2016/08/25 by Ghesquière, Marc, Bourgoin, Thierry, Hacquet, Jacques
#Abiotic stress #Amphiploid #Amphiploidie #Amphiploidy #Amphiploïde #Drought tolerance #Fescue #Festulolium #Fétuque #Hybride interspécifique #Interspecific hybrid #Introgression #Persistency #Plante pérenne #Pérennité #Ray-grass #Ryegrass #Stress abiotique #Tolérance à la sécheresse
paper · doi:10.15454/1.4721079268561484e12
Festulolium are interspecific hybrids between Festuca and Lolium species bred to improve forage performances under climate stresses as low and high temperature and water deficit. Thirty-six varieties are presently registered in the European Union list of which, only four are in the French list. The Festulolium definition changed in 2004 in extending potentially to nine amphiploid combinations and more than sixty forms at various degree of introgression, diploid to hexaploid, into four fescue species and three Lolium species including hybrid rye-grass. In this range of continuous variation, the forage performances among Festulolium varieties are still negatively correlated with seed productivity which closely determines availability and benefits for end-users. The project aimed to provide further data on genetic variability of seed productivity and its components as pollen fertility among present varieties and breeding plant material, up to individual plant level to be used as breeding criteria. The results showed that seed productivity is sufficiently restored in Festulolium as soon as they derive from one generation of back-crossing into any tetraploid ryegrass species. By contrast, amphiploid Festulolium whatever they come from, F. pratensis or F. glaucescens, still remained of low seed productivity which germination rate may fail rapidly to meet the 80 % requirement for seed marketing. Remodelling the genome balance in such Festulolium by speeding up interspecific recombination and using molecular tools seem the only mean to increase seed productivity before conventional breeding can take place usefully. To support this considerable long term investment by plant breeders, better identification of genetic structure of candidate Festulolium varieties is required, also defining better adequate tests for VCU.