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 chromosomalcharacteristics. all populations comprising 16 populations of cultivated l. sativus and 4 wild populations oflathyrus l. were diploid, 2n=2x=14 chromosomes. there were significant variations among populations inthe number of metacentric, submetacentric and subtelocentric chromosomes, the longest and shortestchromosome lengths, total haploid complement, arm ratios and centromeric index. the karyotypic formula ofwild lathyrus spp. populations were quite varied from those in native grass pea cultivars in having either twoor three pairs of subtelocentric chromosomes and accordingly containing one or two metacentricchromosomes. in addition, total chromosome length (tcl) in wild lathyrus l. accessions was less than thosefor grass pea populations. the mean length of the largest chromosome differed significantly amongpopulations, with populations 5 having the largest chromosome (7.2μm). the mean length of the shortestchromosome 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 wildpopulations of lathyrus l have the highest arm ratios and the lowest ci values. there were only slightdifferences in the mean of arm ratios among the native grass pea populations considering a range of 1.3 to 1.9for this morphological trait.