An Investigation of Crossability and Interspecific Hybrids between Cultivated (Carthamus tinctorius L.) and Wild (C. oxyacantha Bieb.) Safflower

Although wild safflower (C.oxyacantha, 2n=24) has not been studied to a very large extent, yet it is believed that it can be used as an important source of biotic and abiotic stress resistance genes for improvement of cultivated safflower (C.tinctorius L., 2n=2x=24). In this study, the crossability between these two (cultivated and wild safflower) species was evaluated as based upon morphology and cytogenesis of F1 hybrid plants. Two accessions of C.oxyacantha (both spiny, yellow color of flower, brown seeded) were reciprocally crossed with two breeding lines of cultivated safflower (both spinessless and white seeded, but yellow and red in color of flower). Morphological traits of hybrid plants were evaluated with heads of hybrid plants fixed in Carnoye’s solution and chromosomes stained with Hematoxyline to detect for any probable chromosome abnormality. The results showed that when C.tinctorius (cultivated species) was crossed as female parent, more hybrid seed was produced as compared to the reciprocal cross process. Seed set percentage was 43 to 67% when cultivated species was used as female parent, but percentage of seed set was 0 to 37% in the case of reciprocal crosses. Morphology of hybrid plants was more closely similar to wild parent plants in which lower leaves were lacerate and upper ones all lanceolate. In all crosses between wild species of yellow flower color and cultivated line of red flower color, the F1 hybrid plants emerged with yellow flower color, indicating the complete dominance of yellow color over red. Also seed coat color in all the F1 seeds was white, implying that white color is dominant over brown seed color. An investigation of meiotic cells in F1 plants indicated that there existed a complete homology between the two genomes of the cultivated vs wild Carthamus species and while complete bivalent pairing being observed. In general, this study showed that two cultivated and wild species of safflower are crossable, thus the genes of desirable traits from wild species can be transferred to the cultivated one through classical breeding methods.