No abstract

The ability of fluorescent Pseudomonas strain EKi, in production of biocontrol and plant growth promotory (PGP) metabolites under saline stress was evaluated. Strain EKi could tolerate NaCl up to 1,550 mM and showed biocontrol of Macrophomina phaseolina (76.19%) in the presence of up to 400 mM NaCl. Strain EKi was able to produce IAA, siderophore and pyocyanin with gradual reduction of up to 76.31, 45.46, and 48.99%, respectively, as NaCl concentration increased from 0 to 500 mM. Reduced growth rate resulted in delayed induction of IAA, siderophore and pyocyanin by the PGPR. Thin layer chromatography of chloroform extract from non-stressed and salt stressed EKi, and inhibition of M. phaseolina by purified pyocyanin clearly indicated its role in biocontrol. In vitro and in vivo results showed the growth promotion and charcoal rot disease suppression of chickpea by strain EKi under both non-stressed and saline stress. There was 76.75 and 65.25% reduction of disease incidence in non-saline and saline conditions, respectively, in vitro conditions. In presence of M. phaseolina strain EKi brought about 67.65 and 58.45% reduction of disease incidence in non-saline and saline soil, respectively.

Pigeon pea () is one of the most important legumes grown in the northern province of Uttar Pradesh, India. However, its productively in Uttar Pradesh is lower than the average yield of adjoining states. During the course of the present study, a survey of pigeon pea growing agricultural fields was carried out and it was found that 80% of plants were inadequately nodulated. The study was aimed to evaluate the pigeon pea symbiotic compatibility and nodulation efficiency of root nodulating bacteria isolated from various legumes, and to explore the phenetic and genetic diversity of rhizobial population nodulating pigeon pea growing in fields of Uttar Pradesh. Amongst all the 96 isolates, 40 isolates showed nodulation in pigeon pea. These 40 isolates were further characterized by phenotypic, biochemical and physiological tests. Intrinsic antibiotic resistance pattern was taken to generate similarity matrix revealing 10 phenons. The study shows that most of the isolates nodulating pigeon pea in this region were rapid growers. The dendrogram generated using the NTSYSpc software grouped RAPD patterns into 19 clusters. The high degree of phenetic and genetic diversity encountered is probably because of a history of mixed cropping of legumes. The assessment of diversity is a very important tool and can be used to improve the nodulation and quality of pigeon pea crop. It is also concluded that difference between phenetic and RAPD clustering pattern is an indication that rhizobial diversity of pigeon pea is not as yet completely understood and settled.