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ThesisItem Open Access Physiological and bio-chemical drought responsive mechanisms in rice genotypes(Department of Plant Physiology, OUAT, Bhubaneswar, 2021-07-30) Parida, Selukash; Swain, Padmini; Samal, K.C.; Panda, R.K.; Pradhan, S. K.Drought is a major abiotic threat that affects rice production. The experiment entitled “Physiological and bio-chemical drought responsive mechanisms in rice genotypes” was conducted during the dry season -2018 and dry season -2019 at Crop Physiology and Biochemistry Division, ICAR-National Rice Research Institute, Cuttack, India. Droughttolerance screening of 100 diversified rice genotypes including four controls (Sahabhagidhan,Vandana as tolerant control and IR 64, IR 20 as susceptible control) was conducted during the dry season -2018 at the vegetative stage based on physiological traits such as drought score (DS), drought recovery score (DRS), SPAD Chlorophyll Meter Reading (SCMR), Normalized Difference Vegetation Index (NDVI) value, Relative Water Content (RWC) and chlorophyll fluorescence (Fv/Fm) in the field condition. After screening, 14 genotypes were selected for drought tolerance capacity viz., five genotypes (Parijata, IC 516313, IC 516130, ARC 10376 and IC 516008) as tolerant, four genotypes (IC 516149, Pathara, Lalat and IR 36) as moderately tolerant, two genotypes (Satabdi and Naveen) as moderately susceptible and Prasad as susceptible genotype including two controls (Sahabhagidhan and IR 64 as tolerant and susceptible control). These fourteen genotypes were further grown in pot experiment during dry season -2019 for detailed physiological, biochemical and molecular assessments under control and water stress conditions and all data were recorded at flowering stage. Simultaneously, these genotypes were grown in the field for evaluation for reproductive stage drought tolerance. The genotypes Parijata, IC 516130, IC 516008, IC 516149 and Sahahagidhan showed higher values of leaf area, total root length, specific root length (SRL), leaf photosynthetic rate, stomatal conductance, transpiration rate, water use efficiency (WUE), photochemical efficiency of photosystem II (Fv/Fm) and membrane stability index compared to susceptible genotypes Prasad and IR 64. However, higher antioxidant activity (Superoxide dismutase (SOD), Catalase (CAT) and Peroxidase (POX)), higher proline accumulation with lesser malondialdehyde (MDA) content in tolerant genotypes was the well-adapted mechanism under water stress condition. Genes encoding antioxidant enzymes, such as OsCuSOD, OsFeSOD OsMnSOD, OsCATC, OsPOX1 and OsPOX2 had higher expression levels in the tolerant genotypes (IC 516130) compared to susceptible genotypes (Prasad) at flowering stage under water stress. At reproductive stage, the genotypes Parijata, IC 516130, IC 516008 and IC 516149 possessed the higher grain yield along with higher biomass accumulation, spikelet fertility percentage, panicle number per m2 with lesser relative yield reduction (below 50%) over susceptible genotypes. Based on these results, three genotypes Parijata, IC 516130 and IC 516008 were identified as tolerant to both vegetative and reproductive stage drought and can be used as parent donors in drought breeding programs of rice.ThesisItem Open Access Evaluation of Ganjam bucks based on body morphometry, breeding behaviour, testicular and seminal characteristics(Department of Animal Reproduction, Gynaecology and Obstetrics, OUAT Bhubaneswar, 2023-01-07) Chaurasia, Deepak Kumar; Nahak, A.K.The present investigation was conducted at Department of Animal Reproduction, Gynaecology and Obstetrics, College of Veterinary Science and Animal Husbandry, OUAT, Bhubaneswar to evaluate the breeding Ganjam bucks based on body morphometry, breeding behaviour, testicular and seminal characteristics. Out of different herds of goats maintained by the farmers, six healthy Ganjam bucks with an average age of 1.5-5 years were selected on the basis of external body measurements and scrotal dimensions. Semen was collected by Artificial vagina and evaluated for microscopic and macroscopic attributes. The sexual behaviour of six Ganjam bucks has been evaluated during two seasons (July-Aug: Season 1 and Oct-Nov: Season 2). The mean reaction time of each of the six bucks were significantly higher (p < 0.01) in season 2 against the recordings in season 1. Frequency of Flehmen’s reaction was recorded after 10 exposures to estrus female. A significantly higher frequency of Flehmen’s reaction was registered in the season 2 indicating breeding activities of the bucks more pronounced in this season. The libido score of the Ganjam goat bucks were significantly higher (p < 0.01) in season 2. Colour of the semen on naked eye observation was found to vary from creamy to milky white and the most of ejaculate having creamy colour. The individual motility per cent recorded in the present investigation ranged from a minimum mean of 76.50 ± 1.47% in B6 in season 1 to a maximum mean value of 83.17 ± 1.19% in season 2 which differed significantly. The concentration of spermatozoa in semen of Ganjam bucks were recorded to vary from 2438 to 2700 million per ml during present investigation. The live sperm cell percentage and individual motility of the 6 bucks even did not vary significantly in season 2 indicating no effect of season on the livability % of spermatozoa in the Ganjam buck semen. The semen of Ganjam bucks had a total morphological abnormalities ranging from 5.58 to 7.30% for the different bucks. A significantly higher value (p < 0.05) of intact acrosome percentage 73.67% and 74.83% have been observed in B2 and B4 respectively in season 2 indicating a probable influence of season on the acrosome integrity of these two bucks. However the time required to reduce the blue coloured methylene blue was significantly lower for the six bucks in the season 2, indicating a higher metabolic rate of the spermatozoa in semen samples in this season. In the present investigation, it was concluded that Ganjam bucks exhibited seasonal variations of breeding activity showing a significantly higher degree of scrotal parameters, sexual behavior, semen volume, sperm concentration, MBRT demonstrated in the month of October to November compared to the other seasons. Body parameters, scrotal width, sexual behavior, colour, volume, mass activity, concentration, live %, acrosome integrity, MBRT, HOST were reported to be higher in bucks of age more than 3 year. Significant degree of association between the scrotal parameters, sexual behaviour, volume, colour, concentration, livability, acrosomal integrity were recorded on the basis of which bucks may be selected for breeding purpose.ThesisItem Open Access Marker trait association studies for resistance to Cercospora Leaf Spot (CLS) in Mung bean [Vigna radiata (L.) Wilczek](Department of Agricultural Biotechnology, OUAT, Bhubaneswar, 2022-10-31) Sahoo, Jyoti Prakash; Samal, K.C.; Rout, G.R.; Lenka, D.; Mishra, M.K.n the present study, 90 mung bean genotypes were included for marker-trait association studies for CLS disease resistance using 66 SSR markers. CLS screening of genotypes were carried out using a 1-5 rating scale in natural field conditions during pre-rabi 2018 and pre rabi 2019 and in controlled greenhouse condition during pre-rabi 2019. Total genomic DNA was isolated from the leaf samples of all the genotypes, and SSR marker genotyping was performed. The genotyping and phenotyping data were analysed by using different websites and software packages. GCV was found high in number of clusters per plant, pod length, number of pods per plant, yield, and high for plant height. However, the genetic advance as percent of mean was found high for all the traits except number of seeds per pod, which was medium. PCA differentiated the traits in two major PCs with up to 85.656 % variation. Three promising varieties, i.e., PDM-11, NMK-15-12, and MH-13-23 were also found to be good yielder with other desirable traits and resistance to CLS disease. CLS resistance screening revealed 32 resistant accessions, and 35 moderately resistant accessions. Genetic diversity analysis revealed a moderate molecular diversity in the panel population as a wide variation in alleles showed a range of 80 bp to 300 bp with the average polymorphic information content value of 0.40. Estimation of allele frequencies by population revealed, some alleles of 9 markers (CEDG001, CEDG006, CEDG153, CEDG210, CEDG117, CEDG020, CEDG067, CEDG146, and CEDG071) had linked to CLS resistance. The molecular variance among populations and among individuals were found to be 58% and 42%, respectively. The maximum % of polymorphic loci was 75.76% in the resistance, followed by 56.06% in moderately resistant genotypes, with estimated Shannon diversity 1.308 and 1.399, respectively. The principal coordinate analysis (PCoA) revealed, the explanation of percentage variation by the first 3 axes with up to 71.37%. The archaeopterx tree differentiated the populations into two major clusters, i.e., I, and II, containing 45 number of genotypes each, which were again subdivided into different sub-clusters and sub-sub clusters. Therefore, it is concluded that the panel population used for the study possesses considerable genetic variation for CLS tolerance. The structure analysis categorized the panel genotypes into 2 structure groups. The linkage disequilibrium (LD) patterns of mung bean reflect its long history of domestication. The marker-trait association were detected based on presence of LD in the population. A sharp decline in the decay of disequilibrium was observed at 2-3 base pair for the linked markers, there after observed a very gradual decay for attaining equilibrium. As per the linked markers, 2 novel QTLs (qCls_2 and qCls_8) were detected for CLS resistance in the present investigation. Furthermore, novel QTLs were also identified for some of the quantitative traits, such as for plant height (qPht_8), for number of clusters per plant (qNcl_6 and qNcl_10), for hundred seed weight (qHsw_3 and qHsw_11), and for yield (qYld_2, qYld_7, and qYld_8) under CLS. The novel QTLs obtained from the present investigation could be further validated in diversified mung beangermplasms to understand the stability of the QTLs and then could be introgressed to elite mung bean varieties to develop CLS resistance lines. This study will help the breeding process towards CLS resistance in mung bean using genomic tools with special reference to QTL mapping and genomic assisted breeding.ThesisItem Open Access Molecular Mechanisms Underlying flowering and fruiting ability associated with circadian clock regulation in Vigna radiata under cold stress(Department of Agricultural Biotechnology, OUAT, Bhubaneswar, 2022-12-06) Manasa S., Lekshmi; Rout, Gyana Ranjan; Panignihi, K.C.; Samal, K.C.; Dash, Abhiram; Dash, ManasiGreen gram or mung bean (Vigna radiata) is the major leguminous crop in tropical countries known for being highly proteinaceous and nitrogen fixing abilities. But, yield loss in mung bean is due to its susceptibility to low temperature is a serious concern for its cultivation and productivity. Low temperature causes flower drop, male sterility, impairs anthesis, and grainfilling. In the present study, screening the 204 genotypes (127 Indian varieties, 62 landraces and 15 recombinant inbred lines) of Vigna radiata for cold germination was carried out at National Institute of Science Education and Research. Further, all the analysis was done in two ways, first one using principal component analysis at 10 ͦ C, where PC1 and PC2 explained 57.7% and 18.7%, respectively. The second one was using stress indices like germination percentage, germination stress index, seedling length stress index, resilience capacity index and productive capacity index. The whole of 204 genotypes were categorized into resistant, susceptible and intermediate. So, PAU 911 was selected as the resistant genotype. PUSA 1672 was selected as the intermediate and PUSA 9531 was selected as the susceptible representative for further investigation. PAU 911 was able to show higher values, for leaf area and rootlet number. In case of shoot length and root length, PAU 911 and PUSA 1672 were found to be at par, but significantly higher than susceptible PUSA 9531. Biochemically, PAU 911 showed low membrane leakage, high proline accumulation, low injury index, higher NBT staining and low MDA accumulation, lower SOD activity. The pigments content was found to be on par with PUSA 1672, but was significantly higher than PUSA 9531. Physiologically, PAU911 was having advantage over the intermediate and the susceptible genotypes. PAU911 showed higher RH%, photosynthetic water use efficiency, transpiration rate and stomatal conductance. PAU 911 was also showed lesser temperature, sub-stomatal CO2 conc. and vapour pressure deficit. Photosynthetic assimilation was seen to be highest in PUSA1672. But, the decline in photosynthetic assimilation under cold stress condition was seen to be least in PAU 911, which makes it more desirable. Anatomically, PAU 911 showed an increase in trichome density under stress. The similar trend was seen in all the three genotypes. But, there was higher autofluorescence at 488nm observed in PAU911, when compared to the other genotypes, indicating the presence of higher secondary metabolites in the plant tissues. This accumulation helps in fending of adverse abiotic stress situations. Also, there was higher microtubule immunofluorescence found in PAU 911. Based on multi elemental analysis, there was a higher accumulation of sodium and boron ions were found in PAU911, indicating its innate ability to facilitate membrane stability and pollen tube growth. SDS-PAGE protein profiling showed the appearance of bands at 75 kDa under cold stress, along with changes in Rubisco LSU was also observed. Further, sequencing of the differentially expressed bands helped in understanding the genes associated with it. It was found that TTL1 gene was up-regulated in PAU911 under cold stress. This was further validated using qRT-PCR, which showed a 30-fold rise from control, 4.8-fold increase in PUSA 1672 and insignificant up regulation in PUSA 9531. TTL1 was characterized in silico. It was found that it had TPR and DNA J domains. Further, expression analysis of ICE1 showed a down regulation in all the three genotypes, providing an insight into the temperature range it needs in Vigna radiata to get up-regulated. Further, the expression pattern of evening complex (ELF3-ELF4-LUX) was also indicated a slight insight into that transcriptional-translational feedback loops that is happening in the genotypes under stress condition, during flowering and pod setting time.ThesisItem Open Access Study of low light stress on molecular regulation and yield performance of rice (Oryza sativa L.)(Department of Plant Physiology, OUAT, Bhubaneswar, 2022-11-05) Dash, Deepali; Baig, M.J; Rout, G.R.; Samal, K.C.; Panda, R.K.; Satapathy, M.K.Light has a significant role in the growth and development of plants because of its crucial role in photosynthesis and photomorphogenesis. To respond to various environmental stimuli, plants have evolved various morpho-physiological modifications. Different light signals have a huge influence on plant growth and development. If the amount of light intensity reaching the plants is less than the optimum level, plants suffer from low light stress, and crop production suffers as a result. Rice, the most important food crop, is extremely sensitive to low light stress, and a marked yield reduction have been observed in eastern and north eastern countries. The current experiment was titled "Study of low light stress on molecular regulation and yield performance of rice (Oryza sativa L.)" based on the facts stated above. The entire experiment was carried out in the Division of Crop Physiology and Biochemistry research plot at the National Rice Research Institute in Cuttack, India. During the Kharif (wet) seasons of 2019-20 and 2020-21, the experiment was carried out in both the field and the net house. Initially, 50 long-duration rice genotypes were chosen for screening, and 11 of them were picked, along with susceptible and tolerant controls based on yield reduction, for further morphological, physiological, biochemical, and molecular studies. Three replications of selected genotypes were grown under normal light (100% light), 75% light, and 50% light treatments. Plant height, tiller number, and leaf area were measured during the vegetative stage, and stem dry weight, panicle dry weight, and plant dry weight were measured at 50% flowering, 7 days after 50% flowering, 14 days after 50% flowering, and harvest. Physiological and biochemical observations were made at the 50% flowering stage. Grain quality parameters such as head rice recovery, milling recovery, alkali spreading value, water uptake, kernel length after cooking, water uptake, and gel consistency were measured on harvested seeds with less than 14% moisture content. To better understand the mechanism of the low light stress response, RT-PCR analysis was used to examine gene expression. Among the eleven genotypes, Nalini Sali and Nasati Sali, as well as the tolerant control variety Swarnaprabha, are the least affected by low light stress. Plant morphology is more affected under 75% light and 50% light stress, and yield is drastically reduced under 50% light intensity. Physiological parameters such as photosynthetic rate, stomatal conductance, and transpiration rate were found to be directly related to rice variety yield performance under stress conditions. Starch and photosynthesis genes like GBSS-I, ADPG, SS-III, Fru-1-6-BP, Sed-1-7-BP, and RuBisCo are directly regulated by light and thus downregulated in low light conditions However, the gene CAB-2 behaves differently because it is up regulated in response to low light stress. Because the Nalini Sali and Nasati Sali varieties performed better under low light stress, they are considered tolerant. At the same time, Kolabardhan and Na Sali were considered susceptible varieties due to their poor performance.ThesisItem Open Access Genetic analysis of quantitative traits and selection of transgressive segregants in crosses of sesame (Sesamum indicum L.)(Department of Plant Breeding and Genetics, OUAT, Bhubaneswar, 2022-11-04) Sahu, Dibyabharati; Mishra, Tapash Kumar; Pradhan, B.; Dash, M.; Samal, K. C.; Senapati, A. K.The present investigation on "Genetic analysis of quantitative traits and selection of transgressive segregants in crosses of sesame (Sesamum indicum L.)" was conducted in the EB-II, Department of Plant Breeding and Genetics, College of Agriculture, O.U.A.T., Bhubaneswar. The experimental materials comprising of nineteen genotypes were sown during Pre rabi 2018 in Randomized Block Design with three replications and evaluated for eight quantitative characters viz., days to 50 % flowering, plant height, no. of branches per plant, capsule length, no. of capsules per plant, no. of seeds per capsule, 1000-seed weight and seed yield per plant for the diversity analysis. In Summer, 2019, seven genotypes (OSM-22, Nirmala, Prachi, Amrit, VRI-1, Rama and PKDS-11) were selected and crossed in half diallel fashion to develop 21 F1s. In Pre rabi 2020, 21 F1 along with their 7 parents were evaluated in RBD design for study of gene action involved in inheritance of quantitative traits and the magnitude of heterosis expressed by the crosses. Four crosses viz. OSM22×Rama, OSM22×VRI-1, Nirmala×Prachi, Prachi×VRI-1 were selected on the basis of sca effect and carried forward to F2 in Kharif 2021 to study the transgressive segregants. Nineteen genotypes were grouped into five clusters based on D2 values following Tocher's method. Cluster III was the largest cluster consisting of seven genotypes followed by Cluster II and V consisting of four genotypes each. Combining ability analysis of the parents and crosses (developed through half diallel fashion) were done following the both graphical and numerical approaches. From Vr- Wr graph it was evident that overdominance was prevalent for four traits viz. plant height, number of branches per plant, number of seeds per capsule and seed yield per plant as the regression line passed below the origin for the above traits. But for rest three traits, partial dominance was prominent, as the regression line passed just above the origin. OSM-22 and Nirmala were the good combiners for seed yield and its component traits. The crosses like OSM-22 × Rama, OSM-22 × VRI-1, Nirmala × Prachi and Prachi × VRI-1 exhibited signifcant sca effect and good amount of heterosis for plant height, no. of capsules per plant and seed yield per plant. Out of the four selected crosses OSM-22 x Rama showed high transgressive segregants in F2 for seed yield and its component traits, indicating its further advancement in segregating generations to select good genotypes, to be developed as a variety.ThesisItem Open Access Pyramiding resistance genes for bacterial leaf blight (Xanthomonas oryzae pv. oryzae) into Pratikshya, a popular rice variety of Odisha(Department of Plant Breeding and Genetics, OUAT, Bhubaneswar, 2022-07-30) Pradhan, Madhuri; Debendranath, Bastia; Pradhan, Bansidhar; Samal, Kailash Chandra; Mishra, Mihira KumarPratikshya is a popular high-yielding rice variety of Odisha with good grain and cooking quality. However, this variety is highly susceptible to bacterial leaf blight disease which is endemic to many rice-growing areas of Odisha. The development of resistant varieties is the most effective and economic method to combat the losses due to this disease. The present investigation was carried out with the objective of the phenotypic screening of segregating population for bacterial leaf blight resistance and marker-based identification of line possessing bacterial leaf blight resistance genes xa5, xa13, and Xa21 individually or in the pyramided form in the population. Genomic DNA from the resistant parent (Swarna MAS) and susceptible parent (Pratikshya) were amplified using the three SSR markers viz., RM122, xa13prom, and pTA248 markers to see polymorphism in parental genotypes. It was concluded that all of the three bacterial leaf blight resistance genes xa5, xa13, and Xa21 conferring resistance were present in Swarna MAS and absent in susceptible parent Pratikshya. Cross was attempted between donor parent Swarna MAS and recipient parent Pratikshya and 26 F1 seeds were obtained. Out of 26, 18 true F1 plants were obtained and hybridized with the recurrent parent Pratikshya to produce BC1F1 seeds. Foreground selection was performed in 117 BC1F1 plants to select plants carrying xa5, xa13, and Xa21 genes in the lines, and 58 plants were found to have all three resistant genes. Selected resistant BC1F1 plants were backcrossed to the susceptible recipient parent Pratikshya to produce BC2F1 seeds. Foreground selection was performed in 170 BC2F1 plants to select plants carrying xa5, xa13, and Xa21 genes in the lines, and 40 plants were found to have all three resistant genes. Seeds from selected BC2F1 plants were planted in the next generation to obtain the BC2F2 population. 35 resistant plants from BC2F2 generation selected by phenotypic screening by artificial inoculation of Xoo inoculum. Seeds from resistant plants having similar agronomic characteristics to Pratikshya were raised to obtain the BC2F3 population. In the BC2F3 generation, thirty-five lines were raised from the cross Pratikshya x Swarna MAS during Rabi, 2019. When all the markers were comparatively studied in all the plants, 31 plants possessed all three genes that conferred resistance to bacterial blight in rice. Based on data generated by foreground selection, background selection was done using forty-five SSR markers in the BC2F3 population to check the recovery of the recurrent parent genome. In BC2F3 generation of the cross Pratikshya x Swarna MAS the recurrent parent genome in the thirty-one bacterial leaf blight-resistant plants ranges from 64.44% to 93.33%. Among the thirty-one bacterial leaf blight-resistant plants, five plants showed the highest recurrent parent genome recovery percentage in the range of 91.11 to 93.33%. The recurrent parent genome recovery percentage was observed to be 91.11% in Pratikshya x Swarna MAS (Plant No. 4), 91.11% in Pratikshya x Swarna MAS (Plant No. 51) and 93.33% in Pratikshya x Swarna MAS (Plant No. 54), 93.33% in Pratikshya x Swarna MAS (Plant No. 65), 93.33% in Pratikshya x Swarna MAS (Plant No. 92). Thirty-one three-gene pyramid lines at BC2F4 generation along with the donor and recipient parents were evaluated during Kharif, 2020. Using mean values of eight agronomic traits, the statistical analysis revealed that many lines did not show any significant variation as compared to Pratikshya for most of the characters. The mean of all characters was at par with Pratikshya in most of the lines and to that of the average of the population. The recipient parent, Pratikshya recorded a mean seed yield of 44g/plant, while the donor parent (Swarna MAS) recorded 49.4g/plant. Many lines showed seed yield higher than recurrent parent Pratikshya. In most of the lines mean seed yield/plant was at par with the recipient parent Pratikshya. The five lines having a parental genome recovery percentage of more than 90% were at par with Pratikshya for all the characters. The yield and agronomic traits of the three gene pyramid line in this study are similar to those of the recurrent parent, Pratikshya, indicating no yield penalty associated with the presence of three bacterial leaf blight resistance genes.ThesisItem Open Access Gene stacking for submergence tolerance and bacterial blight resistance in popular rice variety Ranidhan(Department of Plant Breeding and Genetics, OUAT, Bhubaneswar, 2022-10-27) Pradhan, Kartik Chandra; Bastia, Debendranath; Pradhan, Sharat Kumar; Pradhan, Banshidhar; Samal, Kailash ChandraRanidhan, a popular variety of Odisha state of India in the late maturity group but is affected by the adverse effects of the climate change as the variety is sensitive to submergence and susceptible to bacterial blight (BB) disease. An attempt was undertaken for transferring three BB resistance genes and Sub1 QTL into the variety through marker-assisted backcross breeding approach. Direct and closely linked markers were used for screening of the backcross progenies. CR Dhan 800 is the donor parent for Xa21, xa13 and xa5 BB resistance genes while Swarna-Sub1 for Sub1 QTL were used in the backcross breeding program. Foreground selection detected all the four target genes in 11 progenies in BC1F1 generation. The progeny containing all the target genes and more similar with Ranidhan was backcrossed and a total of 312 BC2F1 seeds were produced. Foreground selection detected all the four target genes in 10 progenies in BC2F1 generation. The progeny containing all the target genes and more similar with Ranidhan was backcrossed and a total of 286 BC3F1 seeds were generated. Foreground screening detected 12 BC3F1 plants carrying all the four genes. A total of 1270 seeds were obtained from the selfed plant of the best BC3F1 progeny. Screening of the progenies resulted in four plants with the four desirable genes (Sub1, xa5, xa13 and Xa21) in homozygous condition. Bioassay of the seven pyramided lines containing BB resistance genes was conducted against 8 different Xoo strains conferred very high levels of resistance to the predominant isolates. These pyramided lines also showed higher submergence tolerance than the recipient parent, Ranidhan. High grain yield was recorded from the pyramided lines, CRSB 159-87-69-942 (71.7 q) followed by CRSB 159-87-69-717 (69.9 q) and CRSB 159-87-69-546 (68.45 q). The pyramided lines were similar to the recipient parent in 11 yield, agro-morphological and grain quality traits. The similarity of these pyramided lines is achieved in 3 backcrosses. It is possible due to the use of two donor varieties, Swarna-Sub1 and CR Dhan 800 which were developed in the same mega variety background, Swarna through MAB and the recipient parent, Ranidhan is also developed from Swarna variety. Therefore, the best pyramided lines carrying the target genes for bacterial leaf blight resistance and submergence tolerance are almost alike the recipient parent and hence will be preferred over,‘Ranidhan’.ThesisItem Open Access Assessment of useful genetic variation for nutrient use efficiency in aus rice (Oryza sativa L.) using genome wide association studies(Department of Plant Breeding and Genetics, OUAT, Bhubaneswar, 2022-10-27) Panda, Siddharth; Bastia, Debendranath; Pradhan, Bansidhar; Anandan, Annamalai; Mohanty, Iswar Chandra; Mohanty, SimantaRice (Oryza sativa L.), the second most cultivated crop nurtures billions of lives including humans and animals. However, the modern high yielding rice genotypes have a low nutrient use efficiency i.e., <50% (of the total applied fertilizers). The breeding activities should focus on developing and/or improving genotypes that can survive under limited inputs utilizing the available resources to the optimum. The Bengal Assam Aus Panel consisting of 298 diverse lines of aus rice was used in this study to identify genetic loci involved in nutrient use efficiency with respect to nitrogen, phosphorus and iron. The nitrogen deficient study was conducted in the field where as phosphorus and iron study was conducted in hydroponics. The BAAP with its nearly 2 million SNP sequence information was processed for association studies with the phenotypic data collected in this study. The results highlighted the different traits contributing the maximum variability under nutrient deficient conditions. In case of nitrogen (N) deficient trial there was positive correlation between grain yield, panicle length and leaf width. Similarly, in case of phosphorus (P) and iron (Fe) deficient trial there was a positive correlation between root biomass and shoot growth. The putative candidate gene for enhancing nitrogen use efficiency via flag leaf width was; LOC_Os6g41750 (25024626 – 25034551 bp), panicle length; LOC_Os04g09900 (5318060 – 5326427bp), and grain yield per plant;LOC_Os11g39220 (23354149 – 23358318bp). Three accessions; DA24, DM56, and AUS210 were identified as superior donors from the better performing haplotype groups of the above mentioned traits. Phosphorus use efficiency was found to be associated with the putative candidate gene LOC_Os04g45370 (26831005 - 26831867bp) via root length, LOC_Os06g41840 (25016001 - 2502001bp) via shoot length, and LOC_Os03g25040 (14294507bp - 14297898bp) via shoot dry weight. Shada boro, Kele (AUS) and Kada 68-1 were the selected as superior donors for the selected traits. Iron use efficiency was associated with a common peak SNP for root volume and average root diameter, LOC_Os04g54200 (32286661bp to 32291459bp) as a putative candidate gene. The peak SNP for shoot length and number of leaves shared a peak and the putative candidate gene was identified as LOC_Os11g28360 (16316873 – 16321329bp). Only five accessions were common in the superior haplotype across the four traits. Among these five lines, Rata boro had the highest root volume (3.316cm3) and average root diameter (2.19mm). The shoot length was highest in Sada boro G1 (26.05cm) and the average number of leaves were 2.8. The variations explored at the SNP level and amino acids in this study can serve as a guide for further genomic studies. The nonsynomyous substitutions can be validated further through protein expression studies. The SNP haplotypes identified in this study can further be used in haplotype assisted breeding approach while the superior haplotype bearing lines can be used as donor for the respective traits.
