Development of Brassica Napus L. Ogu-INRA CMS Restorers Using Recurrent Full-Sib Selection.

Abstract The Ogu-INRA CMS system in canola and rapeseed (Brassica napus L.) uses a cytological variant of the radish- (Raphanus sativus L.) derived Ogu CMS pollination control system introduced through interspecific introgression. The restorers (R-lines) contain an introgression that is associated with poor agronomic performance due to a large undesired segment of the radish chromosome that was introgressed along with the Rfo gene. The introgression contains pentatricopeptide (PPR) motif repeats that confer fertility restoration abilities to the R-lines. The objective of this research was to test the hypothesis that multiple cycles of intermating will result in R-lines with improved agronomic performance. A base population was developed by designing five R-line by R-line crosses. Twelve plants from each initial cross were grown and chain-crossed at random, without selection, other than the presence of the Rfo gene. Twelve flowers from each plant were crossed and the remainder of the plant was selfed. Three intermating crossing cycles (C0, C1 and C2) were completed and each was selfed three times for evaluation. Total pod number, seeds per pod, a visual pod rating, thousand seed weight and yield were evaluated. The visual pod rating showed a positive correlation with seeds per pod. Improvements for all traits were found at C0 and C1 when compared to the best parent. Individual families from two of the crosses showed a yield increase of over 78 % from the best parent. This suggests that improvements in yield components can be obtained from intermating R-lines.