KARYOTYPE STUDY IN SOME LATHYRUS L. ACCESSIONS OF IRAN

Twenty accessions of cultivated grass pea (Lathyrus sativus L.) and wild species of Lathyrus L. collected from western and southern regions of Iran were evaluated for their mitotic metaphase chromosomal characteristics. All populations comprising 16 populations of cultivated L. sativus and 4 wild populations of Lathyrus L. were diploid, 2n=2x=14 chromosomes. There were significant variations among populations in the number of metacentric, submetacentric and subtelocentric chromosomes, the longest and shortest chromosome lengths, total haploid complement, arm ratios and centromeric index. The karyotypic formula of wild Lathyrus spp. populations were quite varied from those in native grass pea cultivars in having either two or three pairs of subtelocentric chromosomes and accordingly containing one or two metacentric chromosomes. In addition, total chromosome length (TCL) in wild Lathyrus L. accessions was less than those for grass pea populations. The mean length of the largest chromosome differed significantly among populations, with populations 5 having the largest chromosome (7.2mm). The mean length of the shortest chromosome did not differ among populations, with wild populations from Ilam (populations 17, 18 and 19) having the lowest value. The arm ratios and centromeric index (CI) data revealed adverse trends, whilst wild populations of Lathyrus L have the highest arm ratios and the lowest CI values. There were only slight differences in the mean of arm ratios among the native grass pea populations considering a range of 1.3 to 1.9 for this morphological trait.