Development of Doubled Haploid Inbred Lines Using Microspore Culture in Radish (Raphanus sativus L.)

Radish (Raphanus sativus L.) is one of important root vegetable in Korea, which was traditionally used for making ‘Kimchi’, soup, stew, pickle, and dried side dish. As fresh radish is required 4 seasons, farmers produce radish in spring and autumn at main low land, summer at high land, and winter at southern island of ‘Jeju’. Thus breeders developed many commercial cultivar following 4 different seasons. 

Microspore cultivation is an effective method of developing various Doubled-haploid (DH) lines in Brassica vegetables (Licher, 1982). Especially the purity of DH inbred line was high comparing to other inbred lines. Thus breeders and genetic researchers prefer DH inbreds. However the number of regenerated embryos in radish microspore culture was low comparing to that of Chinese cabbage. Thus we tried to find out effective condition of radish microspore culture.

We found using NLN medium (1×) added with NLN micro elements (0.5×), AgNO₃(0.1mg L^-1), and charcoal (0.4mg·mL^-1) was effective in embryo genesis of radish. Among 39 Radish accession (commercial cultivar, breeding materials collected from Korea, China), only 2 cultivar produced DH embryos. One of the cultivar ‘Tae-bak’, a Korean hybrid cultivar developed in 1970, produced 10 DH inbred lines. The horticultural trait of 11 DH inbred lines were different. One DH inbred was selected as possessing good horticultural traits through field exhibition. The seeds of this DH inbred were mass produced and will be registered as ‘Wonkyo10051ho’ in 2015.