Electrophoretic Evaluation of Esterase Isozymes from Turfgrass Seed Blends and Mixtures

Abstract

Turfgrass seeds are commonly blended to improve performance. However, once physically blended, no fast, reliable technique is available to identify the cultivars and the proportion of each cultivar in the blend. The objective of this study was to isolate specific species and cultivars in seed blends or mixtures through examination of esterase banding patterns on electrophoretic gels, and to compare band intensities unique to each cultivar or species when blended in increasing or decreasing proportions. Two cultivars of Kentucky bluegrass (Poa pratensis L.) were blended by weight in proportions ranging from 0 to 100%. Protein extracted, separated on isoelectric focusing gels (pH gradient 3 to 9) and stained for esterase activity. Mixtures of fine fescue (Festuca spp.) species only and mixtures of both fine fescue species and Kentucky bluegrass cultivars were prepared in the same manner. Gels were visually analyzed for the presence of characteristic bands unique to each cultivar or species and for intensities of characteristic bands when cultivar proportions were varied within a seed blend or mixture. The results indicated that visual discriminations could be made between cultivars and species in turfgrass blends or mixtures and that bands unique to a cultivar or species varied in intensity with their concentration in a blend or mixture. These findings have importance to seed companies and consumers interested in monitoring the composition of seed blends and mixtures subsequent to physical mixing.