Chrysanthemum morifolium is an important temperate cut flower for Malaysian floriculture
industry and the lack of new local owned varieties led to this mutation breeding research. The
objective of this study was to compare the effectiveness of ion beam irradiation in generating
mutations on ray florets and nodal explants of Chrysanthemum morifolium cv. ‘Reagan Red’. Ion
beams has become an efficient physical mutagen for mutation breeding. The ray florets and nodal
explants were irradiated with ion beams at doses 0, 0.5, 1.0, 2.0, 3.0, 5.0, 8.0, 10, 15, 20 and 30 Gy.
The 50% of in vitro shoot regeneration (RD50) for ray florets explants was 2.0 Gy and for nodal
explants was 4.0 Gy. Thus, relative biological effectiveness (RBE) for ray florets was found 2.0
times higher than the nodal explants. The regenerated plantlets were planted in the greenhouse at
MARDI, Cameron Highlands for morphological screening. Overall performance of survival
plantlets derived from in vitro nodal and ray floret explants was recorded. The characters studied
include plant morphology and flowering characteristic. The ray florets explants were found to be
more sensitive to ion beam irradiation and generated more mutations as compared to nodal
explants.
Chrysanthemum morfolium is an important temperate cut flower and potted plant for Malaysian local market and exporter. Considering chrysanthemum as a popular vegetatively propagated ornamental plant, induce mutations for breeding purposes are more beneficial. Several of physical mutagens have been used in mutation breeding including x-rays, gamma rays and ion beams. Gamma rays and ion beams are from two different linear energy transfer (LET) which are low and high, respectively. The objective of this study was to compare the effectiveness of acute gamma and ion beam irradiation in generating flower colour mutations on nodal explants of Chrysanthemum morifblium cv. Reagan Red'. The nodal explants were irradiated with acute gamma (0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110 and 120 Gy) and ion beam (0, 0.5, 1.0, 2.0, 3.0, 5.0, 8.0, 10, 15, 20 and 30 Gy). The optimal dose for in vitro shoot regeneration using acute gamma was in the range of 10 to .15.0Gy and for ion beam was between 3.5 to 4.OGv. Relative biological effectiveness for ion beam was found 3.75 higher than the acute gamma. The regenerated plantlets were planted in the greenhouse at MARDI, Cameron Highland for morphological screening. The highest frequency of flower colour mutation for acute gamma was 77.8% whilst for ion beam were between 42.3 to 58.3%.