Study of phenological, morphological, and cytogenic diversity of Secale spp. in Iran

Rye (Secale spp.) is native to Southwest Asia and it two species including S. cereale and S. strictum is grown in Iran. This study was conducted to evaluate the diversity of phenological, morphological, and cytogenetic traits in two species of this genus. In this experiment, seeds of 91 ecotypes (including 78 S. cereale and 13 S. strictum) were provided from National Plant Gene Bank of Iran. Seeds sown in the research farm of the Seed and Plant Improvement Institute, Karaj, Iran, in the 2014-2015 crop year. All phenological and morphological traits (quantitative and qualitative) including 23 traits were measured according to the instructions of the International Institute of Bioversity. The descriptive statistics parameters showed different range of variation in traits among the species. Multivariate analysis showed significant differences among the species for phenological traits as flowering date and maturation date and morphological traits as grain shedding index, ear color, spike length and the number of spikelets per spike. These traits were considered of great importance in species segregation. Cytogenetic evaluation of the chromosomes of S. cereale and S. strictum showed that although both species were diploid (2n=14), a noticeable difference in chromosome length and the average arm ratio was observed in these two species, which can help to identify cytogenetically differentiate between them. Overall, the phenological, morphological, and cytogenetic traits in rye species show considerable diversity and can be used to identify and differentiate of the species. If there is a time limit or impossibility of cultivation, cytogenetic evaluation can be used as a fast and reliable method to identify species.