| Popis: |
Brassica napus var. oleifera varieties have traditionally been developed as open-pollinated varieties. The successful introduction of several high-yielding hybrids based on cytoplasmic male sterility or transgenic pollination control systems has generated interest in the development of new hybrid systems. Self-incompatibility could be an additional useful pollination control system for B. napus if a sufficient number of S-alleles could be developed in this species. The S-alleles, S2, S5, S13, S24 and S39, were identified in five hybrids of B. oleracea var. italica and subsequently transferred to B. napus. Doubled haploid lines were produced for the self-incompatible (SI) lines in B. napus and intercrossed to produce SI heterozygotes in order to study allele interaction. There was a greater incidence of interallelic dominance in the stigmas and pollen of B. napes than was reported for the S-alleles in B. oleracea. Allele S24 exhibited the greatest degree of dominance over the other alleles tested, while allele S2 was generally recessive or codominant with other alleles. Self-incompatible expression was very similar in the SI homozygotes and heterozygotes, thus no weakening of the Sl trait in the heterozygote was observed. The implications of S-allele interaction for the use of SI in B. napus are discussed. |
