Interspecific Hybrids Between Carthamus tinetorius and C. alexandrinus1

Cultivated safflower C. tinctorius L. with n=12 was crossed to C. alexandrinus (Boiss. and Heldq;.) Ascher. with m=10, using both as male and female. Two F1 hybrids were obtained when C. tinctorius was the male parent. Analyses of the parents and their hybrids included studies of microsporocytes, pollen stainability, seed‐set, and pollen and corolla color. Meiosis was irregular in the hybrids, giving an average of 5.24 bivalents and 11.58 univalents at MI. At TII from one to six micronuclei were present, which may cause sterility of the hybrids. Low pollen stainability, lack of seed production, and poor chromosome pairing of the hybrids indicated that these two species are distantly related. Backcrossing of the sterile F1 plants to the cultivated safflower failed, precluding examination of the feasibility of obtaining cytoplasmic male sterility in this crop by interspecific hybridization of these two species, followed by backcrossing.