Growth medium and environmental studies of sweet potato meristem culture : a thesis presented in partial fulfilment of the requirements for the degree of Master in Applied Science at Massey University, New Zealand
The ability of three New Zealand local sweet potato (Ipomoea batatas L.) cultivars 'Toka Toka Gold', 'Beauregard', and Owairaka Red' to form plantlets in vitro was investigated Meristematic tips (0.2–0.4 mm) of apical shoots from vines of the three cultivars, and from tubers of 'Owairaka Red' were cultured in modified Murashige and Skoog (1962) medium (MS medium) containing plant growth regulator (s). Cultivars and organs of explants differed in response to exogenous levels of plant growth regulator(s) and in the rate of proliferation. Optimal regeneration occurred in liquid MS medium supplemented with BA 0.1 mg/1 for 'Toka Toka Gold' and Owairaka Red' (from vines), and with BA 0.5 + IBA 0.1 mg/1 for 'Beauregard'. For Owairaka Red' (from tubers), MS liquid medium with BA 0.3 mg/1, and MS liquid medium with GA3 20 mg/1 (plus other organic compounds) proliferated shoots and
plantlets. Continuous lighting inhibited the proliferation of plantlets in all three cultivars. Regeneration was strongly affected by the age of the shoots from which the explants were excised and the season when cultures were begun. Successful culture was obtained by culturing explants from young shoots in the Spring.