Caracterização de progênies F4:5 de alface quanto à resistência ao meloidogyne incognita e características comerciais

Abstract

Lettuce stands out in the market as it is the main leafy vegetable grown, both in area and in volume of production. As it originates from a temperate climate, it usually presents some limitations of cultivation in tropical regions, as is the case of Brazil. These limitations may be associated with climatic conditions, such as early stemming, but also with problems with phytopathogens, especially the attack by the root-knot nematode Meloidogyne incognita that attack the root cells, causing chlorosis and reduction leaf area, which may lead to a reduction in the volume and quality of the final product. In addition to the search for resistance, breeding programs are also concerned with desirable commercial characteristics, such as color, type of border, type of limbus and commercial type, which normally requires the study of many variables, making selection difficult. An alternative would be the use of multivariate analysis, which allows a greater general perception of the studied genotypes. The grouping methods are a great tool to guide the breeding program, as it allows grouping more similar individuals and forming one or more groups with less similar ones. In addition to the clusters, knowing genetic bases linked to the expression of the target characteristics is of crucial importance, becoming possible through studies of genetic parameters. Another aspect that facilitates, in the scope of improvement, is the study of the correlations between the variables, enabling faster and more accurate assessments. Thus, in lettuce breeding programs, the resistance to root-knot nematodes associated with commercial characteristics is a major focus in research, and to guide the programs, breeders use per se and multivariate analysis for decision making. Thus, in this work, we tried to use these methods in order to identify superior lettuce genotypes. It was possible to identify five progenies with the potential to develop new strains of the iceberg lettuce type, resistant to Meloidogyne incognita.