Research was undertaken to determine the response of newly planted saffron to the application of different levels of nitrogen (0, 50 and 100 kg N · ha−1 · year−1), phosphorus (0, 25, and 50 kg P2O5 · ha−1 · year−1), and composted cow manure (0, 20, and 40 tons · ha−1 · year−1) in terms of fresh flower weight (FFW), saffron yield (SY) and leaf biomass. The experiments were conducted in Birjand, and Ghaen, Khorasan province, Iran, from 1991 to 1993. Significant differences were found between the two locations and among the years within each location for FFW and SY. Averaged over all treatments and years, mean values for FFW and SY were 644.3 and 9.1 kg · ha−1, respectively, at Birjand, and 296.0 and 3.7 kg · ha−1, respectively, at Ghaen. At Birjand, mean FFW in the three consecutive years was 229.0, 796.2, and 907.8 kg · ha−1 and mean SY was 3.4, 10.6, and 13.4 kg · ha−1. The corresponding means at Ghaen were 87.5, 225.9, and 574.7 kg · ha−1 for FFW and 1.3, 3.2, and 6.7 kg · ha−1 for SY. Simple correlation coefficients between FFW and SY were positive and highly significant. At both locations, FFW and SY increased significantly from year to year. The rate of increase, however, decreased with the age of the saffron field because of overcrowding of new corms. Different combinations of fertilizers had either a negative or nonsignificant effect on FFW and SY. The application of phosphorus fertilizer did not result in increased FFW and SY. The application of 40 tons · ha−1 of cow manure in the first year followed by no fertilizer in the second year and by 20 tons · ha−1 in the third year increased FFW and SY at Birjand. The use of 100 kg · ha−1 nitrogen only in the third year also increased FFW and SY at Birjand. At Ghaen, only the application of 50 kg · ha−1 nitrogen in the third year resulted in increased FFW and SY.

Carthamus leucocaulos Sibth. &Sm., with n = 10, was found to be closely related to other species of the genus with the same chromosome number, in spite of its distinctive morphological appearance. Like other species with n = 10, it crossed readily with C. divaricatus Beg. et Vacc. (n = 11), giving a fertile hybrid. It was distantly related to C. nitidus Boiss. (n = 12), a species morphologically similar to C. leucocaulos. Relationships to other species were studied and discussed.

Carthamus divaricatus (Beg. et Vacc.) Pamp., found only in Libya, has 11 pairs of chromosomes, a new chromosome number in the genus. The species is distinct morphologically. It has yellow, purple, and white corollas, yellow pollen, dark‐purple striped anthers, horizontal branches, and strongly divaricate outer involucral bracts. The terminal portion of the middle involucral bracts is dentate and reddish brown. It is self‐incompatible. Meiosis is regular in the different corolla‐color types of C. divaricatus and their intraspecific hybrids. C. divaricatus was crossed to six species with n = 12, to three species with n = 10, to C. lanatus with n = 22, and to two species with n = 32 chromosomes. The morphological characteristics and cross‐ability of the parental species plus the pollen viability, seed‐set, and meiotic behavior of the hybrids involving C. divaricatus and other Carthamus species indicated that C. divaricatus is very closely related to species with n = 10, closely related to C. lanatus with n = 22, and less closely related to C. tinctorius with n = 12 chromosomes. C. divaricatus seems to be distantly related to C. nitidus (n = 12). It is proposed that C. divaricatus be included provisionally with 10‐chromosome species in Section II. Alternative hypotheses for the development of the three basic chromosome numbers are discussed.

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