Chromosomal Behavior during Meiosis in the Progeny of <i>Triticum timopheevii</i> × Hexaploid Wild Oat

<div><p>The meiotic behavior of pollen mother cells (PMCs) of the F₂ and F₃ progeny from <i>Triticum timopheevii</i> × hexaploid wild oat was investigated by cytological analysis and sequential C-banding-genomic <i>in situ</i> hybridization (GISH) in the present study. A cytological analysis showed that the chromosome numbers of the F₂ and F₃ progeny ranged from 28 to 41. A large number of univalents, lagging chromosomes, chromosome bridges and micronuclei were found at the metaphase I, anaphase I, anaphase II and tetrad stages in the F₂ and F₃ progeny. The averages of univalents were 3.50 and 2.73 per cell, and those of lagging chromosomes were 3.37 and 1.87 in the F₂ and F₃ progeny, respectively. The PMC meiotic indices of the F₂ and F₃ progeny were 12.22 and 20.34, respectively, indicating considerable genetic instability. A sequential C-banding-GISH analysis revealed that some chromosomes and fragments from the hexaploid wild oat were detected at metaphase I and anaphase I in the progeny, showing that the progeny were of true intergeneric hybrid origin. The alien chromosomes 6A, 7A, 3C and 2D were lost during transmission from F₂ to F₃. In addition, partial <i>T</i>. <i>timopheevii</i> chromosomes appeared in the form of univalents or lagging chromosomes, which might result from large genome differences between the parents, and the wild oat chromosome introgression interfered with the wheat homologues’ normally pairing.</p>