Individual selection of the first backcross generation of passion fruit potentially resistant to the fruit woodiness disease

Abstract

The REML/BLUP procedure has been successfully used for genetic progress through individual selection of high-yielding passion fruit genotypes resistant to the Cowpea aphid-borne mosaic virus. This study was thus developed to estimate genetic parameters and predict the gain obtained from individual selection of genotypes in a population derived from backcrosses in passion fruit. The experiment was set up as a randomized block design with four replicates, involving fi ve full-sib families (genotypes from the fi rst backcross). Variance components and the genetic values were estimated for eight agronomic traits via the REML/BLUP procedure. For all traits, genotypic variance between the genotypes from the fi rst backcross showed little contribution to the phenotypic variance. The low heritability estimates obtained for the traits are overcome via individual BLUP estimates. Therefore, it was possible to obtain considerable gains with individual selection for the variables fruit length, average fruit weight, and pulp weight (19.50 to 14.04%; 22.93 to 17.97%; and 10.08 to 7.95%, respectively). For the traits showing lower gains, it is possible to obtain gains indirectly by selecting genotypes for correlated traits. Because this population derives from the fi rst backcross generation, agronomic traits still must be recovered.

Field assessment of a second generation backcross (BC1 × Passiflora edulis) of passion fruit for agronomic performance and resistance to CABMV

“…The prediction of genotypic values ( µ + g ) and the components of variance of a population are of great relevance to support the choice of parents and improvement strategy in the next selection cycles. The use of mixed models as employed in REML/BLUP is interesting in genetic breeding, since the method seeks to eliminate the effects of the environment and to identify progeny with high genotypic merit (Preisigke et al., 2020) and even for characteristics with low heritabilities, genetic gains are estimated and thus, genotypes can be selected.…”

“…The commercial cultivars of passion fruit ( P. edulis ) are susceptible to diseases, with emphasis on the passion fruit woodiness disease caused by the cowpea aphid‐borne mosaic virus (CABMV), a potyvirus, considered one of the most economically important diseases affecting passion fruit growing in Brazil and transmitted non‐persistently by several aphid species (Preisigke et al., 2020). Infected plants by CABMV have yellowish spots, leaf bubbles and distortions (Freitas et al., 2015), the fruits are generally deformed, smaller and have a hardened pericarp, affecting production in terms of fruit quantity and quality and greatly reducing the useful life of orchards.…”

“…Research has focused on the development of alternative management methods (Spadotti et al., 2019), detection of symptoms induced by CABMV in yellow passion fruit in field conditions (Melo et al., 2015) and transgenic passion fruit with the CABMV capsid protein gene (Correa et al., 2015). However, the development of a resistant variety is the most economical and sustainable method for disease control (Santos et al., 2015), but until now there are no commercial yellow passion fruit cultivars resistant to CABMV (Preisigke et al., 2020).…”

“…Thus, the morphological, agronomic and CABMV resistance characterization of these progeny is essential not only to identify the best genotypes, but also to establish the variance components to better predict the genetic values to maximize selection accuracy. Among the methods for estimating genetic parameters, restricted maximum likelihood/best linear unbiased prediction (REML/BLUP) has been successfully reported for Passiflora (Cruz Neto et al., 2016; Preisigke et al., 2020), due to the better accuracy of the technique in relation to selection index or phenotypic selection (Preisigke et al., 2020). Therefore, the goal of this work was to characterize different progeny of the second backcross generation (BC2) [BC1 × P. edulis ] through morphological and agronomical descriptors, in order to identify promising individuals resistant to passion fruit woodiness disease from natural infection.…”

Research Article Evaluation of resistance to <i>Cowpea</i><i> aphid-borne</i> <i>mosaic</i> <i>virus</i> in passion fruit backcrosses for recurrent selection and development of resistant cultivars

“…In the selection process in breeding programs, accuracy values above 70% are sought. Preisigke et al (2020a) found an accuracy value for FP classified as low. Thus, it can be concluded that the high precision of the predicted genetic values aids in the more reliable selection of superior genotypes.…”