BUDS STERILIZATION AND PLANT GROWTH REGULATORS for IN VITRO REGENERATION OF „BUBU‟ POTATO (solanum tuberosum L.) VARIETY

Potato is one of the important crops in Ethiopia and there is a favourable condition to produce than other African countries. but the production is low because of long dormancy periods which leads to delayed planting, poor crop emergence and vigour and limited availability of planting materials. Thus, this research was conducted to estimate the effect of tuber sizes, GA3 concentration and soaking time on dormancy breaking and sprouting characteristics. Additionally, the effect of Bavistin and mercuric chloride sterilant chemicals with soaking duration, and different concentrations of PGRs (BAP, KIN, NAA and IBA) for in vitro shoot regeneration of the „Bubu‟ potato variety were evaluated using lateral bud as explants. The experiments were laid out in a factorial arrangement Complete Randomized Design with three replications at Plant Biotechnology Laboratory, Haramaya University. The Results of study showed that three-way interaction (tuber size, GA3 concentration and soaking time) showed the presence of significant differences in sprout length and sprout vigour traits. Whereas, the interaction of GA3 and tuber size had a significant effect on dormancy period and sprout thickness. A number of sprout/ tuber traits showed significant differences only by tuber sizes. While the percentage of tuber sprouted was not affected by any factors. The main factor of soaking time had a significant effect on dormancy period and sprout thickness traits. The result showed that large-size tubers with treatment of GA3 at concentrations of 50 ppm & medium with 100 ppm produce short (36.4 days) dormancy period. The large tuber size had a significantly better (2.3) number of sprouts per tuber than the other tuber sizes without difference with (1.9) medium size. The longest sprout (17.7- and 17.3-mm) were recorded from small tuber size soaked with 50 and 100 ppm for 15 min and medium soaked with 100 ppm for 45 min produced sprout lengths respectively. While the shortest (