Caracterização e estimativa da variabilidade genética de genótipos de cebola

Abstract

Characterization and estimation of genetic variability of onion genotypesThis study aimed to characterize onion genotypes grown in Santa Catarina state, Brazil and to estimate their genetic variability. Fifteen onion genotypes were evaluated in two locations, Ituporanga and Lages. The experimental design was of randomized blocks with three replications in each environment. We evaluated the length of the pseudostem, number of leaves per pseudostem, stem diameter, bulb diameter, height of the bulb, bulb weight, height:diameter ratio; total production of bulbs, bulb shape, flowering percentage and percentage of rotten bulbs. The data were subjected to multivariate analysis of variance. The results showed significant effects for genotype-environment interaction, fact that was reflected in the values of dissimilarity in each location. A matrix of dissimilarity was prepared using Mahalanobis distance method. The morphological and agronomic traits used were sufficient to characterize the genotypes, indicating that breeding programs have a wide genetic base for the development of new cultivars.

Research Article Genetic divergence among inbred onion lines and correlation with heterosis and combining ability

“…The mean Mahanalobis generalized distance (D 2 ) was 31.99%, and the smallest genetic distance was between L4833 and L4827 (3.7%; Table 3), whereas the greatest was between L4744 and L4742 (92.5%; Table 3). Buzar et al (2007) and Wamser et al (2012) analyzed the genetic diversity of onion germplasm using morpho-agronomic characters; they obtained similar results and concluded that their genotypes had a high level of genetic diversity. Similarly, based on the results obtained by analyzing morphoagronomic characters, the onion lineages that we evaluated should be classified as exhibiting high genetic variation.…”

“…To determine genetic divergence, it is ideal to use multi-varied techniques that allow several characters to be assessed simultaneously. Such techniques should also estimate the genetic distance between parents, thereby helping breeders to target crosses between the most divergent parents and increasing the possibility of developing productive hybrids quickly (Cruz and Carneiro, 2006;Buzar et al, 2007;Santos et al, 2011;Wamser et al, 2012).…”

“…Since genetic variation is the basis of plant breeding programs (Morales et al, 2011;Camargo et al, 2013;Morales et al, 2013;Mariano et al, 2019), it is important to understand the genetic variation of core germplasms. In onion, morphological markers have been used to study the genetic divergence of different genotypes (Wamser et al, 2012). However, the use of such markers presents several disadvantages, including the need to evaluate certain variables after the plant reaches the adult phase (Figueiredo et al, 2016).…”

“…Few studies have estimated the genetic divergence of onion genotypes to promote productive breeding (Buzar et al, 2007;Ragassi et al, 2012;Wamser et al, 2012). We evaluated the correlation between genetic dissimilarity of inbred onion lines and the SCAs determined by diallelic crosses.…”