tailieunhanh - Chromosome association in allotetraploid interspecific hybrid ryegrass and parental species

This study was carried out in glasshouse conditions in summer 2000. Metaphase I (MI) chromosome association and numbers of chromosome arms bound were studied in autotetraploid perennial (Lolium perenne L.) and annual ryegrass (Lolium multiflorum Lam.) and their interspecific hybrid plants (Lolium hybridum). | Turk J Agric For 26 (2002) 1-9 © TÜB‹TAK Chromosome Association in Allotetraploid Interspecific Hybrid Ryegrass and Parental Species Bilal DEN‹Z Agronomy Department, Agricultural Faculty, Atatürk University 25240, Erzurum - TURKEY Received: Abstract: This study was carried out in glasshouse conditions in summer 2000. Metaphase I (MI) chromosome association and numbers of chromosome arms bound were studied in autotetraploid perennial (Lolium perenne L.) and annual ryegrass (Lolium multiflorum Lam.) and their interspecific hybrid plants (Lolium hybridum). In addition, the relationships among different cytological characteristics with respect to meiotic regularity were determined. Chromosome associations at MI were often regular in the parent species and hybrid ryegrass plants however different pairing irregularities were found to be higher in perennial and especially in hybrid ryegrass plants than in the annual ryegrass plant genotypes. Total bivalent pairing at MI were , and per cell and total quadrivalent pairings were , and 3339 in perennial, annual and hybrid ryegrasses, respectively. The difference was significant between annual ryegrass and hybrid ryegrass in terms of the frequency of ring quandrivalents at MI. All other types of chromosome associations showed no difference statistically between the parent species and hybrid ryegrass. In each ryegrass species, there were negative and significant correlations among the frequency of total quadrivalents and those of total and rod bivalents. The number of chromosome arms bound was lower in the allotetraploid hybrid ryegrass than in the parent species. The difference was significant between hybrid ryegrass and the parent species in terms of the same characteristic. On the other hand, there were positive and significant correlations among the number of chromosome arms bound and the frequency of ring quadrivalents, whereas negative and significant correlations were found .