Varietal Differences in Embryogenic and Regenerative Ability in Microspore Culture of Chinese Cabbage(Brassica rapa L. ssp. pekinensis).

Abstract

Varietal differences in embryogenesis and plant regenerative ability from isolated microspores of Chinese cabbage, Brassica rapa L. ssp. pekinensis, were investigated. There were significant differences (< I%) among the varieties in total embryoid yield and regenerative embryoid yield per 1 × l05 microspores. Tropical varieties had high embryogenesis and regenerative ability.‘Hsifu Early 30 Days' showed the highest embryoid yield and ‘Homei' showed a higher efficiency of plant regeneration from microspores. However, domestic Japanese varieties showed very low embryogenesis and plant regeneration ability in microspore culture. Though ‘Hsifu Early 30 Days' showed a higher embryoid yield than ‘Homei', the latter showed more efficient plant regeneration from embryoids than the former. There was no correlation between the total embryoid yield and the percentage of embryoids with plant regeneration. These results suggest that plant regeneration from embryoids is controlled by some genetic factors different from those controlling embryogenesis. In order to introduce high regenerative ability to domestic Japanese varieties, microspores isolated from the F1 hybrid of ‘Homei'בNozaki No. 2' (domestic Japanese variety) were cultured. Doubled haploid lines, which had both high regenerative ability and characteristics comparatively similar to domestic Japanese varieties, could be selected among these regenerated plants. If high regenerative lines with domestic Japanese characteristics are developed, it is expected that the application of microspore culture to practical plant breeding will become easier for the breeding of Chinese cabbage in Japan.