Arbuscular Mycorrhizal Fungi Associated with Green Gram in South India

Abstract

Field studies are necessary to understand the abundance and type of indigenous arbuscular mycorrhizal (AM) fungi present in the rhizosphere. Green gram [Phaseolus aureus Roxb. (= Vigna radiata var. radiata)] is a major pulse crop of South India. A field study was conducted to identify the AM fungi associated with green gram under field conditions in this region. The rhizosphere soil samples from these fields were analyzed for AM fungal spores. Glomus mosseae, Glomus microcarpum, Gigaspora margarita, and Scutellospora sp. were identified as the AM fungi associated with green gram. Glomus mosseae was the most frequent AM fungal associate identified in 81%, G. microcarpum and G. margarita in 24% each, and Scutellospora sp. in 5% of the soils studied. The range of distribution varied from a single species of AM fungus to three species belonging to two genera in one sample. Correlations of spore count and percentage colonization for all the AM fungi on the crop in the field, along with soil parameters like pH, N, P, and K were studied. Significant negative correlation (P < 0.01) was obtained between percentage colonization and P. The pH and N were positively correlated (P < 0.01) with K. The study indicates involvement of factors other than soil nutrients in the distribution and sporulation of AM fungi.

Arbuscular mycorrhizal and dark septate fungal associations in shallot (Allium cepa L. var. aggregatum) under conventional agriculture

“…Major portions of AMF spores occurring in field soils are either dead or spore cases (MUTHUKUMAR and UDAIYAN 1999) and the spore numbers presented in this study are only for intact spores. The lack of correlation between %RLTC and spore numbers agrees with the observations of VALSALAKUMAR et al (2007) in Phaseolus aureus, ZAHKA et al (1995) in Acer saccharum, KHALIL and LOYNACHAN (1994) in Glycine max and SASAI (1992) in cultivated plants of Miyagi prefecture, Japan. Such a lack of correlation between AMF colonization and spore numbers indicate that the factors influencing these variables are totally different.…”

“…However, the AMF diversity in the present study is within ranges observed for a site by ANANTHAKRISHNAN et al (2004) andSJÖBERG et al (2004). VALSALAKUMAR et al (2007) also reported very low AMF diversities of one to three taxa for the 21 sampling locations under Phaseolus aureus cultivation in Tamil Nadu and Karnataka of South India. The presence of low AMF diversity could be due to the selection pressure imposed by cultivation practices resulting in the dominance of fast growing species (OEHL et al 2004) and species that are able to tolerate stresses like tillage, fertilizer and biocide applications (GOSLING et al 2006, GALVÁN et al 2009).…”

“…71 (1) ventional cultivation of onions (GALVÁN et al 2009). The lack of correlation between soil P and mycorrhizal parameters agreed with the observation of GALVÁN et al (2009), but contrasted with studies where an inverse correlation had been reported between these variables (ANANTHAKRISHNAN et al 2004, LINGFEI et al 2005, KHANAM et al 2006, VALSALAKUMAR et al 2007, Das and KAYANG 2010b. Soil pH has a great relevance for plant growth as it influences nutrient mobilization as well as availability (MARSCHNER 1995).…”

“…Soil pH has a great relevance for plant growth as it influences nutrient mobilization as well as availability (MARSCHNER 1995). Many studies reporting the influence of soil factors on AMF colonization have failed to find any relationship between soil pH and colonization (ZAHKA et al 1995, KHADE and RODRIGUES 2008, VALSALAKUMAR et al 2007, OLIVEIRA and OLIVEIRA 2010, KHANAM et al 2006. In the present study pH of the soil was positively correlated to all AMF colonization parameters except %RLV.…”

Diversity, richness and degree of colonization of arbuscular mycorrhizal fungi in coconut cultivated along with intercrops in high productive zone of Kerala, India

“…The present results are in agreement to the report of Thomas and Ghai (1987) that more than one AM fungal species colonized the same coconut seedlings and the same root segments. There are several reports to indicate that more than one AM fungal species were associated with different crops such as clover (Abbot and Robson 1984) and green gram (Valsalakumar et al 2007).…”