Cytogenetics of Festulolium (<i>Festuca </i>×<i> Lolium</i> hybrids)

Abstract

Grasses are the most important and widely cultivated crops. Among them, ryegrasses (Lolium spp.) and fescues (Festuca spp.) provide high quality fodder for livestock, are used for turf and amenity purposes, and play a fundamental role in environment protection. Species from the two genera display complementary agronomic characteristics and are often grown in mixtures. Breeding efforts to combine desired features in single entities culminated with the production of Festuca × Lolium hybrids. The so called Festuloliums enjoy a considerable commercial success with numerous cultivars registered all over the world. They are also very intriguing from a strictly cytogenetic point of view as the parental chromosomes recombine freely in hybrids. Until a decade ago this phenomenon was only known in general quantitative terms. The introduction of molecular cytogenetic tools such as FISH and GISH permitted detailed studies of intergeneric chromosome recombination and karyotyping of Festulolium cultivars. These tools were also invaluable in revealing the origin of polyploid fescues, and facilitated the development of chromosome substitution and introgression lines and physical mapping of traits of interest. Further progress in this area will require the development of a larger set of cytogenetic markers and high-resolution cytogenetic maps. It is expected that the Lolium – Festuca complex will continue providing opportunities for breeding superior grass cultivars and the complex will remain an attractive platform for fundamental research of the early steps of hybrid speciation and interaction of parental genomes, as well as the processes of chromosome pairing, elimination and recombination.

Fluorescence chromosome banding and FISH mapping in perennial ryegrass, Lolium perenne L.

“…Introgression of alien chromosome or chromosome segments have produced cytogenetic stocks of addition or substitution lines in a number of Pooideae, including Festulolium hybrids [38, 47, 48]. Application of the Q-banding technique in combination with sequential FISH and/or genomic in situ hybridization (GISH) should provide identification of specific chromosomes and, by extension, the nature and extent of introgression.…”

Cytogenetic relationships within the Maghrebian clade of <em>Festuca</em> subgen. <em>Schedonorus</em> (Poaceae), using flow cytometry and FISH

“…On the other hand, it was not possible to distinguish parental genomes in hybrids of Lolium perenne L. and Lolium multiflorum Lam. (Kopecký & al., 2008a) (Loureiro & al., 1997). Similarly, FISH with probes for specific DNA sequences can be employed for evolutionary studies.…”

“…Schedonorus, including tall fescue (F. arundinacea) and meadow fescue (F. pratensis), are widely used for forage and turf. Moreover, the ability of interspecific hybridization within SchedonorusLolium complex is recently used in grass breeding and several interspecific and intergeneric hybrids including hybrid ryegrass and ×Festulolium -hybrids of Festuca and Lolium-have been released and became popular among farmers (Kopecký & al., 2005(Kopecký & al., , 2008a. Climatic changes call for implementation of new alleles into existing crop cultivars and thus, we can predict increasing interest in the employment of other wild species in breeding.…”

An Increasing Need for Productive and Stress Resilient Festulolium Amphiploids: What Can Be Learnt from the Stable Genomic Composition of Festuca pratensis subsp. apennina (De Not.) Hegi?

“…The development of the cytogenetic techniques GISH and FISH for applications with the grasses of the LoliumFestuca complex has enabled the effective discrimination between genomes of several species (Thomas et al, 1994; reviewed in Kopecký et al, 2008b) and allowed determination of the progenitors of certain polyploid Festuca species. A good example was the determination of the ancestry of F. arundinacea Schreb.…”