OBSERVATIONS ON SPREAD AND FRAGMENTATION OF BLUE GRAMA CLONES IN DISTURBED RANGELAND

Establishment of blue grama (Bouteloua gracilis [H.B.K.] Lag ex. Steud .) depends on adequate precipitation at critical times and on reduced competition from associated vegetation, These conditions rarely occur on Central Plains rangelands. Therefore, rapid vegetative spread of ne w seedlings is desirable for colonizing disturbed rangeland, Blue gram a genotypes selected for rapid spread would also be desirable for rang eland seeding, For 6 years, we followed the rate of spread of 19 blue grama clones originating from seedlings which emerged in 1980 and grew under natural competition. We observed a 4.5-fold difference in basal area and a 16.3-fold difference in above-ground biomass of these clon es, perhaps because of genetic differences among clones and varying le vels of competition. Clones must be tested under uniform competition w ith clonal replication to obtain reliable estimates of their capacity to spread.