The effect of gamma radiation doses of 0 Gy, 10 Gy
and 20 Gy to the MV1 do not differ significantly on growth duration as well as radiation dose 20 Gy and 30 Gy did not differ significantly. But irradiation doses of 0 Gy and 10 Gy significantly different with 30 Gy radiation dose. Differences in the amount of plant grow control 0 Gy of 10 Gy and 20 Gy only approximately one day, and 30 Gy approximately ten days than the control plants. The most effective dose range for induction of mutations in vegetative crops such as yam which should between doses can be cause death no more than 50% and no growth reduction of more than 50%. The treatment dose should allow 40-50% survival and or growth slowdown was not more than 50% (Nwachukwu et al., 2009). In this range, enough population of plants that can survive the lethal effects of mutagens and encourage genetic changes sufficient to allow the selection of mutants that is more efficient and desirable. Accession significantly influence the growth duration, it is thought to be caused the yam plants have a dormant period different and every cycle is fixed on the growth of each accession. According to Nwachukwu et al. (2009), that one of the objectives in addition to the genetic improvement of tuber yield increases, include the development of cultivars that can growth well with high yield production without stake. In this study the growth obtained yam plants propagate without stake. Result of gamma irradiation plants are divided into three types of effects, physiological damage, (primary injury), gene mutations and chromosomal mutations (Nwachukwu et al., 2009). Radiation injury can reduce the ability of vegetative growth when used as a material organ radiation. This study shows that the ability to growth yam crops decreased with increasing doses of gamma irradiation. The same trend is occurring in the production of tubers decreased weight, stem diameter and length of tuber with increasing doses of gamma irradiation, contrary to the character of the number of tubers is likely to increase even though the amount is not significant and the size appear smaller tubers. (Abdul et al., 2010) his study showed that gamma ray irradiation significantly affected the germination percentage, survival percentage, shoot and root length, number of branches and leaves per plant, fresh and dry weight of Lepidium, other growth parameters showed a trend declining with increasing doses of gamma irradiation .