L. Srimathi Priya ¹, K. Kumutha ¹

Affiliations
1 Department of Agricultural Microbiology, Tamil Nadu Agricultural University, Coimbatore 641 039, IN

Abstract

An investigation was carried out with the aim to study the interactive effect of Arbuscular Mycorrhizal (AM) fungi and Plant Growth Promoting Rhizobacteria (PGPR), Pseudomonas on growth and yield of Coleus forskohlii. The inoculation of AM fungus, Scutellospora sp. and PGPR organisms (Pseudomonas sp.) showed increase in plant enzyme activities along with enhancement in tuber yield and alkaloid content, than the individual treatments. The combined inoculation of the AM fungus with PGPR recorded maximum shoot and ischolar_main length with 40.4 and 203.1 per cent increase over control and the total dry matter content increased by 104.5 percent over control. The enzyme activities (acid, alkaline and dehydrogenase) were found to have enhanced upto 200 per cent due to the combined inoculation of SCL1+PFC1 which was double than single inoculations. The AM colonization (45-90 per cent) and spore load (155–330 spores) were also higher due to these treatments while, about 6-7, 1-2 and 5-6 fold increase in N, P and K uptake was noticed respectively. The tuber yield (0.73 g plant-1) and forskohlin content (0.03-0.06 per cent) were also found to be doubled due to the inoculation of AM fungi with PGPR.

Keywords

Arbuscular Mycorrhizal (AM) Fungi, Plant Growth Promoting Rhizobacteria (PGPR), Coleus forskohlii, Forskohlin Content.

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V. S. Indhumathi ¹, P. Chandramani ², J. Jayaraj ³, C. Chinniah ¹, P. P. Mahendran ¹, K. Kumutha ¹

Affiliations
1 Tamil Nadu Agricultural University, Agricultural College and Research Institute, Madurai – 625104, Tamil Nadu, IN
2 Tamil Nadu Agricultural University, Agricultural College and Research Institute, Kudumiyanmalai – 622104, Tamil Nadu, IN
3 Tamil Nadu Agricultural University, Grapes Research Station, Theni – 625526, Tamil Nadu, IN

Abstract

To evaluate the effect of four silicon fertilizers, field experiment was conducted in farmer’s holding at Poovanthi village of Sivagangai district, Tamil Nadu during 2017-2018 against sugarcane leaf hopper, Pyrilla perpusilla Walker and its parasitoid, Epiricania melanoleuca (Fletcher). Silicon fertilizers were applied @ 500 and 1000 kg ha^-1 before planting and the leaf hopper population was recorded at 150, 180, 210, 240 and 270 days after application. The results of field experiment revealed that Pyrilla population was minimum in the plots treated with calcium silicate @ 1000 kg ha^-1 (8.20 numbers/leaf) followed by calcium silicate @ 500 kg ha^-1 (8.80 numbers/leaf) as compared over untreated check (98.20 numbers/leaf) and the percent reduction over untreated check was 82.45 and 73.71 per cent, respectively. Similarly, the per cent parasitism was maximum in the treatment with calcium silicate @ 1000 kg ha^-1 (82.33%) during November, which was on par with untreated check. Hence, Pyrilla population declined to an extent of 82.45 per cent by enhancement of E. melanoleuca parasitism (82.33 %) due to the application of silicon fertilizers.

Keywords

Epiricania melanoleuca, Parasitism, Pyrilla perpusilla, Silicon Nutrition.

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