Response of chilly to plant growth promoting rhizobacteria fluorescent pseudomonads

Abstract

The research project entitled 'Response of chilli (Capsicum annuum L.) to plant growth promoting rhizobacteria fluorescent pseudomonads' was carried out as two investigations viz., a pot culture trial and a field study at the College of Agriculture, Vellayani, during July 2002 to April 2003. The study was conducted on chilli cultivar, Jwalasakhi. The pot culture study was aimed at evaluation of fluorescent pseudomonads isolates for growth promotion and yield in chilli. The treatments consisted of five different isolates of fluorescent pseudomonads (PI, P5, P14, P22and KKI6). The trial was laid out in completely randomised design with four replications. Among the five isolates tested, isolate P22 was adjudged as the best one for growth promotion and P I for disease resistance. As far as yield and economics are concerned, these two isolates were found to be on par. Thus a dual culture of Tsolate P22 and PI was selected for further field study. The objective of the field study was to assess the suitability of the best isolate of fluorescent pseudomonads as a biofertilizer either alone or in combination with Azospirillum along with different doses of NPK . fertilizers on growth and productivity of chilli. The field study was laid out in factorial randomised block design with three replications. The different treatments included three different levels of NPK (75 per cent (56.3 : 30 : 18.8 kg ha"), 100 per cent (75 : 40 : 25 kg ha') and 125 per cent (93.8 : 50 : 23.5 kg ha-I) of the recommended dose of NPK as per POP) and four biofertilizer treatments (Fluorescent pseudomonads, Azospirillum; Fluorescent pseudomonads + Azospirillum and no biofertilizers). The abstract of the result is furnished below.

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All the growth characters increased significantly with graded doses or

PK.

Combined inoculation of fluorescent pseudomonads and

Azospirillum was the most superior one among biofertilizer treatments. Similar trend was also observed for yield attributing characters. However with regard to marketable fruit yield, all the levels of NPK fertilizers tested were statistically on par. With respect to biofertilizer application, combined inoculation (7.75 ha") was on par with fluorescent pseudomonads application (7.56 t ha-I). Compared to control of no biofertilizer treatment, Fluorescent pseudo monads + Azospiriflum increased fruit yield by 46.69 per cent. Among the treatment combinations, 75 per cent of the recommended dose of NPK (56.3 : 30 : 18.8 kg ha-I) + Fluorescent pseudomonads + Azospirillum produced significantly higher yield (8.74 t ha-I) and ensured a saving of 25 per cent of recommended dose of NPK. 100 per cent POP + Fluorescent pseudomonads application was on par with this treatment. At 125 per cent of the recommended dose of NPK (93.8 : 50 : 23.5 kg ha I) microbial count in the rhizosphere was significantly lower and fruit rot incidence was significantly higher. Biofertilizer application significantly increased microbial count and reduced disease incidence. 75 per cent of recommended dose of PK + Fluorescent pseudomonads + Azospirillum was rated as the most economically viable treatment combination, with a net profit and benefit-cost ratio of Rs. 59328 ha-I and 1.82 respectively.