Browsing by Author "Sasi Kumar Nair"

Now showing 1 - 6 of 6

Effect of azospirillum inoculation on establishment and growth of bush pepper
(Department of Plant Pathology, College of Agriculture, Vellayani, 1995) Yamini Varma, C K; Sasi Kumar Nair
The study on the effect of Azospririllum inoculation on root induction, establishment and growth of bush pepper was conducted at Collage of Agriculture, Vellayani, Trivandrum during 1992 – 94. Out of the 25 different cultivars of pepper used for initial isolation, Azospirillum was isolated from 16 cultivars. These 16 isolates along with a culture from TNAU were screened for the production of IAA and gibberellins under in vitro conditions. The native isolate 34 produced maximum quantity of IAA equivalent to 69 µg/ml of culture broth. The production of this phytohormone was maximum during the second week of culture growth. However, none of these isolates produced gibberellins under in vitro conditions. Based on the requirement of biotin for growth isolate 34 and TN culture were tentatively identified as Azospirillum brasilense and A. lipoferum respectively. The isolate 34 and TN culture had their maximum growth at pH 6.0 and 8.0 respectively. Azospirillum isolate 34 and TN culture were selected for root induction studies in Panniyur – 1 and Karimunda varieties of bush pepper. The percentage of rooted cuttings varied from 23.3 – 26.8 percent in Panniyur -1 and 17.5 – 17.9 in Karimunda. However, the average number of roots per cuttings and root dry weight were maximum in bacterial treatment. Between the two varieties of bush pepper, root induction was better in Panniyur – 1 variety. The study on the establishment and growth of bush pepper was conducted by using 3 sets of rooted cuttings of Panniyur – 1 and Karimunda varieties where root induction was done by using carrier a based inoculum of Azospirillum and 1000 ppm IBA or without any of the above treatments. These were grown in potting mixture supplemented with 25 g or 100g of isolate 34 and with or without chemical fertilizer application. After 180 days of plant growth, 100 percent establishment was obtained in Panniyur – 1 in treatments such as 100 g Azo 34-F of group 1, 25 g Azo 34-F and 100 g Azo 34+F of group 2 plants. In these treatments the number of roots produced per cutting, fresh and dry weight of roots were significantly high or on par with each other. In Karimunda, also, in treatments such as 25 g Azo 34-F and 100 g Azo 34-F of group 1, 100 g Azo 34-F of group 2 and 25 g Azo 34-F of group 3 plants where 100 percent establishment was obtained, the number of roots produced per cuttings, fresh and dry weights of roots were statistically on par with best treatment for these parameters. The production of new leaves, branches and fresh and dry weight of shoot were significantly high only in Panniyur – 1 and these were in the treatments 100 g Azo 34-F of group 1 and 25 g Azo 34-F of group 2 plants. But in Karimunda, no such treatment effects were noticed except for fresh and dry weight of branches. In Panniyur – 1 the total fresh and dry weight of plants were significant also in 100 g Azo 34-F of group 1 and 25 g Azo 34-F of group 2 plants. In most of the treatments where significant results were obtained, chemical fertilizer application had no significant effect on different growth parameters studied. Further, between the two varieties, Panniyur – 1 responded better than Karimunda in rooting, establishment and growth of bush pepper.
Effect of root knot nematode infestation on nodulation by rhizobium in cowpea
(Kerala Agricultural University, 1986) Nirmala Moni, D; Sasi Kumar Nair
Preliminary study on nodulation in cowpea in acid soil
(Kerala Agricultural University, 1982) Sasi Kumar Nair; Siva Prasad, P
Relative susceptibility of cowpea varieties to infestation by meloidogyne incognita
(Kerala Agricultural University, 1988) Nirmala Mom, D; Sasi Kumar Nair
Studies on host-varietal specificity for Rhizobium for nodulation in groundnut
(Department of Plant Pathology, College of Agriculture, Vellayani, 1982) Girija, V K; Sasi Kumar Nair
An investigation was carried out at the College of Agriculture, Vellayani, Kerala to study the host-varietal specificity, if any, for Rhizobium for nodulation in groundnut. A total of fifteen groundnut varieties were subjected to a preliminary screening on the basis of the number of nodules formed and arranged into five distinct nodulation groups. Seven varieties of groundnut TMV-12, USA-123 Exotic-6, Spanish Peanut, TMV -11, Ak12-24 and Ah-32 were selected from among these groups for use in further studies.
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.