Browsing by Author "Rajendran Pillai, M V"

Now showing 1 - 10 of 10

Associative effect of Azospirillum and Bradyrhizobium on nodulation and growth of cowpea (viqna unquiculata (l.) walp,
(Department of Plant Pathology College of Horticulture Vellanikkara, 1992) Sunitha Menon, S; Rajendran Pillai, M V
Effect of Azospirillum and VA Mycorrhiza on the growth of cocoa seedlings and incidence of seedling blight disease
(Department of Plant Pathology, College of Horticulture, Vellanikkara, 2001) Sunitha Anie Cheriyan; Rajendran Pillai, M V
Effect of selected plant protection chemicals on the beneficial microorganisms in cowpea rhizosphere
(Department of Plant Pathology, College of Horticulture, Vellanikkara, 1995) Raji, P; Rajendran Pillai, M V
A study was conducted at the College of Horticulture, Vellanikkara, during 1992 – 94, on the effect of selected plant protection chemicals on beneficial microorganisms in cowpea rhizosphere. Four fungicides, three insecticides and their combinations were tested in vitro as well as in the field. The tolerance levels of Azospirillum and Bradyrhizobium to different doses of these chemicals were also tested. The fungicide Thiram caused inhibition of Azospirillum in vitro. The adverse effect of Thiram on rhizosphere population of Azospirillum was seen only during initial days after application. The growth performance of cowpea plants were not affected adversely. The fungicides, Carbendazim, Bordeaux mixture and Fytolan and insecticides Carbofuran, Phorate and HCH at their recommended doses did not cause inhibition of Azospirillum in vitro and did not reduce the rhizosphere population of Azospirillum. The growth performance of cowpea plants was also not affected adversely by these fungicides and insecticides. The combinations of insecticides with Thiram caused inhibition of Azospirillum under in vitro conditions and caused reduction in rhizosphere population of the bacteria initially. But no adverse effect on growth of cowpea plant was noticed. Bradyrhizobium was inhibited by the fungicides, Thiram, Bordeaux mixture and Fytolan in vitro. The rhizosphere population of Bradyrhizobium also showed reduction initially. The growth performance of plants was not affected adversely. The number of nodules showed significant reduction. No reduction in nitrogen content was noticed. Carbendazim and insecticides Carbofuran, Phorate and HCH did not show inhibition of Bradyrhizobium in in vitro. The rhizosphere population and growth of cowpea plants were also not affected adversely by these chemicals. Under in vitro conditions the combination of insecticides with Thiram, Bordeaux mixture and Fytolan caused inhibition of Bradyrhizobium. The rhizosphere population showed reduction initially, later on it was increased. The combination of insecticides with Carbendazium did not inhibit the growth of Bradyrhizobium under in vitro conditions and also in the rhizosphere. The treatment combinations did not affect the growth of cowpea plants in the field adversely. The tolerance levels of Azospirillum and Bradyrhizobium to different doses of fungicides and insecticides were also tested. The fungicides Carbendazim, Bordeaux mixture and Fytolan were not inhibitory to Azospirillum, even their highest doses of 0.15, 3.0 and 0.5 per cent respectively. Similarly, the insecticides Carbofuran, phorate and HCH were also not inhibitory to Azospirillum at their highest doses tested. The fungicide Thiram caused inhibition of Azospirillum even at the lowest dose of 0.05 per cent. Bradyrhizobium was inhibited by Thiram and Fytolan even at their lowest doses of 0.05 and 0.1 per cent respectively. Bordeaux mixture 0.25 per cent did not cause inhibition, but the higher doses caused inhibition. Carbendazim and insecticides Carbofuran, Phorate and HCH did not inhibit the growth of Bradyrhizobium in all the five doses tested.
Evaluation of non symbiotic nitrogen fixation by brady rhizobium in cowpea
(Department of Plant Pathology, College of Horticulture, Vellanikkara, 1997) Asha, S; Rajendran Pillai, M V
A study was conducetd at the College of Horticulture, Vellanikkara during the year 1993-95 on the evaluation of non-symbiotic nitrogen fixation by Bradyrhizobium in cowpea. Twelve isolates collected from different agroclimatic regions of Kerala, two exotic isolates and one KA U isolate were used for the study. First, a pot culture experiment was conducted to screen the above 15 isolates for their efficiency in non symbiotic nitrogen fixation. Two media and two methods of application were also tried. A second pot culture experiment was also conducted to find out the most suitable method of application of the best performer in terms of foliar nitrogen fixation. The results of the screening experiment showed that no particular isolate was effective in improving any of the parameters observed. However,out of the ten characters studied, isolate liS (KAU isolate) ranked best in improving five characters namely, plant height, number of leaves, dry weight of nodule, fresh weight of plants and nitrogen content. Thus 115 was selected as the promising isolate for the second experiment. Isolate 114 (CB-7 56), which showed next better performance in improving number of leaves, dry weight of nodules and fresh weight of plants was also selected. Moreover, it was one of the known exotic isolates supporting non-symbiotic nitrogenase activity. The results of the second experiment clearly established the superiority of seed (soil) inoculation (AI) of Bradyrhizobium over different methods of foliar application. However, foliar applications also showed improved performance over control plants in improving the different parameters observed. Spraying the bacteria grown in broth shake culture (A3) was found effective in improving the number of leaves, dry weight of roots, chlorophyll content and nitrogen content of plant. The study show that, eventhough less efficient, the foliar application of Bradyrhizobium can also be resorted to in improving the performance of cowpea plants in situations where seed (soil) inoculation is not possible.
Interaction between VA mycorrhiza and bradyrhizobium in cowpea
(Department of Plant Pathology, College of Horticulture, Vellanikkara, 1999) Beena, S; Rajendran Pillai, M V
New leaf blight of garcinia cambogia desr.
(Kerala Agricultural University, 1996) Vilasini, T N; Estelitta, S; Rajendran Pillai, M V; Nair, P V; Raji, P
Occurrence of endotropic mycorrhiza in rubber (Heavea brasiliensis muell. Arc.)
(Kerala Agricultural University, 1982) Sivaprasad, P; Rajendran Pillai, M V; Nair, M C
Population dynamics of plant growth promoting rhizobacteria under the influence of agricultural chemicals
(Department of Plant Pathology, College of Horticulture,Vellanikkara, 2007) Beethi Balachandran; Rajendran Pillai, M V
Rhizobacteria that are beneficial to the plant growth and development are often referred to as plant growth promoting rhizobacteria (PGPR). Application of PGPR is often found to increase plant growth, development and yield. Now a days, use of PGPR is on an increasing trend in sustainable ecofriendly agriculture. Along with the micro organisms, the farming community is still applying plant protection chemicals and fertilizers in modern agriculture. Even though chemical application will help a lot to protect the crops from pest and diseases, their application may influence the PGPR also. Scientific data on the compatibility aspects of agricultural chemicals with PGPR is scanty. With this in view, the present study on ‘ Population dynamics of plant growth promoting Rhizobacteria under the influence of agricultural chemicals’ was taken up at College of Horticulture, Vellanikkara, during 2003-2007. Five numbers of fungicides, insecticides and herbicides were tested along with their combinations in vitro and in the field. The ultimate idea was to evolve a database for compatibility of chemicals and PGPR. The studies revealed that the fungicide copper oxychloride was most deleterious to the growth of Azospirillum sp. and P. fluorescens, whereas, tridemorph inhibited the growth of B. subtilis under in vitro conditions. In the combination studies, it was found that the fungicide mancozeb when combined with all herbicides and all insecticides inhibited the growth of Azospirillum sp. The combinations of all fungicides with paraquat and the combination of copper oxychloride with carbaryl were found highly inhibitory to the growth of B. subtilis. The combination of the insecticide lindane with the herbicide paraquat was inhibitory to the growth of Azospirillum sp. In the case of B. subtilis, the combination of carbaryl with paraquat was deleterious. Another result was that, the fungicide carbendazim, all insecticides except carbaryl and all herbicides except paraquat were least inhibitory to all the test organisms at their recommended doses under in vitro conditions. In the combination studies, carbendazim with all insecticides and herbicides were found least inhibitory to the growth of PGPR. Also the combination of lindane, lamda cyhalothrin and chlorpyriphos with the herbicide 2, 4 –D were found least inhibitory to the growth of these beneficial rhizobacteria. In the field situation, the chemicals carbendazim, chlorpyriphos and 2, 4-D were evaluated against these beneficial rhizobacteria and it was found that these chemicals affected the bacterial population immediately after their application to soil. All the bacterial populations recorded a decreasing trend as the rice plants grow. This trend was also noticed in the treatments where these PGPR were applied alone. The treatments significantly influenced the growth parameters of the rice plants and the post harvest observations like shoot weight, root weight, root length and panicle weight. Increase in growth parameters like plant height, production of tillers and productive tillers were recorded in the treatments where these PGPR were applied in combination with chlorpyriphos. In the post harvest observations like shoot weight, root weight and root length, positive influence was maximum in the same treatments. But the panicle weight and nutrient content were maximum in the treatments where all the beneficial rhizobacteria applied alone. Based on the overall results on the studies, compatibility charts of agricultural chemicals and PGPR were prepared which will be a base for future recommendations on the use of chemicals and PGPR together.
Role of microflora on the quality of vermi-products in improving plant growth
(Department of Plant Pathology, College of Horticulture, Vellanikkara, 2007) Nisha Jose; Rajendran Pillai, M V
A study on ‘Role of microflora on the quality of vermi-products in improving plant growth’ was carried out in the department of Plant Pathology, College of Horticulture, Vellanikkara during 2005-07. The native microflora associated with the earth worm Eisenia foetida and different vermi-products viz., vermicompost, vermicasting and two types of vermiwash were isolated. Quantitative estimation of microflora revealed that, bacterial population was predominant in vermi-products followed by actinomycetes and fungi. Altogether, 32 fungi, 39 bacteria (including five nitrogen fixing and three phosphorus solubilizing bacteria) and four actinomycete isolates were selected for further work. These isolates were then tested for their efficiency in nitrogen fixation, phosphorus solubilization and antagonistic properties against Rhizoctonia solani, the leaf blight pathogen in amaranth. Based on the efficiency of the above aspects, one isolate each of nitrogen fixing and phosphorus solubilizing bacteria were selected. These isolates were tentatively identified as Azotobacter sp. (NB2) and Pseudomonas sp. (PB1) respectively. Seven isolates of fungi which recorded the promising antagonistic index (AI) and two isolates of bacteria which recorded highest per cent inhibition against R. solani were selected. The fungal isolates were identified as T. harzianum (VF5, VF22 and VF25), T. viride (VF8 and VF16), A. niger (VF2) and A. flavus (VF15). The bacterial isolates were tentatively identified as Bacillus sp. (VB4) and non fluorescent Pseudomonas (VB26). Then three different microbial consortia were prepared using the selected fungal and bacterial isolates alone and in combination. A pot culture experiment was conducted to evaluate the efficacy of these consortia in improving plant growth in comparison to vermi-products. It was found that consortia including both fungal and bacterial isolates found to improve the plant growth by increasing yield other biometric characters. Observations on incidence and severity of leaf blight in amaranth showed that microbial consortia and non sterilized vermi-products had a favorable effect in checking the disease incidence. Considerable variation in population of soil microflora was observed among different treatments. Uptake of major nutrients was found to be more in treatments appied with vermicompost and vermicasting. The in vitro studies on the effect of vermi-products on beneficial and pathogenic microorganisms revealed that steam sterilized extracts inhibited the growth of Rhizoctonia sp. and Colletotrichum sp. and did not inhibit the growth of Trichoderma harzianum and Pseudomonas fluorescens. Vermi-products lost its inhibitory activity after strong heating. Autoclaved extracts of vermi-products did not show inhibition on any of the four organisms tested.
Symbiosis of rhizobium and VA mycorrhiza in subabul
(Department of Plant Pathology, College of Agriculture, 1989) Rajendran Pillai, M V; Sasi Kumar Nair
A survey was conducted at 17 locations in four districts of Kerala for natural nodulation and VA mycorrhizal infection in subabul. The survey revealed that natural nodulation and VA mycorrhizal infection were poor compared to inoculated plants. When all the 17 isolates of rhizobia and four cultures of VA mycorrhizal fungus were tested for effectiveness, the rhizobial isolate R8 and V AM fungus M2 were emerged as most efficient rhizobial and mycorrhizal cultures respectively. An in vitro study conducted revealed that in an acid PH of 6, the rhizobial isolate R8 survived better than other cultures. At pH 8, growth of another isolate R5 was found maximum. However, in an in vivo study, there was not much significance for the soil pH ranging from 6 to 7.1 in influencing various biometric parameters of subabul. In both the pH of 6 and 7.1, the performance of rhizobial isolate R5 and mycorrhizal culture M2 was best. Serological studies revealed that the exotic strains R18 R20 and and isolate from Mimosa indica had serological similarities with the best selected local isolate R8. Fine structure studies of nodules clearly showed the morphological differences between the uninfected nodular tissues and the infected central nodular tissue. The rhizobial infection transformed the normal cells into irregularly shaped cells within which numerous rhizobial cells were visible. In another observation, it was found that subabul plants starts to form nodules only from 15 days of sowing. There- after, the nodule number increased steadily attaining the peak at 70 days of growth and then remained more or less steady. Among various methods of inoculation of the microsymbionts tested, inoculation of both the microsymbionts at the time of sowing in polybag was found good for the better establishment of the plants in the field. In a field study, it was found that inoculation of the local isolate of Rhizobium R8 and mycorrhizal fungus M2 had great influence in increasing all the growth parameters. Standard mycorrhizal culture and local isolate performed equally well. Maximum forage yield was obtained when plants were inoculated with the selected local rhizobial isolate R8 and mycorrhizal fungus M2. Maximum mycorrhizal infection was also seen in the same treatment. Dual inoculation also had significant influence in increasing the leaf protein content. An important observation was that both rhizobial and mycorrhizal inoculation reduced the mimosine content of leaves. However, fertilizer nitrogen increased mimosine content. In short, dual inoculation by Rhizobium and VA mycorrhiza was found necessary for better establishment, growth and low mimosine content of subabul.