Division of Vegetable Crops and Floriculture, Indian Agricultural Research Institute, New Delhi-12
Online published on 25 January, 2012.
Seeds of Single Mixed variety of Zinnia elegans Jacq. were irradiated with 20 kr x-ray. In Mx generation, only 2–5% plants were observed to be partially resistant to the leaf-curl virus disease under field conditions. The resistance to leaf-curl disease is governed by two dominant genes namely, R for resistance and S, a suppressor gene, which inhibits the expression of the gene R, both in homozygous and heterozygous condition. The genotype of completely resistant, highly resistant and partially resistant plants are ssRR, ssRr and SsRr respectively, while of completely susceptible are SSRR and ssrr. A variety which is breeding true for resistance to leaf-curl has been developed by recurrent selection in irradiated progeny.
