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Dr. Rajendra Prasad Central Agricultural University, Pusa

In the imperial Gazetteer of India 1878, Pusa was recorded as a government estate of about 1350 acres in Darbhanba. It was acquired by East India Company for running a stud farm to supply better breed of horses mainly for the army. Frequent incidence of glanders disease (swelling of glands), mostly affecting the valuable imported bloodstock made the civil veterinary department to shift the entire stock out of Pusa. A British tobacco concern Beg Sutherland & co. got the estate on lease but it also left in 1897 abandoning the government estate of Pusa. Lord Mayo, The Viceroy and Governor General, had been repeatedly trying to get through his proposal for setting up a directorate general of Agriculture that would take care of the soil and its productivity, formulate newer techniques of cultivation, improve the quality of seeds and livestock and also arrange for imparting agricultural education. The government of India had invited a British expert. Dr. J. A. Voelcker who had submitted as report on the development of Indian agriculture. As a follow-up action, three experts in different fields were appointed for the first time during 1885 to 1895 namely, agricultural chemist (Dr. J. W. Leafer), cryptogamic botanist (Dr. R. A. Butler) and entomologist (Dr. H. Maxwell Lefroy) with headquarters at Dehradun (U.P.) in the forest Research Institute complex. Surprisingly, until now Pusa, which was destined to become the centre of agricultural revolution in the country, was lying as before an abandoned government estate. In 1898. Lord Curzon took over as the viceroy. A widely traveled person and an administrator, he salvaged out the earlier proposal and got London’s approval for the appointment of the inspector General of Agriculture to which the first incumbent Mr. J. Mollison (Dy. Director of Agriculture, Bombay) joined in 1901 with headquarters at Nagpur The then government of Bengal had mooted in 1902 a proposal to the centre for setting up a model cattle farm for improving the dilapidated condition of the livestock at Pusa estate where plenty of land, water and feed would be available, and with Mr. Mollison’s support this was accepted in principle. Around Pusa, there were many British planters and also an indigo research centre Dalsing Sarai (near Pusa). Mr. Mollison’s visits to this mini British kingdom and his strong recommendations. In favour of Pusa as the most ideal place for the Bengal government project obviously caught the attention for the viceroy.

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2017 - 201820
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Subject: Genetics and Plant Breeding × End date: 2018 × Start date: 2017 × Type: Thesis ×
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    ThesisItemOpen Access
    Studies on divergence in sesame (Sesamum indicum L.)
    (Dr. Rajendra Prasad Central Agricultural University, Pusa, Samastipur, 2018) Kumar, Niraj; Singh, U. K.
    The investigation entitled “STUDIES ON DIVERGENCE IN SESAME (Sesamum indicum L.)” was carried out with 21 genotypes including a check namely Krishna. The genotypes were grown in randomised block design with three replications during kharif 2017 at research farm of Tirhut College of Agriculture, Dholi. Genotypes varied significantly for all the morpho-physiological characters. The mean values shifted bidirectionaly significantly as compared to better check, thus provided scope of selection. A close proximity between PCV and GCV indicated strong base of genetic component in phenotypic expression of all the characters under study. High heritability coupled with high genetic advance for characters plant height, productive capsules per plant, 1000 seed weight, harvest index and seed yield per plant suggested the preponderance of additive gene effects in the expression of these characters. High phenotypic and genotypic correlation coefficients of harvest index, productive capsules per plant, number of seeds per capsule, number of branches per plant, productive branches per plant, biological yield and 1000 seed weight were observed. Path analysis indicated maximum direct effect of number of branches per plant, biological yield and harvest index on seed yield indicating the importance of these traits in determining seed yield. Study of genetic divergence confirmed that there was no parallelism between geographical and genetic diversity. Thus genotypes were grouped into five different clusters on the basis of genetic diversity. In cluster III maximum number of genotypes were found. The maximum and minimum inter cluster distance were observed in between cluster V and II and in between cluster II and I, respectively. Hence, the genotypes of cluster V and II may be utilized for further crop improvement programme. The character productive capsules per plant exhibited maximum contribution towards divergence. The cluster V had maximum cluster mean performance for all the characters except days to 50 per cent flowering, productive branches per plant and days to maturity. On the basis of outstanding mean performance and maximum inter cluster distance, Krishna and Pragati were identified as potential elite parent.
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    ThesisItemOpen Access
    Variability assessment in Mutant Lines of Rice for Submergence Tolerance
    (Dr. Rajendra Prasad Central Agricultural University, Pusa, Samastipur, 2018) Kumari, Nikita; Kumar, Rajesh
    Present investigation was carried out with 240 mutant lines developed from different combination of gamma rays and ethyl methyl sulfonate on three rice varieties i.e FR13A, FR13B and labella along with three untreated checks (FR13A, FR13B and labella). These were evaluated for their survival percentage under submerged condition and yield potential along with 9 other morpho-physiological traits using Type 2 modified augmented design at the Chawania tank of Dr. Rajendra Prasad Central Agricultural University, Pusa, Bihar, during Kharif season of 2017. The objective were to assess the relative performance, estimation of genetic variability, heritability, genetic advance as precent of mean and genetic divergence among the mutant lines for submergence tolerance and grain yield along with yield contributing traits. Data were collected for eleven morpho-physiological characters. Statistical analysis carried out were analysis of variance, genotypic and phenotypic coefficient of variation, heritability, genetic advance, correlation coefficient analysis, path analysis and genetic diversity. Analysis of variance revealed high significant differences among the mutant lines for all the eleven morpho-physiological characters under studied. The mutant lines FR13A (350GY+0.2%EMS)-entry number 1, Labella (200GY)-entry number 146 and Labella (200GY)-entry number 147 and FR13B (350Gy)-entry number 165 were significantly higher in mean value for maximum number of characters including grain yield and survival percentage. Higher magnitude of phenotypic coefficient of variation (PCV), genotypic coefficient of variation (GCV), heritability (broad sense) and genetic advance as percent of mean were observed for number of tillers per plant, number of fertile tillers per plant, relative shoot elongation and survival percentage, indicating that these traits could be used as selection indices for yield improvement and submergence tolerance. Association analysis revealed that number of tillers per plant and survival percentage had significant positive association along with high to moderate direct effect on grain yield per plant indicating that these two traits have significant direct influence on grain yield per plant under submergence stress condition. Thus these traits may be used as selection criteria. All the 240 mutant lines along with three checks were grouped into 16 clusters using Mahalanobis D2 statistics. The maximum inter cluster distance was recorded between cluster IV and XVI (86.00) followed by cluster VIII and XVI (75.59), cluster VII and XVI (75.15) and cluster V and XVI (70.77) indicating that chances of getting recombinants with higher survival percentage and yield per plant is possible if the crosses are made among the mutant lines of these clusters. cluster XVI showed desirable mean value for most of the traits under study except plant height, total shoot elongation and leaf senescence indicating that the mutant lines FR13B (350GY)-entry number 167 and FR13B (350GY)-entry number 168 in cluster XVI can be used as one of the parent for improvement of characters like number of tillers per plant, number of fertile tillers per plant, relative shoot elongation, survival percentage. These traits also had high GCV, PCV, heritability and genetic advance as percent of mean. The maximum inter cluster distance was also recorded between cluster IV and XVI (86.00) followed by cluster VIII and XVI (75.59), cluster VII and XVI (75.15) and cluster V and XVI (70.77).Therefore, the selection of parents from different clusters might be done for desired traits on the basis of higher cluster mean values and distance between them. Survival percentage (38.26) followed by plant height (30.90) and days to 50% flowering (22.05) showed maximum relative contribution towards total divergence indicating the importance of these traits in selection of desirable mutant lines.
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    ThesisItemOpen Access
    Genetic Divergence and Cause Effect Analysis Under Drought Condition on Chickpea
    (Dr. Rajendra Prasad Central Agricultural University, Pusa, Samastipur, 2018) Kumar, Rupesh; Singh, Ajay Kumar
    The present investigation entitled “Divergence and cause effect analysis under drought condition on chickpea” was carried out by using forty one genotypes including check in RBD with two replication at rainout shelter farm of RPCAU Pusa Samastipur. Investigation on eighteen characters were done viz. days to 50% flowering, plant height, number of primary branch per plant, number of secondary branch per plant, number of pods per plant, number of seeds per pod, harvest index, yield per plant, number of nodules per plant, nodule weight per plant, nodule dry weight per plant, root length, root volume, root dry weight, peroxidase, catalase, protease and proline. The observations were recorded based on five randomly selected plants from each plot of the replication and standard recommended statistical procedures were used to estimate the genetic parameters. The analysis of variance revealed that the genotypes had shown the significant differences among themselves for all characters. Wide range of variability was recorded for the traits yield per plant followed by pod per plant, root dry weight and nodule weight per plant indicating the presence of ample amount of variability in the experimental material. In general phenotypic coefficient of variation (PCV) was slightly higher in magnitude than genotypic coefficient of variation (GCV) suggesting that expression of the characters are being controlled by genotype itself. High heritability coupled with high genetic advance was observed for the trait such as number of pods per plant, harvest index, yield per plant, nodule weight per plant, root length, root dry weight, peroxidase and proline content, indicating the preponderance of additive gene action thus simple selection may be rewarding. Pods per plant and peroxidase exhibited positive and significant correlation with the grain yield along with their high and positive direct effect as harvest index, catalase, protease and proline content also exhibited positive and significant correlation with yield owing to the positive and high indirect effect via pod per plant suggesting that the these traits may be considered during the course of selection for enhancement of yield in chickpea. Maximum inter cluster distance was observed between cluster III and cluster VII suggesting that the he genotypes placed in these clusters are most divergent one and so as to have the heterotic recombinant these parents may be used in crossing program. Flip-10-144C in cluster VI had higher cluster mean for most of the yield attributing traits, so, this genotype may be used as donor to incorporate the respective traits in the recipient variety. Proline has contributed maximum towards divergence followed by protease content, catalase content and nodule weight per plant.
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    ThesisItemOpen Access
    Divergence studies in chickpea (Cicer arietinum L.) under Zinc deficient soil
    (Dr. Rajendra Prasad Central Agricultural University, Pusa, Samastipur, 2018) Supriy; Arya, Madhuri
    The present investigation was carried out with twenty four genotypes of chickpea entitled “Divergence studies in chickpea (Cicer arietinum L.) under Zinc deficient soil” was carried out at T.C.A., Dholi, Research Farm of Dr. Rajendra Prasad Central Agricultural University, Pusa, Samastipur, Bihar in a Completely Randomised Block Design with three replications during Rabi 2017-18.The characters studied were Plant height(cm), Number of primary branches per plant, Number of secondary branches per plant, Days to 50% flowering, Number of pod per plant, Number of seed per pod, Zinc content in grain (ppm), Chlorophyll content (mg/g fr. wt.), relative water content (%), 100 seed weight (g), Harvest index (%), Yield per plant (g), score of wilt incidence. Statistical analyses were carried out were, Analysis of variance, genotypic and phenotypic coefficient of variation, Heritability, Genetic advance, Correlation coefficient analysis, path analysis and Genetic diversity. Analysis of variance revealed highly significant differences among the genotypes for all the characters studied showed presence of ample amount of genetic variability studies. The genotypes exhibited high variability for the characters like number of pod per plant, yield per plant, 100 seed weight. Among all the genotypes only ICCV-10 has shown susceptible reaction against wilt.There was meagre differences between GCV and PCV suggesting that the expression of these characters are being governed by genotype itself. Characters like number of secondary branches per plant, number of pod per plant, zinc content in grain, chlorophyll content, relative water content, 100 seed weight, yield per plant have shown high heritability coupled with high genetic advance as percent of mean suggesting that there is preponderance of additive gene action thus for these characters simple selection may be rewarded under Zinc deficient soil. Yield per plant exhibited significant and positive correlation with chlorophyll content and harvest index indicating that these two traits are important in predicting seed yield.Chlorophyll content and harvest index have shown positive and significant correlation with yield per plant comprising their high and positive direct effect suggesting that during the course of selection these traits may be considered as prime trait for improvement of yield in chickpea under Zinc deficient soil. All the twenty four genotypes were grouped into five clusters. Cluster I contains maximum number of genotypes i.e. 8 and cluster IV and V has minimum i.e. one genotype each. Maximum intra-cluster distance has been observed for cluster III and zero for cluster IV and V as they have only one genotype. Maximum inter-cluster distance has been observed between cluster III and V and minimum between cluster IV and V. JG-315 has multiple resistance against disease and pest as well as having higher number of pod per plant. It lies in cluster V which has highest cluster mean for primary branches per plant, zinc content in grain chlorophyll content, harvest index, yield per plant. RSG -888 comprises higher 100 seed weight, highest harvest index as well as highest seed yield. It lies in cluster IV which has highest cluster mean for plant height, pod per plant, 100-seed weight. Chlorophyll content is highest contributor towards divergence in chickpea genotypes followed by zinc content in grain under Zinc deficient soil.
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    ThesisItemOpen Access
    Photo-thermal response of Rice Genotypes under Direct Seeded condition
    (Dr. Rajendra Prasad Central Agricultural University, Pusa, Samastipur, 2018) Kumari, Preeti; Nilanjaya
    The present study was carried out at Rice Research farm of Dr. Rajendra Prasad Central Agricultural University, Pusa, Bihar during Kharif2017 using thirty two rice genotypes including the check, Rajendra Bhagwati in Randomized Block Design with three replications to evaluate their Photo-thermal response under direct seeded condition. The observations were recorded on seventeen putative traits that included both morphological traits and agro-meteorological indices viz., days to fifty per cent flowering, days to physiological maturity, plant height, panicle length, number of tillers per plant, number of panicles per plant, spikelet fertility, 1000-grain weight, growing degree days, photo-thermal unit, helio-thermal unit, photo-thermal index, heat use efficiency, relative temperature depression, critical temperature for reproductive stage, relative water content and grain yield per plant. The different statistical parameters used for interpretationof data were Analysis of variance, Genotypic and Phenotypic variance, Genotypic and Phenotypic coefficient of variance, Heritability, Genetic advance, Correlation coefficient analysis, Path coefficient analysis and Genetic diversity to study nature and magnitude of variability and diversity. Analysis of variance revealed highly significant difference among thirty two genotypes of rice for all the seventeen characters from the variability studies.High estimates of PCV were observed for traits number of panicles per plant and number of tillers per plant whereas moderate GCV and PCV were recorded for days to fifty per cent flowering, 1000-grain weight, heat use efficiency, relative water content and grain yield per plant. In present set of materials high heritability with high genetic advance as per cent of mean was recorded for days to fifty per cent flowering, number of tillers per plant, 1000-grain weight, heat use efficiency, relative water content and grain yield per plant indicating preponderance of additive gene effect, which will facilitate selection in early segregating generation. Traits like Plant height, panicle length, number of tillers per plant, number of panicles per plant, spikelet fertility, heat use efficiency and relative water content showed significant positive correlation with yield and have positive direct effect at phenotypic level indicating the importance of these characters for further yield improvement. Path analysis revealed traits likedays to fifty per cent flowering, growing degree days, photo-thermal unit, heat use efficiency and critical temperature at reproductive stage had positive direct effect as well indirect effect on grain yield at genotypic level and at phenotypic level. Days to physiological maturity, growing degree days, heat use efficiency and number of tillers per plant had positive direct effect and growing degree days and heat use efficiency had positive indirect effect on grain yield at phenotypic level. Thirty two genotypes of Rice were grouped into 7 clusters using Tocher’s clustering method. Cluster I had 9 genotypes, cluster II and IV each had one genotype i.e.monogenotypic, cluster III included 4 genotypes, cluster V with11 genotypes was the largest while cluster VI and VII had 3 genotypes.Highest inter cluster distance was observed between cluster III and cluster VI followed by between cluster VI and cluster VII. Highest intra cluster distance was observed in cluster VII followed by cluster VI. Cluster VII showed higher mean performance for most of the yield attributing characters therefore, selection of parents from this cluster would be effective. Spikelet fertility, 1000-grain weight, relative water content, heat use efficiency and days to fifty per cent flowering were major characters contributing towards genetic divergence.This shows that variability in the genotypes is only due to these characters which will offer a good scope for improvement of yield through rational selection of parental genotypes. Based on the results of all major parameters including agro-meteorological indices under present investigation, genotypes Rajendra Nilam and Vandana appeared to be outstanding performers.
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    ThesisItemOpen Access
    Diversity of early maturing sugarcane clones for cane and juice quality traits
    (Dr. Rajendra Prasad Central Agricultural University, Pusa (Samastipur), 2018) Nishad, Himanshu Kumar; Kumar, Balwant
    A study was conducted with planting 15 early maturing sugarcane clones including two checks in Randomized Block Design with three replications during spring season 2017 at research farm of RPCAU Pusa to evaluate the variability, heritability, GA, character association and its cause and effects and clustering pattern for cane and juice quality traits. Observations were recorded for the eighteen traits viz., germination % at 45 days after planting, number of shoots at 120 days, plant height at 150, 240 days and at harvest, cane diameter at harvest, millable canes at harvest, single cane weight at harvest, brix, pol, purity and ccs at 8and 10th month stage, sugar yield and cane yield at harvest and after its statistical analysis, all the characters were found differed significantly for all the genotypes. Among the test entries, the clone CoP16437 showed highest value for cane yield and sugar yield followed by CoP15437 & CoSe12451. Phenotypic coefficient of variation (PCV) was higher than genotypic coefficient of variation (GCV) for all the traits.High heritability coupled with high genetic advance as percent of means was observed for plant height at 150 DAP, single cane weight at harvest and sugar yield at harvest.High heritability coupled with moderate genetic advance as percent of means was observed for germination % at 45 days after planting, plant height at 240 days after planting, plant height at harvest, cane diameter at harvest and brix at 10th month stage. Moderate heritability coupled with moderate genetic advance as percent of means was observed for number of shoots at 120 days after planting and cane yield at harvest (t/ha). Cane yield showed highly significant and positive association with plant height at 240 days and at harvest, cane diameter at harvest, single cane weight at harvest and sugar yield at harvest. Maximum positive direct effect on cane yield was exhibited by the character pol at 8th month stage followed by brix at 10th month stage and sugar yield at harvest. Maximum positive indirect effect on cane yield was exhibited by the character pol at 10th month stage via brix at 10th month stage. All the early maturing sugarcane clones were grouped into four distinguished clusters among fifteen genotypes. Cluster I contained maximum number of clones (6) followed by cluster IV (4), cluster III (3) and cluster II (2). Maximum intra-cluster D2distance was observed in cluster I and maximum inter-cluster D2distance was observed between cluster II and cluster IV. The trait, Pol percent at 10th month stage showed maximum character contribution percent towards divergence followed by sugar yield at harvest, cane yield and brix at 10th month stage. The clones viz, CoP16437 and CoP15437 have been identified for high yielding early maturing sugarcane clones for cane and sugar yield.
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    ThesisItemOpen Access
    Diversity analysis of Early maturing rice genotypes under drought condition
    (Dr. Rajendra Prasad Central Agricultural University, Pusa (Samastipur), 2018) Kumari, Chanda; Nilanjaya
    Present study was carried out under rain out shelter at Rice Research farm of Dr.Rajendra Prasad Central Agricultural University, Pusa, Bihar using twenty five early maturing rice genotypes including the check Rajendra Bhagwati. The experimental materials were directly sown in completely Randomized Block Design with two replications to evaluate their genetic diversity under well aerated, non-puddled aerobic soil (without standing water) condition. The observations were recorded on fourteen putative traits viz. Days to flowering, Days to maturity, Plant height, Panicle length, spikelet fertility, Number of Tillers per plant, Spikelet fertility, 1000-grain weight, Relative water content in flag leaf, Recovery percent after stress, Chlorophyll content, Canopy temperature Harvest index and Grain yield per plant. The different statistical parameters used for interpretation of data were Analysis of variance, Genotypic and Phenotypic Coefficient of Variability, Heritability, Genetic Advance, Correlation Coefficient analysis, Path Coefficient analysis and genetic diversity to study nature and magnitude of variability. Analysis of variance revealed highly significant variation among the genotypes for all the fourteen characters. From the variability studies, high estimates of GCV and PCV were observed for traits like number of Panicle length, No of Tillers per plant and Recovery percent after stress under stress at tillering stage and Panicle length, No of Tillers per plant and Flag leaf area under stress at flowering stage indicating their importance in selection for yield improvement under the stress condition at tillering and flowering stages. In present set of materials high heritability with high genetic advance as per cent of mean was recorded for number of Number of Tillers per plant, Recovery percent after stress, Harvest index and Grain yield per plant under both the stress conditions at tillering and flowering stages indicating preponderance of additive gene effect, which will help to make selection in early segregating generation. Panicle length, Spikelet fertility and Number of Tillers per plant exhibited significant positive correlation with Grain yield per plant under stress at tillering stage while under stress at flowering stage Panicle length, Spikelet fertility, Number of Tillers per plant, 1000 grain weight and Recovery percent after stress was found to have significant and positive correlation with the Grain yield per plant. The above mentioned characters exhibited positive and significant correlation with grain yield due to high direct effect. The 25 Rice genotypes were grouped into 6 clusters using Ward’s clustering method under both the stress conditions at tillering and flowering stages. Under stress condition at tillering stage the cluster I and I consists of 8 genotypes and was the largest cluster followed by cluster V consisting of 6 genotypes and under stress condition at flowering stage cluster I and cluster V consisting of 7 genotypes was the largest cluster followed by cluster III consisting of 4 genotypes. Highest inter cluster distance was observed between cluster VI and cluster III and cluster VI and IV under stress at tillering and flowering stages respectively. Therefore, genotypes from these clusters can be used in future rice combination breeding programme to get wide array of recombinants. Cluster III and cluster VI exhibited higher mean performance for maximum characters under both the stress conditions. Therefore selection of parents from this cluster for these traits would be effective. Grain yield per plant, Harvest index and Recovery percent after stress were major characters contributing towards genetic divergence under both the stress conditions.
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    ThesisItemOpen Access
    Diversity of bread wheat (Triticum aestivum L.) genotypes under drought and their molecular characterization
    (Dr. Rajendra Prasad Central Agricultural University, Pusa (Samastipur), 2018) Kumar, Ankit; Choudhary, V. K.
    A study was conducted at Wheat Breeding section, RPCAU, Pusa, Samastipur, Bihar during rabi 2016-17 to evaluate the genotypes of bread wheat (Triticum aestivum L.) for drought tolerance under rainfed condition. Investigation was carried out on variability, character association, path analysis and genetic divergence for morpho-physiological characters viz, days to fifty per cent flowering, plant height, days to maturity, total number of tillers, flag leaf area, relative water content, chlorophyll content, canopy temperature, ear length, grains per ear, spikelet length, spikelet fertility, thousand grain weight, harvest index, grain yield and drought susceptibility index. Twenty four genotypes were grown under two environments viz, rainfed and irrigated. The experiment in each environment was laid out in Randomized Block Design with three replications. Analysis of variance revealed highly significant variation among the genotypes for all the characters under studied in both conditions. The variability study indicated high to moderate phenotypic and genotypic coefficient of variation accompanied by high heritability and low to moderate genetic advance as per cent of mean for traits like number of tillers per plant, grain yield per plant, 1000 grain weight, flag leaf area, chlorophyll content and harvest index indicating their importance in selection for yield improvement under both conditions. This study indicates preponderance of additive gene effect, which will help to make selection in early segregating generation. The genetic advance as per cent mean suggesting still there is scope for further improvement of genotypes for these characters. Correlation studies indicated that grain yield per plant exhibited significant positive association with harvest index, chlorophyll content, total number of tillers, grains per ear, ear length, spikelet length, relative water content as well as among themselves at phenotypic and genotypic level under both environments. However, grain yield per plant showed negative significant correlation with canopy temperature in both conditions. Path analysis revealed that under rainfed condition highest positive direct effect was exhibited by total number of tillers and harvest index. While under irrigated condition harvest index, total number of tillers and chlorophyll content had exhibited highest positive direct effect. Thus, these traits may be used as selection criteria for respective environments. The highest negative direct effect was showed by canopy temperature on grain yield under irrigated condition. While, highest negative direct effect was showed by drought susceptibility index under rainfed condition. The twenty four genotypes taken for genetic divergence analysis differed significantly with regard to the characters studied and displayed marked divergence and grouped into five clusters following Tocher’s method. Cluster I had five genotypes. Cluster II comprises three genotypes. Cluster III contains three genotypes. Cluster IV comprises maximum twelve genotype and cluster V was monogenotypic comprises only one genotype HD 2888. Out of 20 SSR markers, five markers did not produce clear scorable bands and were not used for further studies. Fifteen markers produced distinct and sharp scorable bands for all the genotypes. Among these, all microsatellites produced polymorphic bands. On the basis of molecular diversity all 24 genotypes have been categorized in eight groups. Maximum genotype found in group VI and minimum found in group V and IV. The magnitude of similarity coefficient between HD2733 and HD2888 was found to be maximum among pair wise combination of entries and minimum coefficient of similarity was found between RAUW 7 and HD2888.
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    ThesisItemOpen Access
    Diversity of bread wheat (Triticum aestivum L.) under terminal heat stress condition and their molecular characterization
    (Dr. Rajendra Prasad Central Agricultural University, Pusa (Samastipur), 2018) Raj, Navodeeta; Singh, S. K.
    A study was conducted at Wheat Breeding section, DRPCAU, Pusa, Samastipur, Bihar during rabi 2016-17 to evaluate the genotypes of bread wheat (Triticum aestivum L.) for terminal heat tolerance under late sown condition. Observation were recorded on plant height, number of tillers per plant, flag leaf area, days to fifty per cent flowering , canopy temperature, relative water content, spike length, number of grains per spike, spike fertility, chlorophyll content, days to maturity, thousand grain weight, harvest index, yield per plant, thousand grain weight susceptibility index and heat susceptibility index. 24 genotypes were grown under two environments namely non stressed (timely sown ) and stressed (late sown). The experiment in each environment was laid out in Randomized Block Design with three replications. Analysis of variance revealed highly significant differences among the accessions for all the parameters under both timely and late sown conditions. The characters like tillers per plant, flag leaf area , grains per spike, harvest index, grain yield , thousand grain weight susceptibility index, heat susceptibility index exhibited high heritability coupled with high genetic advance as per cent of mean under both environments indicating that simple selection scheme would be effective for these traits to bring genetic improvement in desired direction. Grain yield per plant exhibited significant positive association, with relative water content, spike fertility, harvest index, flag leaf area, chlorophyll content, grains per spike, days to maturity, thousand grain weight. However, it was negatively associated with thousand grain susceptibility index, heat susceptibility index under both conditions. Grain yield per plant showed non-significant negative correlation with days to fifty per cent flowering under timely sown condition, canopy temperature under stress condition. Canopy temperature revealed negative association with grain yield per plant and RWC grain per spike, spike fertility, chlorophyll content harvest index. However, it showed significant positive correlation with thousand grain weight susceptibility index (TSI) and heat susceptibility index (HSI). It indicated that elevated canopy temperature accompanied yield reduction under heat stress condition. The traits viz., harvest index and spike fertility have to be given importance in selection process for improvement in yield, since they had positive correlation with grain yield, Harvest index has high direct effect towards grain yield and also all other characters contributed indirectly towards grain yield via these characters. Hence, selection based on these characters would be more effective for yield improvement in bread wheat under heat stress condition. It could be concluded from correlation and path analysis under timely sown condition that the traits like relative water content, spike fertility, chlorophyll content, harvest index, flag leaf area would be effective and reliable, since they had high positive correlation with grain yield, positive inter correlation among themselves and high indirect effect of most of the characters via these traits on grain yield. All genotypes showed higher yield under timely sown condition compared to late sown condition, indicating the potential of genotypes to yield better if the favourable condition prevailed.24 genotypes were grouped into five clusters in both conditions but distribution of genotypes in cluster was dissimilar. The genotypes namely RAUW6, RAUW4, RAUW7, DBW14 from cluster I were selected as suitable parents for traits number of tillers per plant, flag leaf area, chlorophyll content, relative water content, grain per spike, spike fertility , 1000 grain weight, harvest index and grain yield per plant under timely sown condition. The maximum inter cluster distance was observed between cluster I and V followed by cluster I and IV and cluster II and IV , cluster I and II , cluster II and V and cluster III and V indicating the chances of getting high yielding recombinants would be better if the crosses are made among the genotypes of these groups under timely sown condition. The genotypes in cluster III and cluster V, due to maximum inter cluster distance between them, exhibited high degree of genetic diversity and thus may be utilized under inter varietal hybridization programme (transgressive breeding) for getting high yielding recombinants. Similar inter varietal crosses may be attempted between genotypes in cluster I and III and cluster III and IV, cluster I and IV, cluster I and II , cluster II and III and I and V cluster under late sown condition. The maximum contribution in the manifestation of genetic divergence was exhibited by days to fifty per cent flowering followed by chlorophyll content , harvest index, tiller per plant , grain yield , thousand grain weight , number of grains per spike and canopy temperature in timely sown condition, whereas in late sown condition maximum contribution towards genetic divergence exhibited by days to fifty per cent flowering, chlorophyll content, thousand grain weight susceptibility index , spike fertility. This indicated that selection of genotypes for these traits may be rewarding for future utilization in breeding programme in respective environments. A set of 20 Simple Sequence repeat (SSR) markers were used for estimation of molecular diversity in the present material. Out of these 20 SSR markers, six markers did not produce clear scorable bands and were not used for further studies. Fourteen markers produced distinct and sharp scorable bands for all the genotypes. On the basis of molecular diversity all 24 genotypes have been categorized in 7 groups. Maximum genotype found in group III and minimum found in group I and II. The magnitude of similarity coefficient between RAUW 6 and RAUW 199 was found to be maximum among pairwise combination of entries and minimum coefficient of similarity was found between RAUW 159 and RAUW 221.