Meiotic configuration and chromosome number in some Iranian species of Elymus L. and Agropyron Gaertner (Poaceae: Triticeae)

Abstract

Chromosome numbers and analyses of meiotic metaphase I are reported for the following taxa:Agropyron cristatumsubsp.incanum (2n = 42), A. cristatumsubsp.pectinatum (2n = 28 – 33), Elymus elongatussubsp.ponticus (2n = 69, 70), E. hispidusvar.hispidus (2n = 41 – 43),var.podperae (2n = 42)and var.villosus (2n = 41, 42), E. libanoticus (2n = 14), E. pertenuis (2n = 28, 28+1B), E. repens (2n = 42), E. transhyrcanus (2n = 40–42), E. hispidusvar.villosus × E.cf.repens (2n = 42).Chromosome numbers only are reported for the following taxa:E. gentryi (2n = 41, 42), E. nodosussubsp.dorudicus (2n = 28),andE. elongatiformis (2n = 56, 57).The haploid genomic constitution SP is reported forElymus pertenuis.Variable chromosome numbers (2n= 28–32) were observed in the meiotic metaphase I within single anthers ofAgropyron cristatumsubsp.pectinatum,and the supernumerary chromosomes in this taxon are assumed to have originated from crosses with hexaploids. Partial elimination of these supernumerary chromosomes probably occurs during archesporial mitotic divisions or at an early stage in the meiotic cycle. A hybrid, morphologically intermediate betweenE. hispidusandE. repens,was obtained from a seed ofE. hispiduscollected in the field. The meiotic metaphase I configuration in thisE. hispidushybrid suggests that the pollen parent may itself be a hybrid or hybrid derivative ofE. repens × E. hispidus.