Establishment of Anther Culture of Swida wilsoniana

Swida wilsoniana (Wilson's dogwood) is an ornamental tree with white-cream flowers and exfoliating bark. It is also a candidate plant for bioenergy fuel because of the high oil content in its fruit. Anther culture is the most efficient technique for obtaining a large number of haploid plants in a breeding program. Basal media, light conditions, sucrose concentrations, and pretreatments of anthers at 4 ^oC or 32 ^oC were investigated for maximum callus induction from Wilson's dogwood anthers in five separate experiments. All media were supplemented with 1.0 mg·L^-1 2,4-D (2,4-dichlorophenoxyacetic acid), 0.5 mg·L^-1 NAA (1-naphthaleneacetic acid), and 0.4 mg·L^-1 6-BA (6-benzylaminopurine). Basal media, namely, Gamborg medium (B5), Miller medium, Murashige and Skoog (MS) medium, or woody plant medium (WPM) were compared. MS was the best basal medium with 25.4% of anthers forming callus. When anthers were cultured in constant dark, about 30 times more callus were formed compared to a 12-h/12-h light/dark cycle. Anthers cultured on medium supplemented with 30 g·L^-1 sucrose achieved the maximum callus induction of 28.3%. Pretreatment of anthers at 4 ^oC for 9 days resulted in 36.7% callus induction, while a pretreatment at 32 ^oC for 1 day produced a 30.8% callus induction. In conclusion, anthers of Wilson's dogwood could be stored at 4 ^oC for 9 days and then cultured in the dark on MS medium supplemented with 1.0 mg·L^-1 2,4-D, 0.5 mg·L^-1 NAA, 0.4 mg·L^-1 6-BA, and 30 g·L^-1 sucrose to yield the most callus induction.