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Subject: Horticulture × Author: KAU × End date: 1996 × Start date: 1996 × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    Performance of selected orchids under varying light regimes, culture methods and nutrition
    (Department of Horticulture, College of Agriculture, Vellayani, 1996) Sabina George, Thekkayam; KAU; Mohanakumaran, N
    The present study was undertaken to evolve agrotechniques for cut flower orchid production in Kerala. Two experiments were conducted at the College of Agriculture, Vellayani in 1991 and 1992 with two popular cut flower varieties namely Arachnis Maggie Oei ‘Red Ribbon’ and Dendrobium Sonia – 16. The effects of varying light intensities and nutrient regimes under two methods of cultivation were assessed in Arachnis Maggie Oei ‘Red Ribbon’ (Experiment 1) and in Dendrobium Sonia -16, the performance under varying light intensities and nutrient regimes was evaluated (Experiment 2) In Arachnis Maggie Oei ‘Red Ribbon’, trench culture was found to promote growth, flowering and the floral attributes. The number of leaves, aerial roots, leaf area and plant height were greater in the trench grown plants. The number of inflorescences produced, their branching, length and vase life were also enhanced under trench culture. The effect of light intensities on growth was mediated through interactions with culture methods and nutrients. The trench grown plants under 50 and 75 percent light had a greater number of leaves and leaf area. The plants receiving 500 ppm of P and K under 100 percent light had a shorter stature. The direct effect and interactions of nutrients on growth were observed at certain months during the experimental period which was indicative of differences in the requirement at different stages of growth. The dry matter content of the stem and apical shoot was greater in the plants receiving 500 ppm P. Inflorescence production and the vase life of inflorescences was greater under 100 and 75 percent light. Branching of inflorescences was greater under 75 percent light. In Dendrobium Sonia -16 the number of inflorescences produced was greatest under 75 percent light. The length of the inflorescences was greater under 75 percent light and the span area of the flowers was greater under 50 and 75 percent light. Nitrogen at 500 ppm increased the length of the inflorescences, the number of flowers in an inflorescence, and the span area of the flowers. The number of inflorescences produced was also greater in the plants receiving 400 or 500 ppm N, 400 or 500 ppm K and in those receiving 500 ppm P. Interactions between the nutrients and between light intensities and the nutrients were also observed. The nutrient composition of the leaves in both the cultivars were enhanced by the 400 and 500 ppm doses of N and P and 500ppm K. Based on the observed effects, in Arachnis Maggie Oei ‘Red Ribbon’, trench culture of plants under 75 to 100 percent light and a nutrient dosage of 300 ppm N, 400 ppm P and 300 ppm K from planting till nine MAP and thereafter a dosage of 400 to 500 ppm N, 400ppm, P and 500 ppm K can be recommended. In Dendrobium Sonia -16 growing in pots under 75 percent light with 400 to 500 ppm of N, P and K can be recommended
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    ThesisItemOpen Access
    Somaclonal variation in black pepper (piper nigrum L)
    (Department of Plantation Crops and Spices, College of Horticulture, Vellanikkara, 1996) Shylaja, M R; KAU; Sreekandan Nair, G
    Investigations on the exploitation of somaclonal variation for screening for resistance to Phytophthora foot rot disease in black pepper were carried out at the Plant Tissue Culture Laboratory of the Department of Plantation Crops and Spices, College of Horticulture, Vellanikkara during September 1991 to January 1995. Calliclones of different black pepper cultivars viz. Kalluvally, Cheriakanyakkadan, Balankotta, Karimunda and Panniyur – 1 were produced with and without applying in vitro selection pressure using toxic metabolite(s) of Phytophthora capsici. In vitro induction of mutation using gamma irradiation and partial purification of the toxic metabolite(s) present in the culture filtrate of P. capsici were also attempted in the present study. Leaf puncture bioassay of the concentrated culture filtrate (CCF) of P. capsici showed that toxic metabolite(s) were accumulated in the culture filtrate. The symptoms produced by CCF were quite typical of natural and artificial infection by P. capsici. Concentrated culture filtrate induced quick electrolyte leakage from leaves and calluses. Concentrated culture filtrate induced necrosis on susceptible calli. The cultivars showed significant variation in callus necrosis. Prolonged duration of selection/screening with CCF totally inhibited the regeneration potential of the calli. Concentrated culture filtrate was not found to inhibit shoot proliferation and shoot growth in already regenerated cultures but inhibited the root growth. In the three direct selection/screening methods tried for calli viz. growing in CCF incorporated MS medium (Method 1) shaking in CCF incorporated liquid MS medium (Method 2) and double layer culture technique (Method 3), cultivars showed significant differences in callus necrosis and callus growth. Direct screening of calli was not found to inhibit the regeneration of shoots, shoot proliferation and recovery of rootable shoots but affected the root growth adversely. Gamma irradiation of calli using 60Co source did not give any better response to in vitro screening. The toxic metabolite(s) present in the culture filtrate could not be separated by organic solvent fractionation. However ion exchangers like Dowex 1 and Dowex 50 could be used for separation of the toxic fraction from the filtrate. The response of five different cultivars at various stages of development of cultures when compared, it was found that the cultivars differed significantly in callusing, callus growth, regeneration of shoots, recovery of rootable shoots and root growth. The clones regenerated from screened and unscreened calli were further tested for resistance/ tolerance to P. capsici using different methods of screening viz.natural screening (keeping in infected field), screening by electrolyte leakage method and screening by artificial inoculation of culture disc of P. capsici. None of the regenerated calliclones were found to be resistant to the disease in natural screening. When the tolerance level of the regenerated calliclones was looked into, the performance of the unscreened calli derived clones was found better as compared to the screened calli derived ones. The calliclones of different cultivars differed significantly inthetolerance/susceptibility reaction to the disease. The calliclones of Cheriakanyakkadan recorded greater degree of tolerance to the disease when compared to others. Among the cultivars studied, Kalluvally exhibited high rate of somaclonal variation.
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    ThesisItemOpen Access
    Standardisation of in vitro techniques for the rapid clonal propagation of Mango (Mangifera indica L.)
    (Department of Horticulture, College of Agriculture, Vellayani, 1996) Sulekha, G R; KAU; Rajmohan, K
    Standardization of techniques for the in vitro propagation of mango (Mangifera indica L) varieties was attempted. The studies were carried out at the Plant Tissue Culture Laboratory, Department of Horticulture, College of Agriculture, Vellayani, during 1992-96. Attempts for the in vitro propagation via somatic embryogenesis, somatic organogenesis and enhanced release of auxillary buds were made. Six monoembryonic and six polyembryonic mango varieties were subjected to the initial response studies. Neelum (monoembryonic) and Vellari Manga (polyembryonic) varieties were selected for further detailed studies. Explants like nucellus, embryo mass, segments of leaf and inflorescence were used. The effects of culture medium (basal medium, major and minor nutrients, plant growth substances, casein hydrolysate, sucrose, glutamine, coconut water, activated charcoal, polyvinyl pyrrolidone, sodium butyrate, thidiazuron, polyethylene glycol, sodium chloride, silver nitrate, cobalt chloride and agar), culture conditions (light and temperature) and frequency of subculture on the various stages of somatic embryogenesis were studied. Among the various explants tried, somatic embryogenesis could be induced only from nucellus and embryo mass. In Neelum, somatic embryogenesis could be induced in 66.67 percent cultures of nucellus and 75.00 percent cultures of embryo mass. In vellari manga 83.33 percent cultures of nucellus and 66.67 percent cultures of embryo mass responded. Somatic embryogenesis from nucellus of Neelum could be best induced on half strength MS basal medium supplemented with GA3 5.0mg/l, 2,4-D 2.0mg/l, GA3 5.0mg/l, sucrose 60.0g/l, glutamine 400.0mg/l, coconut water 200.0ml/l, activated charcoal 2.5g/l and agar 5.0g/l. The ideal treatment for inducing somatic embryogenesis from nucellus of Vellari Manga was half strength MS basal medium supplemented with 2, 4-D 2.0 mg/l, GA3 5.0mg/l, sucrose 60.0g/l, glutamine 600.0 mg/l, coconut water 200.0ml/l, activated charcoal 2.5g/l and agar 6.0g/l. Subculturing in medium of the same composition at an interval of five days increased the percentage induction in Neelum (30.0 percent) and five to ten days in Vellari Manga (40.0 percent). The best treatment identified for the initiation of somatic embryoids from nucellus of Neelum was half strength MS basal medium supplemented with 2, 4-D 2.0mg/l, GA3 5.0mg/l, BA 1.0mg/l, sucrose 60.0g/l, glutamine 400.0mg/l, casein hydrolysate 500.0mg/l, coconut water 200.0ml/l, activated charcoal 2.5g/l and agar 5.0g/l. The ideal treatment for the initiation of somaticembryoids from nucellus of Vellari Manga was half strength MS basal medium supplemented with 2, 4-D 0.5mg/l, GA3 5.0mg/l, BA 1.0mg/l, sucrose 60.0g/l, glutamine 400.0 mg/l, case in hydrolysate 600.0 mg/l, coconut water 200.0ml/l, activated charcoal 2.5g/l and agar 5.5g/l. Subculturing at an interval of ten days in Neelum and five to ten days in Vellari Manga was beneficial for the initiation of somatic embryoids. The corresponding percentage of initiation of somatic embryoids was 66.67 in Neelum and 55.56 percent in Vellari Manga. A medium containing B5 major salts and MS minor salts supplemented with abscisic acid 5.0mg/l, sucrose 40.0g/l, casein hydrolysate 100.0mg/l, coconut water 200.0ml/l, polyvinyl pyrrolidone 10.0g/l and agar 4.5g/l was the best for supporting the maturation of the somatic embryoids of Neelum. The best medium for the maturation of the somatic embryoids of Vellari Manga contained B5 major salts, MS minor salts, abscisic acid 4.22mg/l, sucrose 40.0g/l, casein hydrolysate 100.0mg/l coconut water 200.0ml/l, polyvinyl pyrrolidone 10.0g/l and agar 5.0g/l. The size of embryoids was the highest (1.0-1.5cm long) when subcultured at an interval of ten days for Neelum and fifteen days (0.5-1.5cm long) for Vellari Manga. Incubating the cultures in darkness at 26 ± 20C favoured the induction, initiation and maturation of somatic embryoids of both the varieties. Near-normal germination of the somatic embryoids of Neelum was observed when cultured on a medium containing B5 major salts and MS minor salts, BA 0.1 mg/l, sucrose 40.0g/l, sodium chloride 0.5g/l, cobalt chloride 10.0 mg/l, polyvinyl pyrrolidone 10.0g/l and agar 5.5g/l. Near-normal germination of the somatic embryoids of Vellari Manga was observed on a medium containing B5 major salts and MS minor salts, BA 1.0 mg/l, sucrose 50.0g/l, sodium chloride 0.5g/l, cobalt chloride 10.0 mg/l, polyvinyl pyrrolidone 10.0g/l and agar 5.5g/l. A few germinated embryoids were planted out. However, they did not survive. Histological and morphological studies ascertained the status of the somatic embryoids formed. Scanning electron microscope studies depicted the morphological features of the developmental stages of the somatic embryoids. Attempts to standardize in vitro propagation via somatic organogenesis and enhanced release of auxiliary buds were not successful. However, de-diffrentiation could be induced from leaf segment explants of Neelum and Mulgoa.
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    ThesisItemOpen Access
    Bacterial wilt resistance and yield in brinjal (Solanum melongena L.)
    (Department of Olericulture, College of Horticulture, Vellanikkara, 1996) Singh, P K; KAU; Gopalakrishnan, T R
    Investigations on “Bacterial wilt resistance and yield in brinjal (Solanummelongena L.)” was undertaken in the Department of Olericulture, College of Horticulture, Vellanikkara during 1993 – ’96. Preliminary evaluation of seventy eight brinjal accessions during Kharif 1994 revealed considerable variation for most of the economic characters. Twenty four accessions/varieties selected based on productivity, resistance to bacterial wilt, crop duration, fruit and plant characters from the preliminary evaluation were subjected to detailed evaluation during March – November, 1995. In the long duration accessions, the non – prickly SM 141 has yielded as high as 6.4 kg/plant with maximum number of fruits (113.5) having maximum weight (128.27 g). Among short duration accessions maximum yield was recorded in white fruited Swetha (3.9 kg/plant). The study revealed the necessity for differential spacing depending on the duration and spread of the plant. In addition to the already available bacterial wilt (Pseudomonas solanacearum) resistant varieties viz., Surya, Swetha, ArkaKeshav, ArkaNidhi, BB 44 some more varieties/accessions viz., Annapurna, Composite 2, TGR, SM 71, SM 116 and SM 141 were found resistant under artificial inoculation. The contents of total phenol and O.D. Phenol was higher in the resistant varieties than the susceptible ones. The anatomical studies revealed well developed secondary xylem with small compact cortical cells in the resistant variety compared to the susceptible variety. The nine F1 hybrids differing in size, shape and colour of fruits were compared with their parents during summer 1996. Two F1 hybrids viz., the long stout and deep purple fruited ArkaKeshav x SM 71 and oval and deep purple fruited Surya x SM 116 had surpassed the standard parent by 337.62 per cent and 290.04 per cent respectively in productivity. Both the hybrids having bacterial wilt resistance, desired plant habit and attractive fruit characters can be progressed further. In general the F1 hybrids had more vigour and tolerated infestation of jassids better than the parents. In Kerala the cultivation of brinjal during summer is limited mainly due to heavy incidence of jassids. In the present study varietal variation was observed for resistance to jassids (Amrascabiguttulabiguttula). The long trichomes with high density contributing to a matting effect on the leaf surface may be responsible for the jassid tolerance in varieties like Pusa Kranti and BB 7. These jassid resistant but wilt susceptible varieties yielded 2417.2 per cent and 186.0 per cent respectively more over the intact plants after grafting onto Solanumtorvum. The present study revealed the scope of cultivating jassid resistant varieties viz., Pusa Kranti and BB 7, though highly susceptible to bacterial wilt during the summer months in the state.
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    ThesisItemOpen Access
    Genetic and biochemical bases of resistance to bacterial wilt in chilli
    (Department Of Olericulture, College Of Horticulture, Vellanikkara, 1996) Baby Lissy Markose; KAU; Abdul Vahab, M
    Investigation on “Genetic and biochemical bases of resistance to bacterial wilt in chilli’ was carried out in the Department of Olericulture, College of Horticulture, Vellanikkara during 1992-96 to study the inheritance and mechanisms of bacterial wilt resistance and to develop a near isogenic line of Pusa Jwala with resistance to bacterial wilt. Pseudomonas solanacearum, the bacterial wilt pathogen was isolated from infected chilli plants and its pathogenicity was established. The resistance to this disease showed a monogenic and incompletely dominant type of inheritance. Studies on biochemical basis of resistance revealed that total phenol, OD phenol and protein content and enzyme activities had a positive association with bacterial wilt resistance. Ujwala, the resistant variety showed high protein content and had higher activities of peroxidase and polyphenol oxidase enzyme in all plant parts. Higher total phenol was found only in roots and OD phenol in roots and stems of Ujwala. All these biochemical constituents recorded an increasing trend on inoculation in both resistant and subsceptible varieties. The wilt resistant variety had higher OD phenol and protein contents on inoculation whereas the susceptible variety was higher in total phenol content. Both peroxidase and polyphenol oxidase activity were higher in resistant than in susceptible variety. The higher amount of OD phenol and their oxidation products like quinones formed by increased peroxidase and polyphenol oxidase were ascribed for resistance in Ujwala. In the protein gel electrophoresis, the resistant and susceptible genotypes possessed similar bands with identical electrophoretic mobility. The isozyme patterns of peroxidase and esterase were studied. Roots for peroxidase and leaves for esterase showed clear bands. The resistant and susceptible varieties were different in banding pattern before inoculation. Inoculation did not evince any change in the banding pattern for peroxidase and esterase enzymes. The resistant variety had a well developed secondary xylem with thick and compact piliferous layers and cortical cells compared to the susceptible variety. In the radiotracer studies, radioactivity counts were more in susceptible than in resistant variety after inoculation in both 32p and 35S labeled plants. In the autoradiography, the 35S labeled bacteria were more in susceptible plants than in resistant ones. However there was no appreciable difference between resistant and susceptible plants when 32P tagged bacteria were inoculated. A near isogenic line of Pusa Jwala, moderately resistant to bacterial wilt, was developed by crossing Ujwala with Pusa Jwala and advancing the F1s to BC2F4 generation.