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Title: Parental Genome Composition and Genetic Classifications of F1 Hybrids and Backcross Progeny Derived from Intergeneric Crosses of Festuca Mairei and Lolium Perenne

Author
item WANG, J - MICHIGAN STATE UNIVERSITY
item BUGHRARA, S - MICHIGAN STATE UNIVERSITY
item Mian, Rouf
item SAHA, M - SAMUEL ROBERTS FOUNDATION
item SLEPER, D - UNIVERSITY OF MISSOURI

Submitted to: Molecular Breeding
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/3/2008
Publication Date: 2/15/2009
Citation: Wang, J.P., Bughrara, S.S., Mian, R.M., Saha, M.C., Sleper, D.A. 2009. Parental Genome Composition and Genetic Classifications of F1 Hybrids and Backcross Progeny Derived from Intergeneric Crosses of Festuca Mairei and Lolium Perenne. Molecular Breeding. 23:299-309.

Interpretive Summary: Improving the drought tolerance of ryegrasses (Lolium sp.) is an important goal of turfgrass breeders in the USA and elsewhere. Inter-generic hybridization between Fescue and ryegrass has been used by breeders to transfer drought tolerance from fescue to ryegrass. However, inter-generic hybridizations usually result in wild genome being eliminated from the hybrid due to incomplete chromosome pairing and crossovers. Molecular markers can be used to monitor hybridization and the extent of retention of the donor parent genome in wide cross hybridization schemes. In this study, random amplified polymorphic DNA (RAPD) and simple sequence repeat (SSR) markers were used to detect the parental genome composition of 16 progeny generated from crosses between Festuca mairei St. Yves (Fm) and Lolium perenne L. (Lp). Based on marker data, each of the 16 progeny exhibited integration of Fm and Lp genomes with varying levels of Fm/Lp genome ratios. Both RAPD and SSR markers were found effective in monitoring genome integration in these crosses. The progeny were divided in four groups based on the extent of fescue genome integration. Group II included seven progeny that had introgressed more of the Fm than Lp genome. Group III was comprised of six progeny showing similar amounts of genome introgression from both parents. Group IV contained two backcross progeny that had more of the Lp genome. Some of these 16 inter-generic progeny would be useful to turf breeders working on drought tolerance of ryegrasses.

Technical Abstract: Intergeneric hybridization between Festuca and Lolium has been a long-term goal of forage and turfgrass breeders to generate improved cultivars by combining stress tolerance of Festuca with rapid establishment of Lolium. However, wide-distance hybridizations usually result in wild genome being eliminated from the hybrid due to incomplete chromosome pairing and crossovers. In this study, random amplified polymorphic DNA (RAPD) and simple sequence repeat (SSR) markers were used to detect the parental genome composition of 16 progeny generated from crosses between Festuca mairei St. Yves (Fm) and Lolium perenne L. (Lp). Each of the 16 progeny exhibited integration of Fm and Lp genomes with varying levels of Fm/Lp genome ratios. The non-coinheritance of the linked markers suggested chromosome crossover between the two parents. Cluster and principle component analyses of the progeny consistently revealed four groups. Group I composed of one backcross progeny that had a distinctly different genetic background from other individuals. Group II included seven progeny that was introgressed more of the Fm than Lp genome and clustered with the Fm parent. Group III was comprised of six progeny showing similar amounts of genome introgression from both parents. Group IV contained two backcross progeny that had more of the Lp genome and clustered with Lp parents. These results provided information on parental genome composition and classifications of 16 intergeneric progeny that would be useful to forage and turfgrass breeders.