Biology subjects

Vieira, M. L. C.

Publications and source records attributed to Vieira, M. L. C..

2 recordsLinked to original sources

bioRxiv2025

Developing a model to implement marker-assisted selection for root-knot nematode resistance in common bean

Common bean (Phaseolus vulgaris L.) is a vital crop for direct human consumption, with essential nutrients and valuable protein that provides food security in developing countries. However, its cultivation faces significant threats from Meloidogyne incognita, a root-knot nematode (RKN), resulting in considerable yield loss. Developing crop resistance remains a key strategy for mitigating nematode infections. To investigate the genetic architecture of common bean responses to RKN (specifically, race 3 of M. incognita), we performed controlled crosses between the genotypes IAC-Tybata and Branquinho with contrasting resistance. The resulting segregating population (F2) of 333 individuals was genotyped using GBS (genotyping-by-sequencing). We used a phenotyping approach, already optimized in the lab, to collect trait data for a subset of 200 F2:3 families. Evaluations of egg mass (EM), root-galling index (GI), and root dry mass (RM) were conducted 30 days after RKN inoculation under greenhouse conditions, in a completely randomized design with ten replicates. Linkage and quantitative trait loci (QTL) mapping were performed, while functional mapping of associated regions facilitated identification of candidate genes. A linkage map encompassing 954 SNPs assigned to 11 linkage groups totaling 1,687 cM formed the basis for Interval Mapping (IM), Composite Interval Mapping (CIM), and Multiple Interval Mapping (MIM), revealing four major QTLs (on Pv03, Pv05, Pv08, and Pv10) and epistasis between QTL on Pv08 and on Pv10 associated with the GI trait. No significant QTL were identified for EM and RM. The model enabled calculation of genotypic values through marker-assisted selection (MAS). The high correlation between observed and predicted values (0.72) underscores the models significance. Candidate genes previously associated with nematode resistance were also identified within the QTL interval on chromosome Pv10. Our results will be valuable for future selection of varieties resistant to this important crop disease.

genetics↗

bioRxiv2019

Improving yield and fruit quality traits in sweet passion fruit: evidence for genotype by environment interaction and cross-compatibility in selected genotypes

Breeding for yield and fruit quality traits in passion fruits is complex due to the polygenic nature of these traits and the existence of genetic correlations among them. Therefore, studies focused on crop management practices and breeding using modern quantitative genetic approaches are still needed, especially for Passiflora alata, an understudied crop, popular known as the sweet passion fruit. It is assumed to be a self-incompatible species and is highly appreciated for its typical aroma and flavor characteristics. With the aim of estimating the genetic and phenotypic parameters related to fruit traits, our group has already investigated a sweet passion fruit progeny consisting of 100 individuals from which 30 genotypes were selected. In this study, we reevaluated these superior genotypes in three environmental conditions. The results of the multi-environment trial analysis indicate that the genotypes do not behave consistently across these environments, and this was taken into account when selecting genotypes. Pairwise genetic correlations among the fruit traits were evaluated, and different genotype rankings obtained depending on the trait and environment, providing further evidence of genotype by environment interaction. Finally, we used a multiplicative selection index to select 20% of genotypes for weight of pulp and against thickness and weight of the fruit skin. The response to selection was positive for all traits except soluble solids, and the superior (six) genotypes were ranked. The consensus is that open-pollinated populations can be used as commercial varieties in crop species that are sensitive to inbreeding depression or within breeding programs that are not well developed. For these reasons, we performed a complete diallel cross for evaluating the capability of the selected genotypes to be fertilized and set fruits. Most of the crosses were compatible, resulting in over 50% fruit set. It is worth noting that all genotypes produce fruits if used as females, which is essential to guarantee yields in commercial orchards.

plant biology↗