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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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ThesisItem Open Access STABILITY ANALYSIS OF RICE GENOTYPES UNDER BORO CONDITION(Dr.RPCAU, Pusa, 2023) CHHAYA, RUCHIKA; NILANJAYAThe present experiment was carried out at Pusa Rice farm of Dr. RPCAU, Pusa, Bihar during Boro season of 2021-22 and 2022-23 using 30 rice genotypes in Randomized Block Design with two replications and two dates of sowing under four environments. E1 (10th Dec 2021 sowing and transplanting on 05th Feb 2022), E2 (25th Dec 2021 sowing and transplanting on 20th Feb 2022), E3 (10th Dec 2022 sowing and transplanting on 05th Feb 2023) and E4 (25th Dec 2023 sowing and transplanting on 20th Feb 2023) were the combinations of environments. In ANOVA for all the traits, highly significant variation was obtained due to genotypes sources of variation across four environments. The pooled analysis of variance was also observed to be highly significant for all sources of variation for all the traits. By going through mean performance results we could summarize that E3 and E4 environments were found as better for majority of traits studied compared to other environments. G7, G15, G12 and G22 were good performer for almost all the traits in more than one environment (E1, E3 and E4). It became evident by analysis of sixteen traits across four environments that genotypes which performed better as compared to Gautam € were supposed to be promising one for cold tolerance. These are as follows: G21 was found superior for Length of root at seedling stage, Sterility percentage, Test weight, SPAD value, Proline content and Grain yield (g/plant) whereas G27 and G6 were stable genotypes for Length of shoot at seedling stage, Shoot/root ratio, Filled grains, Days to 50% flowering, Days to maturity, Spikelets per panicle and Relative water content. The ANOVA for stability analysis was highly significant for genotypes (G) for all the traits. Environments €, [E+ (GxE)] and non- linear components were highly significant for majority of traits. On consideration of different stability parameters G27, G21 and G14 seemed to record predictable performance with non-significant S2 di and greater (bi>1) value for majority of traits i.e genotypes were responsive and could be recommended for specific or favourable environments whereas G16, G25 and G7 showed predictable performance with non- significant S2 di and less (bi<1) value for most of the traits i.e it can be suitable for poor or unfavourable environmental conditions. GGE biplot graphical representation inferred that single mega environment existed for Sterility percentage, Filled grains, Plant height (cm), Length of root at seedling stage and Grain yield whereas two mega environments present in case of Length of shoot at seedling stage, Shoot/root ratio, Germination percentage, Sterility percentage, Test weight, Proline content, and Relative water content. However, three mega environments were seen in case of Unfilled grains and SPAD Value. From GGE biplot G and E view suggested that G12, G27 and G22 were ideal genotypes. E1, E2 and E3 environments were most discriminating for selecting rice genotype adapted for the region. These stable genotypes could be utilised in future as parents for crop improvement program for developing cold tolerant rice genotypes at seedling stage and heat tolerant at flowering stageThesisItem Open Access VALIDATION OF SSR MARKERS ASSOCIATED WITH RESISTANCE TO BROWN SPOT DISEASE IN RICE(Dr.RPCAU, Pusa, 2021) BANSHIDHAR; KUMAR, RAJESHRice is cultivated in a wide range of agro-climatic and agro-ecological areas under dry to semi dry conditions and/or wet conditions. On account of its extensive cultivation it is adversely affected by a number of insect-pest and diseases. Among, these brown spot of rice caused by Cochliobolus miyabeanus is a disease of economic significance in the locale of study since it is the hotspot for the disease.The pathogen infects the crop on almost all above ground parts, from nursury to maturity stages and form small dark brown to purplish-brown spots on leaves that later enlarge into oval lesions with brown necrotic centers that are frequently surrounded by chlorotic halo. These spots appear even on seeds resulting in significant economic losses both in grain quality and yield. An immediate and judicious solution to these problem lies in breeding of high yielding resistant cultivars that could be strategically employed for disease management. Keeping this in view the present investigation entitled “Validation of SSR markers associated with resistance to brown spot disease in rice’’ was undertaken to phenotypically screen 300 genotypes of rice along with three checks for two consecutive season in Kharif 2019 and 2020 in controlled condition (glasshouse of department of Plant Pathology) as well as in field (Rice research farm, RPCAU, Pusa, Samastipur, Bihar) to identify resistant sources that could be either utilised directly as a resistant variety or as a parent in hybridisation programme to develop resistant varieties. These genotypes were also evaluated for eight morphological traits related with yield in Kharif 2019 and 2020 in field in augmented design to detect an association between disease resistance and morphological traits under study. Further, 15 most resistant and 15 most susceptible genotypes selected on the basis of AUDPC values were subjected to molecular characteristaion to support the phenotypic screening through genotypic evaluation using 18 SSR markers linked with brown spot disease in rice. The findings of molecular characterization were analysed for validation of these SSR markers in the selected population and to identify a significant marker trait association for the validated linked SSR markers. On the basis of phenotypic screening 18 genotypes were categorised as resistant, 90 genotypes were categorised as moderately resistant, 149 genotypes were categorised as moderately susceptible and 46 genotypes were categorised as susceptible. The mean values for various disease estimating parameters and morphological traits were utilized in various statistical analysis to derive all other complex statistics viz. standard deviation, coefficient of variation, genetic advance as percentage of mean, etc. The analysis of variance revealed significant differences among all genotypes for all the traits. This indicates that there is ample scope for selection of promising lines from the present gene pool for yield and disease resistance. The phenotypic coefficient of variation was slightly greater than the genotypic coefficient of variation (GCV) for all traits under study which reveals lower influence of environment on inherent potential of a trait and higher genetic inherent potential which is a prerequisite in any crop improvement programme. High estimates of heritability in broad sense and genetic advance as percent of mean was observed for each trait under study which inferred that selection for these traits promises improvement in desired direction of selection. From the association studies, it was observed that days to 50% flowering, days to physiological maturity and plant height had positive correlation with AUDPC while negative correlation with yield per plant. In contrary to this, panicle length, number of effective tillers per plant, number of grains per panicle and test weight had negative correlation with AUDPC while positive correlation with yield per plant. Number of grains per panicle, number of effective tillers per plant and test weight showed high direct positive effect on grain yield while days to physiological maturity showed the high direct negative effect on yield. Molecular characterization of selected genotypes showed that the amplified product of resistant genotypes with most of the primer pair were in accordance to the expected band size for a primer pair as per Gramene data base for SSR markers. Total of 6 primer pairs out of 18 primer pairs included in the study were validated and showed moderate to highly significant marker trait association. Thus, these markers could be used to differentiate the resistant lines from the susceptible one and could be used for marker assisted selection of brown spot resistance lines. The conclusive findings of present investigation pave the way for high ends breeding programmes aimed at long lasting field resistance against brown spot pathogen. The genotypes which were reported to be resistant can be used as donor in various resistance breeding programmes. Findings from the molecular characterisation and validation of primer pairs will precisely guide the further research activities in selection of markers for brown spot resistance genotyping. In a nutshell, the reported findings from present investigation will be quite helpful for students, breeders, farmers and others who are in academic and research activities as a good source of information in selecting improved genotypes for various breeding programmes.ThesisItem Open Access CANDIDATE GENE BASED MICROSATELLITE PROFILING IN RELATION TO FRAGRANCE OF LAND RACES AND IMPROVED VARIETIES OF AROMATIC RICE(Dr.RPCAU, Pusa, 2021) Kumar, Abhay; SHARMA, V.K.A study was performed to evaluate the genetic polymorphism using candidate gene based microsatellite specific reported and designed primers and to validate them in relation to fragrance in 18 rice genotypes. Molecular-level genetic divergence along with the importance of candidate genes based microsatellite markers was assessed in relation to fragrance in these landraces and improved varieties of aromatic rice used as experimental material during molecular profiling. The experimental materials were grown in aluminum containers to extract genomic DNA from young seedlings. The targeted amplification of genomic DNA was achieved using candidate genes based microsatellite specific 24 reported primer pairs and candidate genes based microsatellite specific 38 designed primer pairs. Based on the information available in the literature, a total of eleven genes, namely, Os03g0327600, Os04g0352400, Os04g0434800, Os04g0401700, Os04g0438300, Os04g0445700, Os04g0468600, Os04g0474800, Os04g046970, Os08g0424500 and OsNPB_0504555500, which are known to be associated with aroma in aromatic rice, were searched through the internet. The fragrance related these 11 candidate genes are located on the short arm of four different chromosomes (3, 4, 8 and 5) existing in the rice genome. A total of 47 SSR sequences were detected for all eleven candidate genes by using BatchPrimer3 v1.0 software under investigation. Most of the SSRs were tri-nucleotides followed by di-nucleotides; only few were tetra- nucleotides. As a result, altogether investigated 38 microsatellites contained 10, 22, and 06 microsatellites with di-nucleotide, tri-nucleotide and tetra-nucleotide repeat motifs, respectively. The gene Os08g0424500 possessed the highest number of SSRs, while gene Os04g0445700 and Os04g0474800 were not observed to possess any SSR. Differential amplification profile was ascertained amongst the genotypes subjected to molecular characterization by employing 24 reported and 38 designed microsatellite specific primer pairs. The migration of amplicons resulted in appearance of bands representing amplification products localized at different positions on the gel, reflecting the variation in product length derived by primer directed amplification of genomic templates. By using 24 reported primers, a survey of the molecular profiles generated on the basis of the evaluation of the amplified products clearly indicated that a total of 160 alleles were detected with an average number of 6.66 alleles per primer. Similarly, by using 38 designed primers, a total of 248 allelic variants were detected with an average number of 6.52 alleles per primer. Null allele was also noticed in the specific combinations between genotypes and primers. Statistical measure of polymorphic information content (PIC) of the 24 reported microsatellite primer pairs, which reflected allelic diversity and frequency among the genotypes, varied from 0.638 to 0.870. Similarly, for the 38 designed primers, polymorphic information content (PIC) varied from 0.692 to 0.880. Polymorphism per cent generated by these 24 reported primer pairs varied from 0.00 to 62.50 with an average of 24.26 per primer. Similarly, by using 38 designed primers, polymorphism per cent varied from the 0.00 to 66.66. The reported primers CHR 8_34, CHR 3_20, CHR 3_24, CHR 4_3, CHR 8_10, CHR 3_10 and CHR 8_5 appeared to be highly informative primers with above average polymorphism per cent and polymorphic information content. Similarly, the designed primers, CHR4.1_1, CHR4.1_5, CHR4.1_6, CHR4.1_10, CHR4.1_11, CHR4.1_13, CHR8.1_4, CHR8.1_6, CHR8.1_9, CHR8.1_10, CHR8.1_11, CHR8.1_12, and CHR8.1_21 appeared to be highly informative primers with above average polymorphism per cent and polymorphic information content. The results indicated a relatively higher magnitude of discrimination coefficient for the reported primer pairs CHR3_16, CHR3_10, CHR3_20, CHR3_24, CHR4_3, CHR4_25, CHR4_26, CHR8_29, CHR8_6, CHR8_49, CHR8_10, and CHR8_5. Similarly, for the designed primers the relatively higher magnitude was found for the primers CHR3.1_2, CHR4.1_1, CHR4.1_5, CHR4.1_6, CHR4.1_8, CHR4.1_10, CHR4.1_11, CHR4.1_12, CHR4.1_13, CHR8.1_4, CHR8.1_7, CHR8.1_9, CHR8.1_10, CHR8.1_11, CHR8.1_13, CHR8.1_15, CHR8.1_17, CHR8.1_20, CHR8.1_21, and CHR8.1_22. Differential amplification pattern revealing molecular level genetic polymorphism among the genotypes subjected to molecular characterization provided a basis for deducting that the sequence length variation observed in candidate genes may be a role player in differential fragrance in landraces and improved varieties of aromatic rice. Sizable variation was clearly recognized in the molecular size of the genomic region targeted by the primer pairs. The values of similarity coefficient ranged from 0.00 to 0.641, 0.024 to 0.481 and 0.015 to 0.545 for pair-wise combinations of genotypes by using 24 reported primers, 38 designed primers and 62 combined (reported and designed) primers based binary matrices data. Wide genetic differentiation and divergence at the molecular level was revealed among the genotypes. Hierarchical pattern of classification based on similarity coefficient matrix of pair-wise combinations of genotypes was in extremely good agreement with principal coordinated analysis based spatial distribution pattern of genetic profiles of genotypes. Hierarchical cluster analysis, as well as principal coordinate analysis using microsatellite-specific markers derived from candidate genes made it possible to differentiate aromatic landraces and improved varieties of rice. The landraces were discriminated from improved aromatic varieties and accommodated into different cluster. The computational analysis of the genetic structure of the aromatic landraces and improved varieties unambiguously reflected that the genotypes subjected to fragrance related molecular characterization are the admixture of three ancestral components present in different combinations in different genotypes. The Practical utility of the fragrance related candidate gene specific designed primers in discrimination of aromatic landraces and improved varieties was amply demonstrated. The results led to validation of designed primers by amply demonstrating their efficiency to discriminate aromatic landraces from improved varieties of aromatic rice. These reported and designed candidate genes based SSR primers could be utilized for molecular characterization, identification, genetic divergence analysis, parental selection and biological individuation in relation to fragrance of landraces and improved varieties of aromatic rice.ThesisItem Open Access GENETIC ANALYSIS IN BREAD WHEAT (Triticum aestivum L.) AND VALIDATION OF SSR MARKERS FOR MICRONUTRIENT CONTENT IN GRAIN(Dr.RPCAU, Pusa, 2021) JAISWAL, PRIYANKA; SINGH, SATISH KUMARBiofortification plays a significant role in reducing hidden hunger by development of improved cultivar having improved nutritional status on ground of increased uptake, mobilisation and translocation of Zinc and Iron to the edible part. Being the 2nd most important staple crop in India, wheat is a better alternative for biofortification to circumvent the hidden hunger by improving the micronutrient composition of wheat grains by either increasing its concentration in edible parts or its bioavailability. In this context, the present investigation entitled “Genetic analysis in bread wheat (Triticum aestivum L.) and validation of SSR markers for micronutrient content in grain” was carried out during Rabi season of 2018, 2019 and 2020 at wheat research farm Dr. Rajendra Prasad Central Agricultural University (RPCAU), Pusa, Samastipur, Bihar to determine the gene architecture of various morpho-physiological and biochemical traits in six basic populations (P1, P2, F1, F2, B1 and B2) of four crosses of bread wheat. The experimental procedure involves making crosses in Rabi 2018 & Rabi 2019 and final evaluation of crosses along with different generation and parents during Rabi 2020 in field condition while the molecular analysis involving molecular characterization of selected F2 plants in crosses HPYT 461 × HD 2733 and BHU 31× HD 2967 using 13 SSR primers linked with grain Zinc content followed by validation of these primers was carried out in 2021 at Molecular Biology Laboratory, Department of Plant Breeding and Genetics, RPCAU, Pusa. In addition to this, the F2 population comprising of 50 plants in each four crosses were characterised for micronutrient content (Zinc and Iron) in grain. Observations recorded on various parameters were statistically analysed to estimate the mean performance which was used in generation mean analysis to detect the presence or absence of epistasis for the traits under study in four crosses followed by identifying the main gene effect and their interactions involved in expression of these traits by either three parameter model or six parameter model on the basis of presence or absence of inter-allelic interaction in the studied population. The interpretation of experimental results showed that mean sum of square of generations that represents the differences among the generations for all the traits under study were significant in all four crosses which indicated the presence of considerable genetic variability in the experimental material for effective selection for the improvement of traits in desired direction. Mean performance of F1 and F2 was lower, in between or higher than the both parents for various traits under study while the mean performance of F2 was higher than F1 for most of traits under study and mean performance of B1 and B2 was lower but closer to the respective parent for most of the traits under study. Scaling and joint scaling test showed that epistasis was observed for most of the traits under study except chlorophyll content. Generation mean analysis by six parameter model exhibited that mean effects were highly significant for all traits in all four crosses. Additive and/or dominant gene effects along with additive × additive, additive × dominance and dominance × dominance interactions alone or in combinations were observed to govern the expression of various traits. Almost all traits in all four crosses HPYT461 × HD 2733, BHU31 × HD2967, BHU31 × HD2733 and HPYT485 × HD 2967 exhibited duplicate type gene interaction which tends to cancel the effect of each other in hybrid combination therefore selection has to be delayed till later segregating generations where dominance effect is almost dissipated and additive effect become predominant in the population. Broad sense heritability was recorded high for most of the traits except for spike length and number of grains per spike for which it was moderate to high while narrow sense heritability was recorded high for days to 50% flowering and plant height in all the crosses. Genetic advance as percent of mean was moderate to high for plant height and spike length. Characterisation of F2 population for micronutrient content in grain showed that for grain Zinc content highest mean was observed in cross I (HPYT 461 × HD 2733) while for grain Iron content highest mean value was observed in cross II (BHU 31× HD 2967). In cross II (BHU 31× HD 2967) one plant showed micronutrient concentration higher than the both parent for each grain Zinc and grain Iron content. Phenotypic correlation study among grain Zinc, grain Iron content and grain yield per plant exhibited a highly significant and positive correlation between grain Zinc and grain Iron content in all four crosses while both grain Zinc and grain Iron content showed a significant negative correlation with grain yield per plant in all four crosses. Molecular characterisation of F2 population with grain Zinc content linked SSR markers showed positive amplification for most of the primers in the expected range of amplified products. Among the 13 primers included in the study, four primers in cross I (HPYT 461 × HD 2733) and three primers in cross II (BHU 31× HD 2967) were validated and showed moderate association with the grain Zinc content. In a nutshell, the genotypes evaluated and the SSR primers validated in present study can be utilized for future studies on identification of superior genotypes with higher grain Zinc content.ThesisItem Open Access STABILITY ANALYSIS OF FODDER COWPEA (Vigna unguiculata) GENOTYPES FOR TOLERANCE TO DROUGHT(Dr.RPCAU, Pusa, 2021) BANIK, MAHAMAYA; NILANJAYACowpea crop has the immense potential to be used as an important fodder crop in future due to its adaptation capacity which makes it possible to grow in sandy, infertile soils and rainfall deficit areas. Fodder cowpea enhances intake and utilization of poor quality roughages which improves livestock productivity and production. Cowpea has more adaptability to stress conditions than other crops. Hence, it is necessary to study about genotype, environment and genotype by environment interaction under irrigated and drought environment. In this context, the present investigation with title ‘‘Stability analysis of fodder cowpea (Vigna unguiculata) genotypes for tolerance to drought’’ was carried out at Pusa farm of Dr. Rajendra Prasad Central Agricultural University, Pusa, Samastipur, Bihar during kharif season of 2019 and 2020. The study was conducted with thirty fodder cowpea genotype under six environment and three replications in Randomized Block Design (RBD) with a spacing 45 x 10 cm. The environment combinations were E1 (Date of sowing 15th July 2019 in irrigated open field condition), E2 (Date of sowing 26th July 2019 in irrigated open field condition), E3 (Date of sowing 15th July 2019 in rain out shelter for drought condition), E4 (Date of sowing 15th July 2020 in irrigated open field condition), E5 (Date of sowing 26th July 2020 in irrigated open field condition) and E6 (Date of sowing 15th July 2020 in rain out shelter for drought condition). Drought condition was created after 15 days of sowing by with holing irrigation. It is evident from ANOVA that for majority of traits highly significant variation was obtained due to genotypes sources of variation across six environments except for days to maturity in E4 and E5; and for relative content in E1, E2, and E4 was found as non-significant. In ANOVA, significant G x E interaction obtained on pooled basis for all traits and genotypes interacted significantly with date of sowing and growing condition under rain-out shelter as well as in open field condition. The stability analysis revealed few stable genotypes ( > , bi=1, NS S2di) with fair stability and wider adaptation for some important traits which are G29 (FD-2258) for plant height, dry matter%, dry matter yield, green fodder yield; G3 (EC 390268) for leaf to stem ratio, seed yield per plant, harvest index%, production efficiency; G13 (EC 390252) for leaf length and leaf width. On the basis of stability and drought tolerance superior fodder cowpea genotypes were executed for important fodder yield and seed yield contributing trait and these are G29 (FD-2258) for plant height, green fodder yield, dry matter%, dry matter yield and biological yield per plant and G3 (EC 390268) for seed yield per plant, biological yield per plant; proline content and leaf to stem ratio. These stable genotypes can be used in future fodder crop improvement program to meet the fodder demand and also to increase quality fodder production at cheaper cost which is crucial to improve farmers’ income.ThesisItem Open Access Genetical and biochemical bases of salt tolerance in rice (Oryza sativa L.)(DRPCAU, Pusa, 1998) Singh, Ajay Kumar; Shahi, V.K.ThesisItem Open Access Cytotoxic effects of pollutants on Fish and Grasshopper(DRPCAU, Pusa, 1997) Bharti, Suman; Kumar, MithileshThesisItem Open Access Genetical and biochemical aspects of weevil (Cylas formicarius Fabricius) infestation in sweet potato (Ipomoea batatas L.)(DRPCAU, Pusa, 1996) Choudhary, Sudhir Chandra; Kumar, HarshaThesisItem Open Access Genetic studies of high temperature tolerance in early sown Indian mustard [Brassica juncea (L.) Czern & Coss.](Dr. Rajendra Prasad Central Agricultural University, Pusa (Samastipur), 2017) Anushree; Pandey, AnilThe present investigation entitled “Genetic studies of high temperature tolerance in early sown Indian mustard [Brassica juncea (L.) Czern & Coss.]” was carried out with 35 Indian mustard genotypes including two checks (Pusa Mahak and Pusa Mustard-25) from AICRP-RM centres located around India. These genotypes, under laboratory condition, were evaluated for seven physiological characters under three temperature stresses (25, 30 & 35oC) at germination for selection of three thermotolerant sources to be used as testers (Line x Tester Design). Same 35 genotypes, under field trial, were evaluated in RCBD with three replications at Research Farm of TCA, Dholi, Muzaffarpur, Bihar for 21 morpho-physiological-quality attributes (including 4 traits at two phenological stages; pre-flowering (30 DAS), and post flowering (60 DAS) for variability and diversity studies under early sown (06.10.2014) conditions at 32.20C temperature during Rabi 2014-15. Three thermo tolerant testers crossed with seven lines to get 21 crosses and these 31 genotypes (21 crosses i.e F1s + 7 lines + 3 testers) were evaluated in RCBD with three replications for same set of traits during Rabi 2015-16 for line x tester analysis under early sown (05.10.2015 at 35.10C temperature) conditions for combining ability and heterosis studies. Best thermo-tolerant genotypes reflecting superiority in physiological traits at germination upto 35oC in Lab. Experiment were RAURD-78 (EL, RL, SL, SDW and VI); NDRE-7 (EL, RL, RSR and VI) and TPM-1 (EL, RL & RSR). High GCV, PCV, heritability in broad sense coupled with high genetic advance under selection at 25, 30 & 35 0C was reflected by RSR, SDW and EL whereas, in field experiment by LAI & SDW (30 & 60 DAS), CGR, SB/pl and HI thus indicating preponderance of additive gene action which could be effectively utilized by Brassica breeders. NRC-DR-2, RAURD-78 and Pusa Mahak (Oligogenotypic clusters) alongwith TPM-1 and NDRE-7, based on physiological traits at germination; whereas DRMR-150-35, TPM-1 (Oligogenotypic clusters) along with Rajendra Sufalam, RAURD-78, KMR-10-2 and Pusa Mahak (morpho-physio-quality traits field evaluation trial) were promising divergent genotypes, reflected overall usefulness of Pusa Mahak, RAURD-78 and TPM-1 with superior per se performance for EL, HI , DPM-Early and DME (TPM-1; VI, SDW at 30 DAS, RL and LAI ( RAURD-78 and EL, SDW at 30 DAS and OC (NDRE-7) further validated their performance as thermotolerant parents utilized in hybridization. High yielding, divergent genotypes with superiority in many component traits were DRMR-150-35, Rajendra Sufalm, PM-28, NDRE-4 and Pusa Mahak, out of which DRMR-150-35, Rajendra Sufalam and Pusa Mahak were most suitable from divergence studies further proved their genetic worth. SDW, EL and RSR (25, 30, 35oC) at germination stage and HI followed by SS, DPM & LPMA (field trial) reflected maximum contribution towards total divergence. There was no parallelism between genetic diversity and their geographical distribution and sizeable number of morpho-physiological-quality traits at different phenological stages (germination, pre-flowering at 30 DAS & post flowering 60 DAS) highly influenced the group constellation of 35 Indian mustard genotypes. The cross between genotypes of cluster II x VI, IV x V, V x VI and III x IV (lab. evaluation) whereas, V x VII, VI x VII (Field Evaluation) were expectedly more divergent based on their inter-cluster distance. Interestingly crosses attempted in L x T design, namely RH-30/TPM-1 (cross no. 4), Varuna/TPM-1 (cross no. 16) and PM-25/TPM-1 (cross no. 19) were also among divergent combinations (both Lab & Field D2 set basis) further validated their importance. Positive, significant association coupled with high positive direct effect of DPM, HI & SB/pl revealed the importance of these traits while selecting for high temperature tolerance under early sown Indian mustard. Most reliable and yield predictor characters were SB/pl and HI as they also reflected high heritability coupled with high genetic advance under selection. The best general combiners, on the basis of GCA and per se performance were NRC-DR-2 (SLW at 30 DAS, CC at 60 DAS and LAI at 30 DAS), RH-30 (SLW at 60 DAS and PB/pl), Rajendra Sufalam (SLW at 60 DAS and 1000 SW), NDRE-7 (Early DFFO & DPM), TPM-1 (SS) and RAURD-78 (PB/Pl). The crosses based on SCA, standard heterosis (SH) and per se performance, namely RH-30/RAURD-78, Rajendra Sufalam/NDRE-7, PM-25/RAURD-78 and RH-8814/TPM-1 were ranked as top yielders. The crosses RH-30/RAURD-78, involving both good (HxH) general combiners might be useful in heterosis breeding. The crosses involving HxL or LxH general combiners, namely Rajendra Sufalm/NDRE-7, and PM-25/RAURD-78 may throw desirable segregants and effectively utilized in transgressive breeding programme. Thus, the present study reflects the usefulness of RAURD-78, NDRE-7 and TPM-1 as good source of thermotolerance for early sown mustard as well as divergent genotypes and good general combiners for 1000 SW, Early DFFO & DPM and SS (both high GCA and per se basis) respectively. Four best economic crosses for SY/pl were RH-30/RAURD-78, Rajendra Sufalam/NDRE-7, PM-25/RAURD-78 and RH-8814/TPM-1 also reflected superior economic heterosis for SLW (60 DAS), CGR, PH (60 DAS) tall, PB/Pl & SB/Pl in all these crosses alongwith individually superior economic heterosis for PH (30 DAS), DFFO (late), DPM (late), DME & SOMS (RH-30/RAURD-78), 1000 SW & OC (Rajendra Sufalam/NDRE-7); DPM late (PM-25/RAURD-78 and RH-8814/TPM-1). These superior economic heterotic F1s significantly out yielding in yield alongwtih above mentioned morpho-physiological and quality attributes may subsequently be utilized in future breeding endeavours. Amongst all the morpho-physio-quality characters (lab. & field trails) harvest index proven its merit as most important character which contributed maximum towards total divergence, significant positive association and high positive direct effect toward yield alongwith high h2 (bs) and high GAM was most important determinant and yield predictor for the thermo-tolerant mustard genetic enhancement under early sown conditions.
