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ThesisItem Open Access DEVELOPMENT OF INTEGRATED PEST MANAGEMENT MODULES AGAINST INSECT PESTS OF BHUT JOLOKIA (Capsicum chinense Jacq.)(2019-09) Bora, Sasanka Sekhar; Saikia, D. K.Experiments were carried out under field conditions at the Experimental Farm, Department of Horticulture as well as in the Department of Entomology and Department of Plant Pathology, Assam Agricultural University, Jorhat during 2017-18 and 2018-19 to study the major sucking and chewing pests of Bhut Jolokia causing substantial losses in fruit yield. At present, IPM has been attaining immense importance in the agricultural scenario of India and abroad. Therefore, evaluation of sustainable IPM modules was felt very much necessary in Bhut Jolokia. The result revealed that altogether twenty three numbers of insect pests were associated with the crop and among them aphid (Aphis gossypii Glover/Myzus persicae Sulzar), Whitefly (Bemisia tabaci Gennadius), thrips (Scirtothrips dorsalis Hood), yellow mite [Polyphagotarsonemus latus (Banks)], Cutworm (Agrotis ipsilon Hufuagel) and fruit fly [Bactrocera dorsalis (Hendel)] were considered as the key pests of Bhut Jolokia. Highest incidence of major pests was obtained in the 1st fortnight of April during 2018 as against 2nd fortnight of April during 2019, respectively. A new invasive pest, spiraling whitefly (Aleyrodicus dispersus Russel, Aleyrudidae:Hemiptera) was also reported for the first time in Bhut Jolokia from Assam. Five IPM modules were evaluated against insect pests of Bhut Jolokia, of which module I comprised of recommended dose of fertilizer and farm yard manure+ application of microbial consortium + growth promoter viz., Tricontanol + weeding at 30, 60 and 90 Days after transplanting (DAT) + imidacloprid 17.8 SL 0.4 ml per lt @ 40 days interval was found to be the most effective module in respect of B: C ratio (3.02: 1) followed by module III (Vermicompost 1.25t/ha+ neem cake 500 kg/ha + application of microbial consortium + black polythene mulching + garlic extract @ 10% at 20 and 70 DAT +NSKE 5% at 35 and 100 DAT + installation of sticky trap @ 25 traps /ha) where the B:C ratio was 2.96 with maximum yield of 740.74 gm per plant with next higher yield of 712.13 gm per plant in module I. Hence, module III in comparison to module I seems to be quite promising strategy as it did not require any insecticidal interference keeping natural enemies and ecosystem undisturbed. Out of eight cultivars collected cv. Assam 1 (King) contributed maximum yield of 719.85 gm per plant followed by Assam 4 with 626.67 gm per plant with minimum susceptibility towards pests and diseases. Correlation studies between sucking pests and phenotypic characters indicated that only number of leaves and leaf area index had negative significant impact while other parameters viz., plant height and branches showed no effect. Result of different shade level, 75 per cent shade showed highest plant height and leaf area index of 90.01 cm and 1.81 as against open condition where it was only 53.18 cm and 1.46. The number of leaves and branches of Assam 1 cultivar were to be highest 220.51 cm and 8.75 in open condition, while they were 80.75 cm and 5.13 in 75 per cent shade level. Likewise, for flowering, 116.75 days required in case of 75 per cent shade level, whereas it was only 93.25 days in case of open condition. Similarly, fruit numbers also reduced in case of 75 per cent shade level which was only 27.0 while 92.13 was in case of open condition. Yield per plant was also around 718.13 gm per plant in open condition, whereas it was only 223.63 gm per plant in 75 per cent shade level. The major sucking pests and coccinellid predator population found to be in higher side in open condition also. In 75 per cent shaded area the pooled infestation of aphid, whitefly, thrips and mite was 0.62, 0.35, 0.26 and 0.54 numbers per three leaves whereas, it was 1.69, 1.58, 1.25 and 2.58 numbers per three leaves in open condition. Predatory spider population found highest with 0.34 numbers per plant while coccinellid population was lowest with 0.15 numbers per plant at 75 per cent shade level. But coccinellid population was highest with 0.40 numbers per plant in open condition while 0.18 numbers per plant spider also found at open condition, respectively. RT PCR method confirmed the presence of Cucumber mosaic virus (CMV) on whole seed and seed coat, which indicates that CMV transmitted through seed.ThesisItem Open Access MORPHO-BIOCHEMICAL CHARACTERIZATION OF ROUGH LEMON (Citrus jambhiri Lush.) OF ASSAM(2019-07) Pathak, Purnima; Khangia, B.Rough lemon (Citrus jambhiri Lush.), commonly known as ‘Gol Nemu’ is an underutilized citrus fruit of Assam. It is mostly grown as backyard crop in homestead garden. The fruit is a rich source of vitamins, minerals, flavonoids, limonoids etc. It is polyembryonic in nature and highly cross pollinated. Most rough lemon plants are of seedling origin in the region and thus tend to exhibit a wide range of variability in terms of morphological and biochemical parameters. Therefore, an investigation was undertaken during 2016-2017 on ‘Morpho-biochemical characterization of rough lemon (Citrus jambhiri Lush.) of Assam to study the existing variability. One district in each of the six agro climatic zones was chosen and five plants were selected in each district, comprising of thirty plants. Wide variability was observed among the selected rough lemon accessions for qualitative characters of tree, leaf, flower, fruit and seed. Four different fruit shapes were recorded viz. spheroid, obloid, obovoid and ellipsoid. Wide variations in pulp colour i.e. ivory white, orange, orange-red, yellow were recorded in the selected rough lemon. Cluster analysis of 45 qualitative and 25 quantitative characters using SPSS resulted in grouping of the rough lemon accessions into three broad groups. Group I consisted of 17 accessions (AR01T1, AR01T2, AR01T3, AR02T1, AR02T2, AR02T3, AR02T4, AR03T2, AR03T3, AR04T4, AR05T1, AR05T2, AR05T3, AR05T4, AR06T2, AR06T3, AR06T5) of all locations. Group II consisted of six accessions (AR01T5, AR03T1, AR03T4, AR03T5, AR04T1, AR06T1). Group III consisted of seven accessions (AR01T4, AR02T5, AR04T2, AR04T3, AR04T5, AR05T5, AR06T4). No groups were formed based on geographical location indicating that qualitative and quantitative traits were largely influenced by genetic factor. The quantitative characters of flower, leaf and fruit showed significant variation among the rough lemon accessions. The maximum fruit weight was recorded in accession number AR02T5 (144.34 g) and the minimum was recorded in AR03T1 (17.36 g). In terms of biochemical constituents, the highest TSS was recorded in accession number AR06T4 (8.87 °B) and the lowest was recorded in AR02T1 (6.13 °B). The highest TSS-acid ratio was recorded in accession number AP06T4 (2.12) and the lowest was recorded in AR02T1 (1.00). HPLC quantification of limonin showed significant variations among the rough lemon accessions which ranged from 10.42 to 24.07 mg/100ml. Among the 30 rough lemon accessions, two main groups were recognized based on 12 biochemical constituents with strong genetic similarity within a location. All the morphological quantitative traits i.e. fruit length, fruit diameter, rind thickness, seeds per fruit, seed weight, juice content, juice per cent showed significant variation among different locations. Significant differences among the locations were observed with respect to biochemical constituents except essential oil content. The highest TSS, total sugar, TSS-acid ratio were recorded in location L6 (Cachar) and the lowest value was recorded in location L4 (Biswanath). Present study on propagation of rough lemon through seed showed an average germination percentage of 87.67 % and air layering recorded a success percentage of 92.11%. However, propagation through stem cutting was found to be comparatively difficult with moderate success percentage (79.11%). Three elite types i.e. AR03T1, AR06T1 and AP06T4 were identified in terms of high overall acceptability (>8), TSS-acid ratio (>2.00), less seed content (≤10 per fruit), low limonin content, high essential oil (>4%), high ascorbic acid and antioxidant activity (>80mg/100ml juice) and thin to medium rind thickness.ThesisItem Open Access GENETIC ENHANCEMENT IN TOMATO (Solanum lycopercicum L.) FOR RESISTANCE TO BACTERIAL WILT AND QUALITY THROUGH INTRA AND INTER-SPECIFIC HYBRIDIZATION(2019-07) Das, S. Yasmin; Borkakaty, R. P.Tomato is the most important solanaceous vegetable crop. To estimate its production under the challenges of bacterial wilt disease, it is important to identify potential genotypes with resistance to bacterial wilt disease of tomato. To achieve this goal an investigation on ‘Genetic enhancement in tomato for resistance to bacterial wilt and quality through intra and inter-specific hybridization’ had been taken up to study the performance of few genotypes, their heterosis and combining ability and nature of gene action. The experiment was carried out at the experimental field of Horticultural Research Station, Assam Agricultural University, Kahikuchi, Guwahati during rabi seasons of 2015-16, 2016-17 and 2017-18. Evaluation of six parents, fifteen F1, fifteen F2, three BC1 and three BC2 generations of tomato revealed existence of sufficient variability and interaction effects in the genotypes. Combining ability analysis in Diallel mating design without reciprocals involving six diverse tomato cultivars/lines, viz., Singimari Local, Megha, Solan Lalima, Arka Abha, Arka Alok and Kon bilahi and their 15 cross combinations in bacterial wilt sick plots revealed importance of both additive and dominance effects. Two parents, Singimari Local and Kon Bilahi were identified as good general combiner. Ten cross combinations out of total fifteen combinations exhibited high estimates of specific combining ability for different desirable traits. Among them the crosses which merit special consideration were Singimari Local x Solan Lalima for yield per plant(g), harvest duration and bacterial wilt survival (% ); Singimari Local x Kon Bilahi for number of fruits per plant(g) and bacterial wilt survival (%) ; Solan Lalima x Kon Bilahi for number of fruits per plant, harvest duration, pH of pulp and bacterial wilt survival (%); Arka Abha x Arka Alok for harvest duration ,pH of pulp, fruit weight(g), number of primary branches per plant and yield per plant (g); Megha x Kon Bilahi for days to first picking, days to maturity, pericarp thickness(mm), TSS (° Brix) and bacterial wilt survival (%) could effectively be used to exploit heterosis in bringing about desired genetic improvement. Besides, the crosses showing desirable SCA for yield per plant (g) and bacterial wilt survival (%) but without significant heterosis were Arka Alok x Kon Bilahi, Megha x Arka Alok, Singimari Local x Arka Abha and Arka Abha x Kon Bilahi. These crosses could be ideal for further selection to bring them into homozygous genetically improved lines. Generation mean analysis was carried out in three crosses viz. Singimari Local x Megha, Singimari Local x Kon Bilahi and Megha x Kon Bilahi involving six generations (P1, P2, F1, F2, BC1 and BC2). The individual scaling tests were used to test the adequacy of additive dominance model. The gene effects were estimated using three parameter model (Joint Scaling Test) suggested by Cavalli (1952) and six parameter model suggested by Haymen (1958). The analysis of variance among different generations of different crosses revealed significant variation for all the eighteen characters indicating considerable variability in the material studied. All the characters except productive flower retention (%) in cross Singimari Local x Megha recorded significance for at least one of the four individual scaling tests in all the 3 crosses. With respect to interaction effects, all the characters except productive flower retention (%) in cross Singimari Local x Megha, exhibited significant interaction effect for one or more epistatic interactions i.e.[i], [j] or [l] in all the three crosses studied. It is evident that for all the morpho-physiological and yield attributing traits, fruit quality traits and bacterial wilt survival(%) additive, dominance and interaction effects were present indicating the complex inheritance of the traits under study. Further enhancement of the genotypes identified in this study will pave the way for the development of high yielding tomato variety with resistance to bacterial wilt disease.ThesisItem Open Access STATUS OF WOMEN TEA PLANTATION WORKERS IN JORHAT DISTRICT OF ASSAM(2019-07) Jumi, Toko; Borah, SayanikaThe present study entitled as “Status of Women Tea Plantation Workers in Jorhat District of Assam” was conducted in Jorhat district of Assam. Four (4) tea gardens under public corporation from Jorhat sub-division were selected using purposive sampling method. A total of 100 women tea plantation workers were selected randomly using a simple random sampling method. The personal interview method was applied for the collection of primary data. Data were analysed using percentage, mean, standard deviation and ranking. It has been observed that the majority of respondents (45.00%) were under the age group young category i.e. 18-30 years. Majority of respondents (77.00%) were married. More than half of the respondents (52.00%) were illiterate. Cent per cent of the respondents was under Minority and Other Backward Class (MOBC). The data also revealed that the majority of respondents were from the nuclear family (77.00%) and 55 per cent of respondents belonged from a small family (till 4 members). Majority of the respondents lived in Katcha house (88.00%). The pipeline was the source of water for 66 per cent of respondents. 46 per cent of respondents had a low-cost latrine. Daily wage labourer was the occupation of respondent's head of the family for 81 per cent of the respondents. 50 per cent of the respondents earned between (Rs. 4492- Rs. 5012) monthly. A large percentage of the respondents had no subsidiary source of income (96.00%). 51 per cent of the respondents had no membership in any organisation. In material possession, a very high percentage of the respondents possessed traditional Chulha (99.00%), 36 per cent of respondents possessed two-wheeler and in livestock, 52 per cent the respondents possessed hen. It was highlighted that 71 per cent of the respondents had a medium level of mass media exposure. More than half of the respondents had a medium level of conservatism- liberalism (63.00%). It is revealed from the findings that the majority of the respondents made a joint decision with their husbands in taking the final decision in various activities. Independent decision was also seen among the respondents which were highest in areas of maintenance of the house (84.00%), selection and preparation of food (73.00%), voting in the election (66.00%), taking part in social events (44.00%), and recreational activities (40.00%). The data revealed that the majority (51.00%) of the respondents were most interested in poultry farming followed by goat rearing (14.00%). The data also highlighted that in an average respondents spent 7.94 hours in working at tea garden in a day followed by 7.88 hours in sleep, 2.08 hours in kitchen, 0.95 hours in watching TV, listening radio etc, 0.91 hours in personal care, 0.815 hours in care for children and family, 0.69 hours in cleaning, 0.29 in fetching water and cleaning, 0.28 hours in religious activities, 0.25 hours in collection of firewood, 0.10 hours in care for animals and 0.77 hours in social activities. The findings revealed that insufficient wage was ranked I with mean score (2.99), lack of toilet facilities at work was ranked II with mean score (2.95), no provisions for protective gears at work was ranked III with mean score (2.82), back pain due to carrying of tea baskets for a long time was ranked IV with mean score (2.45), cuts and rashes on fingers and palm due to plucking of tea leaves was ranked V with mean score (2.43).ThesisItem Open Access HEAT UNIT INDEXING OF GARDEN PEA IN RELATION TO CLIMATE SHIFT AND NUTRIENT MANAGEMENT(2019-07) Sangma, Trudy Tengse A.; Saikia, LuchonAn experiment was conducted consecutively during 2016-17 and 2017-18 in the Experimental Farm, Department of Horticulture, Assam Agricultural University, Jorhat to study the “Heat unit indexing of garden pea in relation to climate shift and nutrient management”. The experiment consist three treatments viz., variety (main), fertility management level (sub) and sowing date (sub-sub) laid out in split plot design with random allocation and replicated thrice. The main treatment consisted Arkel(V1), A1(V2), DS-10(V3) and GS-10(V4); sub treatment was comprised of 5t FYM, 10-46-0 kgha-1 (F1), 10t FYM, 10-46-10 kgha-1 (F2), 10t FYM, 20-46-20 kgha-1 (F3) and 10t FYM, 30-46-30 kgha-1 (F4) and sub-sub treatment was dates of sowing: 10th October (S1), 24th October (S2), 7th November (S3), 21st November (S4), 5th December (S5) and 20th December (S6). Growth, yield attributes, soil related and quality characters viz., plant height(cm), days to 50% flowering, pod plant-1, pod length (cm), pod diameter (cm), seed pod-1, shelling (%), pod yield (tha-1), duration (days), growing degree days, root nodules plant-1, total plant nitrogen (%), total plant phosphorus(%), total potash (%), TSS (0 Brix), crude protein (%), soil organic carbon (%), soil available nitrogen (kgha-1), soil available phosphorus (kgha-1), soil available potash (kgha-1) and soil pH have responded significantly due to treatments as well as their interactions, except pH. Variety evidently produced significant effect on growing degree days (GDD) and results showed V4>V3>V2>V1 with requirement of 955, 948, 933 and 833 GDD for 2016-17 and similarly 958, 949, 942 and 825 GDD. The maximum duration was reported as 76.00days in V4F with (1,2,3,4) and S( with 3,4,5). Duration was closely associated with degree days by sowing date had indicated significant duration among varieties, least with V1(58.73days), to maximum in V4(72.30days). Fertility level had a range of maturity at 68.08 to 68.29days. Sowing dates showed significance as 911(S1), 915(S2), 915(S3), 915(S4), 916(S5) and 918(S6) during 2016-17 and the GDD was found significant as S1ThesisItem Open Access STATUS OF WOMEN TEA PLANTATION WORKERS IN JORHAT DISTRICT OF ASSAM(2019-07) Jumi, Toko; Borah, SayanikaThe present study entitled as “Status of Women Tea Plantation Workers in Jorhat District of Assam” was conducted in Jorhat district of Assam. Four (4) tea gardens under public corporation from Jorhat sub-division were selected using purposive sampling method. A total of 100 women tea plantation workers were selected randomly using a simple random sampling method. The personal interview method was applied for the collection of primary data. Data were analysed using percentage, mean, standard deviation and ranking. It has been observed that the majority of respondents (45.00%) were under the age group young category i.e. 18-30 years. Majority of respondents (77.00%) were married. More than half of the respondents (52.00%) were illiterate. Cent per cent of the respondents was under Minority and Other Backward Class (MOBC). The data also revealed that the majority of respondents were from the nuclear family (77.00%) and 55 per cent of respondents belonged from a small family (till 4 members). Majority of the respondents lived in Katcha house (88.00%). The pipeline was the source of water for 66 per cent of respondents. 46 per cent of respondents had a low-cost latrine. Daily wage labourer was the occupation of respondent's head of the family for 81 per cent of the respondents. 50 per cent of the respondents earned between (Rs. 4492- Rs. 5012) monthly. A large percentage of the respondents had no subsidiary source of income (96.00%). 51 per cent of the respondents had no membership in any organisation. In material possession, a very high percentage of the respondents possessed traditional Chulha (99.00%), 36 per cent of respondents possessed two-wheeler and in livestock, 52 per cent the respondents possessed hen. It was highlighted that 71 per cent of the respondents had a medium level of mass media exposure. More than half of the respondents had a medium level of conservatism- liberalism (63.00%). It is revealed from the findings that the majority of the respondents made a joint decision with their husbands in taking the final decision in various activities. Independent decision was also seen among the respondents which were highest in areas of maintenance of the house (84.00%), selection and preparation of food (73.00%), voting in the election (66.00%), taking part in social events (44.00%), and recreational activities (40.00%). The data revealed that the majority (51.00%) of the respondents were most interested in poultry farming followed by goat rearing (14.00%). The data also highlighted that in an average respondents spent 7.94 hours in working at tea garden in a day followed by 7.88 hours in sleep, 2.08 hours in kitchen, 0.95 hours in watching TV, listening radio etc, 0.91 hours in personal care, 0.815 hours in care for children and family, 0.69 hours in cleaning, 0.29 in fetching water and cleaning, 0.28 hours in religious activities, 0.25 hours in collection of firewood, 0.10 hours in care for animals and 0.77 hours in social activities. The findings revealed that insufficient wage was ranked I with mean score (2.99), lack of toilet facilities at work was ranked II with mean score (2.95), no provisions for protective gears at work was ranked III with mean score (2.82), back pain due to carrying of tea baskets for a long time was ranked IV with mean score (2.45), cuts and rashes on fingers and palm due to plucking of tea leaves was ranked V with mean score (2.43).ThesisItem Open Access MORPHO-BIOCHEMICAL CHARACTERIZATION OF ROUGH LEMON (Citrus jambhiri Lush.) OF ASSAM(2019-07) Pathak, Purnima; Khangia, B.Rough lemon (Citrus jambhiri Lush.), commonly known as ‘Gol Nemu’ is an underutilized citrus fruit of Assam. It is mostly grown as backyard crop in homestead garden. The fruit is a rich source of vitamins, minerals, flavonoids, limonoids etc. It is polyembryonic in nature and highly cross pollinated. Most rough lemon plants are of seedling origin in the region and thus tend to exhibit a wide range of variability in terms of morphological and biochemical parameters. Therefore, an investigation was undertaken during 2016-2017 on ‘Morpho-biochemical characterization of rough lemon (Citrus jambhiri Lush.) of Assam to study the existing variability. One district in each of the six agro climatic zones was chosen and five plants were selected in each district, comprising of thirty plants. Wide variability was observed among the selected rough lemon accessions for qualitative characters of tree, leaf, flower, fruit and seed. Four different fruit shapes were recorded viz. spheroid, obloid, obovoid and ellipsoid. Wide variations in pulp colour i.e. ivory white, orange, orange-red, yellow were recorded in the selected rough lemon. Cluster analysis of 45 qualitative and 25 quantitative characters using SPSS resulted in grouping of the rough lemon accessions into three broad groups. Group I consisted of 17 accessions (AR01T1, AR01T2, AR01T3, AR02T1, AR02T2, AR02T3, AR02T4, AR03T2, AR03T3, AR04T4, AR05T1, AR05T2, AR05T3, AR05T4, AR06T2, AR06T3, AR06T5) of all locations. Group II consisted of six accessions (AR01T5, AR03T1, AR03T4, AR03T5, AR04T1, AR06T1). Group III consisted of seven accessions (AR01T4, AR02T5, AR04T2, AR04T3, AR04T5, AR05T5, AR06T4). No groups were formed based on geographical location indicating that qualitative and quantitative traits were largely influenced by genetic factor. The quantitative characters of flower, leaf and fruit showed significant variation among the rough lemon accessions. The maximum fruit weight was recorded in accession number AR02T5 (144.34 g) and the minimum was recorded in AR03T1 (17.36 g). In terms of biochemical constituents, the highest TSS was recorded in accession number AR06T4 (8.87 °B) and the lowest was recorded in AR02T1 (6.13 °B). The highest TSS-acid ratio was recorded in accession number AP06T4 (2.12) and the lowest was recorded in AR02T1 (1.00). HPLC quantification of limonin showed significant variations among the rough lemon accessions which ranged from 10.42 to 24.07 mg/100ml. Among the 30 rough lemon accessions, two main groups were recognized based on 12 biochemical constituents with strong genetic similarity within a location. All the morphological quantitative traits i.e. fruit length, fruit diameter, rind thickness, seeds per fruit, seed weight, juice content, juice per cent showed significant variation among different locations. Significant differences among the locations were observed with respect to biochemical constituents except essential oil content. The highest TSS, total sugar, TSS-acid ratio were recorded in location L6 (Cachar) and the lowest value was recorded in location L4 (Biswanath). Present study on propagation of rough lemon through seed showed an average germination percentage of 87.67 % and air layering recorded a success percentage of 92.11%. However, propagation through stem cutting was found to be comparatively difficult with moderate success percentage (79.11%). Three elite types i.e. AR03T1, AR06T1 and AP06T4 were identified in terms of high overall acceptability (>8), TSS-acid ratio (>2.00), less seed content (≤10 per fruit), low limonin content, high essential oil (>4%), high ascorbic acid and antioxidant activity (>80mg/100ml juice) and thin to medium rind thickness.ThesisItem Open Access GENETICS OF DROUGHT TOLERANCE IN RICE (Oryza sativa L.)(2019-11) Devi, Laishram Monalisha; Sarma, DebojitThe present investigation was carried out at Instructional-Cum-Research Farm of Assam Agricultural University, Jorhat with the objectives - (i) To assess genetic diversity for drought tolerance in rice and (ii) To study the combining ability and gene action. We evaluated 46 rice genotypes in water sufficient non-stress and water-deficit stress conditions during Ahu season of 2018 in PVC pipes. Evaluation of the 6-parent diallel crosses was carried out during Ahu 2019 in plastic tubs. The phenotypic evaluation revealed significant variation for all the characters. Leaf rolling (LR) and drought recovery (DR) had a significant correlation with root traits only, positive with root length and negative with root dry matter and root-shoot ratio. Based on the lowest average LR plus DR score of unity, Basantabahar, Haru Bengunigootia, Lewly, Basmoti Red, Banglami, Ikhojoi, Dimrou, Lachit, Disang and Inglongkiri possessed tolerance to drought stress (7-8% soil moisture content) both at vegetative stage up to 3 weeks and reproductive stage up to 1 week. Root-shoot ratio, root dry weight, proline content, root length, productive tillers, grain yield, grains per panicle and biomass yield registered a high magnitude of PCV and GCV estimates. High heritability coupled with high genetic advance for 1000-grain weights, proline content, grains per panicle, root dry weight, days to first panicle emergence, days to 50% flowering, root-shoot ratio, biomass yield per plant, root length, grain yield per plant, productive tillers per plant, harvest index and shoot length implicating the role of additive gene action and scope of simple selection for these traits. D2 statistics grouped the genotypes into 14 clusters with the highest inter-cluster distance between cluster V-XIII and V-XII. Thousand-grain weights contributed the maximum (74.69%) to the genetic divergence among the genotypes followed by grains per panicle (9.76), proline content (3.29%), root dry weight (3.09%) and grain yield per plant (2.71%). At the molecular level, we detected a total of 86 alleles by using 34 pairs of SSR primers with an average of 2.53 per marker. The Jaccard’s coefficient of similarity ranged from 0.200 to 0.944, with an average of 0.360, suggesting diverse nature of the genotypes. The diallel analysis revealed the significance of both GCA and SCA variances for all the characters in both non-stress and stress environments, indicating the importance of additive and non-additive gene action in their expression. SCA variance was higher than GCA variance for most of the characters except pollen sterility in both the conditions and harvest index in non-stress condition alone. Simple selection would confer rapid improvement of pollen sterility in both the conditions. Among the parents, the good general combiners were IR 64, IR 36, Tamdao and Inglongkiri for early flowering and early maturity; Banglami and Sahbhagi Dhan for low pollen sterility; IR 64, IR 36 and Sahbhagi Dhan for reduced plant height; Banglami and Sahbhagi Dhan for high productive tillers per plant; Sahbhagi Dhan and Banglami for longer panicle with heavier grain weights; Banglami, Inglongkiri and Tamdao for harvest index in both the conditions; Sahbhagi Dhan, Inglongkiri and Banglami for grains per panicle; IR 64, Sahbhagi Dhan and Banglami for biological yield in stress condition. The cross combinations namely, Sahbhagi Dhan/Inglongkiri and Banglami/IR 64 in non-stress condition and Sahbhagi Dhan/Banglami, Sahbhagi Dhan/IR 64, Banglami/Tamdao, IR 36/IR 64, Inglongkiri/Tamdao in stress condition exhibited significant positive yield-SCA effects along with desirable GCA of parents and SCA for other characters. Hayman’s genetic analysis indicated partial to complete adequacy of the additive-dominance model for all the characters in both the conditions. The component of dominance variance was predominant for almost all the characters with mostly overdominance expression of genes demanding a more prudent breeding exercise for genetic manipulation of these traits such as heterosis breeding. The narrow-sense heritability estimates were moderate to high for pollen sterility, plant height, panicle length and harvest index in both the conditions. Partial dominance for pollen sterility in both the conditions suggested its worth for fairly dependable selection. The study also indicated a similar genetic interpretation of the characters with the approaches of Griffing (1956) and Hayman (1954a, 1954b).ThesisItem Open Access HEAT UNIT INDEXING OF GARDEN PEA IN RELATION TO CLIMATE SHIFT AND NUTRIENT MANAGEMENT(2019-07) Sangma, Trudy Tengse A.; Saikia, LuchonAn experiment was conducted consecutively during 2016-17 and 2017-18 in the Experimental Farm, Department of Horticulture, Assam Agricultural University, Jorhat to study the “Heat unit indexing of garden pea in relation to climate shift and nutrient management”. The experiment consist three treatments viz., variety (main), fertility management level (sub) and sowing date (sub-sub) laid out in split plot design with random allocation and replicated thrice. The main treatment consisted Arkel(V1), A1(V2), DS-10(V3) and GS-10(V4); sub treatment was comprised of 5t FYM, 10-46-0 kgha-1 (F1), 10t FYM, 10-46-10 kgha-1 (F2), 10t FYM, 20-46-20 kgha-1 (F3) and 10t FYM, 30-46-30 kgha-1 (F4) and sub-sub treatment was dates of sowing: 10th October (S1), 24th October (S2), 7th November (S3), 21st November (S4), 5th December (S5) and 20th December (S6). Growth, yield attributes, soil related and quality characters viz., plant height(cm), days to 50% flowering, pod plant-1, pod length (cm), pod diameter (cm), seed pod-1, shelling (%), pod yield (tha-1), duration (days), growing degree days, root nodules plant-1, total plant nitrogen (%), total plant phosphorus(%), total potash (%), TSS (0 Brix), crude protein (%), soil organic carbon (%), soil available nitrogen (kgha-1), soil available phosphorus (kgha-1), soil available potash (kgha-1) and soil pH have responded significantly due to treatments as well as their interactions, except pH. Variety evidently produced significant effect on growing degree days (GDD) and results showed V4>V3>V2>V1 with requirement of 955, 948, 933 and 833 GDD for 2016-17 and similarly 958, 949, 942 and 825 GDD. The maximum duration was reported as 76.00days in V4F with (1,2,3,4) and S( with 3,4,5). Duration was closely associated with degree days by sowing date had indicated significant duration among varieties, least with V1(58.73days), to maximum in V4(72.30days). Fertility level had a range of maturity at 68.08 to 68.29days. Sowing dates showed significance as 911(S1), 915(S2), 915(S3), 915(S4), 916(S5) and 918(S6) during 2016-17 and the GDD was found significant as S1
