QUANTITATIVE GENETICS OF RICE - IV - A BREEDING STRATEGY

A systematic and objective breeding strategy is proposed, involving th ree stages of selection carried out at the F-1, F-3 and F-6 generation s of pedigrees founded on single crosses between inbred parents. The f irst two of these stages involve selection between pedigrees and the t hird, selection within the pedigrees that survive the first two stages of scrutiny. The key features of this procedure are: that selection w ithin pedigrees is delayed until individuals are effectively homozygou s; that all characters are measured directly; and that decisions are b ased on the performance of plants that are raised in replicated and ra ndomised trials. The replacement of the pedigree method by the new met hod should allow breeders to recognise and exploit the genetical varia tion between and within their crosses for characters of interest more efficiently than hitherto at an appreciably lower cast. While this new method has been proposed in response to a specific problem with rice, it is applicable to all crop plant species where the end products of breeding programmes are inbred lines. (C) 1998 Elsevier Science B.V.