Mutation breeding in rose and pigmentation studies in rose and hibiscus

Abstract

An investigation was carried out at IIHR, Bangalore to study the effect of gamma rays on 3 rose cultivars along with qualitative and quantitative estimation of flower pigments of rose and hibiscus cultivars. Budwoods of rose cvs. Paradise, Raja Surendra Singh of Nalagarh and Sindoor were irradiated at 3,4,5 and 6 kR gamma rays and budded on the rootstocks. Increased dosage of gamma rays reduced sprouting and survival of vegetative buds. Four induced mutants were reduced in cv. Paradise. However, the Raja Surendra Singh of Nalagarh was found to be less sensitive to higher doses of irradiation. The detailed morphological studies were carried out in the induced mutants. The morphological studies were also carried out in 6 spontaneous rose mutants developed at the institute along with their respective parents. Analysis of pigments in rose genotypes indicated that somatic flower colour is due to both qualitative and quantitative changes in pigments resulted by induced and spontaneous mutation. Paper chromatographic studies revealed that among the induced mutants, increased gamma irradiation reduced the anthocyanin contents where as the spontaneous rose mutants had higher concentration of anthocyanin than their parents exhibiting somatic flower colour change. The study of pigments was also extended to 15 hibiscus cultivars developed at the institute to understand the biochemical basis of their flower colour variation. More of anthocyanin with high concentration was observed in red and orange/orange yellow groups having darker shades as compared to yellow/yellow orange group of cultivars having lighter petal shades. Thus both in rose and hibiscus, the major pigment estimated was anthocyanin and tentatively as cyanin.