1. KAUTIR (Kerala Agricultural University Theses Information and Retrieval)
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Item Characterization of Ralstonia solanacearum (Smith) Yabuuchi et al. causing bacterial wilt in ginger using molecular marker(Department of Plant Pathology, College of Horticulture, Vellanikkara, 2003) Sambasivam, P K; Girija, DIn Kerala, bacterial wilt caused by Ralstonia solanacearum is one of the major constraints in ginger cultivation. Earlier, the pathogen was characterized based on cultural, morphological and biochemical tests. Since these methods are time consuming and involve repeated subculturing and tedious biochemical tests, an attempt was made to characterize the pathogen at molecular level using plasmid profile and RAPD technique. Wilted plant samples were collected from ginger growing tracts of Palakkad, Eranukulam and Wynad districts. The pathogen was isolated on TZC medium, it produced creamy white pink centred fluidal colonies. Stock cultures prepared by suspending single colonies in sterile water were maintained at 4 QC. Pathogenicity of the isolates was established using pseudostem inoculation method. Tomato and brinjal were found to be collateral hosts of the pathogen. Based on hypersensitivity reaction on capsicum the isolates were identified as race 3. This was further confirmed by RAPD assay. The isolates were found to. be Gram negative and showed positive reaction for solubility. in KOH, nitrate reduction, production of catalase and oxidase enzyme, fermentation of glucose. All the isolates utilized lactose, maltose, cellobiose, manitol, sorbitol but not dulcitol and hence, were grouped as biovar III A. Plasmid profile developed for the isolates showed presence of two bands of . . approximately 21 kb size .. Plasmids when transformed to E. coli DH 5a cells, conferred resistance to ampicillin and rifampicin, indicating that the genes encoding resistance to these antibiotics were located on the plasmid. RAPD analysis using 16 primers showed much diversity among the isolates. Primers OPU .13, OPU 17 and OPX 9 showed 100 per cent polymorphism. Dendrogram obtained through cluster analysis showed one major and one sub cluster. All the Palakkad isolates were grouped under a single cluster. The present study indicated possibility of using molecular marker as a tool to detect even slight variability among R. solanacearum isolates infecting ginger.Item Biomass production and partitioning of photosynthates in ginger (Zingiber Officinale R.) under different shade levels(Department of Horticulture, College of Agriculture, Vellayani, 1999) Sreekala, G S; Jayachandran, B KA pot culture experiment was conducted at the College of Agriculture, Vellayani during the year 1997 - 1998 to study the effect of shade on biomass production and partitioning of photosynthates in ginger cv. Rio-de-Janeiro. The experiment was laid out in completely randomised design with five shade levels (open, 20, 40, 60 and 80 per cent) and four replications. Artificial shade was provided using high density polyethylene shade nets and calibrated using quantum photo sensors. Two months after planting, ginger plants were labelled using 14C . After tagging, one set of samples were collected immediately. Subsequently, harvesting of the tagged plants were done once in sixty days after labelling. Monthly observations of various growth parameters were taken from two months after planting. At six months after planting photosynthetic related parameters were measured using leaf chamber analyser. The various growth parameters like number of tillers, leaf area, leaf dry weight, dry matter production, crop growth rate, relative growth rate, net assimilation rate at final stage, leaf area index which contributed to yield was highest under 20 per cent shade. This shows that the plant prefers low shade intensity compared to open. The yield recorded under 20 per cent shade was significantly superior compared to open. But the yield at open and 40 per cent shade were on par. Higher shade levels decreased the yield. This shows that the crop can tolerate shade up to 40 per cent. Different shade levels influenced the quality of ginger rhizomes. While volatile oil was maximum under heavier shade levels in general ( 60 and 80 per cent ), non- volatile ether extract was higher under 20 per cent shade. Starch as well as crude fibre content was more in plants grown under open condition. The photosynthetic rate and related parameters of ginger were measured at six months after planting using leaf chamber analyser. Photosynthetically active radiation on leaf surface as well as stomatal conductance was high under open condition. But leaf internal carbon dioxide concentration as well as stomatal resistance was high under heavier shade levels (60 and 80 per cent). Photosynthetic rate as well as the transpiration rate was maximum in plants grown in open. Though, at 20 per cent shade, the photosynthetic rate was less, the yield was high. This might be because of the photo oxidation that has taken place at high light intensities or due to the inefficient translocation of the photosynthates in open condition compared to 20 per cent shade. Radio tracer analysis done using labelled 14C has shown that under open condition, though initial intake of carbon dioxide was more, most of the carbon dioxide taken are seen in the above portion itself. While in 20 per cent shade most of the carbon dioxide taken in has translocated to the lower portion. This shows that under low light intensity the photosynthates produced has translocated efficiently to the lower portion while in open condition efficient translocation has not taken place. The results indicate that 20 per cent shade level is favourable for growing ginger plants to get higher rhizome yield. The yield at 40 per cent was on par with that of open. This shows that crop can tolerate shade upto 40 per cent. Thus the partially shaded coconut gardens can be exploited for increasing the area under ginger which may help in doubling the production.Item Influence of organic manures and Azospirillum on growth, yield and quality of ginger (Zingiber officinale Rosc.)(Department of Plantation Crops and Spices, College of Horticulture, Vellanikkara, 1997) Thulasi Chengat; Prasannakumari Amma, SAn investigation was undertaken at the College of Horticulture, Vellanikkara during May, 1994-January, 1995 with the objectives of studying the influence of organic manures and Azospirillum on growth, yield and quality of ginger, finding out their impact on chemical properties of soil and uptake of plant nutrients, studying influence on pests and diseases and working out economics of cultivation. The experiment was laid out in randomized block design. The different organic manures included were farmyard manure, poultry manure and neem cake. The experiment was carried out using the cultivar Maran. The salient findings are abstracted below. Plant height was found to be favourably influenced by the treatments except neem cake. Number of tillers per plant and number of leaves per tiller were not influenced by the different treatments. Dry matter accumulation in the leaves and rhizomes was comparatively higher in the treatments poultry manure alone and farmyard manure alone. Root dry weight was the maximum in the treatments, Azospirillum + 75 per cent N. The treatment farmyard manure was significantly superior to others as far as total dry matter production was concerned. Yield of green ginger and dry ginger and dry ginger recovery were found to be higher in the treatments farmyard manure and Azospirillum, though not significant. Oleoresin content was unaffected by the different treatments. Percentage of essential oil was significantly higher in the treatments. Azospirillum + 75 per cent N and farmyard manure. Uptake of N and P was higher in the treatments poultry manure alone, Azospirillum + 50 per cent N and farmyard manure alone. Incorporation of farmyard manure in the soil resulted in the enhancement in organic carbon content of soil. Plots receiving inorganic form of N contained more available N in soil after the experiment. Neem cake was found to be effective in reducing the incidence of soft rot disease. The most profitable among the different treatments was farmyard manure alone.Item Induced mutations in ginger (Zingiber Officinale R.)(Department of Horticulture, College of Agriculture, Vellayani, 1989) Jayachandran, B K; Mohanakumaran, NInvestigations in ginger cv. Rio-de-Janeiro, were carried out during 1985-89 for studying the effect of gamma rays and ethyl methane sulphonate (EMS) on the growth, yield and flowering in the VM1 generation, for assessing the variability including tolerance/resistance to bacterial wilt and soft diseases in the VM2 and for studying the VM3 progenies of the desirable VM2 plants. Dose standardization studies using 10 doses of gamma rays (from 0.5 to 5.0 krad) and 11 doses of EMS (from 8 to 150 mM) revealed that the LD50 for sprouting and survival was between 0.5 and 1.0 krad gamma rays and below 8 mM EMS. For the VM1 study, five doses each of gamma rays (0.5 to 1.5 krad) and EMS (2 to 10 mM) were used. Delayed sprouting occurred to a limited extent. Sprouting, survival, plant height, number of tillers and leaves, and rhizome yield decreased as the doses of the mutagens increased. In general, there was a tendency for recovery of growth parameters as the growth phase advanced. The number of plants with chlorophyll chimera was more in the radiation treatments. Flower production was not sufficient to draw valid conclusions. In the VM2 generation, plant height exhibited a negative shift. Tiller, leaf and rhizome production, at the lower doses of the mutagens in general, exhibited positive shifts and at the higher doses, negative shifts. Wide range of variability was observed with respect to these characters. Pollen fertility was not seen influenced by the treatments. Screening the VM2 plants against bacterial wilt and soft rot diseases did not enable the isolation of tolerant/resistant material. Study of the mutant in the VM3 revealed that majority of the plants failed to express all or some of the characters. A few plants with more yield and dryage, and more volatile oil and NVEE content, were located. The studies indicated that though the range of variability induced is high, recovery of the mutants is very low; probably due to the multicellular nature of the apices of the rhizomes treated, and the consequent chimera formation and diplontic selection. Follow up of the mutation generation up to VM4 or VM5 or till stability is achieved and avoiding storage of the rhizomes between the generations have been considered necessary. Repeated, intensive and large scale induction and continuous screening for disease resistance is worth attempting. Using in vivo and in vitro adventitious bud techniques, somaclonal variation, in vitro screening for disease resistance, induction of mutation immediately after the harvest when buds are in ontogenetically young stage of development, and raising of VM2 and subsequent generations without storage of seed rhizome irrespective of the season, are areas suggested for future research.