Generating F₁ hybrids of stevia (stevia rebaudiana BERTONI) using trigona-assisted pollination technique / Mohd Farit Ab Hamed

Stevia was first introduced into Malaysia in 1970s; however, to date there is no variety that is practical or suitable for local production under our tropical environmental conditions. Hybridization by manual crossing is extremely laborious and difficult. It is further aggravated by its very poor seed germination. Utilization of stingless bees in assisted-pollination contributed towards a significant breakthrough in overcoming barriers in hybridization for stevia breeding work. The main objective of the study is to generate a new hybrid local stevia variety. Six of ten accessions were selected as parents namely MS0012, Kl, Bangi, MS023, Rawang and Taman Pertanian. Parents differed significantly in terms of plant height (13.5 cm - 28.0 cm), days to flowering (4 weeks - 17 weeks) and number of branches (1 - 7). 7rz'gorca-assisted pollination generated 389 seeds which comprised 76.1 percent black seeds. Five of 27 potential hybrids were selected based on their overall seedling vigour and a number of characteristics namely leaf size, number of branches, and height. However, only two potential hybrids survived due to acclimatization problems. For maternity test, five ISSR markers were used, and only two primers (IS57 and IS85) were found to be polymorphic. Molecular marker analysis confirmed that two hybrids were putative. Only Fi hybrid 2 survived acclimatization and was evaluated. Fi hybrid 2 was unlike its male parent Kl, since it was significantly different in terms of its profuse branching habit. The study proved that the new technique of hybridization using Zhgo/ia-assisted pollination was able to produce successful Fi hybrid for stevia breeding work