ALTERNATE COMBINED SELECTION OF S1 AND S2 LINES

Abstract

A plant breeding method called Alternate combined selection of S1 and S2 lines (SCA) is proposed and described, including its genetic response. It alternates one cycle of combined selection of S1 lines (SCS1) with one cycle of combined selection of S2 lines (SCS2), through two successive generations of self-pollination. One cycle of SCA requires three planting seasons: S1 lines development, evaluation and self-pollination on SCS1, and evaluationrecombination on SCS2. According to the derived genetic response (R) and comparing efficiencies per year with respect to the modified ear-to-row selection response(L), computed with the formula (RSCA-RL)/RL in populations with p=q=0.5, the SCA method was 1.47 times more efficient per year than L when the recombination of S2 lines is with a common pollinator, and 2.15 times higher when the recombination of S2 lines is plant to plant or by mass crossing at flowering.