Single seed descent as a breeding method for swedes (Brassica napus L. var. napobrassica Peterm)

Abstract

The results are presented of two single seed descent (SSD) breeding programmes for swedes (Brassica napus L. var.

Swedes and Turnips

“…A cheaper method than the biennial inbreeding program was wanted. Single seed descent had been used on a small scale for experimental work and had produced the cultivar 'Virtue' (Bradshaw et al, 2009), so it was decided to use this method for the commercially funded project (Bradshaw et al, 2009). It involved the production and trialling in 1999 of 1,037 F 6 families from 15 crosses made in 1993.…”

“…However, it was not possible to grow a large number of plants at really high density because the inflorescences needed to be covered with Glassine bags to prevent cross-pollination. Bradshaw et al (2009) recommended a modified SSD breeding scheme in which family selection is practiced at F 3 .…”

“…In turn, the cultivars listed in the 1980s and early 1990s (Angus, Melfort, Angela, Airlie, and Ruby) showed a further 8% improvement on RutaǾtofte, Marian, and Magres (1993 NIAB Recommended List). Cultivar Kenmore, National Listed in 1994, is the highest yielding Scottish one to date (Bradshaw and Wilson, 1993;Bradshaw et al, 2009) (Table 8.1).…”

“…In Scotland the main diseases affecting swede yields are clubroot (Plasmodiophora brassicae) and powdery mildew (Erysiphe cruciferarum). The first cultivar to combine resistance to these diseases was 'Invitation,' released in 1995 (Bradshaw et al, 1997), followed by 'Gowrie' and 'Lomond' in 2006 (Bradshaw et al, 2009) (Table 8.1). Breeding for powdery mildew resistance can be considered a major success as the susceptible cultivars Acme and Doon Major have been replaced with resistant ones in which the resistance is controlled by partially recessive genes and is likely to prove durable .…”

“…These were more uniform than older cultivars produced by selection of attractive looking bulbs which were then seeded in isolation, but where cross-pollination could occur between the genetically different selections. More recently high-yielding and uniform inbred line cultivars have been produced by single seed descent (Bradshaw et al, 2009) and microspore culture (Hansen and Bratberg, 2003). The alternative way of producing high-yielding and uniform cultivars of both swedes and turnips is through F 1 hybrids, and this is another achievement.…”