OCCURRENCE AND DIVERSITY OF INDIGENOUS MYCORRHIZAL FUNGI IN DIFFERENT SUDAN SOILS USING SORGHUM [Sorghum bicolor (L.) Moench] AS A HOST PLANT

Abstract

The mutual relationship between arbuscular mycorrhizal fungi (AMF) and plants is ancient. However, there are some environmental factors, which affect the occurrence and diversity of this relationship. This study was conducted to investigate the indigenous AMF occurrence and diversity indices at six sites (two sites from Gezira, two from Sennar and one from each of Gedarif and North Kordofan States) which represent four geographical locations in the Sudan in 2016. Three rhizosphere samples from sorghum were taken from each site to estimate soil physical and chemical properties, total spores density, invalid spores percentage and root colonization to evaluate their roles in AMF occurrence and diversity. Results showed that the average total spores density ranged from 418 /100g soil at Gedaref to 1781 /100g soil at North Kordofan. The highest invalid spores percentage was found at Gedaref (21.5%) and the lowest at North Kordofan (12.5%). Root colonization percentage ranged from (11.3%) at Gedaref to (32.1%) at North Kordofan. There was a highly positive correlation between root colonization percentage and total spores density, invalid spores and sand percentage. A highly negative correlation existed between root colonization percentage on one hand and CEC, clay percentage and soil pH on the other hand. Twelve genera and 26 species were morphologically identified and two species were not identified. Rhizophagus, Glomus, Claroideogloms, Funneliformis, Acaulospora, Scutellospora and Entrophospora were dominant genera at all sites. However, Septoglomus and Ambispora were normally distributed genera and Gigaspora, Scelerocystes and Dentiscutata were rare genera. Diversity index detected a normal diversity and richness except for Gedarif having a lower diversity index, and the situation was reversed for North Kordofan, having a higher diversity index. It could be concluded that AMF occurrence and diversity were affected by soil chemical and physical properties. It is recommended to add AMF inoculums to heavy clay soils to increase spore density.