西南地区立枯丝核菌菌丝融合群及其生态学研究

从川、滇、黔、藏的代表地区，采集植物及土壤样品８１２份，分离出具丝核菌特征的菌株３６１株。根据菌丝细胞宽度，细胞核数目等，鉴定出立枯丝核菌（ＲｈｉｚｏｃｔｏｎｉａｓｏｌａｎｉＫｕｈｎ）２２９株，双核丝核菌１３２株。将立枯丝核菌分离菌与已知融合群菌株分别配对进行菌丝融合试验，结果有２０７株分属于ＡＧ－１，ＡＧ－２，ＡＧ－３，ＡＧ－４，ＡＧ－５，ＡＧ－６，ＡＧ－７７个菌丝融合群。其中ＡＧ－４频率最高（６７．７），ＡＧ－１次之（２２．７）。ＡＧ－６，ＡＧ－７为我国首次记录。还有２２株不与现有已和融合群发生融合。立枯丝核菌在西南地区地理分布很广，寄主或基物种类多。在海拔３００－３７６０ｍ的高度范围及ｐＨ５－８的土壤中都有发现，但在３００－１０００ｍ的高度，ｐＨ６－７．５及０－１０ｃｍ的土壤中分布更丰富。季节变化对土壤中主要融合群的分布无显著影响。

ANASTOMOSIS GROUPS OF RHIZOCTONIA SOLANI AND THEIR ECOLOGY IN SOUTHWEST CHINA

Two hundred and seven isolates of Rhizoctonia solani Kuhn (Thanatephorus cucumeris(Frank) Donk) were obtained from 812 diseased plants and soil samples collected from Sichuan, Guizhou, Yunan and Tibet. Intraspecific groups were identified by hyphal fusion with representative strains of known anastomosis groups(AGs, testers). Seven AGs,i.e, AG-1, AG-2,AG-3, AG-4 , AG-5, AG-6, AG-7 were identified. AG-4 is the major group (frequency: 67.7%)and AG-1(22.7%)follows. AG-6 and AG-7 are reported for the first time in China. The ecology of these AGs in southwest China has been studied. The results show that the fungus is widely distributed and has a wide host range. The AGs in soil are most preferable at pH 6.0-7. 5 in a depth of 0-10cm.The seasonal variation of main AGs seems inconspicuous.