Efficiency of selection indices to identify superior clones of potato

Abstract

Most breeders, either analytically or intuitively, practice multiple trait selection when developing cultivars. The objective of this paper was to evaluate the selection methods used to identify high yielding potato (Solanum tuberosum L.) clones, with high percentage of large tubers, good general tuber appearance and superior specific gravity. In Lavras, State of Minas Gerais, Brazil, 817 experimental clones were evaluated by means of augmented block designs. Using either independent culling level or Elston (1963) indices allowed selection of clones with defined limits, but the population size was severely reduced possibly excluding genotypes with wide adaptation. Selection indices improved the distribution of genetic gains of important characters compared with direct selection for the same characters. Indices of Smith (1936), Hazel (1943), Williams (1962), Pesek & Baker (1969) and Mulamba & Mock (1978) were indicated to be used in potato breeding programs making use of the genetic standard deviations and or their reciprocals as economic weights.