A Meiotic Examination of Lolium multiflorum Lam. × Festuca arundinacea Schreb. F 1 Hybrids 1

Abstract

An understanding of the genetic and cytogenetic relationships of the Lolium and Festuca species would facilitate the utilization of their intergeneric hybrids in breeding efforts to improve the parental species. Meiotic chromosomal behavior was examined in two Lolium multiflorum Lam. × Festuca arundinacea Schreb. F1 hybrids to provide more complete data on the meiotic process and to determine whether such information is useful in providing more specific knowledge concerning the transfer of genetic information in these crosses. The hybrids displayed similar frequencies of bivalents and trivalents per cell but differed significantly in the frequencies of univalents and quadrivalents at Metaphase I. The number of lagging univalents observed at Anaphase I corresponded well with the number of micronuclei per dyad at interkinesis. The number of quartet micronuclei was similar in the hybrids and indicated that the result of meiosis is similar for the hybrids despite the differences in initial chromosomal pairing frequencies. Dicentric bridges were also observed at Anaphase I and II, indicating structural heterogeneity within the paired chromosomes. The current analysis did not indicate whether the paracentric inversions involved L. multiflorum : F. arundinacea chromosomal pairs or F. arundinacea : F. arundinacea pairs. The distribution of lagging univalents in Anaphase I cells with and without dicentric bridges separated two groups of chromosomes relative to pairing probability present in these hybrids. The bivalents appeared to involve basically the same chromosomes in all cells, whereas the univalents and/or multivalents were drawn from a different group of chromosomes.