Genetic diversity in half-sibling progenies of kale: A multivariate approach

ABSTRACT Kale is one of the most widely cultivated leafy vegetables in Brazil, but its breeding genetic is still limited. Therefore, it is crucial to develop research that explores the genetic diversity of the available germplasms, aiming to establish promising crosses in the studied populations. The present study aimed to evaluate the genetic divergence between half-sibling progenies of kale, obtained through recurrent selection, using multivariate methods to select the most promising progenies for forming a recombinant population. The plants obtained from the seeds of 25 pre-selected half-sibling progenies and three commercial cultivars were evaluated as treatment groups. These seeds were produced in 2018 by subjecting the clones of the progenies to recombination, followed by the selection of appropriate seeds from plants with superior agronomic performance. In the present study, plants in each plot were evaluated for twelve quantitative and fifteen qualitative traits. Genetic divergence was studied based on canonical variables to obtain quantitative data. The UPGMA method was applied to the quantitative, qualitative, and combined data, and Mahalanobis genetic distance was adopted. The first three canonical variables explained 73.75% of the total cumulative variation compared to the commercial cultivars and 55.29% when considering the half-sibling progenies exclusively. The half-sibling progenies P1, P2, P3, P4, P5, P9, P11, P15, P16, P18, P20, P22, P23, P24, and P25 were the most divergent and should, therefore, be prioritized when composing the recombinant population for the third cycle of recurrent selection because, in addition to genetic variation, these progenies also present characteristics of interest to the kale genetic breeding program. The commercial cultivars exhibited the most divergent genotypes and should, therefore, be included in the next recombination cycle. RESUMO A couve-de-folhas é uma das hortaliças folhosas mais cultivadas no Brasil, porém seu melhoramento ainda é limitado. Portanto, é crucial desenvolver pesquisas que explorem a diversidade genética dos germoplasmas disponíveis, visando estabelecer cruzamentos promissores nas populações estudadas. O objetivo deste estudo foi avaliar a divergência genética entre progênies de meios-irmãos de couve-de-folhas obtidas por seleção recorrente e selecionar as progênies mais promissoras para compor uma população recombinante utilizando métodos multivariados. Como tratamentos, foram avaliad