STERILE FUNGI FROM ZOYSIAGRASS RHIZOSPHERE AS PLANT-GROWTH PROMOTERS IN SPRING WHEAT

Eleven out of 18 sterile fungal isolates and an isolate each of Penici llium sp. and Trichoderma sp. from the zoysiagrass rhizosphere were ef fective in enhancing the growth of two wheat varieties in greenhouse c onditions. They enhanced the top length and top dry biomass of plants significantly and induced the plants to produce long earheads and more seeds. Notable among isolates were GS6-1, GS6-2, GS7-3, GS7-4, GS8-6, GS10-1, GS10-2, and GU23-3, which enhanced the growth by several time s, resulting in a conspicuous growth promotion effect that differed de pending on the variety. Penicillium and Trichoderma species were less effective than sterile isolates in enhancing growth. Seven of the 11 e ffective sterile isolates from the zoysiagrass rhizosphere (as determi ned under greenhouse conditions) and a wheat rhizosphere isolate (K-17 ) were further tested under field conditions. Most of the isolates exc ept K-17 enhanced the growth of one variety, whereas a few isolates en hanced the growth of the other variety. However, at least four isolate s each increased yields of both varieties. Isolate GS6-1, which was ve ry effective under greenhouse conditions in promoting overall growth, was less effective under field conditions; however, the yield componen ts were not affected. The efficiency of the plant growth promoting iso lates depended upon the wheat variety and soil nutrient conditions in addition to their inherent growth promotion abilities.