Popcorn germplasm resistance to fungal diseases caused by Exserohilum turcicum and Bipolaris maydis

<div><p>ABSTRACT Compared with the common corn, popcorn shows greater susceptibility to pests and diseases occurrence, being the use of resistant cultivars the most efficient strategy. In this regard, Germplasm Banks deserve special attention because they contain accessions that can be used as sources of resistance in breeding programs. The State University of Northern Rio de Janeiro (UENF) maintains a popcorn Germplasm Bank with accessions from tropical and temperate countries, including Diversity Centers for the species. In this study, we investigated the performance of 37 popcorn accessions landraces, hybrids, and inbreed lines ― from the Germplasm Collection of UENF’s Popcorn Breeding Program with respect to the fungal leaf diseases northern leaf blight (NLB) and southern leaf blight (SLB), caused by Exserohilum turcicum and Bipolaris maydis, aiming to select promising accessions for genetic resistance to be used in future crosses to generate new resistant cultivars for farmers. The dendrogram scattering by the UPGMA multivariate technique was efficient in discriminating resistant accessions. Satisfactory results were obtained for resistance to NLB in accessions L71, L75, L76, P7, and PARA-172, which can thus be considered remarkable sources of resistance. For resistance to SLB, the superior accessions that can be indicated as sources of resistance are ARZM-05083, ARZM-07049, and PARA-172.</p></div

Popcorn germplasm resistance to fungal diseases caused by Exserohilum turcicum and Bipolaris maydis

<div><p>ABSTRACT Compared with the common corn, popcorn shows greater susceptibility to pests and diseases occurrence, being the use of resistant cultivars the most efficient strategy. In this regard, Germplasm Banks deserve special attention because they contain accessions that can be used as sources of resistance in breeding programs. The State University of Northern Rio de Janeiro (UENF) maintains a popcorn Germplasm Bank with accessions from tropical and temperate countries, including Diversity Centers for the species. In this study, we investigated the performance of 37 popcorn accessions landraces, hybrids, and inbreed lines ― from the Germplasm Collection of UENF’s Popcorn Breeding Program with respect to the fungal leaf diseases northern leaf blight (NLB) and southern leaf blight (SLB), caused by Exserohilum turcicum and Bipolaris maydis, aiming to select promising accessions for genetic resistance to be used in future crosses to generate new resistant cultivars for farmers. The dendrogram scattering by the UPGMA multivariate technique was efficient in discriminating resistant accessions. Satisfactory results were obtained for resistance to NLB in accessions L71, L75, L76, P7, and PARA-172, which can thus be considered remarkable sources of resistance. For resistance to SLB, the superior accessions that can be indicated as sources of resistance are ARZM-05083, ARZM-07049, and PARA-172.</p></div

Genetic diversity between papaya lines and their correlation with heterosis in hybrids for disease resistance and morpho-agronomic traits

<div><p>ABSTRACT This study aimed to verify if the genetic divergence between papaya lines, obtained by means of molecular markers, is correlated with heterosis in the hybrids for characteristics related to production, fruit quality and disease resistance. Eight parents and 56 hybrids obtained from diallel crosses were evaluated in randomized blocks, with four replicates. The number of commercial fruits (NCF), the average fruit weight (AFW), the productivity (PROD), the fruit firmness (FIRM) and the total soluble solids (TSS) were evaluated, as well as the severity of black spot on leaves (BSS) and fruits (BSSFr), phoma spot (PSS) and powdery mildew on leaves (PMS). Correlations were estimated between genetic divergence, obtained based on SSR, and heterosis, estimated for each characteristic in four possibilities of crossings within the diallel: i) all crossings; ii) between parents of the ‘Solo’ group; iii) between parents of the ‘Formosa’ group; and iv) between parents of ‘Solo’ with ‘Formosa’ group and ‘Formosa’ with ‘Solo’ group. Results indicate the possibility of exploring heterosis both in crossings between groups and in crossings within groups. The low magnitude of the estimates of correlation between heterosis and morphological characteristics of the hybrids with genetic distance obtained by SSR in the parents indicates that the behavior of hybrids cannot be inferred based on the genetic divergence between parents.</p></div

The GT biplot analysis of green bean traits

<div><p>ABSTRACT: The green bean (Phaseolus vulgaris L.) is a nutrient-rich vegetable much appreciated; although, little studied, in Brazil. The aim of the current study was to investigate the nature of traits of interest, as well as to select plants for the green bean breeding program based on genotype vs. trait biplot analysis. The experiment followed a randomized block design, with 4 repetitions and 17 genotypes. Analysis of variance, principal component analysis and biplot charts were performed to analyze the number of pods per plant, the number of seeds per pod, the number of seeds per plant, seed weight per plant, 100-seed weight, as well as grain and pod yields. The analysis of variance showed genetic variability between genotypes. Grain yield, pod yield and seed weight per plant were highly correlated. The number of seeds per pod was negatively correlated with pod weight, grain weight and with seed weight per plant. Lines Feltrin and UENF 14-30-3 were indicated to increase gains in variables such as grain yield and pod yield.</p></div