitudinal and transversal section. Such variability in fruit traits can be exploited to develop new genotypes with BS resistance for various types of market consumption. RILs numbered 1, 3, and 6 were the most homogenous, whereas those coded 2, 5, 8, and 11 had the same level of heterogeneity as that observed in 'Casca Dura Ikeda'. Molecular analysis clustered the genotypes into 5 groups, with RILs 1, 2, 3, and 5 allocated in isolated groups. RILs 1, 2, 6, and 8 confirmed resistance to BS. Considering homogeneity level and BS resistance, RILs 1 and 6 were suitable for use as pre-cultivars in final tests to register and release two new C. annuum cultivars.

A breeding program carried out under Brazilian growing conditions to obtain Capsicum annuum cultivars with disease resistance to bacterial spot (BS) produced 8 promising recombinant inbred lines (RILs). The present study aimed to characterize these RILs using phenotypic descriptors and molecular markers (inter-simple sequence repeat) and to confirm their resistance to BS. Twenty-two phenotypic descriptors and 15 inter-simple sequence repeat primers were used to characterize the RILs. The parent, UENF 1381, which is resistant to BS, and 'Casca Dura Ikeda', a traditional cultivar, were used as standards. Variability among genotypes was observed considering either binary or multicategorical characteristics, such as fruit length, fruit diameter, and fruit longitudinal and transversal section. Such variability in fruit traits can be exploited to develop new genotypes with BS resistance for various types of market consumption. RILs numbered 1, 3, and 6 were the most homogenous, whereas those coded 2, 5, 8, and 11 had the same level of heterogeneity as that observed in 'Casca Dura Ikeda'. Molecular analysis clustered the genotypes into 5 groups, with RILs 1, 2, 3, and 5 allocated in isolated groups. RILs 1, 2, 6, and 8 confirmed resistance to BS. Considering homogeneity level and BS resistance, RILs 1 and 6 were suitable for use as pre-cultivars in final tests to register and release two new C. annuum cultivars.