Stability of esterases and total proteins during seed storage of perennialryegrass (Lolium perenne L.) and their use for cultivar discrimination

Polymorphisms in electrophoretic patterns obtained by isoelectric focusing (IEF) were examined to evaluate their suitability for cultivar identificati on in perennial ryegrass (Lolium perenne L.). It was possible to discrimina te 64 (94%) of 68 cultivars by combining results from esterase and total pr otein analysis. Discrimination was based on quantitative differences (relat ive band intensity) rather than on qualitative differences (presence or abs ence of bands). Esterase patterns from different recent (fresh to seven yea rs old) seed lots of the same perennial ryegrass cultivars were very stable . Occasionally, minor differences in band intensity were observed between r ecent and old (up to 30 years old) seed lots of a cultivar. Storage of meal samples up to two years at -20 degrees C had no effect on the total protei n patterns. No correlation was found between esterase patterns and ploidy l evel, cultivar type (pasture or turf), heading date or breeding company. Es terase patterns appeared to be unsuitable markers for the selection of refe rence cultivars for distinctiveness, uniformity, and stability (DUS) testin g, because no correlation was found between cultivars on the basis of ester ase banding patterns and morphological characteristics.