Theses

Browse

Search Results

Now showing 1 - 9 of 45

Open Access
Comparative micromorphologial and physico- chemical study of the upland and midupland laterite soils of Kerala
(Department of soil science and agricultural chemistry, College of Agriculture, Vellayani, 1986) Sankarankutty Nair, R; KAU; Aiyer, R S
Open Access
Cellular and humoran immune responses to corynebacterium presudotuberculosis infection in goats
(Department of microbiology, College of veterinary and animal sciences, Mannuthy, 1986) Jayaprakasan, V; KAU; Sulochana, S
Caseous lymphadenitis was experimentally produced in cross-bred malabari goats aged 8 to 12 months by bilateral inoculation of 1 x 106 viable C. pseudotuberculosis (ATCC 19410) through intradermal, subcutaneous and submucosal routes. The clinical picture, immune response and pathological features were studied up to a period of 13 weeks. The development of immune response in experimentally infected goats was assessed, by comparing the data with those of the controls, with respect to total serum protein, serum protein fractions, antibody activity of the serum, leukocyte count, counts of lymphocyte subpopulations, leukocyte migration inhibition index and skin hypersensitivity reaction. Pathological features in the lymphnodes and other tissues of infected goats necropsied at 15 days interval were also studied. Initial febrile reaction which lasted for 72 to 96 h, local inflammatory changes caused at the site of inoculations during the first two to three weeks of infection and the development of lesions typical of caseous lymphadenitis in local/regional lymphnodes within 21 days post-inoculation were the main features of clinical manifestations of the disease. aS a result of infection, neutrophilic leukocytosis was maximum during the 2nd week of infection. No appreciable was maximum during the 2nd week of infection. No appreciable change in counts of other cells in terms of their absolute numbers was noted during the entire period of observation. The humoral immune response in infected goats was indicated by the rise in serum protein, antitoxic antibody and B-lymphocyte count in the peripheral blood. The serum protein concentration increased to significant levels from the 5th week onwards and it reached the peak value (11.346 g%) by the 8th week. From the 3rd week onwards haemolysis inhibition test, which detected goats and persisted till the end of the observation period. The peak antibody level was recorded by the 5th week of infection and thereafter there was gradual reduction in the titre. Significantly high percentage of B- lymphocyte was recorded in infected animals from the 2nd to 10th week, except at the 5th week. The percentage of B-cells in infected goats ranged between 12.3 + 0.85 – 17.63 + 1.2 while it was 8.56 + 0.75-12.3 + 1.09 in control goats. This was considered as an indication of stimulation of humoral immune response. The cell-mediated immune response was evidenced by the increased T- lymphocyte count in the peripheral blood, inhibition of leukocyte migration and the development of delayed skin hypersensitivity. The mean percentage of T-lymphocytes in the peripheral blood of infected goats by E-rosette assay recorded an initial reduction at the first week (18.44 + 1.4) followed by an increase which was significant during the 5th, 6th, 7th, 8th, 12th and 13th week of infection. The maximum value was recorded (35.24 + 1.58) at the 13th week. In the case of control goats the percentage values ranged from 24.55 + 3.66 to 26.74 + 1.34. The T-lymphocyte count in the peripheral blood enumerated the ANAE method did not show any significant change even after infection. In the experimentally infected goats, leukocyte migration inhibition index was less than 0.8 during post-infection period while the control goats had the index value above 0.8. Significant reduction in the migration index was noted by 45th day of infection and the maximum reduction was on the 60th day. Intradermal injection of the toxic supernatant of the culture elicited characteristic delayed skin hypersensitivity reaction in all the experimentally infected goats while there was no reaction in the controls. The positive reaction was found to be maximum by the 48th hour post-injection. The pathological changes were characterized by an initial stimulatory hyperplastic reaction in the lymphnodes and this was accompanied by necrobiotic changes typical of caseous lymphadenitis. The hyperplastic stimulatory reactions were characterized by the presence of several active follicles with well developed germinal centres in the cortex, distinct medullary cords densely lined with plasma cells and sinus histiocytosis indicating the early elicitation of humoral immune response to the bacterium or to its in vivo products. The results obtained from the present study revealed the operation of both cell-mediated and humoral immune responses in goats against C. pseudotuberculosis infection. Of the various methods employed to monitor the immune response, leukocyte migration inhibition and delayed skin hypersensitivity tests were found to be of value in assessing the cell-mediated immune response and haemolysis inhibition test for humoral immune response. Leukocyte migration inhibition test and haemolysis inhibition test could be employed for early diagnosis of C. pseudotuberculosis infection in goats. FINDINGS : The immune responses and pathological features in Corynebacterium pseudotuberculosis infection were studied by experimental infection of cross- bred Malabari goats of S-12 months of age. Single cell bacterial suspension in chilled sodium chloride bile salt solution was used for this purpose. Goats were inoculated at both sides of the body by three routes viz., intradermal, subcutaneous and submucosal, with 2 x 106 bacteria per site of injection. The experimentally infected and control goats were observed for clinical manifestations of caseous lymphadenitis for a period of 13 weeks. The development of immune response in experimentally infected goats was assessed by comparing the data with those of the controls with respect to total serum protein, serum protein fractions, antibody activity of the serum, leukocyte counts, counts of lymphocyte sub-populations, leukocyte migration inhibition index and skin hypersensitivity reaction. Gross and histopathological changes in the lymphnodes and other tissues of necropsied goats were studied at 15 days interval for a period of 90 days. All experimentally infected goats exhibited rise in temperature, general weakness, lethargy and impaired appetite which lasted for 72 to 96 h. The sites of inoculations showed varying degree of inflammatory reaction during the first two to three weeks of infection. All experimentally inoculated goats except one developed lesions typical of caseous lymphadenitis in regional/local lymphnodes within 21 days post-inoculation. Route of infection did not influence the ability to set up lesions in lymphnodes. Although massive dose of bacterial (1.2 x 107) was administered, none of the goats had fatal infection indicating that goats are relatively resistant to this infection. Majority of goats did not develop generalized form of caseous lymphadenitis as there was no lesions in visceral/deep seated lymphnodes or organs. The normal serum protein concentration of cross-bred Malabari goats was estimated to range from 7.187 to 9.750 g %. Consequent to experimental infection, serum protein concentration was increased and recorded significant rise from the 5th week onwards reaching the peak value by the 8th week – 11.346 g%. Estimation of quantitative distribution of serum protein fractions was done by agar gel electrophoresis and densitometer tracing of electrophoretogram. Though there was initial increase in globulin content in infected animal followed by a decrease, no significant alteration in the albumin-globulin ration (A:G ratio) was noted compared to the control group. C. psuedotuberculosis was cultivated in lemco proteose broth containing sheep serum and incubated aerobically at 370C for 72 h. Supernatant obtained from the above culture, having maximum haemolysin titre and dermonecrotoxicity was used as the toxin of the bacterium in the present studies. The haemolysin content of the culture supernatant was estimated by the haemolysis test using sheep red cells. A maximum titre of 1:256 was found in the culture aged 72 h. The dermonecrotoxicity of the toxic culture supernatant was tested by intradermal inoculation into the rabbit skin. The inflammatory and necrotic reactions were maximum by 48 h post-injection. Specific antibody activity against toxin of C. pseudotuberculosis in the serum was monitored by haemolysis inhibition test and the test was adjudged as a useful test for detecting humoral immune response to C. pseudotuberculosis infection in goats. In infected goat from the 3rd week of infection onwards MIT was positive while it was negative in control goats during the period of 13 weeks of observation. The peak antibody level was achieved by the 5th week of infection and thereafter the titre was found to dwindle gradually till the 11th week. Towards the end of the observation period (12th week) there was a marginal increase in the antibody titre, which would be considered as secondary immune response against the toxin of the multiplying bacteria. Infected goats showed leukocytosis during the entire period of observation and maximum leukocytosis was observed during the 2nd week of infection. The periodical fluctuation in leukocytosis indicated the recurrent flare up of bacterial invasion in the body. The absolute lymphocyte count obtained both at pre and post-infection periods with experimentally infected goats did not show any change which indicated no deleterious effect on peripheral blood lymphocytes. Throughout the period of observation infected animals showed numerically low lymphocyte percentage in differential counts and with several samples the percentage distribution was significantly low. Absolute counts of neutrophils were consistently high in experimental goats when compared to those of controls and the same was reflected in differential count also. The other blood cells were absolutely without any change in infected as well as control goats. Density gradient centrifugation using Ficoll-paque (1.077 g/ml, centrifuged at 720 x g) was found quite useful for separation of mononuclear leukocytes from the whole blood of goats. Such separated mononuclear cells were found to contain on an average 91.80% lymphocytes and 8.2% monocytes with an average viability of 91.2%. Peripheral blood B-lymphocytes of goats were successfully enumerated by EAC rosette assay employing bovine red cells. The normal percentage of B-cells was estimated to range 8.56 and 12.3. Significantly high percentage of B-cells was recorded in infected animal from the 2nd to 10th week post- infection except at the 5th week. B-cell percentage in infected goats ranged between 12.3 + 0.85-17.63 + 1.2 while it was 8.56 + 0.75 to 12.3 + 1.09 in control goats indicating the operation of humoral immune response to concurrently boost the specific antibody activity in the serum. T-lymphocytes of goats were identified and enumerated by E-rosette assay and ANAE activity. Goat lymphocytes presented several receptors to sheep red cells, as majority of rosettes presented erythrocytes at the entire periphery of lymphocytes. The mean percentage of E-rosette positive lymphocytes in the peripheral blood of control goats ranged from 24.55 + 3.66 to 26.74 + 1.34 during 13 weeks of observation. The E-rosette technique employed in the present study was assumed unaffected by unknown variables as the data recorded in the control goats remained near normal throughout the observation period. During the first two weeks of infection E-rosette positive lymphocyte count was found numerically decreased and the reduction was significant at the first week (18.44 + 1.40). From the third week onwards an increase in the E-rosette forming cells was observed and significant increase was noted during the 5th, 6th, 7th, 8th, 12th and 13th week of infection, the maximum being at the 13th week (35.24 + 1.58). T-cells were also identified and enumerated based on the demonstration on ANAE activity. Fixing of mononuclear cells in acetone-citric acid solution enabled the fixed smears to be stored in dry state without any interference to the enzymic activity for longer periods. T-lymphocytes presented one or two localized red coloured reaction product in the cytoplasm adjacent to the cell membrane. Mean percentage of ANAE positive cells in experimental goats was 28.09 + 1.51 while it was 35.80 + 4.86 for control goats when estimated before the start of the experiment. During infection, the count of ANAE positive cells in the peripheral blood did not show any change as the mean percentage ranged between 28.9 + 2.06-33.78 + 1.99 as against the corresponding values (30.83 + 3.5-36.91 + 3.61) in controls. In infected animals significant hike in E-rosette positive lymphocyte counts was recorded while such a change could not be observed with ANAE positive lymphocytes. Thus the results of T-cell estimation by E-rosette assay and ANAE demonstration indicated that estimation of total rosette forming cells could reflect better the T-cell competence. Cell mediated immune response to C. pseudotuberculosis infection in goats was demonstrated by leukocyte migration inhibition test under agarose. A population density of 1.5 x 108 leukocytes/ml was found suitable for LMIT. Toxic culture supernatant having haemolysin titre 1:16 whose pH adjusted to 7.2 could be successfully used as antigen in the test. In experimentally infected goats leukocyte migration index was less than 0.8 during post-infection period while with control goats it was above 0.8. Significant reduction in LMI index was noted by 45th day of infection through 75 days showing maximum reduction by the 60th day. Intradermal injection of toxic culture supernatant elicited characteristic delayed type skin hypersensitivity reaction in all experimentally infected goats, while a negative reaction in controls. Skin hypersensitivity reaction was found to be maximum by 48 h post-injection. Histopathology of skin biopsy taken from the site of inoculation revealed infiltration of lymphocytes, and macrophages at perifollicular and periglandular areas, congestion of blood vessels with perivascular infiltration of lymphocytes and macrophages and dermal oedema. Tuberculin failed to produce a positive skin hypersensitive reaction in C. pseudotuberculosis infected or control goats. From 15th day onwards, experimentally infected goats which were necropsied presented gross lesions typical of caseous lymphadenitis in lymphnodes. The lesions were found to confine to superficial lymphnodes adjacent to the site of inoculations. The histological changes observed in lymphnodes were basically of two types: hyper-plastic stimulatory reaction and degenerative changes. The changes were hyper-plastic reactive follicles with well distinguished germinal centre, accumulation of lymphocytes and varying degrees of sinus histiocytosis in medullary region, dense lining of medullary cords with plasma cells, depletion of lymphocytes from the cortical area; subcapsular and cortical oedema, congestion of blood vessels, haemorrahage, infiltration of mononuclear cells in lymphatics and blood vessels, accumulation of macrophages and plasma cels in the medulla, dilatation of sinusoids, fibrous tissue proliferation, degenerative and necrotic changes of lymphocytes in the cortex and medulla, fibrous tissue encapsulated focal areas of caseation of calcification surrounded by lymphocytes, macrophages and giant cells and finally conversion of parenchyma to a caseated mass enclosed in fibrous tissue capsule. In brief, the results obtained from the present study revealed the operation of both cell-mediated and humoral immune responses in goats against C. pseudotuberculosis infection. Of the various methods employed to monitor the immune response, leukocyte migration inhibition and delayed skin hypersensitivity tests were suitable for ascertaining the cell-mediated immune response and haemolysis inhibition test for humoral immune response. Leukocyte migration inhibition test and haemolysis inhibition test can be successfully employed for the early diagnosis of C. pseudotuberculosis infection in goats.
Open Access
Radiation induced variability in interspecific hybrids involving abolmoschus esculentus moench and abolmoschus manihot
(Department of Olericulture, College of Horticulture, Vellanikkara, 1986) Dalia Cherian; KAU; Peter, K V
Yellow vein mosaic is the most destructive viral disease of bhindi, which takes heavy toll of the crop, infecting at all growth stages. Attempts to isolate source(s) of resistance to yellow vein mosaic disease from cultivars and wild relatives were proved to be of limited success because of either incompatibility or sterility barriers between the cultivars and wild relatives. An experiment was planned and carried out during June - October,1984; November - April, 1984-'85 and June - October 1985 at the Instructional Farm _ of the College of Horticulture, Vellanikkara, Trichur to induce variability in interspecific hybrids involving Abolmoschus esculetus (L.) Moench and Abolmoschus manihot (L.) Medic. The three accessions of Abolmoschus manihot were observed cross compatible with Abolmoschus esculentus cv. ‘Pusa Sawani', Abolmoschus menihot sap, tetraphyllus crossed readily with abolmoschus esculentus (Cl = 95%) . This was proved through Fo fruit set, Fo seed set and germination of F0 seeds. The F1 plants did not bear normal seeds and F2 generation could not be raised. The pollen fertility of F1 hybrids were much lower than the parents. There was reciprocal difference in the crossability index. radiation created considerable variability in interspecific F1 hybrids for days to flower, plant height,leaf length, leaf width, fruit length, fruit girth, nodes on main stem, fruiting nodes on main stem, intemodal length, fruits/plant, ridges/fruit and fruit yield/plant, in Abolmoschus esculentus x 2 accessions of Abolmoschus manihot. There was preponderance of characters of Abolmoschus manihot in the interspecific hybrids. Considerable changes in discrete characters were observed in irradiated F1 hybrids. Dominant characters like branched habit, pubescence and pigmentation of vegetative parts, and hairiness of fruit got changed with gamma radiation. Though the radiation enhanced the pollen fertility of interspecific hybrids, they had seedless fruits or fruits with incompletely filled seeds. With the doses 15 kR, 20 kR and 25 kR tried, quantitative and qualitative characters were affected, though there appeared to be scope for the use of still higher dose of rays to create wider variability in interspecific hybrids. Under natural field conditions and artificial inoculation, ‘Pusa Sawani’ was infected by yellow vein mosaic virus, whereas none of the wild species did exhibit any symptoms. Artificial inoculation provides a means to select desirable plant types having resistance to yellow vein mosaic disease.
Open Access
Delineating the various agroclimatic zones of Kerala & identifying the cropping patterns for the different zones
(Department of Agronomy, College of Horticulture, Vellanikkara, 1986) Karmachandran, K M; KAU; Balakrishna Pillai, P
An investigation was carried out for delineating the various agroclimatic zones of Kerala and for identifying the cropping patterns for the different zones. Meteorological data were collected from 100 stations in Kerala. Soil and crop data were collected for the whole state. The agroclimatic features of Kerala were studied. The water balance elements and indices of 14 representative stations in the state were computed and presented on annual basis. Six moisture availability regimes (MAR) were proposed and delineated following the guidelines of Hargreaves (1971 & 1975). Twenty agroclimatic zones were identified by superimposing the six moisture availability regimes over seven soil groups. The zones are (1) Dry-Forest loam (AF1), (2) Semi dry-Red loam (BR1) (3) Semi dry-Laterite (BLa), (4) Semi dry-Alluvium (BA1), (5) Semi dry-Black soil (BBs), (6)Semi dry-Forest loam (BF1), (7) Sub humid-Red loam (CR1), (8) Sub humid-Laterite (CLa), (9) Sub humid-Alluvium(CA1), (10)Sub humid-Saline (CSa), (11) Sub humid-Forest loam (CF1), (12) Humid-Laterite (DLa), (13) Humid-Alluvium (DA1), (14) Humid-Greyish Onattukara (DGo). (15) Humid-Saline (DSa) (16) Humid-Forest loam (DF1), (17) per humid-Laterite (ELa), (18) per humid-Forest loam (EF1), (19) Wet-Laterite (FLa) and (20) wet-Forest loam (FF1). Twelve cropping patterns of the state were also identified. Suitability of the existing cropping patterns for the agroclimatic zones were examined. It is found that the cropping patterns existing in almost all the agroclimatic zones are suitable to the zones. Coconut is not suitable for BBs zone and the eastern part of the BLa zone, while rubber is not congenial for the zone BF1. Mango and jack are not suitable for the high altitude areas of DF1zone. Coconut, tapioca and cocoa are suitable only up to 900 m above M. S. L. in the zone EF1. In FLa zone rubber grows well up to 600 m above M. S. L, while cardamom is better for higher elevations. Tapioca is not suitable for areas 800 m above M. S. L in the zone FF1. The important crops except tapioca are unsuitable for AF1 zone. It is felt that a detailed study with a denser network of meteorological stations is necessary for examining the suitability of crops to the zone CF1. Crops such as millets with low water requirement should be given more importance in the zones like BBS and AF1. Dry (A) type MAR demands great care of crops at least for six dry months. Perhumid (E) and Wet (F) types of MAR demand proper drainage for crops except rice. Proper soil conservation measures have to be taken up when tapioca is grown on the slopes, especially of the sub humid (C), Humid (D), perhumid (E) and wet (F) types of moisture availability regimes.
Open Access
Evaluation of available phosphorus and potassium in soil using a common extractant
(Department of Soil Science and Agricultural Chemistry, College of Horticulture, Vellanikkara, 1986) Durga Devi, K M; KAU; Jose, A I
A laboratory evaluation and an uptake study using Neubauer seedling technique was carried out for evolving a single extractment suitable for extracting both available P and available K, so as to simplify the process of extracting these available plant nutrients in soil testing works. Eighty seven soil samples from different parts of the State were used to evaluate the performance of the selected number of extractants based on a 3 step evaluation i.e., (i) an initial study consisting one soil, 18 extractants at a single soil solution ratio (1:10) and two equilibration periods (30 and 60 min); (ii) a preliminary screening consisting of 9 soils, 15 extractants at a single soil solution ratio (1:10) and 5 equilibration periods (5, 10, 15, 30 and 60 min). An uptake study was also conducted using Neubauer seedling technique and correlation coefficients were worked out between the amount of P extracted by the various extractants and the P and K uptake by rice; (iii) a final selection of the common extractant consisting of 10 extractants with suitable equilibration periods, at 1:10 soil solution ratio and 87 soils. In combination of NH4 F and DTPA, increasing concentration of NH4 F retarded the extraction of both P and K and they extracted much smaller quantities of P and K as compared to that of Bray No.1 and neutral normal NH4 OAC. Use of ammonium acetate along with Bray No.1 inhibited the release of P drastically. Mathew’s triacid extractant viz., 0.06 N H2 SO4 + 0.06 N HCL + 0.05 N oxalic acid extracted relatively large amounts of P and K. The pattern of P and K release when examined together as a function of period of equilibration found that the equilibration period for different extractants was varying. The suitable equilibration period for 0.1 M NH4F + 0.001 M DTPA, 0.1 M NH4F + 0.003 M DTPA, 0.5 M NH4F + 0.005 M DTPA, 0.05 M NH4F + 0.05 M acetic acid, and Dray No. 1 is 5 min. for 0.3 M NH4F + 0.001 M DTPA combination and Bray No.1 + 0.005 M DTPA an equilibration period of 10 min is found to be the optimum. An equilibration period of 30 min is suitable for Mathew’s triaced extractant, Olsen’s extractant and neutral normal ammonium acetate. Since the initial and preliminary studies established the suitability of Bray No.1 for available P and the neutral normal ammonium acetate for available K and because the coefficient of correlation between the amount of K extracted by the extractants and the K uptake by rice were highly significant at all the equilibration periods the final selection of the common extractant was based on the correlation of the P and K values of the selected extractants with that of Bray No. 1 P and neutral normal ammonium acetate extractable K. The correlation coefficients with Bray No.1 P established by the various extractants have shown the following decreasing order of efficiency. 0.5 M NH4F + 0.005 M DTPA > 0.05 M NH4F + 0.05 M acetic acid > NH4OAC > Olsen > Mathew’s triacid > Bry No.1 + 0.005 M DTPA > 0.3 M NH4F + 0.001 M DTPA > 0.1 M NH4F + 0.001 M DTPA > 0.1 M nH4F + 0.003 M DTPA. All the extractants were not significantly and positively correlated with NH4 OAC (std) K. The three extractants viz., Mathew’s triacid, 0.1 M NH4F + 0.001 M DTPA and Olsen’s extractant have given significant positive relationship with NH4 OAC (std) K. Highest correlation was obtained with Mathew’s triacid followed by 0.1 M NH4F + 0.001 M DTPA and Olsen’s extractant. Thus it is confirmed that Mathew’s triacid extractant is the best common extractant for available P and available K. No analytical difficulty in the determination both P and K was observed while using this extractant. Inter-correlations worked out between the various soil properties have cleared the following facts. Mathew’s triacid P and Bray No.1 P were significantly and positively correlated with total P and negatively correlated with P fixing capacity. NH4 OAC (std) K and Mathew’s triacid K gave significant positive correlation with total K as well as CEC. Mathew’s triacid extractant viz., 0.06 N H2SO4 + 0.06 N HCL + 0.05 N oxalic acid with a soil solution ratio of 1:10 and an equilibration period of 30 min is recommended as a commom extractant for available P and available K by the present study, since it saves considerable time and materials in soil testing.
Open Access
Genomic relationship in vigna species
(Department of Agricultural Botany, College of Horticulture, Vellanikkara, 1986) Neema, V P; KAU; Narayanan Namboodiri, K M
Investigations on the genomic relationship in Vigna species were undertaken in the Department of Agricultural Botany, College of Horticulture during 1983-1985. Pure seeds of the two subspecies of Vigna unguiculata, viz. unguiculata and sesguipedalis were sown and crop raised. Direct and reciprocal crosses were made. Morphological and cytological investigations were done. It was found that the two subspecies easily crossable. In both the subspecies there was high prefertilisation shed. The chromosome number of subsp. unguiculata was 2n=22, of subsp. sesguipedalis 2n=24 and of F1 hybrid was 2n= 23. Both the parents and hybrid showed cells with laggards. Length of meiotic and somatic metaphase chromosomes was more in subsp. sesguipedalis, lowest in subsp. unguiculata and intermediate in their F1 hybrid. Both the subspecies and their hybrid had almost similar TF % which gave an indication of similarity in their karyotypes. Pollen fertility was more in subsp. sesguipedalis. Reciprocal difference was seen in the case of morphological characters like height of the plant, number of primary branches, internodal length, seeds per pod, seed colour and seed volume. However, these differences were not seen traceable in the cytology of the hybrid.
Open Access
Relative advantages of F1 hybrids and 50:50 physical mixture in tomato
(Department of Olericulture, College of Horticulture, Vellanikkara, 1986) Sheela, A G; KAU; Peter, K V
Bacterial wilt caused by Pseudomonas solanacearum E.F. Smith is the most serious disease limiting the successful cultivation of tomato (Lycopersicon esculentum Mill.) in the acidic soils of Kerala. Development of F1 hybrids possessing different resistant gene systems would be a desirable step in tomato improvement. Development of specific physical mixtures could also minimise crop damage considering the ‘Obstruction’ given by the component lines. Experiments were carried out during 1984-’85, at the Instructional Farm of College of Horticulture, Vellanikkara, Trichur to identify new sources of resistance to bacterial wilt. The susceptible check Pusa Ruby showed 100% susceptibility in all the trials. Six specific tomato lines-LE 79 LFE, LE 214, LE 217, IIHR Bwr 93, IIHR Bwr 34A and LE 206-were crossed in all possible combinations. All F1 hybrids except IIHR Bwr 93 x IIHR Bwr 34A and IIHR Bwr 34A x LE 206 were resistant to bacterial wilt. LE 214 x LE 206 were resistant to bacterial wilt. LE 214 x LE 206 (921.75 g/plant), the best F1 hybrid, had 27.15 fruit/plant and was earlier to fruit set (57.8 days) and fruit harvest (85 days). Among the 15 physical mixtures, six were resistant-LE 214 + LE 217 (16.67%), LE 214 + IIHR Bwr 93 (18.33%), LE 214 + IIHR Bwr 34A (10%), LE 217 + IIHR Bwr 34A (13.33%). LE 214 + IIHR Bwr 93, the best resistant physical mixture, had 24 fruits/plant weighting 600.38 g/plant. Intervarietal heterosis was observed for plant height, primary branches/plant, days to fruits/plant and fruit yield/plant. Combining ability analysis indicated the role of both additive and non-additive geneaction in the expression of days to fruit set, days to fruit harvest, and plant height. Additive gene action was predominant for primary branches/plant. A preponderance of non-additive gene action over additive gene action was observed for fruit/plant and fruit yield/plant. To study the maternal parental effect, five lines of tomato- LE 79 LFF, LE 214, LE 217, IIHR Bwr 93 and LE 206- were crossed in all possible combinations including reciprocals. Maternal parental effect was pronounced for days to fruit set, days to fruit harvest and fruit set (%). Evaluation of 15 reportedly resistant lines of tomato confirmed resistance in LE 211, LE 214, LE 217, LE 79 LFG and LE 79 DG. The line LE 79 LFG was the highest yield (742.6 g/plant) with 19.67 fruits/plant.
Open Access
Screening plant materials for nitrification inhibition properties and testing the field performance of promising materials
(Department of Agronomy, College of Horticulture, Vellanikkara, 1986) Gracy Mathew; KAU; Vikraman Nair, R
The present study ‘screening plant materials for nitrification inhibition properties and testing field performance of promising materials’ was conducted during May 1984 to November 1985 at the College of Horticulture, Vellanikkara, Trichur. A total of 17 materials were used for screening using already proved nitrification inhibition materials like N-Serve and neem cake as reference. Nitrification rate in the soil was found to be very low and there was no appreciable conversion of NH+4 form to NO 3. Since there was no significant difference in the NH+4 content between treatments due to the naturally low rate of nitrification, selection of promising materials possessing nitrification inhibition property could not be done. Attempts were made to locate the factors that resulted in the low rate of nitrification in the soil. Organic matter content, pH, cropping history, amount of NH+4– N build up in the soil, incubation conditions and low microbial population were not indicated as responsible for the noted low degree of nitrification. In red and black soils of Coimbatore, nitrification was appreciable and there was fast disappearance of NH+4–N. Data on various growth parameters like mean, height, LAI and dry matter production of the test crop. Fodder maize, did not show any treatment difference. The yield in the treatment which received no fertiliser nitrogen was significantly lower than in other treatments. Similar were the results on nitrogen content of plant parts at various stages and those on total nitrogen uptake. The addition of materials used as nitrification inhibitors did not show any added advantage over untreated urea since the degree of nitrification in the soil was not appreciable.
Open Access
Effect of varying light intensities on the growth and development of indoor foliage and flowering plants
(Department of Horticulture, College of Agriculture, Vellayani, 1986) Aasha, K; Aasha, K; KAU; KAU; Ramachandran Nair, S; Ramachandran Nair, S
An investigation was carried out in the Department of Horticulture, College of Agriculture, Vellayani, during the year 1985-86 to find out the effect of various light intensities on the growth and development of the important indoor foliage and flowering plants such as aglaonea, aralia, alocasia, chlorophytum, coleus, cordyline, dieffenbachia, dracaena, maranta, peperomia, pleomale, rheo, balsam, begonia and verbena. The treatments consisted of five intensities of light as follows, Full sunlight 75,50, 25 and 10 per cent light. The experiment was laid in a Completely Randomised Design.Shading was provided by using gunny cloth streched over g.1 poles. Plant height increased with decrease in light intensities in most of the plants except in aralia, coleus, maranta, pleomele and aglaonema. In aglaonema the height of the plants were influenced by the treatments only at the initial growth stages. In other staller plants were produced under high light intensities. In general diminishing light intensities enhanced leaf production , leaf area and chlorophyll content in all plants except in coleus where leaf area increased with increase in intensities of light. Destruction of chlorophylll in the leaves of plants kept in the open as evidenced by the yellowish colour was not observed for those plants in shade.

Theses

Browse

Thesis Type

Type

Author

Date

Subject

Search Results