Effect of recurrent mutagenesis on some induced genotypes in safflower (Carthamus tinctorious L.)

Mutation breeding is a tool to induce new genetic variation for improving agronomical important traits. Thus, an investigation was carried out during two successive growing winter seasons 2017/2018 and 2018/2019 on safflower plants, at the Experimental and Research Farm, Faculty of Agriculture, Al-Azhar University, Assiut, Egypt. Three mutagen treatments i.e., dimethyl sulfoxide, electric shock and gamma rays, were used to isolate the desirable mutants in M4 and M5 generations of thirty three safflower genotypes. Three mutagen treatments were used, such as; the chemical mutation mutagen was more effective than the two other mutagens to induce mutant genotypes. On the other hand, some mutant progenies were derived from gamma rays treatment with dose 20 kr which was more effective mutagen for induction of stable promising mutants in safflower, according to final results of M5 generation, particularly high yielding ability trait, softness and earliness as compared to untreated plants. Concerning the important traits, the results showed that the earliest progenies for flowering date were 11 gave 119 days while, 9 gave 120 days with the h1 treatment and rad. in M5 generation. Also, the results showed that two mutated progenies 9 and 12 gave the highest seed yield/plant, 355.64 and 317.67 gm respectively from h3 treatment, one progeny 13 gave 382.90 gm from t1 treatment. The seed oil content trait, showed that the highest progenies no.11 and 12, gave 44.80 and 44.76 % respectively, on using h1 treatment, while, the mutated no. 13 gave 45.32% from t1 treatment. Finally, these results supported that the recurrent mutagenic treatments can be used to induce new mutant safflower genotypes which are characterized by spineless, earliness high seed yield and seed oil content. Thus, they can be involved in breeding programs to get new suitable varieties with high seed and oil yield.