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ThesisItem Open Access Spatial mapping of flood prone areas and risk assessment of Chalakudy river basin using HEC-HMS and HEC-RAS models(Department of Irrigation and Drainage Engineering, Kelappaji college of Agricultural Engineering and Technology,Tavanur, 2021-10-17) Gudidha Gopi.; Rema, K P.Floods are one among the most devastating natural disasters that affects life on the globe. For the planning and design of water resources projects in the preferred area, planners and engineers usually require reliable estimates of flood magnitude and frequency. Kerala state in the Indian sub continent received a catastrophic flood in the year 2018. The present study attempts to model the flood flows and map the flood prone areas of a river basin in Kerala. The Chalakudy river basin, one of the worst-affected river basins due to heavy rains and floods was selected for the present study. This is the fifth largest river in Kerala. The basin is predominant with agricultural land and falls under the humid tropical zone, where water resources planning and management is necessary for irrigation scheduling, flood control and design of various engineering structures. In order to address the above issues, an attempt was made to calibrate and validate HEC-HMS model for simulating the flood hydrograph for the Chalakudy river basin. Flood frequency analysis was carried out to estimate the flood peak values using frequency distributions in HEC-SSP software. The results were compared with the estimated flood peak values for different return periods obtained from the HEC-HMS model. Hydraulic routing was done in HEC-RAS model and the flood inundation maps were prepared. The cadastral level risk areas were identified based on water surface profiles of velocity and depth of flood extent and its characteristics. Food vulnerability maps based on land use patterns were developed in order to identify the severely affected land uses. The HEC-HMS model for the basin was developed using SCS-UH, SCSCN, Recession and Muskingum methods to find out the loss rate, runoff transformation and routing of flood respectively. Statistical performance indices of the model, Nash-Sutcliffe efficiency (NSE) and Coefficient of correlation (R²) values were obtained above 0.7, Error in Peak Flow (%) and Error in Volume (%) were figured below 20% and Root Mean Square Error-Standard Deviation Ratio (RSR) was acquired as 0.5 and below. These values indicated that HEC-HMS model simulation performed well in both calibration and validation. The frequency discharge values calculated using Log Pearson type-III distribution indicated a high degree of similarity to the HEC-HMS generated values with an R 2 value of 0.862. The results of the Log Normal and Gumbel distributions are significantly lower than those of the HEC-HMS model values. The assessment of the vulnerability due to the flooding was made with regard to the land use pattern and cadastral level risk map of Chalakudy river basin was developed for different return periods. Kadukutty Panchayat located in the downstream of Chalakudy river basin was found to be the maximum flood inundated area for 10 year return period ( 557 ha) and for 200 year return period (681 ha). Manjapra Panchayat located in upstream was found to be the least flood inundated area for 10 year return period (6 ha) and for 200 year return period (9 ha). Annamanada, Kadukutty, Melur and Pariyaram panchayats were under high risk areas, with depths greater than 20 m. Ayyampuzha, Chalakudy, Mala, Kuzhur, Parakkadavu and Puthenvelikara panchayats were under medium risk areas with depths varying from 10 to 20 m. Athirappilly, Manjapra and Karukutty panchayats were under low risk areas with depths less than 10 m. The flood vulnerability maps were generated by intersecting the flood plain land use map with the flooded area polygons. Paddy land near to the river banks was found to be the highest inundated by different return period floods, followed by forest and other vegetation, barren land and other land use classesThesisItem Open Access Response of banana Musa (AAB) 'Nendran' to nutrient sources(Department of Fruit Science, College of Agriculture ,Vellanikkara, 2021) Manohar Lal Meghwal.; Jyothi, M L; KAUanana is the leading tropical fruit in the world market today with a highly organized and developed industry. Banana having a root system spread in the top 60 cm soil, is heavy feeder of nutrients and requires large quantities of nutrients for its growth, development and yield. Nutrient removal from soil by crops must be replenished. Under good management conditions and adequate supply of biofertilizers and organic manures, the nutrient removal can be replenished and soil physical, chemical and biological properties can be improved. Organic and inorganic sources of nutrients have significant influence on fruit quality and soil characteristics. The current agricultural policy emphasize a shift towards safe agricultural practices for which organic management is the best option. However the crop behaviour under organic and inorganic management needs elaborate studies. Hence the research entitled ‘Response of banana Musa (AAB) 'Nendran' to nutrient sources was formulated to elucidate response of banana in terms of growth, yield and quality to nutrient sources and to compare the fruit quality of banana grown under organic and conventional systems in farmer’s field. The study revealed that vegetative growth of Musa Nendran banana was not influenced by different sources of nutrients in early stage in both the years but later differences were recorded between the treatments. Plant height, number of leaves and pseudostem girth showed significant differences from 90 DAP. At bunching stage plant height and pseudostem girth were higher in organic treatments. There was significant difference in pseudostem girth between the treatments throughout the growth stage of Nendran banana. Among the treatments, T8 resulted in better growth of plants. Leaf characters like number of leaves and leaf area index were not influenced significantly between organic and integrated nutrient management. Early leaf production was also noticed in treatment T8 as indicated by the observations on phyllocron. Growth was delayed in control where no manures and fertilizers. In general more number of leaves per plant and lesser duration for leaf emergence was recorded in both the years in organic treatments. Chlorophyll production in the index leaf of banana was influenced with organic and inorganic nutrition. Chlorophyll a, b and total chlorophyll in the index leaf were distinctly higher in treatment T8 (fertigation with FYM) which was on par with treatments T3 and T5 where organic manures alone were applied. Early flowering and early harvesting were observed in organic treatments. Higher total biomass production was recorded in organic treatments. Yield and yield attributing characters like bunch weight, number of finger, finger weight were highest in treatments with organic sources of nutrients. The mean bunch weight was influenced significantly by organic and inorganic sources of nutrients. Fertigation with organic sources of nutrients resulted in the production of heavier bunches in both years. Maximum bunch weight was recorded from treatment T8 which was on par with other organic treatments as well as integrated management with fertilisers applied as fertigation as well as based on soil test results. No significant variation was observed between treatments on number of hands per bunch and finger characters like finger length and girth. Peel thickness of fruits were not significantly influenced but the pulp to peel ratio was significantly influenced by the treatments. Pulp to peel ratio was higher in all treatments other than T1 and control where T1 is the POP recommendation for TC banana under integrated nutrient management. Yield per plant was positively correlated with available N, P, K, Calcium, magnesium, sulphur, Zn, Cu, B, content of the soil. Yield was also positively correlated with soil properties like pH, organic carbon content, CEC, Bulk density, and Dehydrogenase enzyme activity. Higher biomass production was recorded in plants that received nutrients from organic sources compared to integrated nutrient management and control. Shelf life of fruits were improved in organic treatments. Fruit quality parameters like TSS, Total sugars, ascorbic acid and β carotene of ripe banana fruits were improved in organic treatments compare to inorganic system. Sensory score of ripe fruits and fruit chips were maximum in organic treatments. The taste of ripe banana fruits was improved in plants grown under organic treatments. Fertigation with organic manures (T8) resulted in improved fruit quality of Nendran banana in both the years. Different soil physical and chemical properties also improved when nutrients were supplied through organic sources. Soil pH, electrical conductivity, organic carbon content, cation exchange capacity, available, N, P, K, Mg, Iron, Copper, Zinc, Mn and boron were better in soils receiving organic manures alone. Similarly the soil biological properties like dehydrogenase activity, nitrogenase activity, microbial biomass carbon, and viable counts of total fungi, bacteria and actinomycetes were better in organic treatments. Bulk density of soil was low in soils receiving organic manures alone compared to integrated nutrients. Total uptake of nutrients in organic and integrated nutrient management system was compared. Uptake of N, Ca, S, Fe, Mn, Zn and Cu was higher in organic system of cultivation of banana compared to integrated system. Higher benefit cost ratio was recorded banana grown in organic system. The study revealed that organic sources of nutrients improved soil properties and thereby improved growth, yield and quality of banana.ThesisItem Open Access Productivity enhancement of blackgram (Vigna mungo (L.) Hepper) intercropped in coconut gardens(Department of Agronomy, College of Agriculture,Vellayani, 2021) Pooja, A P; Ameena, MThe research work entitled ‘Productivity enhancement of blackgram (Vigna mungo (L.) Hepper) intercropped in coconut gardens’ was undertaken at College of Agriculture, Vellayani during 2018-2021. The study aimed to identify shade tolerant blackgram varieties suitable for coconut gardens, to study the effect of foliar nutrition and plant growth regulators on growth and yield of the shade tolerant blackgram varieties intercropped in coconut garden and to work out the economics of cultivation. The investigation was carried out as two experiments: (i) screening of blackgram varieties for shade tolerance, and (ii) performance evaluation of shade tolerant varieties under foliar application of nutrients and growth regulators in rainfed coconut garden. The first experiment was conducted during Rabi 2019-20 in coconut garden having a light intensity equivalent to 50 per cent of that under open condition (56.25 klux), planted at a spacing of 7.6 m x 7.6 m. Seeds of 12 promising blackgram varieties collected from different research stations of south India (Sumanjana, DU 1, DBGV 5, VBN 5, VBN 6, VBN 8, Rashmi, CO 6, TAU 1, TAU 2, Blackgold and AKU 15) and three cultures (Culture 4.5.8, Culture 4.5.18 and Culture 4.6.1), were raised in micro plots laid out in randomized block design with three replications. The crop was raised as per KAU package of practices. The results of the study revealed significant variation in growth characters among the varieties screened for shade tolerance under partial shade in coconut garden. Plants of DBGV 5 were significantly taller (96.89 cm) with higher initial number of leaves at all the stages and was on par with Sumanjana and CO 6. Higher leaf area index (LAI) and leaf area duration were recorded in CO 6 (5.77, 65.66 days) and DBGV 5 (5.36, 58.40 days) followed by Sumanjana. Early flowering was observed in Sumanjana (34.33 days) and DBGV 5 (36.33 days). The variety DBGV 5 had the highest photosynthetic rate and resulted in significantly more pods per plant (23.67) which was on par with CO 6, VBN 5, VBN 6, Sumanjana and Rashmi. DBGV 5 produced the highest seed yield per plant (5.44 g) followed by VBN 5 and Sumanjana. Haulm yield per plant was higher for DBGV 5 (19 g) and was on par with VBN 5, Sumanjana and CO 6. The variety DBGV 5 produced the highest seed yield (1183 kg ha-1 ) followed by VBN 5, Sumanjana and CO 6. A higher harvest index of 0.24 was recorded by Sumanjana which was on par with DBGV 5 and VBN 6. Among the varieties screened, five varieties which performed better in terms of yield per unit area under the partial shade in coconut garden viz., DBGV 5, VBN 5, Sumanjana, CO 6 and VBN 6 were selected for experiment II undertaken in summer 2020 followed by the confirmatory trial during Rabi 2020 -21. The experiment was laid out in split plot design with five varieties (v1 - Sumanjana, v2 - DBGV 5,v3 - VBN 5,v4 - VBN 6,v5 - CO 6) as main plot treatments and six foliar sprays of nutrients and plant growth regulators as subplot treatments (f1: 19:19:19 (1%) at 45 and 60 DAS, f2: SOP (0.5%) at 45 and 60 DAS, f3: NAA 40 mg L-1 and salicylic acid 100 mg L-1 at pre-flowering (30-45 DAS) and 15 days later, f4: f3 + f1, f5: f3 + f2 and f6: Control - KAU POP). Among the varieties, Sumanjana (v1) grew taller during both the seasons and was comparable with CO 6 and DBGV 5 at harvest. Sumanjana produced higher number of branches with more number of leaves during both the seasons. At flowering, higher LAI, number and dry weight of nodules per plant were realized by Sumanjana and was on par with CO 6 (v5) in summer and DBGV 5 (v2) in Rabi. Sumanjana exhibited the highest crop growth rate (CGR) and relative growth rate (RGR) during both the seasons at 45-60 DAS. However, DBGV 5 recorded the highest net assimilation rate (NAR) between 30-45 DAS and 45-60 DAS during both the seasons. The highest chlorophyll content was recorded by DBGV 5 (1.96 mg g-1 fresh tissue) during summer and by Sumanjana (2.36 mg g-1 fresh tissue) during Rabi. The highest stomatal conductance (30.22 m moles m-2 s -1 and 28.34 m moles m-2 s -1 ) and lower stomatal index (15.16% and 13.34%) were recorded in Sumanjana during both the seasons. The variety Sumanjana flowered earlier compared to other varieties during both the seasons and produced the highest number of pods per plant (27.30 and 26.54). Hundred seed weight was significantly higher for DBGV 5 (5.01 g and 4.92 g) and remained at par with Sumanjana (4.99 g and 4.88 g) during both the seasons. Seed yield, haulm yield and total dry matter production (TDMP) were higher for Sumanjana and comparable with DBGV 5 during both the seasons. Sumanjana recorded higher NPK uptake during both the seasons followed by DBGV 5. The subplot factor foliar spray had significant effect on growth, physiological and yield attributes of blackgram varieties. Foliar spray of 19:19:19 (1%) at 45 and 60 DAS + foliar spray of NAA 40 mg L-1 and SA 100 mg L-1 at pre-flowering and 15 days later (f4) resulted in significantly taller plants, more number of branches and leaves. The highest CGR, RGR (at 45-60 DAS), LAI, number and dry weight of nodules per plant at flowering were recorded in f4 during both the seasons. During summer, f3, f4 and f5 recorded higher NAR between 45-60 DAS. Higher chlorophyll content and stomatal conductance were recorded by f4 during both the seasons. Plants supplied with f3 attained 50 per cent flowering earlier and was on par with f5 during both the seasons. Highest number of pods per plant, 100 seed weight, seed yield, haulm yield and TDMP were recorded by f4 during both seasons. The grain protein content was improved by f4 and was on par with f3, f1 and f5. The NPK uptake was higher in f4 and was on par with f3 and f5 during summer. Significantly higher organic carbon, available N and P was recorded in f4. Among the treatment combinations, Sumanjana (v1) with f4 produced taller plants at two months after sowing (MAS), higher number of branches and leaves per plant during summer and Rabi. Leaf area index, number of nodules and dry weight of nodules at flowering were higher for v1f4 followed by v2f4. Sumanjana in combination with f4 measured significantly higher CGR and RGR (at active growth stages), highest chlorophyll content, stomatal conductance and lower stomatal index during both the seasons. The variety Sumanjana with f4 produced superior number of pods per plant (30.24 and 29.40) and hundred seed weight during summer and Rabi. A higher seed yield was realized in v1f4 (1750 kg ha-1 ) which was on par with v2f4 (1713 kg ha-1 ) during summer. Seed yield was the highest (1700 kg ha-1 ) in v1f4 during Rabi. Haulm yield and TDMP recorded were higher for v1f4 and was on par with v2f4 during both the seasons. The available N status in soil was higher during both the seasons in v1f4 with the highest NPK uptake during Rabi. Sumanjana and DBGV 5 with f4 realized higher mean net income (₹ 70411 ha-1 and ₹ 61256 ha-1 ) and mean B: C ratio (2.04 and 1.95). The present study identified DBGV 5 and Sumanjana as shade tolerant blackgram varieties with superior growth and yield attributes under partial shade and could be recommended for intercropping in coconut garden. Further, the yield of the shade tolerant varieties could be enhanced by recommended dose of nutrients as per KAU package supplemented with foliar spray of 19:19:19 (1%) at 45 and 60 DAS + foliar spray of NAA 40 mg L-1 and SA 100 mg L-1 at preflowering (35 DAS) and 15 days later. Sumanjana and DBGV 5 raised under partial shade in coconut garden with recommended dose of nutrients supplemented with the above said foliar spray realized higher mean net income and mean B: C ratio.ThesisItem Open Access Protocol development for gel stabilization and nutraceuticals in aloe vera (L.) Burm. f.(Department of Plantation Crops and Spices, College of Agriculture, Vellayani, 2021) Maheswari R S Nair; KAU; Sreekala, G SThe investigation entitled “Protocol development for gel stabilization and nutraceuticals in Aloe vera (L.) Burm. f.” was carried out in the Department of Plantation Crops and Spices, College of Agriculture, Vellayani during March 2016 to December 2019. The project envisaged formulation of a low cost stabilization technique for aloe gel using herbal extracts and aromatic oils and development of protocols for the preparation of dried latex and marketable nutraceuticals using aloe gel. The study was carried out as four experiments. The first experiment was to study the keeping quality and natural spoilage flora of fresh gel while the second experiment was for the standardization of curacao aloe (dried latex). The third experiment was on gel stabilization using herbal extracts and essential oils. Preparation of nutraceuticals from the stabilized liquidized aloe gel juice was the final experiment. The keeping quality and natural spoilage flora of fresh gel were assessed by subjecting the liquidized aloe gel juice to storage in glass bottles under ambient condition for seven days. The liqudized aloe gel juice was off white in colour for first three days of extraction with mild vegetative odour and got sedimented with foul smell from fourth day onwards. The liquidized aloe juice could not be stored for more than a day due to increased microbial population from the second day of storage. Preliminary trails conducted by pasteurizing the liquidized aloe gel juice at 65 0C and 15 psi pressure for 13 minutes followed by flash cooling registered no microbial population even after seven days of storage. The latex collected from aloe leaves was subjected to different methods of drying such as boiling followed by cooling, sun drying, shade drying and oven drying. Appearance, colour and aloin content (271.62 mg/ml) of dried latex was significantly higher for shade drying. Liquidized aloe gel juice was pasteurized and added with varying concentrations of three forms (aqueous, tincture, decoction) of herbal extracts and essential oils after adjusting the pH to 3.5 by adding 0.5 per cent of citric acid for gel stabilization. The treated samples were kept for a month and based on microbial population and minimum inhibitory concentration best treatment of each form was selected from preliminary trials for aloe gel stabilization. Gymnema sylvestre aqueous extract (1 ml), tincture (1 ml), decoction (2 ml), Centella asiatica aqueous extract (1 ml), tincture (2 ml), decoction (1 ml), Achyranthes aspera aqueous extract (2 ml), tincture (2 ml), decoction (1.50 ml), Tridax procumbens aqueous extract (2 ml), tincture (2 ml) , decoction (1 ml), Terminalia chebula aqueous extract (1 ml), tincture (1 ml), decoction (1 ml), Punica granatum aqueous extract (1 ml), tincture (2 ml), decoction (1 ml), green tea aqueous extract (2 ml), tincture (1 ml) and decotion (2 ml) and 1 ml each of sacred basil oil, lemon grass oil, cinnamon bark oil, clove oil and cardamom oil were selected and added to pH adjusted , pasteurized and liquidized aloe gel juice (25 ml) for gel stabilization. The gel stabilization was thus done using the selected twenty six treatments in a Completely Randomised Design replicated five times and compared with 0.08 per cent sodium benzoate as control and stored for six months. Appearance, colour and odour of all forms of the herbal extracts reduced on storage while those treatments with aromatic oils showed lesser percentage reduction in these parameters. Total solids, amylase and lipase activity decreased on storage. The amino acid content was the highest for liquidized aloe gel juice added with aqueous, tincture and decoction of Achyranthes aspera (0.08 ppm).Vitamin A and C were highest for treatment with green tea leaf aqueous extract which decreased subsequently on storage. An increase in microbial load was observed for all the treatments with herbal extracts from first month of storage. But addition of 1 ml clove oil resulted in stabilization of liquidized aloe gel juice which could be stored upto five months without microbial contamination or affecting the nutritive and sensory parameters. Nutraceuticals were prepared using stabilized liquidized aloe gel juice containing clove oil blended with lemon juice, orange juice and honey in proportions of 50 : 50, 75 : 25 and 90 : 10 followed by pasteurization, flash cooling and stored for 6 months. Appearance, colour and vitamin C were significantly higher for Lemon juice (50 ml) + Liquidized aloe gel juice (50 ml) + 2 ml clove oil while odour, taste, overall acceptability, pH, TSS, carbohydrates and calories were significantly superior for Honey (50 ml) + Liquidized aloe gel juice (50 ml) + 2 ml clove oil. Growth of microbes could be detected from third month of storage for all the treatments. Aloe health drink with honey in the ratio 50 : 50 added with clove oil were selected as the accepted drink which could be preserved for two months without microbial contamination. The preparation of aloe herbal powder by solar drying, air drying, oven drying or freeze drying resulted in a sticky product which could not be reconstituted with distilled water for quality comparison with fresh gel, thus warranting further investigation. The present study revealed that liquidized aloe gel juice pasteurized and mixed with clove oil (4 per cent) is a low cost stabilization method which can be taken as a base material for the preparation of health drink. The nutraceutical with liquidized and stabilized aloe gel juice mixed with equal proportion of honey and preserved with clove oil is a palatable drink having higher calories which could be stored for two months. The dried aloe latex a byproduct produced by shade drying is superior with high aloin content and can also be used for the development of marketable product.ThesisItem Open Access Characterization and evaluation of plant growth promoting rhizobacteria from rice soils of Wayanad(Department of Agricultural Microbiology, College of Agriculture, Vellanikkara, 2021) Wickramasinghe, W R K D W K V; KAU; Girija, DPlant growth promoting rhizobacteria (PGPR) are a group of bacteria that colonize the plant rhizosphere and enhance the growth and yield of plants. The present investigation entitled “Characterization and evaluation of plant growth promoting rhizobacteria from rice soils of Wayanad” was undertaken at the Department of Agricultural Microbiology” during the year 2018-2020, with the objective of isolation, characterization and evaluation of plant growth promoting rhizobacteria from rice soils of Wayanad and formulation of a consortium to improve the growth and yield of rice. Isolation of rhizobacteria with potential plant growth promoting (PGP) activities was attempted from rice rhizosphere soils collected from ten locations in Wayanad district of Kerala. Selective media were used for the isolation of PGPRs including nitrogen fixers, solubilizers of phosphate, K and Zn and fluorescent pseudomonads. A total of 149 isolates obtained on different media were subjected to preliminary screening for growth on selective media, which yielded 32 N-fixers, 16 phosphate solubilizers, four K solubilizers, six Zn solubilizers and two fluorescent pseudomonads. These isolates were evaluated in vitro for PGP activities (production of IAA, NH3, HCN and siderophore) and antagonistic activities against R. solani and X. oryzae. Twenty promising isolates were selected based on their functional efficiency for further characterization using cultural, morphological, biochemical and molecular methods. Four isolates were found to be Gram-positive rods and sixteen isolates were Gram-negative short rods. Eighteen isolates were identified based 16S rRNA gene sequencing and the sequences of all the eighteen isolates deposited in the GenBank of the NCBI. Phylogenetic analysis using MEGA 7 software showed two major clusters and several sub-clusters. A few of the native isolates stood out distinctly from the available accessions in the database, showing that they are genetically diverse. Based on the efficiency of N fixation, P, K and Zn solubilization and other PGP activities, isolates were ranked. Based on ranking, three N-fixers (Bacillus sp. AkNF3, Pseudomonas sp. PkNF4 and Pseudomonas putida KgNF1), three phosphate solubilizers (Bacillus megaterium PkPS1, Acinetobacter schindleri AkPS4 and Achromobacter sp. AvPS1), two K-solubilizers (Microbacterium sp. MvKS1 and Acinetobacter calcoaceticus MvKS3) and two zinc solubilizers (Achromobacter marplatensis ThZnS2 and Cytobacillus kochii PkZnS3) were selected for consortial formulation. Compatibility of ten promising isolates was tested by cross streaking and dual culture methods. Three PGPR based consortia (Consortium 1, 2 and 3) were formulated, each consisting of 5 native isolates (two N-fixers, one each of phosphate, K and Zn solubilizers). These consortia were evaluated in pot culture experiment, along with KAU commercial formulation (PGPR mix-1), at RARS, Ambalavayal, with rice (variety Valichoori) as the test crop. PGPR application was combined with two levels (50% and 75%) of recommended dosage of inorganic fertilizers (RDF). Population of total bacteria, N fixers, P, K and Zn solubilizers was higher in combined application of biofertilizer with inorganic fertilizers than uninoculated treatments and this was indicative of better colonization of native PGPRs in the rice rhizosphere. Growth and yield parameters indicated that application of PGPR consortium with 75% RDF was statistically on par with PoP (KAU) and 100% RDF. Results suggested that 25% inorganic N, P and K can be replaced by using native PGPR consortium without affecting plant growth, yield, plant nutrient content and soil nutrient content. Considering the above parameters, two best consortia (Consortium 2 and Consortium 3) were selected for further field evaluation. Field evaluation was carried out to assess the efficiency of two selected native PGPR consortia at RARS, Ambalavayal. Five treatments included were, consortium 2 + 75% RDF, consortium 3 + 75% RDF, reference biofertilizer PGPR mix-1 + 75% RDF, 100% RDF and farmer’s practice (farm yard manure 5t ha-1 ). Results suggested that root colonization of total bacteria, N fixers, P, K and Zn solubilizers was higher in all treatments of combined application of biofertilizers with 75% inorganic fertilizer than 100% RDF alone. Growth and yield parameters suggested that combined application of Consortium 2 with 75 % RDF was statistically on par with 100% RDF. Therefore, it can be concluded native PGPR strains in consortium 2 (Bacillus sp. strain AkNF3, Pseudomonas putida strain KgNF1, Bacillus megaterium strain PkPS1, Acinetobacter calcoaceticus strain MvKS3 and Cytobacillus kochii PkZnS3) successfully colonized the rice rhizosphere, increased nutrient availability to the plants and produced higher yield. The results also emphasized on the importance of exploiting native, location specific microorganisms as biofertilizer consortium, rather than a common consortium for the entire State. Native PGPR based consortia 2 reduced the 25% of inorganic fertilizer (N, P and K) without affecting the growth and yield of rice. This would be more cost effective and ecofriendly when compared with the use of chemical fertilizers alone. Further multi-locational field trials are required to validate the results before commercialization of this consortium, as a biofertilizer.ThesisItem Open Access Fertigation studies in Papaya (Carica papaya L.)(Department of Fruit Science, College of Agriculture, Vellayani, 2021) Karishma, Sebastian; KAU; Bindu, BThe investigation entitled “Fertigation studies in papaya (Carica papaya L.)” was carried out in Instructional Farm, College of Agriculture, Vellayani during the period 2018 – 2020 with the objectives to standardize the nutrient level for yield improvement through fertigation and foliar nutrition in papaya variety Surya and to study the postharvest management practices for extending the shelf life of papaya fruits. The experiment was undertaken in two parts. In part I, standardization of nutrient level for fertigation and foliar nutrition was carried out in RBD with 14 treatments replicated thrice. A combination of four fertigation doses of 75 %, 100 %, 125 % and 150 % RDF of N (304.89, 406.52, 508.15 and 609.78 g urea plant⁻¹ year⁻¹ respectively based on soil test data in 76 fertigation) and K (426.25, 568.33, 710.42 and 852.50 g MOP plant⁻¹ year⁻¹ respectively based on soil test data in 76 fertigation) and three foliar sprays (1.0 % 19:19:19 at bimonthly interval starting from 4 MAP to 16 MAP, 0.5% ZnSO4 + 0.3% borax at 4 th, 8th, 12th and 16th MAP and water spray at bimonthly interval starting from 4 MAP to 16 MAP) were compared with soil application of recommended dose of NPK (187:170:341 g NPK plant-1 year-1 based on soil test data) (control 1) and 187:170:341 g NPK plant-1 year-1 based on soil test data as organic manures as combination of FYM, poultry manure and vermicompost in the ratio of 2:1:1 (control 2). In control 2, additional requirement of P and K were met through the application of rock phosphate and potassium sulphate respectively. Organic manure (15 kg FYM plant-1 ) was given uniformly to all treatments as basal. Lime and rock phosphate (500g and 850g respectively based on soil test data) was applied uniformly for all treatments as basal except controls. Urea and Muriate of Potash (MOP) were used as fertilizer sources for fertigation and applied weekly from 1 MAP to 20 MAP. Application of different levels of fertigation and different foliar sprays had significant effect on growth, yield and quality of papaya. Growth parameters viz., plant height, stem girth and number of leaves were significantly higher in plants receiving 100 % RD of N and K through fertigation and foliar sprays of 1.0 % 19:19:19 (T4) at bimonthly interval starting from 6 MAP to 16 MAP. T4 also recorded highest leaf area index at 6, 12, 18 MAP and at final harvest, flowering at the shortest height, highest number of female plants and highest fruit set (86.27 %). However, application of 100 % RD of N and K through fertigation and foliar sprays of 0.5 % ZnSO4 and 0.3 % borax at 4 th, 8th, 12th and 16th MAP (T5) initiated earliness in flowering (142.67 days) and harvest (275.00 days). Treatments T4 and T5 were on par in fruit length, fruit girth, fruit volume, pulp percentage, flesh thickness and yield contributing characters like fruit weight, number of fruits per plant and yield per plant (38.30 kg plant⁻1 and 37.60 kg plant⁻1 respectively). Fruit quality parameters viz., TSS, carotenoids, ascorbic acid, total sugar, reducing sugar and non reducing sugar were found highest in T5. Fruits from T5 also registered longest shelf life (5.78 days) and highest mean sensory score for all parameters. Index leaf analysis at 6 MAP revealed highest nitrogen and potassium content of leaf in T10 (150 % RD of N and K through fertigation and foliar sprays of 1.0 % 19:19:19). Calcium, magnesium and sulphur content of leaves were highest in T5, whereas boron and zinc content were highest in T8 (125 % RD of N and K through fertigation and foliar sprays of 0.5 % ZnSO4 and 0.3 % borax). Highest nitrogen and potassium of fruits were observed in T12 (150 % RD of N and K through fertigation with water spray). Highest nitrogen content in soil was noticed in T11 (150 % RD of N and K through fertigation and foliar sprays of 0.5 % ZnSO4 and 0.3 % borax) and T10 witnessed highest potassium content. T4 and T5 were at par regarding B : C ratio (2.58 and 2.54 respectively). In part II of the investigation, postharvest management for extending shelf life of papaya was carried out with nine treatments replicated thrice. Different postharvest treatments given were precooling - hydro cooling (S1), surface sanitization with 150 ppm sodium hypochlorite (S2), external coating with 1% chitosan (S3), precooling followed by external coating with 1% chitosan (S4), packaging with ethylene scrubber 8% KMnO₄ (S5), precooling followed by packaging with ethylene scrubber 8% KMnO₄ (S6), precooling followed by external coating with 1% chitosan and packaging with ethylene scrubber 8% KMnO4 (S₇), hot water treatment followed by waxing with 6% carnauba wax and packaging with ethylene scrubber 8% KMnO₄ (S8) and control (S9). Papaya variety Surya was raised at Instructional Farm, Vellayani and fruits at fully mature green stage were harvested, subjected to different postharvest treatments and packaging was done in CFB boxes and stored under ambient conditions till the end of shelf life. Papaya fruits subjected to precooling followed by external coating with 1% chitosan and packaging with ethylene scrubber KMnO₄ (S7) recorded the longest shelf life of 9.67 days, which was at par with S8 (hot water treatment followed by waxing with 6% carnauba wax and packaging with ethylene scrubber KMnO₄). Physiological loss in weight, ion leakage, percentage disease index, bacterial and fungal count were significantly lowest in S7 and S8 after three days of storage. These treatments also recorded maximum total carotenoids, total soluble solids, total sugar, reducing sugar and minimum acidity after nine days of storage which indicated extended shelf life. Highest mean rank score for sensory attributes were also recorded in treatments S7 and S8 after nine days of storage. In conclusion, application of 100 % recommended dose of N and K (406.52 g urea plant⁻¹ year⁻¹ and 568.33 g plant⁻¹ year⁻¹ respectively) through weekly fertigation from one to 20 months after planting and foliar sprays of 0.5 % ZnSO4 + 0.3 % Borax at 4 th, 8th, 12th and 16th MAP, along with basal application of 850g rock phosphate and 15 kg FYM resulted in increased growth, yield and quality characters of papaya variety Surya with highest B: C ratio. Fruits at fully mature green stage when subjected to precooling followed by external coating with 1% chitosan and packaging with ethylene scrubber 8% KMnO₄ in CFB boxes exhibited a shelf life of 9.67 days in storage under ambient condition in papaya variety Surya.ThesisItem Open Access Gene action and gene expression analysis in tomato (Solanum iycopersicum L.) under moisture stress(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 2021) Chippy, A K; KAU; Beena, ThomasThe present investigation entitled ‘‘Gene action and gene expression analysis in tomato (Solanum lycopersicum L.) under moisture stress” was conducted during the period 2017-2021, in the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani. Thirty-two genotypes including local genotypes of tomato were collected from different sources and studied under three different experiments. In the first experiment, twenty-one F1 hybrids derived from the line x tester mating and their ten parents were transplanted in the field and the treatment mean sum of square due to genotypes was found to be highly significant for all the characters studied which would ultimately indicate diverse nature of selected genotypes. The mean performance showed wide range of variation for most of the characters studied. Among lines, L7 (Pusa Ruby) showed higher mean performance for all-out of nine characters viz., plant height, fruit length, fruit girth, fruit volume, fruit weight, yield per plant, yield per plot, root length, root volume and relative water content. Among three testers, T2 (Kuttichal Local) showed favourable mean performance for seventeen traits viz., plant height, primary branches per plant, number of leaves per plant, number of flowering clusters per plant, number of fruits per cluster, fruit length, fruit girth, fruit volume, fruit weight, yield per plant, yield per plot, vitamin C, total acidity, stomatal frequency, root length, root volume and proline content. Under moisture stress (Second experiment), among the lines, L7 (Pusa Ruby) showed higher mean performance for eleven characters viz., plant height, fruit length, fruit girth, fruit volume, fruit weight, yield per plant, yield per plot, total soluble solids, root length, root volume and pollen viability. Among three testers, T2 (Kuttichal Local) showed favourable mean performance for sixteen traits viz., plant height, primary branches per plant, number of leaves per plant, number of flowering clusters per plant, number of fruits per cluster, number of fruits per plant, fruit length, fruit girth, fruit volume, total soluble solids, total acidity, stomatal frequency, root length, root volume and canopy temperature. Based on general combining ability analysis, the line L6 (Arka Alok) ranked as top by exhibiting significant gca effects for six traits viz., fruit length, fruit girth, fruit volume, fruit weight, specific leaf area and root length. Among the testers, T3 (Kottayam Local) had superior gca effects for Days to 50% flowering, number of flowering clusters per plant, number of fruits per cluster, fruit length, fruit volume, yield per plot, total soluble solids, lycopene, titrable acidity canopy temperature and proline content. Under moisture stress, the line L3 (Akshaya) ranked as top by exhibiting significant gca effects for ten traits viz., primary branches per plant, number of fruits per cluster, number of fruits per plant, fruit weight, yield per plant, yield per plot, stomatal frequency, specific leaf area, canopy temperature and pollen viability. Among the testers, T1 (Palakkad Local) had superior gca effects for plant height, number of fruits per cluster, number of fruits per plant, fruit girth, fruit volume, yield per plant, yield per plot, total soluble solids, relative water content, canopy temperature and proline content. In the case of hybrids, Based on mean performance, the crosses L1 x T1 (Vellayani Vijay x Palakkad Local), L2 x T3 (Anagha x Kottayam Local), L3 x T1 (Akshaya x Palakkad Local), L3 x T3 (Akshaya x Kottayam Local), L4 x T1 (PKM 1 x Palakkad Local), L4 x T2 (PKM 1 x Kuttichal Local), L5 x T1 (Arka Meghali x Palakkad Local), L5 x T2 (Arka Meghali x Kuttichal Local), L5 x T3 (Arka Meghali x Kottayam Local), L6 x T2 (Arka Alok x Kuttichal Local) and L6 x T3 (Arka Alok x Kottayam Local) were superior for different yield characters. Under moisture stress, Hybrids L3 x T1 (Akshaya x Palakkad Local), L3 x T3 (Akshaya x Kottayam Local), L4 x T1 (PKM 1 x Palakkad Local), L4 x T2 (PKM 1 x Kuttichal Local), L5 x T2 (Arka Meghali x Kuttichal Local), L7 x T2 (Pusa Ruby x Kuttichal Local) and L7 x T3 (Pusa Ruby x Kottayam Local) were superior for yield based on mean value. Based on combining ability studies under normal field condition, identified superior crosses such as L1 x T1 (Vellayani Vijay x Palakkad Local), L2 x T1 (Anagha x Palakkad Local), L2 x T3 (Anagha x Kottayam Local), L3 x T1 (Akshaya x Palakkad Local), L3 x T3 (Akshaya x Kottayam Local), L4 x T1 (PKM 1 x Palakkad Local), L4 x T2 (PKM 1 x Kuttichal Local), L6 x T2 (Arka Alok x Kuttichal Local), L6 x T3 (Arka Alok x Kottayam Local), L7 x T1 (Pusa Ruby x Palakkad Local) and L7 x T3 (Pusa Ruby x Kottayam Local) exhibited higher sca effects for yield per plant. Under moisture stress, identified superior crosses such as L1 x T2 (Vellayani Vijay x Kuttichal Local), L2 x T3 (Anagha x Kottayam Local), L3 x T1 (Akshaya x Palakkad Local), L4 x T2 (PKM 1 x Kuttichal Local), L5 x T2 (Arka Meghali x Kuttichal Local), L6 x T2 (Arka Alok x Kuttichal Local) and L7 x T3 (Pusa Ruby x Kottayam Local) exhibited higher sca effects for yield per plant. Based on heterosis, Overall, nineteen hybrids (L1 x T1, L1 x T2, L1 x T3, L2 x T1, L2 x T2, L2 x T3, L3 x T1, L3 x T3, L4 x T1, L4 x T2, L4 x T3, L5 x T1, L5 x T2, L5 x T3, L6 x T1, L6 x T2, L6 x T3, L7 x T1 and L7 x T3) from twenty one crosses revealed significant and positive heterobeltiosis for yield per plant under normal field condition. In the case of gene action, dominance genetic variance (σ2D) is higher than additive genetic variance (σ2A) was observed for all the traits under normal field condition and water stress condition, indicating that traits are controlled by non-additive gene action. Correlation study revealed yield per plant was positively and significantly correlated with the traits viz., primary branches per plant, number of flowering clusters per plant, number of fruits per cluster, number of fruits per plant, fruit girth, fruit volume, fruit weight and yield per plot. Based on qRT-PCR, the expression of both genes (moisture stress related genesSlDREB 1 and SlWRKY 4) was upregulated under water stress in all selected genotypes and the expression was more than moisture stress tolerant check variety. The result is in accordance with the analysis of moisture stress related physiological characters in these genotypes in the field under stress. From the study, identified tolerant sources for moisture stress viz., Akshaya, Pusa Ruby and Kuttichal Local, these lines and tester can be used in breeding programmes for moisture stress tolerance. Based on mean performance and gca, the genotypes Vellayani Vijay, Akshaya, Arka Meghali, Arka Alok and Kottayam local which showed superiority in yield and fruit quality traits can be used for breeding for improvement of yield and quality traits. The hybrids L3xT1 (Akshaya x Palakkad Local), L4 x T2 (PKM 1 x Kuttichal Local), L5 x T2 (Arka Meghali x Kuttichal Local) and L7 x T3 (Pusa Ruby x Kottayam Local) which showed superiority for yield and quality characters with tolerance to moisture stress can be recommended for release after yield trials.ThesisItem Open Access Irrigation scheduling and water stress mitigation strategies in upland rice (Oryza sativa L.)(Department of Agronomy, College of Agriculture, Vellayani, 2021) Gritta, Elizabeth Jolly; KAU; Sajitha Rani, TThe study entitled “Irrigation scheduling and water stress mitigation strategies in upland rice (Oryza sativa L.)” was carried out as two field experiments at the Instructional Farm, College of Agriculture, Vellayani from 2017 to 2020 to identify a suitable variety and irrigation method for upland rice, to standardize irrigation scheduling and to assess the effect of moisture stress mitigation strategies on the growth, yield and economics of upland rice. Experiment I entitled “Identification of suitable variety and standardization of irrigation method” was conducted from January 2019 to May 2019. The experiment was laid out in split plot design with five main plot treatments and two sub plot treatments, in four replications. The treatments included sprinkler irrigation at 100% PE, sprinkler irrigation at 75% PE, drip irrigation at 100% PE, drip irrigation at 75% PE and hose irrigation (farmer’s practice-irrigation given thrice in a week) as main plot treatments and rice varieties Uma and Prathyasa as sub-plot treatments. The height of the plant, number of tillers m -2 , leaf area index and dry matter production were observed to be significantly the highest for the variety Prathyasa irrigated using sprinkler irrigation at 100% PE and hose irrigation was significantly inferior to all other methods of irrigation. The variety Prathyasa irrigated using sprinkler irrigation at 100% PE also recorded the highest number of panicles m -2 (226.00), number of grains per panicle (159.75) and grain yield (4.37 Mg ha -1 ). The highest RLWC and consumptive use (434.25 mm) by the crop was observed in the variety Uma irrigated using sprinkler at 100% PE, followed by drip irrigated plots at 100% PE. The highest crop water use efficiency (1.53 kg m -3 ) was observed in the variety Prathyasa irrigated using hose method and the highest field water use efficiency (0.95 kg m -3 ) was observed in the variety Prathyasa irrigated using sprinkler at 100% PE. 282The economics of cultivation in terms of net returns ( ₹ 1,32,465.50 ha -1 ) and B:C ratio (2.67) were observed to be the highest in the variety Prathyasa irrigated using sprinkler irrigation plots at 100% PE, followed by the variety Prathyasa irrigated using drip irrigation at 100% PE. Field experiment II entitled “Standardization of irrigation scheduling and moisture stress mitigation strategies for upland rice” was conducted during January 2020 to April 2020. The experiment was laid out in split plot design with four main plot treatments and five sub plot treatments in five replications (the best treatment from the experiment I - sprinkler method of irrigation at 100% PE and the variety Prathyasa were used for the experiment II). The main plot treatments included approaches of scheduling irrigation: IW/CPE of 0.8, critical growth stage approach, irrigation to maintain soil moisture at 100% FC and irrigation to maintain soil moisture at 75% FC. The sub-plot treatments included field application of hydrogel polymer (20 kg ha -1 ), seed treatment with hydrogel polymer (10 g kg -1 ), hydrogel polymer (field application @ 2.5 kg ha -1 + seed treatment @10g kg -1 ), foliar application of PPFM (1%) and absolute control. The plant height, number of tillers m -2 , leaf area index and dry matter production were observed to be significantly higher in the plots irrigated at 100% FC, treated with hydrogel polymer (field application @ 2.5 kg ha -1 + seed treatment @10 g kg -1 ), which was followed by the plots irrigated to maintain 2 cm depth of water at critical stages of crop growth. The number of days for 50% flowering, the number of panicles m -2 (233.20), length of panicle (20.36 cm), weight of panicle (3.07 g), number of grains panicle -1 (169.20), grain yield (5.00 Mg ha -1 ) and straw yield (8.07 Mg ha -1 ) were the highest in the plots irrigated at 100% FC and treated with hydrogel polymer (field application @ 2.5 kg ha -1 + seed treatment @10g kg -1 . . The consumptive use by the crop was significantly the highest in the plots irrigated at 100% FC (1265.60 mm) and treated with hydrogel polymer (field application @ 2.5 kg ha -1 + seed treatment @ 10g kg -1 ).The crop water use efficiency recorded the highest value (0.69 kg m -3 ) in the plots irrigated at IW/CPE 283of 0.8 and treated with hydrogel polymer (field application @ 2.5 kg ha -1 + seed treatment @ 10g kg -1 ) and a significantly higher field water use efficiency (0.58) was recorded in the plots irrigated at IW/CPE of 0.8 and treated with hydrogel polymer (field application @ 2.5 kg ha -1 + seed treatment @ 10g kg -1 ) The highest B: C ratio (2.92) and net returns ( ₹ 1,58,000.00 ha -1 ) were obtained from the plots irrigated at 100% FC and treated with hydrogel polymer (field application @ 2.5 kg ha -1 + seed treatment @ 10g kg -1 . The results of the study revealed suitability of the variety Prathyasa, irrigated using sprinkler irrigation at 100% PE for higher yield and monetary returns under upland conditions. It also reflected the suitability of irrigating upland rice at 100 % FC as an effective approach of scheduling irrigation, along with the application of hydrogel polymer (field application @ 2.5kg ha -1 + seed treatment @ 10 g kg -1 ) as the most suitable moisture stress mitigation strategy for upland rice cultivation for enhanced yield and economic returns under water stress conditions.ThesisItem Open Access Productivity enhancement of blackgram (Vigna mungo (L.) Hepper) intercropped in coconut gardens(Department of Agronomy, College of Agriculture,Vellayani, 2021) Pooja, A P; KAU; Ameena, MThe research work entitled ‘Productivity enhancement of blackgram (Vigna mungo (L.) Hepper) intercropped in coconut gardens’ was undertaken at College of Agriculture, Vellayani during 2018-2021. The study aimed to identify shade tolerant blackgram varieties suitable for coconut gardens, to study the effect of foliar nutrition and plant growth regulators on growth and yield of the shade tolerant blackgram varieties intercropped in coconut garden and to work out the economics of cultivation. The investigation was carried out as two experiments: (i) screening of blackgram varieties for shade tolerance, and (ii) performance evaluation of shade tolerant varieties under foliar application of nutrients and growth regulators in rainfed coconut garden. The first experiment was conducted during Rabi 2019-20 in coconut garden having a light intensity equivalent to 50 per cent of that under open condition (56.25 klux), planted at a spacing of 7.6 m x 7.6 m. Seeds of 12 promising blackgram varieties collected from different research stations of south India (Sumanjana, DU 1, DBGV 5, VBN 5, VBN 6, VBN 8, Rashmi, CO 6, TAU 1, TAU 2, Blackgold and AKU 15) and three cultures (Culture 4.5.8, Culture 4.5.18 and Culture 4.6.1), were raised in micro plots laid out in randomized block design with three replications. The crop was raised as per KAU package of practices. The results of the study revealed significant variation in growth characters among the varieties screened for shade tolerance under partial shade in coconut garden. Plants of DBGV 5 were significantly taller (96.89 cm) with higher initial number of leaves at all the stages and was on par with Sumanjana and CO 6. Higher leaf area index (LAI) and leaf area duration were recorded in CO 6 (5.77, 65.66 days) and DBGV 5 (5.36, 58.40 days) followed by Sumanjana. Early flowering was observed in Sumanjana (34.33 days) and DBGV 5 (36.33 days). The variety DBGV 5 had the highest photosynthetic rate and resulted in significantly more pods per plant (23.67) which was on par with CO 6, VBN 5, VBN 6, Sumanjana and Rashmi. DBGV 5 produced the highest seed yield per plant (5.44 g) followed by VBN 5 and Sumanjana. Haulm yield per plant was higher for DBGV 5 (19 g) and was on par with VBN 5, Sumanjana and CO 6. The variety DBGV 5 produced the highest seed yield (1183 kg ha-1 ) followed by VBN 5, Sumanjana and CO 6. A higher harvest index of 0.24 was recorded by Sumanjana which was on par with DBGV 5 and VBN 6. Among the varieties screened, five varieties which performed better in terms of yield per unit area under the partial shade in coconut garden viz., DBGV 5, VBN 5, Sumanjana, CO 6 and VBN 6 were selected for experiment II undertaken in summer 2020 followed by the confirmatory trial during Rabi 2020 -21. The experiment was laid out in split plot design with five varieties (v1 - Sumanjana, v2 - DBGV 5,v3 - VBN 5,v4 - VBN 6,v5 - CO 6) as main plot treatments and six foliar sprays of nutrients and plant growth regulators as subplot treatments (f1: 19:19:19 (1%) at 45 and 60 DAS, f2: SOP (0.5%) at 45 and 60 DAS, f3: NAA 40 mg L-1 and salicylic acid 100 mg L-1 at pre-flowering (30-45 DAS) and 15 days later, f4: f3 + f1, f5: f3 + f2 and f6: Control - KAU POP). Among the varieties, Sumanjana (v1) grew taller during both the seasons and was comparable with CO 6 and DBGV 5 at harvest. Sumanjana produced higher number of branches with more number of leaves during both the seasons. At flowering, higher LAI, number and dry weight of nodules per plant were realized by Sumanjana and was on par with CO 6 (v5) in summer and DBGV 5 (v2) in Rabi. Sumanjana exhibited the highest crop growth rate (CGR) and relative growth rate (RGR) during both the seasons at 45-60 DAS. However, DBGV 5 recorded the highest net assimilation rate (NAR) between 30-45 DAS and 45-60 DAS during both the seasons. The highest chlorophyll content was recorded by DBGV 5 (1.96 mg g-1 fresh tissue) during summer and by Sumanjana (2.36 mg g-1 fresh tissue) during Rabi. The highest stomatal conductance (30.22 m moles m-2 s -1 and 28.34 m moles m-2 s -1 ) and lower stomatal index (15.16% and 13.34%) were recorded in Sumanjana during both the seasons. The variety Sumanjana flowered earlier compared to other varieties during both the seasons and produced the highest number of pods per plant (27.30 and 26.54). Hundred seed weight was significantly higher for DBGV 5 (5.01 g and 4.92 g) and remained at par with Sumanjana (4.99 g and 4.88 g) during both the seasons. Seed yield, haulm yield and total dry matter production (TDMP) were higher for Sumanjana and comparable with DBGV 5 during both the seasons. Sumanjana recorded higher NPK uptake during both the seasons followed by DBGV 5. The subplot factor foliar spray had significant effect on growth, physiological and yield attributes of blackgram varieties. Foliar spray of 19:19:19 (1%) at 45 and 60 DAS + foliar spray of NAA 40 mg L-1 and SA 100 mg L-1 at pre-flowering and 15 days later (f4) resulted in significantly taller plants, more number of branches and leaves. The highest CGR, RGR (at 45-60 DAS), LAI, number and dry weight of nodules per plant at flowering were recorded in f4 during both the seasons. During summer, f3, f4 and f5 recorded higher NAR between 45-60 DAS. Higher chlorophyll content and stomatal conductance were recorded by f4 during both the seasons. Plants supplied with f3 attained 50 per cent flowering earlier and was on par with f5 during both the seasons. Highest number of pods per plant, 100 seed weight, seed yield, haulm yield and TDMP were recorded by f4 during both seasons. The grain protein content was improved by f4 and was on par with f3, f1 and f5. The NPK uptake was higher in f4 and was on par with f3 and f5 during summer. Significantly higher organic carbon, available N and P was recorded in f4. Among the treatment combinations, Sumanjana (v1) with f4 produced taller plants at two months after sowing (MAS), higher number of branches and leaves per plant during summer and Rabi. Leaf area index, number of nodules and dry weight of nodules at flowering were higher for v1f4 followed by v2f4. Sumanjana in combination with f4 measured significantly higher CGR and RGR (at active growth stages), highest chlorophyll content, stomatal conductance and lower stomatal index during both the seasons. The variety Sumanjana with f4 produced superior number of pods per plant (30.24 and 29.40) and hundred seed weight during summer and Rabi. A higher seed yield was realized in v1f4 (1750 kg ha-1 ) which was on par with v2f4 (1713 kg ha-1 ) during summer. Seed yield was the highest (1700 kg ha-1 ) in v1f4 during Rabi. Haulm yield and TDMP recorded were higher for v1f4 and was on par with v2f4 during both the seasons. The available N status in soil was higher during both the seasons in v1f4 with the highest NPK uptake during Rabi. Sumanjana and DBGV 5 with f4 realized higher mean net income (₹ 70411 ha-1 and ₹ 61256 ha-1 ) and mean B: C ratio (2.04 and 1.95). The present study identified DBGV 5 and Sumanjana as shade tolerant blackgram varieties with superior growth and yield attributes under partial shade and could be recommended for intercropping in coconut garden. Further, the yield of the shade tolerant varieties could be enhanced by recommended dose of nutrients as per KAU package supplemented with foliar spray of 19:19:19 (1%) at 45 and 60 DAS + foliar spray of NAA 40 mg L-1 and SA 100 mg L-1 at preflowering (35 DAS) and 15 days later. Sumanjana and DBGV 5 raised under partial shade in coconut garden with recommended dose of nutrients supplemented with the above said foliar spray realized higher mean net income and mean B: C ratio.
