PG Thesis
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Item Vegetative propagation in jamun (Syzygium cumini (L.) Skeels)(Department of Fruit Science, College of Agriculture, Vellanikkara, 2023-03-17) Vishnupriya, V.; Jyothi BhaskarJamun (Syzygium cumini (L.) Skeels) is a popular, but underutilised indigenous fruit crop in India with high nutritive value. It can be multiplied through both seed and vegetative propagation methods. Due to the long juvenile period, huge size of the tree and short shelf life of fruits, jamun is not preferred for commercial cultivation in Kerala. As jamun fruits are highly nutritious and possess good medicinal properties, there is an urgent need to commercialise this crop in Kerala. To achieve this goal, availability of true to type, early bearing and dwarf statured clones of superior jamun types should be assured in sufficient quantity and this can be achieved only through vegetative propagation methods. Under this context, the present study entitled “Vegetative propagation in jamun (Syzygium cumini (L.) Skeels)” was carried out in the Department of Fruit Science, College of Agriculture, Vellanikkara during the year 2021-2022 with the objective of standardizing an effective vegetative method of propagation in this fruit crop. The research programme consisted of four experiments. The first experiment was on propagation by hardwood cuttings which was laid out in CRD with two factors and was done during June (2022). The first factor was growth stimulants with six treatments viz., T1 (AMF), T2 (IBA), T3 (Pseudomonas fluorescens), T4 (Aloe vera gel), T5 (Cow dung slurry) and T6 (Tender coconut water). The second factor was growing condition with two treatments, T1 (Mist chamber) and T2 (Shade house). All these treatments were replicated thrice with twenty plants in each replication. The cuttings kept under mist chamber started sprouting earlier (8.49 days) than those cuttings kept under shade house (11.09 days). Though sprouting was observed, after one month the plants started to dry up and failed to develop roots and did not survive under both growing conditions. The second experiment, propagation by air layering was done during November (2021) and was laid out in CRD with five treatments replicated thrice with twenty plants per replication. Treatments were T1 (Coir pith compost), T2 (Vermicompost), T3 (Sphagnum moss), T4 (Saw dust), and T5 (FYM). Minimum number of days for the emergence of roots (55 days) in air layers was recorded in T2 (Vermicompost) and longest root was observed in T1 (Coir pith compost). Though the air layers produced using sphagnum moss (T3) and coir pith compost (T1) survived during the experiment period, the survival percentage (6.67% and 5.00% respectively) was very low and were found to be on par with each other. Air layers produced using vermicompost, saw dust and FYM as the media rooted but failed to survive till the end of the experiment. The third experiment (propagation using budding) was also laid out in CRD with six treatments replicated thrice with twenty plants in each replication and it was carried out during the month of June (2022). The budding methods tried were T1 (T budding), T2 (Patch budding), T3 (Forkert budding), T4 (Flute budding), T5 (Ring budding) and T6 (Yemma budding). These budding methods failed to sprout except patch budded plants which took 102.78 days for initial sprouting and about 10.00 per cent of patch budded plants were found to survive 190 days after budding. The fourth experiment, propagation using grafting, was also laid out in CRD with eight treatments replicated thrice with twenty plants in each replication and it was also done during June (2022). The methods of grafting tried were T1 (Epicotyl grafting), T2 (Softwood grafting), T3 (Whip grafting), T4 (Whip and tongue grafting), T5 (Veneer grafting) and T6 (Approach grafting), T7 (Wedge grafting on one year old rootstock) and T8 (Wedge grafting on three year old rootstock). Results from the present study showed that hardwood cuttings, air layering and budding methods were not suitable for commercial propagation of jamun plants under the climatic conditions prevailing in Thrissur. Among the grafting methods, wedge grafting done on three year old rootstock showed better growth performance with respect to production of maximum number of leaves and shoots and also longest shoot (17.73, 3.55 and 16.40 cm respectively). With regard to survival rate, wedge grafting performed on one year old rootstock of jamun was found to be the best (53.33% survival) among the different methods of grafting carried out during the period under study.Item Standardization of vegetative propagation techniques in dragon fruit( Hylocereus spp.)(Department of Fruit Science, College of Agriculture , Vellanikkara, 2023-02-02) Mohammed Billal, M.; Aswini, ADragon fruit which belong to the family Cactaceae is commonly referred to as Pitaya, Pithaya, Queen of the Night, Night blooming Cereus. It is one among the exotic fruits, cultivated primarily for its attractive and highly nutritious fruit. It is native to Costa Rica, Guatemala and Southern Mexico, and are primarily found in tropical and subtropical regions. Though this can be easily multiplied through seeds, seedlings are not preferred as they have a long pre-bearing age and also not true to type in nature. Among the vegetative propagation methods, cuttings alone are used for mass multiplication of planting materials all over the world, whereas layering, grafting and budding are not in commercial use. Hence, the present study entitled “Standardisation of vegetative propagation techniques in dragon fruit (Hylocereus spp.)” was carried out in the Department of Fruit Science during 2022-2023, comprising three experiments: standardisation of length of rooted cuttings for propagation, standardisation of propagation by air layering and standardisation of propagation by grafting with the objective of evaluation of different vegetative propagation methods in dragon fruit. In the first experiment, the performance of different length of rooted cuttings were evaluated. Rooted cuttings of 120 cm length (T4) were found to be the best as it produced the maximum number of segments (13.10), number of newly emerged segments (3.70), number of spine areoles (556.00), number of roots (14.00), longest root (52.50 cm), duration of flowering (107.80 days), number of fruits (19.2 fruits/pole) and fruit yield (4.96 kg/pole). Flower and fruit morphology did not exhibit any significant variation with the treatments, as the same variety (“Cambodian Red” – red fleshed variety) was used for the study, and the flowering and fruiting characters are associated with the genetic nature of the variety. In the second experiment, the different rooting media for air layering were evaluated. Coirpith compost (25.00 days) and Arbuscular Mycorrhizal Fungi (AMF) with perlite and vermiculite (26.50 days) recorded the minimum number of days for root emergence. Sphagnum moss recorded the maximum number of adventitious roots per air layer (15.30). Longest roots were observed in AMF with perlite and vermiculite (11.04 cm) and sphagnum moss (10.85 cm) and were found to be on par with each other. The AMF with perlite and vermiculite (5.45 mm) and sphagnum moss (5.38 mm) recorded maximum root diameter. In terms of survival percentage, sphagnum moss recorded the highest survival percentage of 81.25%. Sawdust (3.33 air layers) and sphagnum moss (3.25 air layers) produced the maximum number of rooted air layers after 90 days of air layering. In the third experiment, different grafting methods were evaluated with two varieties of dragon fruit, Mexican Red and Malaysian Red. When Mexican Red was used as the rootstock, horizontal grafting (T1) (16.00 days), shoot grafting (T3) (18.50 days) and seedling grafting (T6) (18.80 days) recorded the minimum number of days taken for sprouting. Horizontal grafting recorded the maximum number of segments (2.00). V-cut bud grafting (T5) and seedling grafting (T6) did not produce any segments. Shoot grafting recorded the longest segments (101.80 cm) and maximum survival percentage (100%). The girth of the rootstock did not vary in both the rootstocks. The maximum girth of the scion (135.20 mm), maximum scion length (117.40 cm) and taller grafts (158.40 cm) were observed in shoot grafting. When Malaysian Red was used as the rootstock, the minimum number of days for sprouting were recorded for seedling grafting (15.75 days) and horizontal grafting (16.20 days). Bone grafting (T4) (1.40), horizontal grafting (1.33) and shoot grafting (1.33) recorded the maximum number of segments. Horizontal grafting produced the longest segments (115.50 cm). Shoot grafting and L-grafting recorded the maximum survival percentage (100%). The maximum girth of the scion was observed in shoot grafting (148.50 mm). The length of the scion was the maximum for horizontal grafting (T1) (131.30 cm) and shoot grafting (T3) (116.50 cm). Both horizontal grafting (165.10 cm) and shoot grafting (158.80 cm) produced taller grafts. Initially, the success percentage was the highest in horizontal grafted plants thereafter shoot grafting recorded the highest percentage throughout the study when Mexican Red was used as the rootstock. When Malaysian Red was used as the rootstock horizontal grafting recorded the highest success percentage at 15 days after grafting. But, 30 to 75 days after grafting shoot grafting recorded the highest percentage. Finally, shoot grafting and L-grafting were found to be the best with maximum success percentage. The percentage of graft establishment was highest in shoot grafting at 30, 60 and 90 days after grafting when both rootstocks were used. Additionally, L-grafting recorded the highest graft establishment at 90 days after grafting when Malaysian Red was used as the rootstock. The method of V-cut bud grafting (T5) was considered as a failure one with no success percentage. The present research revealed that using 120 cm long rooted cuttings (T4) (4 feet) is the most suitable planting material for dragon fruit in order to produce the highest yield, longest fruiting period, the largest number of fruits and significant improvement in vegetative characteristics. Sphagnum moss (T3) was found to be the most effective rooting medium for air layering in dragon fruit due to its higher success rate. The best grafting technique for dragon fruit was found to be shoot grafting (T3), which produced maximum scion girth, scion length, graft height and success percentage.Item Vegetative propagation through cuttings and air layering in cinnamon (Cinnamomum verum presl)(Department of plantation, spices, medicinal and aromatic crops , college of agriculture, Vellanikkara, 2023-12-06) Dharani, B.; Vikram, H CCinnamon commonly referred to as sweet wood or dalchini is one of the earliest recognized spices which is cultivated primarily for its dried inner bark. It is indigenous to tropical regions and naturally thriving in Sri Lanka and the southern coastal areas of Indian subcontinent and belonging to the Lauraceae family. This versatile spice is extensively employed as a flavour enhancer including cakes, sweets, incense, toothpaste, and perfumes etc. It is an evergreen perennial spice commonly propagated through seeds. The cinnamon seeds cannot endure desiccation, so they must be planted promptly after being extracted from the fruit. Many of the cinnamon plantations are of seedling origin, exhibiting natural variability. Vegetative propagation techniques will pave the way to develop true-to-type progenies and helpful in conservation of genotypes. Hence, the present study entitled “Vegetative propagation through cuttings and air layering in cinnamon (Cinnamomum verum Presl.)” was carried out in the Department of Plantation, Spices, Medicinal and Aromatic Crops during 2022-2023 which comprises of three experiments viz., standardization of propagation by cuttings, standardization of growing media for cuttings and standardization of air layering. In the first experiment, the propagation by cuttings was evaluated. For softwood cuttings, the minimum number of days for sprouting was observed in IAA at 300 ppm (11.00 days). The shoot length was not significantly affected by different growth regulators. The number of leaves produced was significantly superior at 120 DAP in IBA 100 ppm with 6.91 leaves planted during monsoon season (first fortnight of June). Whereas, IAA at 100 ppm recorded the maximum leaf area (5.80 cm²) in 120 DAP. The cuttings planted during the first fortnight of June with IAA at 300 ppm induced the maximum number of sprouts (2.63). The maximum root length (7.15 cm) and volume (1.95 cm3) was recorded in IBA 100 ppm treated cuttings during post monsoon season (first fortnight of November). With respect to sprouting percentage at 120 DAP, IBA 100 ppm was significantly superior (55.00 %) compared to other treatments. Cuttings planted during monsoon season (first fortnight of June) with IBA 200 ppm recorded the maximum survival percentage (52.50 %) followed by IBA 300 ppm (42.50 %) in 90 DAP (First fortnight of September and February). With respect to semi-hardwood cuttings, those treated with IBA at 400 ppm recorded a minimum sprouting duration of 6.75 days. The highest shoot length, reaching 4.31 cm, was observed in IAA at 600 ppm at the end of 120 DAP (first fortnight of October and March). The maximum number of leaves (6.11) was noted in IAA at 400 ppm during monsoon season (first fortnight of June) at 120 DAP. In terms of leaf area, cuttings planted during monsoon season with IBA at 600 ppm showed superiority, recording a maximum of 7.88 cm2. At 90 DAP, the highest number of sprouts (2.62) was recorded in the monsoon season. Semi-hardwood cuttings treated with IBA at 800 ppm produced maximum root length of 5.46 cm and a volume of 1.43 cm3 during post-monsoon season (first fortnight of November). The highest sprouting percentage (67.50%) was recorded with IBA at 600 ppm in 60 DAP. Additionally, IBA at 800 ppm exhibited the maximum survival percentage of 32.50. The hardwood cuttings planted during the monsoon season (first fortnight of June) had shortest duration for sprouting, taking 10.29 days. The maximum shoot length was observed in IBA at 2000 ppm, reaching 8.46 cm. The maximum number of leaves (6.56 leaves) was also recorded in IBA at 2000 ppm, whereas cuttings treated with IBA at 1000 ppm had the maximum leaf area (5.30 cm2). Compared to post monsoon season, the highest number of sprouts (2.20) was recorded during the monsoon season. Cuttings treated with IBA at 1000 ppm during the monsoon season exhibited maximum sprouting percentage (82.50%) and maximum survival percentage of 21.25%. In the histological studies, it was observed that semi-hardwood cuttings had a lower xylem frequency compared to softwood cuttings. In the second experiment, semi-hardwood cuttings planted during the rainy season using different growing media were evaluated. The coir pith used for planting had an ideal pH of 6.8 and an electrical conductivity (EC) of 0.15 d S/m. Coir pith + FYM + VAM recorded the shortest sprouting duration, taking only 6.75 days. At 120 DAP (first fortnight f October), Coir pith + FYM + Trichoderma viride recorded the maximum shoot length (2.12 cm). The maximum number of leaves was recorded in the control (Sand + Soil + FYM) with 6.13 leaves. Coir pith + FYM + Trichoderma viride resulted in the maximum leaf area (4.78 cm2), whereas Coir pith + FYM + VAM had an area of 4.71 cm2. Coir pith + Vermicompost was found to be significantly superior, with a sprouting percentage of 36.25. No significant differences were observed with respect to survival percentage and number of sprouts produced from the cinnamon cuttings in all the growing media. Due to the lack of rooting, root length, and volume were not recorded in all growing media. In the third experiment, the performance of air layering at different time intervals was examined. The maximum root length (5.41 cm), number of adventitious roots (5.26) and root volume (2.86 cm3) were found to be significantly superior in June-July month compared to other months. The number of days taken for separation was recorded minimum in June-July (66.00 days) and maximum in August-September (68.57 days). The shoots layered during June-July and August-September resulted maximum rooting success (61.43 % and 57.14 %) respectively. At the same time October- November air layered shoots had formed no roots. The present study revealed that monsoon season is the best period for cinnamon vegetative propagation. Among softwood, semi-hardwood and hardwood cuttings, it is recommended to use semi-hardwood cuttings with IBA 800 ppm for planting due to their higher survival percentage. The suitable growing media for semi-hardwood cuttings was a combination of coir pith, FYM (Farm Yard Manure), and VAM (Vesicular Arbuscular Mycorrhiza). Air layered during June-July recorded maximum survival percentage (82.50 %) and minimum in August-September (75.00%). When comparing the both vegetative propagation methods, air layering is the most ideal method of propagation in cinnamon with respect to the ease of doing and the resources required and higher success percentage. Hence, air layering is the most ideal propagation method which can be commercially practised in the months of June- July and August- September under humid tropical conditions of Kerala.Item Characterization of different viruses infecting small Cardamom (Elettaria cardamomum Maton) and production of disease free plants(Department of Plant Pathology, College of Agriculture, Vellayani, 2019) Vangala Bhavana; Radhika, N SThe study entitled “Characterization of viruses infecting small cardamom (Elettaria cardamomum Maton) and production of disease free plants” was conducted at Department of Plant Pathology, College of Agriculture, Vellayani during 2017-2019, with the objective to study the occurrence and distribution of viruses infecting small cardamom, molecular characterization of the viruses and elimination of viruses through meristem culture for the production of disease free planting material. Survey was conducted in Kattappana, Pampadumpara and Ambalapara panchayats of Kattappana block; and Nedumkandam, Thukkupalam and Chembalam panchayats of Nedumkandam blocks of Idukki district during November 2018 – May 2019. The incidence of katte disease caused by Cardamom mosaic virus (CdMV) was present in all the panchayats surveyed and it ranged from 3.75 to 43.0 per cent in Kattappana block and 5.0 to 31.33 per cent in Nedumkandam block. Disease incidence for chlorotic streak caused by Banana bract mosaic virus (BBrMV) was recorded from Kattappana (41%), Pampadumpara (30%) and Nedumkandam (8.33%) panchayats. The aphids infestation was absent in all the surveyed plots. Colocasia spp. and Alpinia spp. were the major plants observed in and around the cardamom fields and were not having visible symptoms of the viral infections. The virus inoculums were maintained under insect proof net house at Cardamom Research Station, Pampadumpara. Katte disease produced slender chlorotic flecks developing into pale green discontinuous stripes running parallel to veins from midrib to leaf margin of the infected leaves. Mosaic mottling and chlorotic specks were seen on the infected leaves and young pseudostems. In case of severe infection, plants produced stunted tillers. Chlorotic streak disease was characterised by continuous and discontinuous chlorotic streaks along veins and midribs of the infected leaves and green discontinuous spindle streaks on pseudostem. CdMV (a potyvirus) and BBrMV in cardamom was detected using polyclonal antibodies of Potato virus Y (PVY) and BBrMV respectively procured from DSMZ, Germany by direct antigen coating- Enzyme linked immunosorbent assay (DAC-ELISA) and Dot immunobinding assay (DIBA).The highest virus titre of CdMV and BBrMV was obtained in samples collected from Pampadumpara and Kattappana respectively. Molecular detection of the viruses was carried out using reverse transcriptase - polymerase chain reaction (RT-PCR) with specific primers for CdMV and BBrMV; and obtained amplicons of expected size of 879-905 bp for CdMV- and 625-633 bp for BBrMV- infected samples. The sequences of the isolates of CdMV from Kattappana, Pampadumpara and Nedumkandam were subjected to BLAST analysis and found to be similar to Indian cardamom mosaic virus isolates from Thalathamane and Appangala with > 96 per cent similarity. The BBrMV in cardamom from Kattappana, Pampadumpara and Nedumkandam was similar to Banana bract mosaic virus (BBrMV) CdM isolate of Karnataka (91.01%), Coimbatore (90.29%) and Thrissur (95.76%) respectively. Phylogeny tree constructed in MEGA 6.0 software differentiated CdMV and BBrMV into four clades, in which CdMV Kattappana and Nedumkandam isolates were clustered together whereas CdMV Pampadumpara isolate was in separate clade. Similarly, BBrMV isolates of Pampadumpara and Nedumkandam clustered together while BBrMV Kattappana was in separate clade. Meristem of 2 mm size separated from infected plants were grown in Murashige and Skoog medium supplemented with 3 mg benzyl amino purine (BAP), 1.5 mg indole acetic acid (IAA) and 0.8 mg kinetin expressed direct organogenesis but multiple shoots were not produced. The TC plants were subjected to DAC-ELISA with the specific polyclonal antibodies and PCR with specific primers of the viruses and confirmed that the plants produced from meristems were free of both the viruses. Thus, the present study revealed that two viral diseases viz., katte and chlorotic streak affecting small cardamom in Idukki. Serologically and molecularly it was detected that katte disease was caused by Cardamom mosaic virus (CdMV) and chlorotic streak disease was caused by Banana bract mosaic virus (BBrMV), and the viruses could be eliminated from the infected plants through meristem tip culture to produce the diseases free plants.Item Propagation studies in nutmeg(Department of Horticulture (Pomology & Floriculture and Landscaping), College of Horticulture, Vellanikkara, 1979) Lila Mathew, K; Damodaran, V KThe studies on the propagation of nutmeg (MYRISTICA fragrans Houtt) were carried out at the Instructional Farm of the College of Horticulture, and at the District Agricultural Farm, Mannuthy during the period from April 1978 to July 1979. The studies consisted of two methods - namely, the seed propagation and vegetative propagation. The seed propagation studies included viability studies and the effect of growth regulators on germination and the subsequent growth of the seedlings. Under vegetative propagation, the main objective was to standardise an economical and effective method of vegetative propagation of nutmeg. The studies revealed that maximum per cent and quicker germination was obtained by sowing the seeds during the month of June and there was significant difference between the heavy and light group of seeds. Seeds stored in moist sand remained viable for a longer period than those stored in metalic containers. Gibberllic acid treatment had significant effect on the germination of seeds and the subsequent growth of the seedlings. Seeds treated with 200 ppm GA for 24 hours gave good results as compared to other treatments. Among the different methods of vegetative propagation tried, inarch grafting gave the highest per cent of sucess - about 95 per cent during the month of June. The growth of the grafts was poor when compared to the seedlings of same age during the initial stages, but the growth was progressive and satisfactory after two months (of seperation). Other methods of vegetative propagation viz., side-grafting, veneer grafting and wedge grafting were also successful up to 40 per cent, but the growth of the grafts was less than that of the seedlings. However, these methods need standardisation for use on a large scale programme of propagation of nutmeg.Item Response of immature inflorescence for in vitro regeneration on coconut (cocos nucifera L)(Centre for Plant Biotechnology and Molecular Biology, College of Horticulture, Vellanikkara, 2006) Siny, C V; Nazeem, P AInvestigations on 'Response of immature inflorescence for in vitro regeneration in coconut (Cocos nucifera L.)' were carried out at the Centre for Plant Biotechnology and Molecular Biology, College of Horticulture, Vellanikkara during 2005 to 2006. Y3 medium was found to be the best basal medium for in vitro culture of immature inflorescence of coconut. Inflorescence of length 40 to 50 cm was found to posses male flowers at pollen mother cell stage of microsporogenesis. Wiping the spathe with 70 per cent ethyl alcohol before excising the immature inflorescence parts could effectively control contamination with 100 per cent culture establishment. The young inflorescence parts could survive up to 12 minutes treatment with 0.1 per cent HgCl2. Among the different explants tried, anthers at premeiotic stage and immature rachillae were found to be the best for callus induction and embryo formation. When the explants were inoculated the exudation of polyphenols from the explants adversely affected their survival. Polyphenol exudation was checked by incorporating PVP 0.1 per cent and activated charcoal 0.2 per cent in the medium and by incubation under dark condition. 2,4-D at 15 to 30 mgl-1 was found to be the most effective auxin for callus induction and proliferation. Y3 basal medium with growth regulator combinations of 15 mg l-1 2,4-D, 0.5 mg l-1 picloram, 1mg l-1 NAA and 0.1 mg l-1 TDZ was identified as the best medium for callus induction and embryogenesis of immature anther. Sucrose at 5 per cent concentration was identified as the optimum concentration for callus induction. Pretreatment of inflorescence at 4°C for 24 hrs or 30 hrs doubled the callus induction and reduced the browning of explant. Callus induction was observed from rachillae tissue in Y3 medium containing15 mg l-1 2,4-D, 1 mg l-1 picloram, 1 mg l-1 IAA and 0.1 mg l-1 TDZ.Item Micropropagation of gerbera (Gerbera jamesonii Bolus) and assessment of genetic stability of plantlets using ISSR assay(Centre for plant biotechnology and molecular biology, College of horticulture, Vellanikkara, 2014) Awchar Datta Manikrao; Shylaja, M R