Seed production potential evaluation of sugar beet half-sib families in Morocco

In Morocco, sugar-beet seed production represents a new challenge to meet the main breeding programme goals. The identification of a suitable zone for plant vernalization represents a bottleneck for seed production. This study aimed chiefly at evaluating the vernalization aptitude of 18 sugar beet half-sib progenies. Trials were conducted during three selection cycles in a specifically chosen environment. The experimental site of Merchouch is 40 km south-east of Rabat city. Field trials design is according to an open-pollinated experimental block. Yield components and five phenological traits were recorded during the growing cycle and at the plant maturation. The variance analysis showed a significant effect of the selection cycle on the phenological traits and grain yield. The plant cycle duration increased by 10.7 days between the first and the third selection cycles. According to the principal component analysis and the hierarchical clustering, F2, F5, F6, F9, F10, F11, F14 and F15 half-sib progenies are described as long cycle and high grain yield families. Grain yield reached 257.3 g per plant, the duration to maturity 350.6 days and the germination rate 93%. The three selection cycles and the suitability of the site vernalization conditions are potentially effective for seed production progress. Our results are relevant as they established an adequate site for the sugar beet seed production. The half-sib selection is a valuable method for sugar beet germplasm enhancement.

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

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.