Effects of arbuscular mycorrhiza and pseudo-endo mycorrihza symbiosis on seed yield and some physiological responses of chickpea (Cicer arietinum L.) genotypes

It has been proven that microorganisms such as mycorrhiza and rhizobium can improve the nutrients absorption in crops such as chickpea. Rhizobiums are effective to provide nitrogen by biological form in crops and mycorrhizal fungi are involved to supply biological phosphorus to the plants. Among them, the endo myccorihza (or Vesicular Arbuscular Mycorrhiza) that abbreviated VAM, in creation of symbiosis with the roots of crops such as legumes have been more successful. Of course, the mycorrhizal fungi and rhizobium bacteria before create symbiosis with host plant, directly affect in the overlay in rhizosphere environment of host plant. Creating colonies in the roots by mycorrhizal fungi leads to conducive for forming nodulation of rhizobium. Studies have shown that the VAMs (which are newly named AMF (Arbuscular Mycorrhizal Fungi)) are generally belongs to Zigomaycota groups and ecto-myccorihza are mainly to Basidiomaycota. But recently a new species of Basidiomaycota has been identified with name of Piriformospora indica that acts as AMF and is an entophyte fungus (or pseudo endo mycorrihza). It seems that this symbiotic relationship between plants, mycorrhizal and rhizobium can be either normal or adverse environmental conditions, is effective in promoting the product of crop. In Iran, among pluses, chickpea has been allocated the most area under cultivation. Meanwhile, the average yield of irrigated and dryland chickpea is about 1000 and 500 kg ha-1, respectively and Iran is located the lowest ranking among the countries producing this product. Thus, the triplet symbiosis of chickpea, mycorrhiza and rhizobium and also chickpea genotypes response to this symbiosis were examined in this research. 

This study was conducted to investigate the inoculation of Kabuli seeds of chickpea genotypes with arbuscular mycorrhiza and pseudo endo mycorhiza, in split plot by arrangement of two factors with a randomized complete block design and three replications in Research Field, Faculty of Agriculture, Ferdowsi University of Mashhad in 2014. Main plots were consisted of three levels of mycorhiza (arbuscular mycorhiza of Glomus mosseae, pseudo endo mycorhiza of Piriformospora indica and non-used mycorhiza) and sub plots were consisted of nine genotypes of chickpea: MCC80, MCC358, MCC361, MCC392, MCC427, MCC537, MCC693, MCC696 and MCC950. These genotypes had good yield potentials and selection and presented in the studies on germplasm from the Institute of Plant Sciences, Ferdowsi University of Mashhad seed bank. Before the sowing, all seeds of genotypes were infected to the symbiotic rhizobium bacteria of chickpea. During the growing season, traits of chlorophyll a and b, carotenoids, SPAD readings and protein of plant tissues were measured and by measuring dry matter and leaf area, their process was investigated under different treatments. Also, at the end of the growing season, seed yield of genotypes was measured. 

The results indicated that G. mosseae significantly increased seed yield and dry matter of chickpea since mid-season upward compared to other treatments. Arbuscular mycorrhiza significantly increased chlorophyll a and chlorophyll b, carotenoids and SPAD readings. Also the most protein of plant tissues belonged to the factor of arbuscular mycorrhiza in two genotypes of MCC537 and MCC427. The combined application of rhizobium and mycorrhiza increased leaf area index. Evaluation of leaf area index process at the end of the growing season showed an increase in the lower range of leaf area index curve in rhizobium and mycorrhiza treatments, which was not significant in the fifth sampling and was significant in the sixth sampling. Among study genotypes, MCC537 showed the highest seed yield and higher dry matter than other genotypes during the growing season at harvest time. The most content of carotenoids and SPAD readings were in genotypes of MCC537, MCC427 and MCC392. 

It seems that application of pseudo endo mycorrhiza had not significant effect on the absorption of seed yield in chickpea. But application of G. mosseae along with rhizobium can improve the physiological traits and seed yield of chickpea. Also, in a general conclusion, among the studied genotypes, MCC 537 and MCC 427 were better than the others.