THE USE OF SEED PROTEIN BANDING PATTERNS FOR IDENTIFICATION OF PASTURE CULTIVARS

Abstract

Because of the growing number of pasture cultivars used in NZ and the difficulty of reliably separating cultivars of the same species by morphological characters, seed protein banding patterns have become a useful supplementary means of cultivar identification for the purposes of seed certification and plant variety rights applications. Sodium dodecylsufphate polyacrylamide gel electrophoresis of proteins extracted from ground seed samples produces distinctive patterns of bands representing seed storage proteins of different molecular weights. The procedure can be carried out in two days using viable or dead seed, and the results are not affected by site and season of growth. Although individual seeds of outbreeding species such as perennial ryegrass and white clover produce different banding patterns, the combined population representing the cultivar remains constant unless there has been genetic shift during seed multiplication. Speckes for whrch this procedure is being successfully used include the ryegrasses and fescues, browntop, cocksfoot, bromes, red and white clovers, subterranean clover, serradella and lotus. Even cultrvars as closely related as Nui and Ellett ryegrasses and Huia and Pitau white clovers can be separated by careful work. Because of minor technical differences between runs, all cultivars to be compared must be run on the same gel. Keywords: Seed certification, Plant variety rights, sodium dodecylsulphate polyacrylamide gel electrophoresis.