本試驗研究目的，在調查與大豆根部及根圈土壤相關連之內生菌根菌，及寄生性線蟲之種類。依篩網傾注法（Wet sieving and decanting method）調查內生菌根菌，並以改良柏門氏漏斗法分離調查寄生性線蟲。
在1979年大豆生長季節，採集調查20地點之大豆田土樣及根部，發現所有土樣中，均含有內生菌根菌之孢子，內生菌根菌以形成厚膜孢子之Glomus clarus 最為普遍，其次為形成Azygospore 之Acaulaspora laevis，再次為Gigaspora margarita，Glomus mosseae及G. macrocarpus。寄生性線蟲則以螺旋線蟲Helicotylenchus sp. 發生最多，其次為矮化線蟲Tylenchorhynchus sp., Tylenchus sp., Hirschmanniella sp.和根瘤線蟲Meloidogyne incognita。以前二者發生較普遍，在某些地點此種線蟲量多時，內生菌根真菌孢子數亦多，這顯示這些線蟲之存在並不受內生菌根之影響。有些採集地點內生菌根菌孢子數多時，根瘤線蟲數且很少或沒出現。
內生菌根菌Glomus clarus為絕對寄生真菌，不能在人工培養基上培養繁殖。本試驗尋得適當寄主百喜草（Paspalum notatun Flugge）能培養並保存之而供作接種源。在玻璃溫室試驗結果顯示，大豆台農4號及十石品種接種內生菌根菌G. clarus 之厚膜孢子，能顯著地（P＝0.05）增加植株量之生長及豆莢數之生產。
Investigation of Endomycorrhizal Fungi and Their Relation with Parasitic Nematodes on Soybean
Y. H. Cheng and C. C. Tu
The objective of this study was to investigate the incidence of endomycorrhizal fungi and parasitic nematodes associated with soybean in Taiwan. A method of wet sieving and decanting was used for surveying VA-mycorrhizal fungi and the improved Baermann’s funnel method was used for investigating parasitic nematodes. In a survey of soybean roots and rhizosphere from 20 locations during the growing season in 1979. Spores of endomycorrhizal fungi were found in every soil sample. The chlamydosporic species Glomus clarus was the most common endomycorrhizal fungus, the azygosporic species Acaulaspora laevis was the next common one, followed by Gigaspora margarita, Glomus mosseae, and Glomus macrocarpus. Spiral nematode (Helicotylenchus sp.) was the predominanted parasitic nematode, followed by stylet nematode (Tylenchorhynchus sp.), Tylenchus sp., Hirschmanniella sp., and root-knot nematode (Meloidogyne incognita).
There was no consistent relationship between the occurrence of a specific parasitic nematode and a specific VA-mycorrhizal fungus. The number of Meloidogyne spp., however, was lesser when higher number of chlamydospore of VA-mycorrhizal fungi was appeared.
Glomus clarus could be cultivated and maintained on the pot culture of Bahia grass (Paspalum notatum Flugge) and be served as inoculum. Inoculation of soybeans (Glycine max ‘Tainoun No. 4’ and ‘Shih-shih’) with chlamydospores of Glomus clarus significantly (P=0.05) increased top growth and pods production over nonmycorrhizal plant in greenhouse studies.