The objectives of this study were to establish an efficient protocol for somatic embryogenesis in triploid hybrids between napiergrass (Pennisetum purpureum Schumach.) and pearl millet (P. glaucum (L.) R. Br.), and to assess the genomic stability by flow cytometry of the plants obtained in vitro. Somatic embryogenesis and plant regeneration were successfully established from mature zygotic embryos of napiergrass and pearl millet hybrids. Four treatments with 2,4 dichlorophenoxyacetic acid (2,4-D) at 0, 1, 2 e 3 mg L-1 were tested for embryogenic calli induction and two treatments with inositol at 1 e 2 g L-1 were tested for plant regeneration. The treatments were arranged in a completely randomized design. The optimum hormone combinations were 2 mg L-1 of 2,4 D for embryogenic callus induction, and 1 g L-1 of inositol for embryos conversion and plant regeneration. The analysis of DNA content by flow cytometry of the regenerated plantlets indicated that no ploidy changes had been induced during somatic embryogenesis and plant regeneration. The nuclear DNA content and ploidy levels of the regenerated plants were stable and homogeneous in comparison to those of the control plants. There was no occurrence of karyological instability in the regeneration system utilized for Pennisetum hybrid.
Pennisetum glaucum; Pennisetum purpureum; tissue culture
