Efficient plant regeneration in three cultivars of Hami melon [Cucumis melo L. ssp. melo convar. ameri (Pang.) Greb] via organogenesis

Abstract

SummaryHami melon [Cucumis melo L. ssp. melo convar. ameri (Pang.) Greb] is reputed to be the ‘king of melons’, but commercial development of transgenic Hami melon cultivars is limited by low levels of plant regeneration and a high incidence of polyploid regenerants. Regeneration systems for three Hami melon varieties, namely ‘Jin Queen’, ‘Hongmibao’, and ‘Huangzhuixian’, were developed via organogenesis in tissue culture. Leaf explants ranging from 0.125 – 0.500× the full-size of each leaf were prepared in vitro from seedlings of different ages, then cultured on Murashige and Skoog (MS) medium containing various concentrations of 6-benzylaminopurine (BAP; 1.0 – 9.0 mg l–1) to determine optimal conditions for induction of adventitious shoots. Leaves from 8-d old seedlings were cut into four, approximately-equal segments. Plant regeneration was greatest on MS medium containing 3.0 mg l–1 BAP, with a shoot induction frequency of 90% for ‘Hongmibao’. For ‘Jin Queen’ and ‘Huangzhuixian’, the highest frequencies of shoot induction (86% and 88%, respectively) were obtained on MS medium supplemented with 4.5 mg l–1 BAP.Adventitious shoots were then elongated on MS medium containing 0.1 mg l–1 BAP, but rooted successfully on hormone-free MS medium. Approx. 88% of the regenerated plants were diploid, as determined by flow cytometry.