Seleção de clones de batata-doce resistentes ao Meloidogyne incognita raça 1

Abstract

The objective of the present work was to select sweetpotato new clones with resistence to Meloidogyne incognita race 1, and to assess the efficiency of the selection method deployed through the estimation of genetic (CVg) and environmental (CVe) coefficients of variation, as well as broad-sense heritabilities. Genotypes assessed comprised 123 sweetpotato entries altogether, including four commercial cultivars (Brazlândia Rosada, Brazlândia Roxa, Brazlândia Branca, Palmas) and 119 clones previously selected by the Universidade Federal de Lavras sweetpotato breeding programme. The experimental setup was an augmented randomized block design, with three common treatments (sweetpotato cultivars Brazlândia Branca and Palmas, and the nematode-susceptible tomato cultivar Santa Clara). Levels of nematode resistance were defined both by the nematode reproduction factor and by the nematode reproduction index relative to tomato cv. Santa Clara. The ratios b= CVg/CVe and the broad-sense heritability estimates were high for both the reproduction factor and the reproduction index, indicating that the selection method deployed was efficient for the selection of resistant genotypes. Fifty-seven sweetpotato clones (45.97% of the total number of clones) were identified as nematode resistant, and were selected for further agronomic evaluations in the sweetpotato breeding programme.