Cytogenetics and Plant Breeding Laboratory, Botany Department, Lucknow University, Lucknow
Mutation frequency in diploid and autotetraploid of Portulaca grandiflora, Hook. (var. perennial) following treatment of 2n and 4n cuttings with gamma-rays at 2, 4 and 6 krad was compared. The 4n had higher frequency of mutation. The scope of 4n in mutation breeding has been discussed. Apart from floral mutants, morphological variations were also noted. Pointed leaf mutant in 4n at 4 krad revealed a case of somatic reduction. Suppression of flowering in this mutant has been attributed to the lack of ‘florigin’. Role of gibberellins in flowering has been discussed.
