We report here the results of a unique, large-scale research project that focused on the problem of clonal selection of saffron (Crocus sativus L.). Samples of saffron populations from the five most ancient cultivation regions in Iran were obtained for the study, with a parts per thousand yen20,000 corms comprising the sampled populations from each region. The corms were divided onto weight groups (for example, 3.0-3.9, 4.0-4.9 g, up to the largest) and then planted in rows separately in the field with one corm per hole (pit). This strict separation of the corms and the strict planting procedure was maintained for four growing seasons, enabling a comparison of the pits with grown plants and a study of the differences between clones. A comparison of many hundreds and thousands of clones, each grown from one corm of the same weight, resulted in the identification of "superior" clones in terms of exceptionally large numbers of flowers and large (a parts per thousand yen10 g) corms. Based on the number of flowers and number of large corms, which are the two most economically important attributes of saffron, the clones were classified as extraordinary, superior, ordinary, inferior and declining clones. The first two classifications of clones, which had the highest numbers of flowers and largest corms, have been chosen for use in a saffron breeding program aimed at developing new high-yielding cultivars of saffron. Those clones would also be very suitable for facilitating the mechanization of saffron agriculture in terms of the lifting, sorting and planting of corms, weeding, softening ground and harvesting flowers.
