Inflorescence development and seed production inLoliumspp. ×Festuca pratensistetraploid hybrids

SUMMARY The reproductive development and seed production characters of aLolium multiflorum×Festuca pratensistetraploid hybrid and aLolium perenne×Festuca pratensistetraploid hybrid were compared with those of their tetraploid parental cultivars. Experiments were carried out under glasshouse and natural conditions; single plants were studied as only small quantities of seed were available from the breeder. The lowtemperature/short-day requirements for inflorescence induction of the two hybrids were in between those of the corresponding parental species. The variance of the date at which vegetative primordia changed to the reproductive condition was greater in the hybrids than in the parental cultivars, but the variance of the dates of inflorescence emergence were similar for the hybrids and parental cultivars. Inflorescences ranged from theLoliumtype with only sessile spikelets to theFestucatype with primary branches. Inner glumes, which are absent in theLoliumparents but present inFestuca pratensis, were found in the hybrids, though not in all spikelets. In theLolium perenne×Festuca pratensishybrid pollen release, potential pollen viability and floret fertility were low, but theLolium multiflorum×Festuca pratensishybrid produced large amounts of pollen with a higher potential viability and had floret fertilities similar to those of its two parental cultivars. There was sufficient variation in reproductive characters for further selection, particularly in theLolium perenne×Festuca pratensishybrid.