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ThesisItem Open Access Refinement of softwood grafting technique in Sapota (Manilkara zapota L.)(Department of Fruit Science, College of Agriculture, Padanakkad, 2022-07-22) Archana, P V; Meera Manjusha, A V; KAUSapota (Manilkara zapota L.) family sapotaceae is one of the fruit trees which is adapted to humid tropical climate and diversified soil conditions. Softwood grafting in sapota has become common among farmers and horticulture nursery sector because it is an easy, as well as cheap method and helps in rapid multiplication of plants with considerable success rate. Generally, Khirni (Manilkara hexandra L.) is used as rootstock for grafting in sapota. The investigation entitled “Refinement of softwood grafting technique in sapota (Manilkara zapota L.)” was carried out at department of Horticulture, College of Agriculture, Padannakkad, Kasaragod, during 2020-2021.The study was conducted in completely randomized block design with factorial concept. The first experiment was done with the objective to find out the best practice for enhancing success percent in softwood grafting of sapota varieties under different environmental conditions with different precuring treatments having 27 treatment combinations replicated twice. The factors of first experiment were environmental conditions (open-C1, polyhouse-C₂ and polytunnel followed by shade net-C3) with cultivars (Cricket Ball-V1, Pala-V₂ and Oval-V₃) and scion precuring treatments (defoliation 10 days prior to grafting-S₁, defoliation followed by grafting on the same day-S₂ and grafting without defoliation-S₃). Interaction effect of environmental conditions, cultivars and scion precuring up to final stage of growth indicated that C3V1S3 (Polytunnel+ Cricket Ball+ Without defoliation) had maximum value with respect to growth parameters viz. girth of stem except 30 DAG(3.05),leaf area (35.42), length of leaf except 30 DAG (11.22), breadth of leaf except 60 DAG (4.32), number of leaves except 30 DAG, length of scion except 30 DAG and height of graft (34.75), fresh weight (32.06) and dry weight (15.04). C1V3S2 (Open+ Oval+ Same day defoliation) recorded lowest value with respect to growth parameters viz. length of scion (16.83 cm), girth of stem (2.32 cm), number of successful grafts (3.00), success percentage (20.00 %), survival percentage (20.00 % ), leaf area (16.45cm2 ), length of leaf (7.25 cm), breadth of leaf (3.11 cm), number of leaves (except 120 DAG) and height of graft(31.13 cm). The second experiment was undertaken to study the effect of cytokinin on success of sapota grafting. Factors are different concentration of cytokinin (P₁-100 ppm, P₂-150 ppm, P₃-200 ppm and P₄-control) and different days of application (D₁-0 thday, D₂-5 thday and D₃-10thday prior to grafting). Among the individual effect of cytokinin concentration, P3- cytokinin at 200ppm was found to be highest in terms of number of successful grafts, success percentage (82.22%), survival percentage (77%), length of leaf(12.06cm ), leaf area, breadth of leaf, girth of stem at 30,90 and 120 DAG, length of scion (120,150 and 180 DAG) and number of leaves (except 60 DAG). Considering individual effect of days of cytokinin application, D1 had the maximum value on observations like length of leaf (11.80cm), number of leaf (22.62), dry weight (11.26g), fresh weight (27.05g), height of graft, leaf area and girth of stem (3.06 cm), length of scion and breadth of leaf. Considering the interaction effect between concentration of cytokinin and days of cytokinin application, P3D1 (cytokinin at 200 ppm+ 0th day prior to grafting) proved to be the best treatment combination in terms of observations like length of scion, number of leaf (24.30), height of graft, leaf area (41.27 cm2 ), breadth of leaf (30 and 150DAG), length of leaf (90 to 150 DAG) and girth of stem (90,120,180 DAG). P4D3 (control treatment+10th day prior to grafting) was found to be lowest in terms of observations like number of leaf (18.80), leaf area (21.27 cm2 ) and length of scion (13.40 cm). The results obtained from present study revealed that grafting of sapota cv. Cricket ball without defoliation of scion and kept under polytunnel condition (T21-C₃V₁S₃) as the best treatment which recorded highest graft success and survival percentage. Grafts under C3-polytunnel found to be better in growth parameters compared to open and polyhouse conditions. Among scion precuring treatments, defoliation 10 days prior to grafting-S₁ provided highest percentage of graft success. Hence, modified grafting technique can be recommended as an ideal approach for sapota propagation during off season also. Application of cytokinin at 200ppm concentration on the same day of grafting (T₇-P₃D₁) enhanced graft growth. Regarding concentration of cytokinin, at 200ppm showed higher value which was on par with P1 and P2 in terms of success and survival percentage. So, cytokinin application at 100ppm (lower dose) for graft success can be recommend as economically beneficial.ThesisItem Open Access Management of calcium, magnesium and boron deficiency for enhancing yield and quality in chilli (Capsicum annuum L.)(Department of Soil Science and Agricultural Chemistry, College of Agriculture ,Padanakkad, 2022-04-28) Anjitha K.; KAU; Sailaja kumari M SThe investigation entitled ‘Management of calcium, magnesium and boron deficiency for enhancing yield and quality in chilli’ was carried out at Instructional farm, Nileshwar, College of Agriculture Padannakkad, with an objective to develop nutrient management practices for mitigating calcium, magnesium and boron deficiency and to evaluate its effect on growth, yield and quality parameters. The field experiment was carried out during December 2020 to May 2021. The experiment was carried out with chilli variety Anugraha, in randomized block design with ten treatments and three replications. Treatment combinations were T1(KAU POP + lime (based on soil test)), T2 (T1 + 125 kg gypsum per hectare), T3 (T1 + 80 kg magnesium sulphate per hectare), T4 (T1 + 125 kg gypsum per hectare + 80 kg magnesium sulphate per hectare), T5 (T1 + foliar application of borax (0.2%)), T6 (T2 + foliar application of borax (0.2%)), T7 (T3 + foliar application of borax (0.2%)), T8 (T4 + foliar application of borax (0.2%)), T9 (KAU POP + dolomite (based on soil test)) and T10 (T9 + foliar application of borax (0.2%)). Soil application of amendments were done as a single dose and foliar nutrition was given four times in a 20 days interval. Analysis of experimental results showed that various treatments showed significant effect on growth characters, fruit quality parameters as well as nutrient content in both soil and plant, over KAU POP recommendation. Significant positive effect of treatments on plant root characters and total dry matter production was observed whereas plant height and days to 50% flowering were found to be non significant. Among the treatments, maximum tap root length (13.50 cm), root volume (23.23 cm3 ), root shoot ratio (0.16) and total dry matter production (2694.65 kg ha-1 ) were recorded in T8 (KAU POP + lime application based on soil test) +125 kg gypsum per hectare + 80 kg magnesium sulphate per hectare + foliar application of borax (0.2%). Various treatments showed significant influence on yield and yield attributes. Maximum fruit weight (37.16 g) and total fruit yield (4456.79 kg ha-1 ) was also observed in T8 and in case of fruit yield, it was significantly superior to all other treatments. Combined application of gypsum, magnesium sulphate and borax were effective and maximized fruit yield. 94 Soil analysis was carried out at flowering and harvest wherein, the treatments showed significant effect on soil pH, EC, available potassium, calcium, magnesium, sulphur, iron, manganese and zinc content whereas available nitrogen, phosphorus, copper and boron were not influenced by treatments. Addition of calcium and magnesium sources significantly increased available calcium and magnesium content in soil. Among the various treatments, the highest available calcium was recorded in T8 and was on par with T2, T6 and T4 at flowering. Highest available magnesium content was recorded in T9 and T10 at flowering and harvest respectively. Analysis of Index leaves at flowering and total plant analysis at harvest were carried out and it was found that plant nutrient content was significantly influenced by treatments. Significant effect of various treatments on plant nutrients except nitrogen and phosphorus was observed. Foliar application of borax significantly improved boron content in plants. Fruit quality parameters such as capsaicin, oleoresin, ascorbic acid and shelf life and total nutrient content were analysed and results showed significant positive response to treatments. Analysis of nutrient content in fruits showed that primary nutrients mainly, nitrogen and potassium, secondary nutrients and micronutrients in fruits were significantly influenced by various treatments. The treatment, T8 (KAU POP + lime based on soil test) +125 kg gypsum per hectare + 80 kg magnesium sulphate per hectare + foliar application of borax (0.2%)) recorded highest capsaicin (0.352 %), oleoresin (11.00 %), ascorbic acid (96.83 mg 100 g-1 ) and maximum shelf life (13.66 days) in chilli. The results obtained from the experiment revealed the significant influence of soil amendments over KAU POP recommendation and it can be concluded that combined application of gypsum, magnesium sulphate and borax was effective for increasing fruit yield and quality in chilliThesisItem Open Access Controlling seedling height of cowpea (Vigna unguiculata (L.) Walp.) transplants using plant growth regulators(Department of Vegetable Science, College of Agriculture, Vellanikkara, 2022-04-28) Anu Latha Robi; KAU; C NarayanankuttyCowpea (Vigna unguiculata (L.) Walp) is an annual leguminous vegetable crop. It is grown throughout india for its tender green pods used as vegetable. Green cowpea seeds are boiled as a fresh vegetable or may be canned or frozen. The beans are nutritious and provide complementary proteins to cereals diets. Seedlings like cowpea, cucurbits having lanky growth growing in polyhouses is an undesirable quality, especially in plugs intended for mechanized planting and long distance transport. Seed treatment with growth retardants is an effective method for controlling seedling height .However limited studies have been conducted in vegetable crops The present study was undertaken with the objectives of controlling seedling height of vegetable cowpea and to assess the field performance of treated seedlings. The experiment was conducted at the Centre for Hi-Tech Horticulture and Precision farming, Vellanikkara KAU, Thrissur during the year 2020-2021 In seedling stage, highest germination was recorded in control treatment on 5th and 10th days after sowing (89%) and (91%) respectively in Vellayani Jyothika. Minimum germination percentage was recorded in Paclobutrazol @ 200 ppm on 5th and 10th day after sowing (64.3%) and (66.0%) respectively in cowpea genotype Vellayani Jyothika. Significantly lower germination percentage was recorded in treatments receiving Paclobutrazol @ 200 ppm on 5th and 10th day after sowing (70.0%) (72%) in the genotype Kashi Kanchan. In both the genotypes there were no significant difference between the treatments on 15th days after sowing. Paclobutrazol treatment took more number of days for emergence of seedling up to the first node compared to control treatment ie Paclobutrazol @ 200 ppm (8.13) and (8.00) respectively in both the genotypes. Highest shoot length was recorded in control treatment on 5th, 10th and 15 th days after germination in both the genotypes. Significantly lower shoot length was recorded in treatments receiving Paclobutrazol @ 200 ppm irrespective of the number of days after germination. Growth retardants in general reduce root growth, shoot weight and root weight of the seedlings. In both the genotypes (Vellayani Jyothika and Kashi Kanchan) significantly lower root length, shoot weight and root weight was obtained in Paclobutrazol treatments compared to non-treated control. Height of seedling up to the first node was directly linked to shoot length. In both the genotypes of the cowpea significantly lower shoot length was recorded in treatments receiving Paclobutrazol @ 200 ppm (4.09) and (4.03) respectively. Paclobutrazol treated seedlings had dark green leaves when compared to other growth regulator and control treatments on 5th ,10th and 15th days after germination. In both the cowpea genotypes, when compared to other growth retardant and control treatments highest stem girth of the seedlings was recorded in treatments receiving Paclobutrazol @ 200 ppm on 5th (3.19 mm) 10th (3.45mm) and 15th (3.7mm) in Vellayani Jyothika and on 5th (3.3mm ) 10th (3.4mm) and 15th (3.8mm) in Kashi Kanchan. There were no significant difference between the treatments on 5th (2) and 15th days (7-8) after germination in both the genotypes. The total chlorophyll content and carotenoid content was recorded highest in treatments receiving Paclobutrazol treatments on seedling stage. Minimum auxin content and gibberellic acid contents were observed in Paclobutrazol treatments. In the field experiment, in both the cowpea genotypes, plant growth regulator Ethrel recorded maximum plant height where as in Vellayani Jyothika minimum plant height was recorded in Cycocel@ 50 ppm (112.40 cm) .In Kashi Kanchan lowest plant height was recorded in Paclobutrazol @ 200 ppm (33.06 cm) in Kashi Kanchan. In vellayani Jyothika highest internodal length was recorded in Ethrel @100 ppm (3.13 cm) and Ethrel @50 ppm (3.04 cm). Minimum was recorded in Paclobutrazol@ 200 ppm (2.63 cm). In the genotype Kashi Kanchan maximum internodal length was recorded in Ethrel@ 200 ppm (3.34 cm) and minimum was recorded in Cycocel @ 100 ppm (2.53cm). Highest number of primary branches was recorded in treatments receiving Paclobutrazol @ 200 ppm which was on par with Paclobutrazol @ 100 ppm compared to control in Vellayani Jyothika. In Kashi Kanchan there were no significant differences found between the treatments. Growth retardants had significant effect on the viz days to first flowering, days to first harvest and crop duration. Early flowering results in early harvesting of pods. Plant growth retardant Cycocel @ 200 ppm (41day) and Cycocel @ 25 ppm (36.80 days) recorded earliest flowering in the field in both the genotypes. In both the genotypes delayed flowering and maximum crop duration was recorded in Paclobutrazol treatments. Pod length and pod girth are related with pod weight. Ethrel treatment had highest pod length and pod girth compared to control .The higher number of flowers, pod girth and pod length contributed to production of more number of pods which in turn resulted in higher yield per plant. In both the cowpea genotypes, highest number of pods per plant and yield per plant was recorded in Ethrel treatments (Ethrel 100 ppm) in Vellayani Jyothika followed by Paclobutrazol treatment (Paclobutrazol 100 ppm) where as in Kashi Kanchan Paclobutrazol 100 ppm was on par with Ethrel 100 ppm. From the above study it could be concluded that, Paclobutrazol 100 ppm seed treatment was effective in controlling seedling height as well to obtain good yield in vegetable cowpea.ThesisItem Open Access Population structure and genetic diversity analysis in traditional rice landraces of Kerala(Department of Plant Biotechnology, College of Agriculture, Vellayani, 2022-08-19) Sowmiya S; Beena, R; KAUThe study entitled "Population structure and genetic diversity analysis in traditional rice landraces of Kerala" was undertaken during 2021-22 at the Department of Plant Biotechnology and Department of Plant Physiology, College of Agriculture, Vellayani. The study was undertaken for the genotyping of fifty rice landraces using SSR markers and population structure analysis. Fifty traditional rice landraces collected from RARS, Pattambi were raised in pots and the genomic DNA from one-month-old leaf samples were isolated by CTAB method. Fifty DNA samples were screened using thirty microsatellite primers and out of which five primers (RM431, RM154, RM85, RM5735, and RM104) did not show any amplification. Also, three SSR markers viz., RM554, RM246, and RM3825 amplified monomorphic banding patterns and hence they were not considered for further analysis. Twenty-two markers which yielded polymorphic bands were thus selected for final analysis. The Polymorphism Information Content (PIC) values for polymorphic markers ranged from 0.13 to 0.49. The primers which showed the highest PIC values were RM10793 (0.49) followed by RM310 (0.49) and RM5749 (0.48). The population structure of the fifty rice landraces performed using a software (STRUCTURE V2.3.4) divided the fifty rice landraces into four sub-populations. Phenotypic data of the same genotypes were collected from the Department of Plant Physiology, College of Agriculture, Vellayani and utilized to correlate the phenotypic data with genotypic data and to identify the tolerant landraces. Cluster analysis based phenotypic data resulted in four major clusters which was found to be similar with that of cluster produced by genotypic data. Phenotypic traits such as photosynthetic rate, transpiration rate, number of panicles per plant, and spikelet fertility per centage were used to identify the landraces that were tolerant to high temperature. According to the phenotypic data, the spikelet fertility of sub-population 1 ranged between 20-30% in high temperature condition, photosynthetic rate ranged between 15-30 µmolCO2m-2 s -1 , transpiration rate ranged between 8-15 mmolH2OCO2m-2 sec-1 , and number of panicles per plant ranged from 11-20, and this sub-population is considered to be moderately heat tolerant. The spikelet fertility of sub-population 2 ranged between 11-25% in high temperature condition, photosynthetic 117 rate ranged between 10-25 µmolCO2m-2 s -1 , transpiration rate ranged between 6-10 mmolH2OCO2m-2 sec-1 , and number of panicles per plant ranged from 7-15, and this sub-population is considered to be heat susceptible. The spikelet fertility of subpopulation 3 ranged between <25% in high temperature condition, photosynthetic rate ranged between 5-10 µmolCO2m-2 s -1 , transpiration rate ranged between 0-5 mmolH2OCO2m-2 sec-1 , and number of panicles per plant ranged from 5-10, and this sub-population is considered to be highly susceptible to heat. The spikelet fertility of sub-population 4 ranged between 11-20% in high temperature condition, photosynthetic rate ranged between 5-10 µmolCO2m-2 s -1 , transpiration rate ranged between 5-8 mmolH2OCO2m-2 sec-1 , and number of panicles per plant ranged from 5-10, and this sub-population is considered to be highly susceptible to heat. The phylogenetic tree was constructed using UPGMA (Un-weighted pair group method with arithmetic mean) using NTSYSpc cluster analysis software, and the dendrogram showed that all fifty rice landraces were divided into four major clusters. The pattern of grouping landraces into the clusters was similar to that obtained in the population structure analysis. Based on the interpretation of all the data obtained, among the fifty rice landraces; LB-2000-28-TCR-6985, Kuruva, Ittikandan, Champan, LN9937-Cherumallaram (Vatharam), Cheruvellari, Kokkan, Kurutha chitteni, Kathikannan, and Vellari were grouped as moderately tolerant to high temperature.ThesisItem Open Access Soil test crop response studies in cluster bean (Cyamopsis tetragonoloba L.) in lateritic soils of Kerala(Department of Soil Science and Agricultural Chemistry, College of Agriculture,Vellanikkara, 2022) Ayisha, V V; KAU; Rajalekshmi, KCluster bean, commonly known as guar, is a legume crop cultivated as a vegetable, green manure and forage crop. India is the leading producer of cluster bean in the world and accounts for around 80 per cent of global production. The generalised application of fertilizers by farmers result in under or over fertilization, lowering production and profitability while also polluting the environment. So the emphasis on soil test based balanced fertilizer recommendation has become more pertinent in the current scenario of high fertilizer costs and yield maximisation programmes. Hence, the investigation entitled “Soil test crop response studies in cluster bean (Cyamopsis tetragonoloba L.) in lateritic soils of Kerala” was undertaken. The study was conducted at College of Agriculture, Vellanikkara in lateritic soils (Ultisol) in the STCR field during 2020-2021 with the objective of developing soil test based fertilizer prescription equation for cluster bean using inorganic fertilizers alone and with the combined use of organic manures. A fertility gradient experiment was conducted to create soil fertility gradient in the field by applying graded doses of N, P and K fertilizers and raising fodder maize var. CO1. After the development of fertility gradient, the main STCR experiment was conducted in the same field with the test crop, cluster bean var. Pusa naubahar. The treatment structure consisted of four levels of nitrogen (0, 10, 20 and 40 kg ha-1 ), four levels of phosphorous (0, 30, 60 and 120 kg ha-1 ) and four levels of potassium (0, 40, 80 and 120 kg ha-1 ) along with three levels of FYM (0, 15 and 25 t ha-1 ). The basic parameters such as nutrient requirement (NR) and contributions of nutrients from soil (CS), fertilizer (CF) and FYM (COM) were computed from the field experimental data. The nutrient requirements (NR) for cluster bean were worked out as 0.68, 0.05 and 0.22 kg N, P2O5 and K2O to produce one quintal yield. The contributions from soil (CS) were estimated as 9.84, 2.29 and 1.99 per cent of N, P2O5 and K2O respectively. The contributions from fertilizer (CF) were calculated as 90.90, 3.29 and 10.82 per cent and that from FYM (COM) were 7.17, 1.92 and 2.96 per cent for N, P2O5 and K2O respectively. From the above basic data, fertilizer prescription equation for specific yield targets of cluster bean in the lateritic soils were derived as follows, NPK alone: FN = 0.74*T - 0.11*SN FP2O5 = 1.47*T – 1.59*SP FK2O = 2.05*T- 0.22*SK NPK + FYM (IPNS) FN = 0.74*T - 0.11*SN – 0.08*ON FP2O5 = 1.47*T – 1.59*SP – 1.34*OP FK2O = 2.05*T - 0.22*SK – 0.33*OK Where, FN, FP2O5 and FK2O = Fertilizer N, P2O5 and K2O in kg ha-1 T = Yield target in q ha-1 SN, SP and SK = STV for available N, P and K in kg ha-1 . ON, OP and OK = Amount of N, P and K supplied through FYM in kg ha-1 . The multiple regression model calibrated with yield as dependent variable and soil test results and inorganic fertilizer doses as independent variables had 62.5 per cent predictability. The yield of cluster bean increased with the application of NPK alone and IPNS viz. NPK plus FYM treatment and the magnitude of increase was higher under IPNS over NPK alone. The study is useful to adjust fertilizer doses based on yield target and available resources of organic manure with the farmers. The equations developed for cluster bean should be tested in places with similar agro climate and soil situations for validation.ThesisItem Open Access Genetic diversity of Dimocarpus longan Lour., in Southern Western Ghats(Department of Forest Biology and Tree Improvement,College of Forestry, Vellanikkara, 2022) Devika, P S; KAU; Manju Elizabeth, PLongan (Dimocarpus longan Lour.), is an important commercially cultivated fruit tree, belonging to the family Sapindaceae. It is commonly known as dragon-eye. In Kerala, it is known by the names chempoovam, mullai etc. It is widely cultivatedin many Asian countries like China, Thailand, and Taiwan etc. Recently many other countries including India, Sri Lanka etc. have started cultivating longan tree as a commercial fruit tree. Longan is used as a traditional medicine in China due to its high medicinal and nutraceutical value. The global demand for longan fruit has hiked rapidly due to its sweet taste and nutritional value. Fruit consist of a white edible juicy aril which is surrounded by a leathery pericarp. The fruit is rich in various bioactive polyphenols, vitamin C, volatile compounds, minerals, amino acids, proteins, fats, carbohydrates etc. Longan leaf, fruit pericarp, seed and pulp were used for extracting various polyphenols. Extracts from various parts of longan have shown pharmaceutical properties like antioxidance, anti-tyrosinase, anti-cancerous, anti-glycated, immunomodulatory activity, antihypertensive etc. Thus the importance of fruit can also be emphasized due to its richness in nutritional value. The longan tree is a subtropical fruit tree native to the southern regions of China and Indo-Burma. D. longan is indigenous to India's Western Ghats, ranging from Konkan to Tinnevelly. Other distributions in India include Eastern Bengal and Western Peninsular regions. In the Western Ghats region of Kerala, longan is a species widely distributed in evergreen forests. There is a small distribution in the semi-evergreen forests of Kerala as well. The diversity of indigenous longan populations in Western Ghats has never been studied before. In this study, morphological and genetic diversity of longan populations from six different locations in the Western Ghats regions of Kerala were selected. Among these six locations, three were located in the north of Palghat gap and three were in the South ii of Palghat gap. Morphological parameters like crown shape, branching pattern, tree height, tree girth, leaf length and leaf width was considered for studying the morphological diversity. Results from morphological traits revealed that the population from Meppadi region from north of Palghat gap stood different from other longan populations. Cluster analysis conducted using UGPMA method based on the morphological traits showed that population from Mankulam was closely related to the Meppadi population. The populations from six locations were divided into two major clusters. ISSR primers were used to investigate the genetic diversity existing among the six populations. 15 ISSR primers screened from total of 19 primers were used to amplify the DNA sample from different longan populations. Average polymorphism rate of 69.51% was observed. Matrix data was obtained and hierarchical dendrogram was produced using UGPMA method in NTsys pc 2.02 and DARwin software which clusters the populations into two major groups. Jaccard’s dissimilarity index was calculated using R software and the values ranged from 0.00 to 0.51. Genetic relation existing between the natural populations of longan in Kerala, cultivated longan cultivars and litchi were identified. Cluster analysis using UGPMA method pooled different populations into four major clusters and study proved that litchi is genetically more related to the cultivated longan variety rather than the wild populations. This is the first report on the molecular characterization of D. longan from Western Ghats regions in India. The results from this research study can provide valuable information to distinguish, classify and identify the origin of longan populations in India and can be applied for future breeding programs.ThesisItem Open Access Etiology of bud proliferation in vegetable cowpea(Department of Plant Pathology, College of Agriculture, Vellayani, 2022) Devika, S; KAU; Radhika, N SThe study entitled „Etiology of bud proliferation in vegetable cowpea‟ was conducted at Department of Plant Pathology, College of Agriculture, Vellayani during 2019-2021 with an objective of studying the symptomatology, immuno-molecular detection and characterization of incitant/(s) of bud proliferation in vegetable cowpea. Bud proliferation disease of cowpea has been observed in different varieties in different locations. Purposive sampling was carried out in different locations of Thiruvananthapuram, Kollam, Alappuzha and Thrissur and collected symptoms were used for further studies. The characteristic symptom of the disease is the abnormal proliferation of bud which showed an increase in number of buds up to 16-35. The proliferated buds also showed pinkish- brown patches in it. Noticeable symptoms were also seen in the leaves of the diseased plant. They were smaller, crinkled and unusually dark in colour. The fasciation of stem has also been observed in the fields of Onattukara and Chavara. The infected plants were stunted and completely sterile. The highest disease incidence was found to be in the variety Bhagyalakshmy cultivated in Mannuthy (6.57 per cent). The population of hoppers was observed in the field and the insects identified were Exitanus sp., Balclutha sp., Nilaparvata lugens, Ptoleria sp., Nisia nervosa. The weeds Phyllanthus, Neer-grampu and Jack bean were found to be showing similar symptoms near the diseased cowpea fields. The graft transmission was successful from cowpea to periwinkle with 40 per cent efficiency. The leaves of the graft inoculated periwinkle plants showed severe interveinal chlorosis and later on yellowing. Graft transmission was unsuccessful from cowpea to cowpea. The transmission studies for viruses from cowpea to cowpea and cowpea to Chenopodium revealed the absence of viruses. The DAPI staining of diseased and healthy plants affirmed the presence of phytoplasma in the diseased samples. Small fluorescent-coloured bodies were seen in the stem and leaf of infected plants compared to healthy. The hormonal analysis of the symptomatic plants compared to the healthy ones showed significant difference. The GA content in diseased leaf and bud was increased by 20.88 and 17.46 per cent respectively. The IAA content in diseased leaf (older) and bud was increased by 61.55 and 46.52 per cent respectively. The serological detection for viruses using monoclonal antibodies of CABMV and BICMV and polyclonal antibodies of TSWV and WSMoV divulged the absence of viruses in the diseased samples. The graft inoculated periwinkle plants also showed no presence of viruses. The molecular detection of phytoplasma with nested PCR was carried out. The first primers P1/P7 amplified a 1.8kb fragment and the second set of primers; R16F2n/R16R2 amplified a 1.2kb fragment, giving positive results. The final amplified product was sequenced and by BLAST analysis it was found that the 16S rDNA sequence shared 99.80 per cent similarity with that of the „Candidatus Phytoplasma asteris‟ reference strain (GenBank accession: M30790). Hence the phytoplasma under study is a „Candidatus Phytoplasma asteris‟-related strain. The virtual RFLP pattern derived from the query 16S rDNA F2nR2 fragment was identical (similarity coefficient 1.00) to the reference pattern of 16Sr group I, subgroup B (GenBank accession: AP006628). The phytoplasma under study was found to be a member of 16SrI-B.ThesisItem Open Access Statistical assessment of banana ripening using smartphone - based images(Department of Agricultural Statistics, College of Agriculture, Vellayani, 2022) Haritha, R Nair; KAU; Pratheesh, P GopinathThe research work entitled “Statistical assessment of banana ripening using smartphone-based images” was carried out at College of Agriculture, Vellayani during the period 2019 to 2021. The objectives were the development of suitable model to establish the relationship between Total Soluble Solids (TSS) and L*(lightness), a*(green-red ratios), b*(blue-yellow ratios) values and for prediction of TSS values using L*, a*, b* values. Development of a protocol for accurate data collection to assess TSS content in Banana using smart-phone-based images. Good quality Nendran variety with only minor shape and peel colour flaws were obtained from a nearest field randomly chosen for the study. Each time 3 hands at the ripening stage 1 (green) with 10 fingers by hand were collected. The fruits were stored in a normal day/ night cycle. Bananas were taken randomly from each hand and their color changes and development of brown spots were measured daily during 10-12 days. Banana samples were placed on the table covered with a non-reflecting white paper as a background of the image. For white light illumination, two of 36 W fluorescent lamps were fixed at ceiling above the experiment setup. Three smartphones were used for image acquisition. Smart phones were placed at a distance of 20 cm above the banana. Samples of banana were blended using a fruit juicer. The TSS were determined using a digital refractometer. For the images obtained, RGB and L*a*b* were extracted using ImageJ software. The observations on TSS, R, G, B, L*, a*, b* were used for fitting regression models after splitting the data into train (80%) and test (20%) sets. When linear model was fitted between TSS and R, G, B values for all the three devices, each of the independent variables were found to be significant. Adjusted Rsquared values obtained were 0.80, 0.80, and 0.84 for the three devices. It means about 80% of the variation in the TSS was explained by R, G, B values. For the predicted values of TSS R-squared values were 0.84, 0.90, and 0.95. Hence linear model was found to be better fit for predicting TSS. Since RGB color model is device dependent model, it may not always represent the same colour on different devices. But in case of CIE L*a*b*, it is device independent and shadows and areas of glossiness on the object surface had less impact. Therefore, linear model was fitted between TSS and L*, a*, b* values. Adjusted R-squared values obtained were 0.78, 0.81, and 0.85 for the three 126 devices. For the predicted TSS values R-squared values were 0.84, 0.76, and 0.95. Therefore, linear model between TSS and RGB model found to predict TSS much accurately than L*a*b* color space when prediction accuracy was compared. On visualization of data, TSS and L*a*b* found to have non-linear relationship for all the devices. When spline regression was fitted between TSS and L*, a*, b* values R-Squared obtained were 0.91, 0.90, and 0.89, which was higher compared to Rsquared values for linear model. Also, deviance explained by the models were 92%, 92.3%, and 90.7% for corresponding device 1,2 and 3. Therefore, spline regression found to be better model for TSS and L*, a*, b* data and for prediction of TSS values. Protocol for accurate data collection was developed with modification in the procedure performed. Possibility of Deep learning was explored in the study using CNN. Convolutional neural network (CNN) was developed using 3 categories Raw (TSS 4-10), Medium (TSS 11-17) and Ripe (TSS 18-32) with 30 samples each. 25 images from each category were taken as training set and 5 were taken as test set. 100 epochs were performed to mitigate overfitting and to increase the generalization capacity of the neural network. Model evaluation of training set gave an accuracy of 84% with loss value 0.45. For the training set, all 25 from ripe category were able to identify into that particular category. In case of raw 24 were identified as raw with 1 identified as medium. For medium 14 were identified as medium,3 identified as ripe and 8 identified as raw. Model evaluation of test set provided 73% accuracy with 0.81 loss. The model successfully classified 5 ripe bananas, 4 raw bananas (1 classified as medium) and 2 medium bananas (3 classified as raw). The results of the research work to identify the best fitting model concluded that RGB model found to predict TSS much accurately than L*a*b* color space when linear regression model was fitted and spline regression model was found to be the best fit for L*, a*, b* and TSS values, R-squared values were much higher with a good percentage of variation explained. The CNN developed classified images into raw, medium, and ripe with approximate accuracy of 74%. Therefore, CNN can be used to predict range of TSS in no time, if a large number of images are uploaded into this model. The CNN can be optimized further with higher number (atleast 10,000 samples) of samples to improve the efficiency of classification.ThesisItem Embargo Prevalence of sesamum phyllody in Onattukara tract and evaluation of fungal root endophyte Piriformospora indica for its management(Department of Plant Pathology, College of Agriculture, Vellayani, 2022) Gifty, K J; KAU; KAU; Radhika N SThe research work entitled ‘Prevalence of sesamum phyllody in Onattukara tract and evaluation of fungal root endophyte Piriformospora indica for its management’ was conducted during 2019-21 at Department of Plant Pathology, College of Agriculture, Vellayani and Onattukara Regional Agricultural Research Station with the objectives to study the symptomatology, molecular detection and characterization of phytoplasma inciting sesamum phyllody disease in AEU 3 (Onattukara tract); and evaluation of fungal root endophyte P. indica for its management. Phytoplasma infected sesamum samples were collected from D and F blocks of Onattukara Regional Agricultural Research Station and Karthikapally. Karthikapally recorded highest disease incidence (39.44 per cent) and vulnerability index (23.75). Chocolate weed, Melochia corchorifolia, was found to be exhibiting symptoms of shoot proliferation. Hoppers collected from the infected fields were identified as Orosius albicintus, Hishimonas phycitis and Nephotettix sp. Disease symptoms were observed at the stage of flowering of sesamum plants in all the sampled locations. The associated symptoms were reduction in internodal length of stem, axillary bud proliferation, thickening of the floral veins, phyllody and floral proliferation. Microtome sections of infected and healthy leaf, stem of sesamum stained with 4,6-diamidino-2-phenylindole (DAPI) stain, and observed under fluorescence microscope emitted diffuse fluorescence from the infected tissues, which was brighter than the one from the parenchymal cells indicating the presence of phytoplasma in the infected tissues. Studies on variations in the level of gibberellic acid (GA) and indole-3-acetic acid (IAA) in phyllody infected and healthy sesamum was undertaken. GA content was increased by 2.25 times and 10.46 times, and IAA content was decreased by 1.25 times and 1.97 times in leaves and flowers of infected samples compared to the healthy samples. Molecular characterization of sesamum phyllody was performed with leaf samples collected from ORARS lowland, ORARS upland, Vellayani and Karthikapally. Amplicons of 1.4kb was obtained by amplifying with universal primers P1/P6 for detection of phytoplasma. The sequences obtained were subjected to BLAST analysis and the 16S rDNA gene sequence showed that all the isolates shared more than 99 per cent similarity with that of the ‘Candidatus phytoplasma aurantifolia’ strains in GenBank data base. In the phylogenetic tree constructed, the sesamum phyllody phytoplasma under study clustered with the 16SrII group (Candidatus Phytoplasma aurantifolia) phytoplasmas causing sesamum phyllody in various regions. The virtual RFLP pattern generated by iPhyClassifier, derived from 16S rDNA fragment was found to be identical to the reference pattern of 16Sr group II, subgroup D (GenBank accession: Y10097). Based on the results obtained from sequence analysis and virtual RFLP pattern, the phytoplasma associated with sesamum phyllody was identified as ‘'Candidatus Phytoplasma aurantifolia”-related strain belonging to subgroup 16SrII-D. P. indica obtained from Department of Plant Pathology, College of Agriculture, Vellayani was mass multiplied in sterilized coir pith: FYM mixture (1:1) amended with 2 per cent gram flour and sesamum seeds were sown. Colonization was observed seven days after germination. Wedge grafting was standardized in sesamum at 30 days after germination. Pot culture experiment was conducted to evaluate the effect of P. indica against phytoplasma causing sesamum phyllody, by grafting the colonized and non-colonized plants with infected scion. P. indica colonization could significantly reduce the incidence and severity of infection. After 30 and 45 days of grafting, an incidence of 20 and 60 per cent, and severity of 5 and 50 were recorded in the colonized plants grafted with infected scion, whereas an incidence of 60 and 80 per cent and severity of 45 and 75 were recorded in non-colonized plants grafted with infected scion. In colonized plants, enhanced shoot and root length at 30 and 55 days after germination were recorded and also earliness in flowering compared to noncolonized plants. Hence the associated symptoms of phytoplasma infection in sesamum are virescence, thickening of floral veins, phyllody and floral proliferation. The study revealed the association of Candidatus phytoplasma aurantifolia group with sesamum phyllody prevalent in Onattukara tract. The evaluation of beneficial fungal root endophyte P. indica against phytoplasma revealed delayed expression of symptoms in the colonized plants.
