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2016 - 2019132020 - 20215
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Subject: Seed Science and Technology × Author: KAU × Start date: 2010 × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Impact of biopriming on seed quality and longevity in Rice (Oryza sativa L.)
    (Department of Seed Science And Technology, College of Agriculture,Vellanikkara, 2021) Ruth Olivya Sarella; KAU; Dijee Bastian
    The study "Impact of bio-priming on seed quality and longevity in rice" (Oryza sativa L.) was conducted at the Department of Seed Science and Technology, College of Agriculture, Vellanikkara to study the effect of different seed priming treatments on seed quality and seed longevity under natural as well as accelerated ageing. Pseudomonas fluorescens, Trichoderma viride, coconut water was used for seed priming rice variety Jyothy. Seeds of rice variety Jyothy were treated with the following treatments: -, Pseudomonas fluorescens @ 10g/kg (T1), Trichoderma viride @ 4g/kg (T2), Coconut water @ 75% (T3), P. fluorescens + T. viride (T4), P. fluorescens + coconut water (T5), T. viride + coconut water (T6), P. fluorescens + T. viride + coconut water (T7), Hydro priming (T8), Control (untreated) (T9). Both treated and untreated seeds were dried to <10 per cent moisture content and packed in Polyethylene bags (700 guage). The treated seeds were allowed to age both naturally and under accelerated ageing conditions. There were significant differences among the treatments on seed quality parameters. Irrespective of the treatment, germination, seedling growth (dry weight, length of root and shoot), vigour index- I (VI-I), vigour index- II (VI-II), speed of germination, SOD enzyme activity, dehydrogenase enzyme activity decreased significantly over the storage period. A significant increase in seed moisture content, electrical conductivity, Mean Germination Time (MGT), Time taken for 50% germination (T50) and seed microflora, was observed with increase in storage period. Seed treatment with P. fluorescens (10g/kg) + T. viride (4g/kg) + coconut water (75%) retained a germination per cent of (83.69%) and higher vigour indices among the treatments after nine months of storage followed by Pseudomonas fluorescens @ 10g/kg (T1) and P. fluorescens + T. viride (T4) while treatment hydropriming (T8) was found to be inferior in all quality parameters. Coconut water treatments were found to be superior in increasing root and shoot length of the seedlings across the storage period which was reflected in the vigour indices. Bio priming with P. fluorescens resulted in early emergence of seedlings. Seed microflora was found to increase significantly towards the end of storage period. This increase was least in P fluorescens @ 10g/kg (T1), Aspergillus spp., Pencillium spp. were observed in the primed seeds. In present study it was found that among bio primed treatments P fluorescens treated seeds performed better than T. viride treated seeds in all quality parameters. Accelerated aged seed samples were gathered and tested at daily intervals for 7 days to evaluate seed quality parameters. In general, dry priming performed better than wet primed seeds. Vigour indices was found to be highest in bio primed seeds (T2, T4 , T7) than othertreatments Seed longevity is found to be higher in bio primed seeds which can be evaluated from speed of germination (T1, T4, T7), electrical conductivity (T2, T4 ), dehydrogenase and SOD enzyme activities. Seed infection (%) increased towards the end of ageing period and recorded least in P. fluorescens treatments (T1, T7, T5) Seed treatments P. fluorescens (10g/kg) + T. viride (4g/kg) + coconut water (75%) was the best treatment followed by P fluorescens @ 10g/kg of seeds in improving seed quality as well as seed longevity. Treatments P fluorescens @ 10g/kg (T1), T. viride @ 4g/kg (T2), P. fluorescens + T. viride (T4), P. fluorescens + T. viride + coconut water (T7) of seed may be used as seed treatments to enhance seed longevity in rice.
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    ThesisItemOpen Access
    Impact of potassium and ABA application on vivipary and seed quality in oriental pickling melon (Cucumis melo var. conomon Mak.)
    (Department of Seed Science and Technology, College of Agriculture, Vellanikkara, 2021) Vaisakh, K; KAU; Dijee Bastian
    Oriental pickling melon is a crop with cultural and economic significance in Kerala. Vivipary has been observed in this crop which reduces the seed yield and quality. Adjusting the planting time and application of some chemicals were found effective in controlling vivipary. The study on ‘Impact of potassium and ABA application on vivipary and seed quality in oriental pickling melon (Cucumis melo var. conomon Mak.)’ was conducted at the Department of Seed Science and Technology, College of Agriculture, Kerala Agricultural University, Vellanikkara, Thrissur during the year 2019-2021 using the variety ‘Saubhagya’ to understand the effect of different levels of potassium and ABA on vivipary and the quality of seeds. The crop was sown during the month of February (2021) following randomised block design with eight treatments and three replications. The treatments consisted two foliar sprays of potassium (0.5% MOP, 1% MOP, 1.5% MOP) at 50 per cent flowering and at an interval of two weeks after flowering, one foliar spray of abscisic acid (100 mg/l ABA, 200 mg/l ABA and 300 mg/l ABA) at 50 per cent flowering and a basal application of recommended fertilizers with 50 percent additional potassium (POP + 50% K). The treatments had significant impact on fruit and seed quality parameters. The fruit length and yield were enhanced in the ABA treatments. The potassium treatment, POP + 50% K also gave significantly higher fruit yield which was on par with the ABA treatments. Higher content of potassium in fruit flesh and placenta was observed in 300 mg/l ABA treatment. The treatments were effective in controlling the vivipary. The abscisic acid treatment (300 mg/l ABA) was the most effective which reduced the vivipary up to 1.37 per cent followed by the treatment with potassium (1.5 per cent MOP) where the vivipary was 3.29 per cent. The number of seeds per fruit and the total seed yield was the highest in the treatment with 300 mg/l abscisic acid. The seeds extracted from fruits harvested from the field experiment were used for the seed longevity studies. The storage potential was assessed with the help of accelerated ageing test. The seeds were tested for different quality parameters after each day of accelerated ageing and the results showed that the seed quality deteriorated during the 7-days of ageing in all treatments. The seed quality parameters like vigour, germination, shoot and root length decreased whereas the electrical conductivity of seed leachate, mean germination time, seed moisture and seed infection per cent increased indicating a decline in seed quality over accelerated ageing. The highest germination and vigour throughout the accelerated ageing was observed in seeds collected from treatment 100 mg/l ABA and it maintained minimum germination for seed certification prescribed by IMSCS (60.00% for melon) till day 4 of accelerated ageing. The highest dry weight of seedling and lowest electrical conductivity of seed leachate were observed in seeds extracted from treatment 300 mg/l ABA. The seed infection did not vary among the treatments. Initially there was no incidence of any pathogens but as the ageing period advanced the seed infection per cent increased. The pathogens like Aspergillus sp. and Pencillium sp. were identified. The agar plate method showed higher infection per cent compared to blotter method. From the study it can be concluded that the overall performance of the seed was found to be higher in abscisic acid treatment (300 mg/l ABA) indicating that it is the best treatment among all the treatments given.
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    ThesisItemOpen Access
    Halogenation for improvement of seed yield and quality in chilli (Capsicum annum L.)
    (Department of Seed Science and Technology, College of Agriculture, Vellayani, 2020) Milu, Herbert.; KAU; Dijee, Bastian
    The research on ‘Halogenation for improvement of seed yield and quality in chilli (Capsicum annuum L.)’ was undertaken in the Department of Seed Science and Technology, College of Horticulture, Kerala Agricultural University (KAU), Vellanikkara, Thrissur, during the year 2018-2020. The study aimed to assess the impact of halogenation on growth and field performance of treated seeds, as well as its influence on seed quality during ambient storage. The study comprised of two experiments. In experiment I, the field performance of halogenated chilli seeds was assessed. Freshly harvested seeds of chilli variety Anugraha treated with different doses of halogens indirectly through a carrier were the treatments used. The experiment was laid out in a Randomised Block Design (RBD) with four replications and five treatments viz., T1: Control (Untreated), T2: CaOCl2 + CaCO3 (2 g each/kg seed), T3: CaOCl2 + CaCO3 (4 g each /kg seed), T4: Iodine crystal + CaCO3 (50 mg each/kg seed), T5: Iodine crystal + CaCO3 (100 mg each/kg seed). Observations on growth and yield parameters were recorded at appropriate growth stages. The results revealed that seed yield attributes such as fruits per plant, fruit weight, seed yield per plant and hundred seed weight were significantly influenced by the treatments. Among the CaOCl2 treatments, T2 (CaOCl2 + CaCO3 @2 g each/kg seed) recorded higher values for fruits per plant, fruit weight and seed yield per plant. Of the two seed invigoration treatments with iodine, T5 (Iodine crystal + CaCO3 @100 mg each/kg) performed superior for fruits per plant, fruit weight, seed yield per plant and hundred seed weight. Seeds obtained from Experiment I were used for seed storage studies (Experiment II). The seeds were dried to a moisture content less than eight per cent, bagged in 700 gauge polyethylene bag and stored under ambient conditions for six months. Samples were drawn at monthly intervals and various seed quality parameters were analysed. The experiment was laid out in Completely Randomized Block Design (CRD) with five treatments (T1 to T5 as in experiment I) and four replications. Seed quality parameters such as germination per cent, vigour indices and seedling dry weight declined with the progress of storage, whereas electrical conductivity of seed leachates increased over the storage period. Significant differences were observed among the treatments for germination per cent from first month onwards to the end of storage. All treatments including the control maintained MSCS (Minimum Seed Certification Standard) of 60 per cent germination till the end of six months of storage. At the end of storage, T2 (CaOCl2 + CaCO3 @2 g each/kg) followed by T5 (Iodine crystal + CaCO3 @100 mg each/kg) recorded higher germination per cent and vigour indices. The influence of halogen treatments on seed infection was found significant at the start and end of storage. Treatments, T5 (Iodine crystal + CaCO3 @100 mg each/kg seed) and T2 (CaOCl2 + CaCO3 @2 g each/kg) were found superior with lower infection. In order to identify treatments effective for improvement of seed yield and quality, scoring and ranking were carried out for all the characters studied under experiment I and for germination per cent and vigour indices in experiment II. While considering the total score obtained by the treatments for both the experiments, T2 (CaOCl2 + CaCO3 @2 g each/kg seed) was found to have multiple benefits of enhancement of growth and seed yield attributes and maintenance of seed quality during storage. T2 was followed by T3 (CaOCl2 + CaCO3 @4 g each/kg seed) and T5 (Iodine crystal + CaCO3 @100 mg each/kg). Hence, it is concluded that seed treatment with CaOCl2 + CaCO3 @2 g each/kg seed was effective in improving seed yield and quality in chilli variety Anugraha. The treatment is simple and chemicals are easily available hence farmer friendly. The study may be extended to other chilli varieties to standardise the dosage for recommendation.
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    ThesisItemOpen Access
    Standardization of hybrid rice seed production for Kerala using three line system of breeding
    (Department of Seed Science and Technology, College of Agriculture, Vellayani, 2020) Arunkumar, C; KAU; Jayalekshmi, G
    The present study entitled “Standardization of hybrid rice seed production for Kerala using three line system of breeding” was carried out in the College of Agriculture, Vellayani and Integrated farming system research station (IFSRS), Karamana during 2019-2020, with an objective to standardize GA3 and brassinosteroid and to optimize the planting ratio in restorer line (R line) and male sterile line (A line) to get maximum hybrid seed yield under Kerala condition. The study comprised of two experiments, the phenological studies in male sterile line (Aline) and standardization of GA3 and brassinosteroid dose for the planting ratio of A, R line in 6:2 and 8:2. Phenological studies of the CMS line CRMS31A were taken under protected condition during different growth stages. The production of tillers on male sterile line started at 23.3 days after sowing. At maturity, the plant height reached up to 123.33 cm length with 18.1 total numbers of tillers. The sterile plant produced total of 91 leaves and the flag leaf had 39.01 cm2 area. The initiation of the panicle was observed on 58.9 days old plants and panicles were developed between internodes of the first stem. The panicle initiation was associated with the beginning of stem internodes formation and the initiated panicle was microscopic in size (2-4 mm) with a fuzzed tip inside the main culm. The increase in size of the panicle primordia and its upward extension inside the leaf sheath were detected inside the rapidly elongated culm. The booting stage was started at an age of 67.2 days then the first panicle was emerged on 74.1 days old plant and fifty percentages of panicles were emerged within a week. Flag leaf angle play a vital role in the percentage of seed filling (fertility percentage) by acting as a barrier between pollen from the male parent and the CMS plants spikelets. The average flag leaf angle of CRMS 31 A was 15.60 which was very less when compared to traditional varieties. The CRMS 31 A had taken 85.5 days to anthesis and taken 9 days to finish the anthesis of whole spikelets on panicle. In the second experiment, field evaluation of hybrid seed production in the cross between CRMS 31A and the identified restorer „Remya‟ was done in the fields of IFSRS Karamana for standardising the planting ratio and the doze of growth hormones. This experiment was laid out in Randomized Block Design (RBD) with three replication during March-July 2020 (Virippu). The parental lines were sown in staggered dates according to the duration of the CMS line and the pollen Restorer line. The sowing of male and female parents were planned to achieve the synchronization in flowering. The R line was sown in three staggered dates. i.e., one at three days before the sowing date of CMS lines, the second set along with CMS line and the third set were sown three days after the sowing of CMS lines. The sterile R line and pollen parent were sown in the planting raio of 6:2 and 8:2 and two doses of GA3 (50 and 70 ppm) and brassinosteroid (2 and 6ppm) were sprayed at 15-20% heading and 35-40% panicle emergence. Observations on eight morphological and five yield traits were recorded during the crop production. All the traits used in the study showed significant variations. The mean performance of CRMS 31 A observed better performance in morphological and yield parameters at 70 ppm GA3. The treatment T5 (GA3-70 ppm, BRs-2ppm with 6:2 planting ratio) recorded the highest panicle exsertion (8.707 cm), plant height (145.653 cm) and flag leaf area (64.747 cm2) followed by T6 (GA3-70 ppm, BRs- 2ppm with 8:2 planting ratio). The highest productive tiller (25.00), total tiller (27.00), number of leaves (135.00) and leaf angle (26.600º) were observed in T6 (GA3-70 ppm, BRs-2ppm with 8:2 planting ratio) and followed by T5. The higher concentration of BRs reduced the flag leaf area (42.767) in T3 (GA3-50 ppm, BRs-6ppm with 6:2 planting ratio). The morphological traits of the male sterile line was improved with respect to panicle exsertion, flag leaf area, productive tillers and leaf area index by the application of GA3 70ppm and BRs 2ppm. The 1000 grain weight was higher in T3 (19.400g) followed by T5 (17.267g) and T6 (16.500g) and the least was in control treatment T4 (13.733g) and T7 (13.900g). The highest number of filled grain per panicle (33.00 nos) and lowest number of unfilled grains per panicle (17 nos) were observed in T5 with 70ppm GA3. The highest number of unfilled grains per panicle was found in control plants (T4 and T7). The Spikelet fertility percentage was more in T5 (19.507%), followed by T3 (16.140%) and less fertility percentage was observed in control plants T4 (7.127%) and T7 (7.397%). Highest seed yield per plot was recorded in T6 (1489.320g) followed by T5 (1355.746g) lowest seed yield was observed in control plants T4 and T7. The drawback of CMS line could be minimized by the application of hormones and improve seed set can be obtained. Humidity and the wind velocity prevailing in the location was not favorable for free flow of pollen and better seed set. So a more favorable season has to be tested for better yield. In this study the doze of Brassino steroids 2ppm and GA 70 ppm in both planting ratios of 6:2 and 8:2 had given substantially higher yield over the control. So hybrid rice seed production in Kerala can be enhanced by spraying of GA3 70ppm and brassinosteroid 2ppm at 15-20% heading of tillers and 35-40% panicle emergence. The row ratio of the female parent to the restorer parent can be 8:2 considering the increased seed yield realized. More seasons and locations have to be tested to identify the best season and location for hybrid rice seed production in Kerala.
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    ThesisItemOpen Access
    Effect of high temperature stress on seed fillings and nutritional quality of rice (Oryza sativa L.)
    (Department of Seed Science and Technology, College of Agriculture, Vellayani, 2020) Kandanulu, Pravallika; KAU; Beena, R
    Kandanulu Pravallika Date: 26-06-2020 2018-11-162 Time: 2.00- 2.30 pm EFFECT OF HIGH TEMPERATURE STRESS ON SEED FILLING AND NUTRITIONAL QUALITY OF RICE (Oryza sativa L.) The present study entitled “Effect of high temperature stress on seed filling and nutritional quality of rice (Oryza sativa L.)” was conducted in the Department of Seed Science and Technology, College of Agriculture, Vellayani during the period from 2018-2020 with the objective to study the effect of high temperature stress on seed filling and nutritional quality of rice. The extent of variation for various seed quality parameters, enzymes and yield parameters were assessed as an indicator of high temperature stress from three rice varieties namely Prathyasa, Hraswa and Manuratna. These varieties were collected from Regional Research Station (RRS), Moncombu and from Agricultural Research Station (ARS), Mannuthy respectively. The experiment was laid out in CRD with two treatments such as control and high temperature conditions and replicated thrice. The plants were kept in a temperature controlled polyhouse from seedling to maturity stage. Seed quality and enzyme parameters were analyzed at 30 and 50 days after 50 percent flowering and yield parameters were taken at harvest stage. Seed filling parameters recorded at milky and dough stage had revealed that high temperature stress condition resulted an increase of reducing sugar (14.810 mg g-1), carbohydrates (898.310 mg g-1), starch (14.961 mg g-1), and flavonoids (14.385 mg 100g-1) compared to control. However, amylose (17.692 %), seed protein (4.081 %), and anthocyanin (15.490 mg 100g-1) showed reduction under high temperature stress condition. Activity of invertase was reduced under high temperature condition compared to control in all varieties from 15 to 30 days after 50 % flowering. Under high temperature condition, spikelet fertility percentage and grain yield/plant were reduced compared to control condition. Among three varieties, highest grain yield/plant (22.790 g/plant) and spikelet fertility percentage (80.598 %) under high temperature was recorded by Prathyasa. Average reduction of grain yield/ plant and spikelet fertility percentage under high temperature was 18.733 g/plant and 74.245 % respectively. Percentage of yield reduction was maximum for Hraswa variety (27.57 %) when compared to varieties Prathyasa (21.1 %) and Manuratna (21.18%). Pollen viability percentage was reduced under high temperature condition compared to control. Prathyasa recorded the highest pollen viability (86.358 %) and Hraswa recorded the lowest pollen viability (77.948 %). Average reduction in pollen viability under high temperature condition was 82.653 %. There is significant difference for seed protein content among varieties. Highest seed protein content was recorded by Hraswa. There is no significant difference between Prathyasa and Manuratna for reducing sugar content, amylose, starch, invertase and yield. High temperature stress in rice recorded an increase of reducing sugar, carbohydrates, starch and flavonoids. Grain yield/ plant, spikelet fertility percentage, amylose, anthocyanin, seed protein and invertase activity were reduced under high temperature condition in all the varieties. Flavonoids are the secondary metabolites that are increased in high temperature condition and it helped in defense. High temperature had adverse impact on yield, spikelet fertility and pollen viability and the impact were greater in Hraswa variety. The correlation analysis revealed that under high temperature condition yield showed positive and significant correlation with total carbohydrate, starch, anthocyanin, spikelet fertility and pollen viability. Hence it is important to identify the rice varieties which possess the major seed filling parameters which play a vital role in increasing thermotolerance that result in giving a satisfactory grain yield even under conditions of heat stress.
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    ThesisItemOpen Access
    Precision farming techniques for quality seed produciton in okra (abelmoschus esculentus (l.) moench)
    (Department of Seed Science and Technology, College of Horticulture, Vellanikkara, 2019) Rosna, S; KAU; Sreelatha, U
    Quality seeds of okra, a popular vegetable crop in Kerala, are in great demand. An experiment was conducted during the period from January to April 2019 at the Centre for High-tech Horticulture and Precision Farming, Vellanikkara, to study the effect of precision farming techniques on growth, fruit and seed yield of okra. The field experiment was laid out in a Randomized Block Design (RBD) with 7 treatments which included two levels of irrigation viz., I1- Drip irrigation at 75% evapo-transpiration (EP) and I2- Drip irrigation at 100% EP and three levels of Fertigation viz., F1: 75% RDF (recommended dose of fertilizer), F2:100% RDF and F3:125% RDF. Fertilizer doses as per POP recommendation for the crop i.e., 110:35:70 kg NPK/ ha was adjusted based on soil test data. Drip irrigation was given daily based on PAN evaporation data while fertigation was administered twice a week. All the drip fertigation plots were mulched with 30 μ silver polythene film. A plot that was administered flood irrigation along with soil application of fertilizer as per POP fixed, vide soil test data, served as the control. The growth parameters of the crop in all the drip fertigation treatments were significantly superior to control. I1F1 exhibited significant superiority over other treatments with respect to plant height (84.40 cm), height of the first bearing node (17.55 cm), LAI (1.19) and fruit set (73.00%). Early flowering (47.33days) was also observed in this treatment. Between the different levels of irrigation, I1 (irrigation at 75% EP) showed significant increase in plant height (79.23 cm), height of the first bearing node (14.40 cm), LAI (1.01) and fruit set (70.33%) when compared to I2 (100% EP). I1 also registered earlier flowering (48.89 days) when compared to I2 (53.33 days). However, LAI was not influenced by different levels of irrigation. No significant difference was exerted by different levels of fertigation on characters like plant height, LAI, days to 50% flowering and fruit set. However, in the case of first bearing node, F1 (15.21 cm) followed by F3 (13.90 cm) was superior to F2 (12.95 cm). Significant interaction effect of irrigation and fertigation levels was evident with respect to LAI and fruit set. Fruit characters like length, girth, weight, mature fruit yield per plant and number of mature fruits per plant were significantly superior in drip fertigation treatments compared to control. Except I2F3, all other fertigation treatment produced significantly thicker fruits than the control (1.90 cm). Mature fruit weight was significantly high in treatments 11F1 (9.10 g) and I1F2 (8.59 g), followed by I2F2 (7.60g). However, mature fruit yield (154.85 g) and number of mature fruits (30.91) were significantly high in I1F1. Fruit characters like fruit length and girth were not influenced by different levels of irrigation and fertigation as well as their interaction effect. However, I1 showed significant increase in fruit weight (8.09 g), mature fruit yield (116.49 g) and number of fruits (25.67g) when compared to I2. Mature fruit weight (8.20 g & 8.09 g) and number of fruits (24.19 & 22.98) were on par in F1 and F2. Among the interactions, I1F1 showed superior performance in fruit weight, mature fruit yield/plant and number of fruits/plant. With respect to seed characters like number of seeds per fruit, seed weight /fruit, seed yield per plant, 100 seed weight, seed germination and seedling vigour index, the drip fertigation treatments were significantly superior to control. Between the irrigation levels, I1 significantly increased number of seeds/fruit, seed yield/plant and seedling root length when compared to I2. But seedling vigour index was significantly higher in I2 (2504) compared to I1 (2424). However, characters like seed weight/fruit, 100 seed weight, 100 seed volume, germination, moisture content, hard seed content and seedling shoot length were not affected by irrigation levels. Among the fertigation levels, seed germination and seedling vigour index was highest in F1 (93.33 % and 2914) while F2 showed increased number of seeds/fruit (42.87) whereas F3 showed increased 100 seed weight (6.70g), seedling shoot length (22.68 cm) and low hard seed content (8.48%). Seed weight and seed yield were not influence by fertigation levels. Significant interaction effect of irrigation and fertigation levels were evident in number of seeds/fruit, 100 seed weight, seed germination and seedling root length. I1F1 was found to be significantly superior for most seed traits studied. But seedling vigour index was significantly higher in I2F1 (2947). Storage studies were conducted with seeds of okra variety, Arka Anamika procured from Centre for High-tech Horticulture and Precision Farming, Vellanikkara. The seeds were treated with polykote (synthetic polymer) @ 5 and 10 ml per kg of seed along with plant protection chemicals viz., carbendazim-mancozeb (Saaf- 2g/kg of seed) and bifenthrin (0.1%) or biocontrol agent- Trichoderma viridae (4g/kg of seed). Untreated seeds served as control. The seeds were packed in 700 gauge polyethylene bags and stored under both cold (refrigerated) and ambient conditions and seed quality parameters assessed at bimonthly intervals. With the advancement of storage period, germination declined irrespective of the treatments in both the storage conditions. Throughout the storage period, performance of treated seeds was found to be significantly superior over control. At the end of twelve months of storage, higher seed germination was recorded in seeds treated with polykote (10ml) + carbendazim- mancozeb (2g) + bifenthrin (0.1%) both under cold (75.33%) and ambient (71.33%) conditions. Lower values were recorded in untreated control (60.33 per cent under cold storage and 56.33 under ambient storage). Both seedling shoot length and root length were significantly higher in treatment with polykote (10ml) + carbendazim- mancozeb (2g) + bifenthrin (0.1%) both under cold and ambient conditions. Seedling dry weight was also significantly higher in the same treatment in the cold storage while in the ambient condition, there was no significant difference among the treatments. The EC of seed leachate and seed microflora also showed the same trend with very low value for polykote (10ml) +carbendazim- mancozeb (2g) + bifenthrin (0.1%) in both cold and ambient conditions. From the study it can be concluded that drip irrigation at 75% EP and 75% of RDF along with mulch, is best for seed production in okra. Storage of seeds treated with polykote (10ml) + carbendazim- mancozeb (2g) + bifenthrin (0.1%) in cold is recommended to ensure minimum seed certification standards.
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    ThesisItemOpen Access
    Susceptibility of red flour beetle, tribolium castaneum (herbst) (coleoptera:
    (Department of Seed Science and Technology, College of Horticulture, Vellanikkara, 2019) Anusree, R P; KAU; Berin, Pathrose
    The red flour beetle, Tribolium castaneum (Coleoptera: Tenebrionidae) is a cosmopolitan stored grain pest, causing postharvest losses of more than 20 per cent in developing countries and up to nine per cent in developed countries. Even though several practices are available for management of T. castaneum, chemical control remains the most efficient, easy and economic method to reduce the insect pest populations to acceptable levels. Selection pressure from insecticides, however has led to development of resistance in T. castaneum to insecticides. Tribolium castaneum ranks 17th among the 20 most insecticide resistant arthropods in the world and it has already developed resistance against phosphine, methyl bromide, organophosphates, pyrethroids and insect growth regulators which are the commonly used insecticides for its management. The present study entitled “Susceptibility of red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) to insecticides” was undertaken at the Department of Agricultural Entomology, College of Horticulture, Vellanikkara during October 2018 to July 2019. The objective of the study was to assess the susceptibility of red flour beetle populations to selected insecticides, to study the biochemical basis of resistance and to screen new molecules for the safe management of T. castaneum. Different populations of T. castaneum were collected from five different godowns of Food Corporation of India (FCI), viz., Thikkodi, Olavakkode, Mulangunnathukavu, Angamaly and Valiyathura. These five strains, along with the susceptible strain of T. castaneum (procured from Division of Entomology, Indian Agricultural Research Institute (IARI), New Delhi) which was maintained without exposure to any insecticides for more than 35 years, were used to conduct the experiments. Residual film bioassay with malathion, dichlorvos and deltamethrin, which were the recommended and commonly used insecticides in FCI godowns, revealed that susceptibility to malathion was lowest in the Angamaly strain of T. castaneum, while susceptibility to dichlorvos and deltamethrin was lowest in Olavakkode and Thikkodi strains, respectively. While, all the three recommended pesticides were toxic to the susceptible strain. Resistance ratio for all the field collected strains, with malathion, ranged from 10.95 in Thikkodi strain to 13.34 in Angamaly strain. There was a significant decrease in susceptibility to dichlorvos also. Biochemical basis of insecticide resistance was investigated by estimating the amount of detoxifying enzymes such as carboxyl esterase, glutathione-Stransferase and cytochrome P450 in different strains of T.castaneum. The activity of all the three detoxifying enzymes were significantly higher in field collected populations over that of the susceptible strain. Correlation studies indicated that carboxylesterase and cytochrome P450 levels were significantly correlated with the LC50 values. Residual film bioassay was done to evaluate the susceptibility of different strains of T. castaneum to new insecticide molecules viz., bifenthrin, chlorfenapyr, spinosad and flubendiamide. Bifenthrin and chlorfenapyr was found to be most toxic to all the T. castaneum strains, while, spinosad and flubendiamide were not effective in controlling T. castaneum. When compared to malathion, bifenthrin was 104 to 378 times more toxic, while chlorfenapyr was 1214 to 2236 times toxic to the field collected strains. The most effective insecticides, selected based on the relative toxicity studies along with FCI recommended pesticides, were sprayed on small jute bags containing 1 kg of rice. A method was developed and validated to analyse the residues of malathion, deltamethrin, chlorfenapyr and bifenthrin in rice samples with limit of detection and limit of quantification of 0.02 and 0.08 ppm, respectively. Pesticide residue analysis was carried out at different sampling intervals. When the sprayed sample was analysed after 2 hours of pesticide spray, 0.084 ppm of malathion was detected, which was below the MRL level of 4 ppm. However, residue levels, 1 and 3 days after spraying were below detection limit. In case of chlorfenapyr, bifenthrin and deltamethrin the residue levels were below detection limit throughout the study period.
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    ThesisItemOpen Access
    Potassium nutrition on vivipary and seed quality in oriental pickling melon (cucumis melo var. conomon mak.)
    (Department of Seed Science and Technology, College of Horticulture, Vellanikkara, 2019) Athulya Kumar, S; KAU; Dijee, Bastian
    Oriental pickling melon ( is an important vegetable crop cultivated in Kerala. This short duration crop has the potential to produce high yields with low input requirements, so often referred as unique vegetable of Kerala. Quality seed production in melon is affected due to the occurrence of vivipary. A study in oriental pickling melon varieties, Saubhagya and Mudicode was conducted in the Department of Seed Science and Technology, College of Horticulture, Vellanikkara, Thrissur, during 2017-2019 to elucidate the effect of potassium nutrition on vivipary and seed quality. The objective of the study was to assess the effect of time of planting and potassium application on vivipary and their effect on seed quality. The effect of time of planting on vivipary was assessed with three different time of planting i.e., December, January and February following a factorial randomized design with four replications. The fruit and seed yield attributes were found to be significantly influenced by varieties, time of planting and their interaction. Variety Mudicode was superior in parameters like fruit weight, fruit yield and female flower emergence was early in the crop sown in December. However, the presence of viviparous seeds and chaffy seed percentage were observed to be high in December planted crop. The potassium content in fruit flesh and placenta was found to be highest in the crop sown during February with minimum percentage of viviparous and chaffy seeds. The results point out that December planting is advantageous for fruit yield while February planting is advantageous for seed production in variety Mudicode. The interaction between varieties and time of planting on seed quality indices pointed out that it is advantageous to go for February time of planting for variety Mudicode for seed production. In order to study the effect of potassium on vivipary a crop was raised in February 2018 following a factorial randomised design with six treatments and three replications. During the experiment, fruit and seed quality parameters were found to be significantly influenced by varieties, fertilizer levels and their interaction. Variety Mudicode exhibited high fruit yield attributes, fresh and dry weight of seeds and 100 seed weight whereas seeds per fruit, seed yield was superior in Saubhagya with low percentage of viviparous seeds. Irrespective of varieties, treatments with additional potassium application i.e., POP + 25% K, POP + 50% K, and POP + foliar spray recorded high fruit and seed yield. Organic nutrient management also resulted in seed yield of 7.48 kg ha-1. High potassium content in fruit placenta and fruit flesh was found in treatments which exhibit least percentage of viviparous and chaffy seeds i.e., POP + foliar spray and POP + 50% K. Additional potassium application was found to be advantageous for reducing the occurrence of viviparous seeds by increasing the K content in fruit placenta and flesh. The interaction between varieties and fertilizer levels on fruit and seed parameters pointed out that additional potassium nutrition was advantageous for fruit and seed yield production of Mudicode whereas fruit weight, seeds per fruit, seed yield and occurrence of viviparous seeds and chaffy seed percentage was the least among the treatment combination of variety Saubhagya with POP + foliar spray. The seed quality during storage was evaluated following a factorial completely randomized design with the seeds collected from Experiment-II (six treatments and two replications). The seeds were dried to less than 8 per cent moisture and packed in polyethylene covers of 700G and stored under ambient conditions for a period of six months. The seed quality parameters were recorded at monthly intervals. The seed moisture and seed micro flora per cent were recorded at the start and end of the storage. Seed longevity was found to be significantly vary between varieties, fertilizer levels, and their interaction throughout the storage period. Germination, vigour indices I and II, decreased progressively over the storage period. However, towards the end of storage period, there was an increase in mean time to germination, time taken for 50 per cent germination, electrical conductivity of seed leachate, seed micro flora per cent. Irrespective of the varieties, fertilizer levels and their interaction, germination percentage of 60 per cent was retained even after six months. The study revealed that that the seeds can be stored for 6 months under the ambient conditions.
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    Seed invigoration with inorganic nanoparticles in chillies (capsicum annuum l.)
    (Department of Seed Science and Technology, College of Horticulture, Vellanikkara, 2019) Gayathri, Sathees; KAU; Dijee, Bastian
    A study entitled ‘Seed invigoration with inorganic nanoparticles in chillies (Capsicum annuum L.)’ was conducted in the Department of Seed Science and Technology, College of Horticulture, Vellanikkara between February 2018 and May 2019 to investigate the effect of nano and bulk particles of zinc oxide (ZnO) and titanium dioxide (TiO2), on longevity of chilli variety Anugraha. The present study was subdivided into four experiments. In experiment I, fresh seeds of chilli were treated with ZnO (nano and bulk particle) and stored under ambient conditions. Experiment I consisted of dry dressing chilli seeds with TiO2(nano and bulk). In both the experiments treated seeds performed better than the control. In experiment I, the seeds treated with T3 - ZnO @ 900 mgkg-1, T4 - ZnO @ 1300 mgkg-1, T6 - nano ZnO @ 250 mgkg-1 and T7 - nano ZnO @ 500 mgkg-1 were able to maintain the minimum germination standard of 60.00 per cent stipulated by the IMSCS (Indian Minimum Seed Certification Standards) in chilli upto 10 MAS. The vigour index-I and II were found to be high in T4 (ZnO @ 1300 mgkg-1), T7 (nZnO @ 500 mgkg-1) and T3 (ZnO @ 900 mgkg-1). The seed leachate obtained from T7 gave the lowest measurement (246 μS cm-1) of electrical conductivity. Control seeds were found to contain higher per cent of infection on comparison with the treated seeds. Chilli seeds treated with T3 - TiO2 @ 900 mgkg-1, T4 - TiO2 @ 1300 mgkg-1, T6 - nanoTiO2 @ 250 mgkg-1 and T7 - nanoTiO2 @ 500 mgkg-1 were able to maintain IMSCS up to ten months of storage, while the control (T1) lost the germination after eight months, i.e., T7 (63.00 per cent), T3 (61.33 per cent), T4 (61.00 per cent) and T6 (60.00 per cent). At the end of ten months of storage, all the treated seeds had lower electrical conductivity compared to control seeds. In both experiments, the seed infection per cent was found to be higher in untreated seeds compared to the treated ones. It was also evident that the treated seeds possessed better seed quality parameters compared to untreated seeds (control). In experiments III and IV fresh seeds which were treated with various doses of zinc oxide and titanium dioxide respectively, were subjected to accelerated ageing at a temperature of 40±1°C and relative humidity of 100 per cent for one day. In experiment III, the zinc oxide treated seeds after accelerated ageing revealed that seeds treated with T7 - nano ZnO @ 500 mgkg-1 retained a high germination of 49.00 per cent, followed by T4 (43.00 per cent). In terms of vigour index I and II, T7 and T4 were found to be on par with each other. The seed infection was found to be lower in nano ZnO treated seeds compared to control and normal grade ZnO treated seeds. The least infection was detected in T7 - nano ZnO @ 500 mgkg-1. Experiment IV consisted of untreated and TiO2 treated seeds which were subjected to accelerated ageing. Even after artificial ageing, T7 - nano TiO2 @ 500 mgkg-1 was able to retain 51.67 per cent germination in the first month. It was on par with T4 - TiO2 @ 1300 mgkg-1 (47.33 per cent) and T3 - TiO2 @ 900 mgkg-1 (44.67 per cent). The highest vigour index was observed in seeds treated with T7 - nano TiO2 @ 500 mgkg-1 (520) and it was on par with T4 - TiO2 @ 1300 mgkg-1 (437). T7 exhibited the highest vigour index-II (953) and was on par with T3 - TiO2 @ 900 mgkg-1 (863) and T4 - TiO2 @ 1300 mgkg-1 (813). The lowest electrical conductivity was obtained from the seed leachate of T7 (246 μS cm-1). The seed infection per cent was found to be the least in T7 - nano TiO2 @ 500 mgkg-1 treated seeds. Scanning electron micrograph of the radicles of seeds treated with nZnO and nTiO2 @ 500 mgkg-1 revealed higher cell proliferation at root tip and larger cells in the zone of elongation. The results obtained indicate that dry dressing of chilli seeds with zinc oxide and titanium dioxide is effective in improving the seed quality parameters during storage. The results of accelerated ageing test are also in agreement with the results obtained from storage under ambient conditions during natural ageing. Among various doses of zinc oxide T7 - nano ZnO @ 500 mgkg-1 and T4 - ZnO @ 1300 mgkg-1 exhibited the best results, whereas, among titanium dioxide treatments, T7 - nano TiO2 @ 500 mgkg-1 and T4 - TiO2 @ 1300 mgkg-1 seed were found to be the best doses.