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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 ELUCIDATING THE EFFECT OF HEAT AND WATER DEFICIT STRESS COMBINATION IN WHEAT (Triticum aestivum L.)(RPCAU, Pusa, 2023) Kumar, T. Muni Sai; Kumar, ShaileshIn the context of global climate change, the influence of environmental stresses such as heat and drought on agricultural production is a crucial concern. The present study was aimed to quantify effects of Drought stress [DS], heat stress [HS] and combined heat and drought [HS+DS] during heading and grain filling stages on wheat yield and to identify physio-biochemical traits which were strongly associated with improved yield and tolerance of wheat under stressful conditions. Wheat genotypes were treated to individual and combined stress treatments under controlled experimental circumstances, simulating heat and drought conditions. To investigate the interactive impact of these stresses on wheat plants, physiological, biochemical, and morphological characteristics were evaluated. Independent and combined drought and heat stress negatively affect wheat yield and physiology. Five promising wheat genotypes were exposed to [HS], [DS] and [HS+DS] treatments after heading stage. Sowing was done on 28th November, 2022. Grain yield was reduced by 31.9%, 61.6% and 66.6% under HS, DS and HS+DS respectively. There was significant (P<0.05 to <0.01) genetic diversity observed for traits across the genotypes. Major traits that contribute to the yield loss under HS, DS and HS+DS was grain yield, seed set and total biomass. On the other hand traits such as SPAD, relative water content and transpiration rate were positively correlated with yield and biomass. Under heat stress, wheat plants exhibited reduced photosynthetic efficiency, altered antioxidant enzyme activity, and changes in hormonal regulation. Drought stress led to decreased water potential, stomatal closure, and accumulation of ROS species. Grain yield is reduced due to reducing metabolism and mobilization of reserves to developing grains and leaves. A significant variations was observed in the combination of HS and DS where all the traits measured showed higher variations than the individual HS and DS. More over genotypes under HS showed more grain yield and helps to maintain more biomass. During individual and combined stress we have seen accumulation of more ROS species which causes damage to the plant system. Genotypes having a major contribution under different stress treatments may lead to improved varieties with heat and drought tolerance. To best of over knowledge, the present study which used physiological and biochemical traits to explain the variation in grain yield and related traits in wheat genotypes. This study also aimed to find the root morphology under combination of heat and drought stress. The findings show complex alterations in root morphology and architecture as a result of combined heat and drought stress. Combination of both stress resulted in a reduction in root growth characteristics such as volume, area, and length. Root volume, area and length was reduced by 42.8%, 27.8% and 32% respectively when compared to control.ThesisItem Open Access INVESTIGATING THE ROLE OF PHENOTYPIC PLASTICITY IN TERMINAL HEAT STRESS TOLERANCE IN WHEAT (Triticum aestivum L.)(Dr.RPCAU, Pusa, 2022) PARMESHWAR, PADILE GANESH; Bahuguna, Rajeev NayanThe global mean temperature is increasing at a rapid pace due to atmospheric warming. Consequently, heat stress events are becoming more frequent and severe and affecting global food production. For the current study, we gave grown thirty wheat genotypes at two (timely and late) sowing dates and two planting densities viz. optimum and low density (LD) resulting in three treatments viz. Control, terminal heat stress (HT), and terminal heat stress with low planting density (LD+HT). Genotype HD-2967 was used as a check variety for heat stress tolerance. Timely sowing in control treatment was done on 26th Nov, 2021 while for the HT and LD+HT treatments, sowing was delayed by 19 days. Late sowing of genotypes exposed them to a higher temperature of 6.6 oC and 4.5 oC at flowering and active grain filling stages, respectively. As a result, a reduction in the grain yield of up to 59 % and biomass reduction of up to 55 % were observed under HT conditions. Conversely, 15 days reduction in total crop duration and 10 days reduction in grain filling duration has been under HT condition, which was a crucial determinant of seed weight, and grain yield. There was significant (P<0.05 to <.001) genetic diversity observed for traits across the genotypes. Key traits that contributed to yield loss under heat stress were reduced spike weight, grains per spike (seed set) and spikelet fertility. Correlation analysis of traits showed that there was a significant negative correlation between canopy and spike temperature with yield and yield components. In general, spike temperature was significantly higher than canopy temperature across the treatments. Moreover, higher spike temperature was negatively correlated with spikelet fertility, seed set and seed weight. Canopy cover was observed as helpful in maintaining a lower canopy and spike temperature. On the other hand, traits such as tillering ability, SPAD, relative water content and spike weight were positively related to yield and biomass accumulation under control and LD+HT conditions. Lower spike temperature with a better canopy cover was crucial to maintain a high grain number under reproductive heat stress. A significant variation was noted in the phenotypic plasticity where all the traits measured showed higher variations under low planting density. Moreover, genotypes under low density showed higher yield per plant due to better space and light helping accumulate more biomass and dense canopy. Low density helped in maintaining a higher seed set and fertility ratio in responsive genotypes under reproductive heat stress. However, low density did not show similar effectiveness under heat stress at the grain filling stage, as the minimum temperature was the dominant factor where a merely cooler canopy was ineffective. The cumulative response index for 8 key traits showed a wider range in phenotypic plasticity in wheat genotypes, which can be utilized in crop improvement programs for terminal heat stress tolerance.ThesisItem Open Access EFFICACY OF NANO ZINC OXIDE ON PHYSIOLOGY OF WHEAT (Triticum aestivum L.) UNDER NORMAL AND SALINITY STRESS CONDITION(DRPCAU, PUSA, 2021) M, SEETHALAXMI; Kumar, ShaileshWheat, the king of cereals is the world’s important crop occupying major diet of the people. Salinity stress is the serious problem in arid and semi arid parts of the world. On a global scale, 20-33% of cultivated areas and 50% of irrigated area have been affected by salt stress. Wheat seedlings are more sensitive towards soil salinity. In order to increase the productivity of crop to meet out the growing population, nanotechnology have been proven as the emerging trend to alleviate salinity stress. ZnO nanoparticles due to its unique properties acts as fertilizer releasing Zn, a potential micronutrient through which adverse effects of salinity could be mitigated, thus promoting growth and development. Also, the efficiency of nanoparticles have been proved in comparison with their bulk form (ZnSO4). The current studies entitled, “Efficacy of nano Zinc oxide on physiology of wheat (Triticum aestivum L.) under normal and salinity stress condition” was performed with three objectives viz. to find out the adverse effects of salinity on growth and development of wheat seedlings, to recognize the ameliorating effect of ZnO nanoparticles on morpho-physiological traits and finally to prove the excellence and efficiency of nanoparticles over their bulk forms (ZnSO4). In first objective, thirty genotypes viz., WB 02, HPYT 424, RAU W 3001, BHU 31, RAU W 105, HD 2733, HPYT 452, RAU W 4041, HPYT 483, HD 2967, SONALIKA, RAU W 3060, RAU W 9010, HPYT 458, RAU W 9025, NEST 17-39, ESWYT 123, BHU 25, HD 2824, HPYT 405, NEST 18-5, NEST 18-25, NEST 18-16, RAU W 6007, HPYT 429, HPYT 480, RG 1, PBW 343, RAU W 7016 and NEST 18-33 were tested at a salinity level of 4.2 dSm-1 (EC). The genotype screening was performed based on emergence percentage, seedling length, seedling dry weight, seedling vigour I and II in 15-day-old plants and a contrasting set of genotypes have been selected. Salinity have highly reduced the aforementioned parameters where the reduction percent in all the above metrics was high in ESWYT 123 and low in NEST 18-16. In second objective, seed priming have been done with seeds of selected set of genotypes with ZnO nanoparticles at different concentrations (50, 100, 250, 500 and 1000 ppm). The genotypes were grown in both normal and saline soil conditions and morpho-physiological traits like emergence percentage, shoot and root length, shoot and root dry weight, seedling vigour I and II, SPAD value have been measured in 15-day-old seedlings of both the genotypes. The results revealed that ZnO nanoparticles at low concentrations have enhancement effect on those previously mentioned parameters at 50 ppm and 100 ppm concentrations in both normal and saline soil conditions. There was also a promoting effect with 250 and 500 ppm concentrations which were a bit less in efficiency than the former. Nanoparticles at high concentrations have exhibited negative effects indicating phytotoxicity. Thus, the maximum effect was observed with 100 ppm concentration, ameliorating the effects of salinity stress. In third objective, the efficacy of ZnO nanoparticles was compared with their bulk form (ZnSO4) on morphological (plant height, dry matter accumulation, leaf area and specific leaf weight), physiological (RWC, MSI, photosynthetic pigments, SPAD value, chlorophyll stability index, lipid peroxidation) and biochemical (antioxidant enzymes like SOD, peroxidase, catalase and proline) parameters of 30-day-old wheat seedlings of both the genotypes. Salinity stress had negative impacts on all those parameters stated above which could be alleviated or mitigated by both ZnO nanoparticles and ZnSO4. The alleviating potential was greater in nanoparticles when compared with their bulk form thus, proving their performance excellence. The present findings have concluded that salinity had adverse effects on seedling growth and development of wheat crop which could be alleviated by seed priming with ZnO nanoparticles. ZnO nanoparticles at 100 ppm concentration i.e. at low concentration had promoting effect on morpho-physiological and biochemical parameters of wheat. Also, nanoparticles have been proven to be more efficient than the bulk forms. Therefore, nanoparticles could be utilized as fertilizers or stress alleviators with better results in the near future.ThesisItem Open Access Influence of epibrassinolide on physiobiochemical traits of wheat (Triticum aestivum L.) under water deficit at vegetative stage(DRPCAU, PUSA, 2022) Sharma, Amit Kumar; Pradhan, JyostnaraniWater deficit have been observed frequently, especially in rain-fed wheat, causing severe yield losses in most wheat grown regions of the world. Its impact on crop productivity on growth differentiation development, dry matter accumulation, and productivity might vary substantially depending on the genetic composition of the plant. A class of phytohormones known as brassinolide is crucial for plant development and adoptability to environmental stresses. This study sough to identified changes in physio-biochemical processes due to exogenous application of brassinolide regarded the alleviation of negative impact of low moisture stress in wheat crop. This experiment was conducted with three objectives (1) To screen out the genotypes for water deficit stress and to identify contrasting sets on the basis of physiological traits. (2) To compare the morpho-physiological traits under water deficit during the vegetative stage of wheat. (3) To investigate the influence of epibrassinolide in relation to water deficit during vegetative stage of wheat. For the first objective, 10 cultivars were taken under four concentrations of PEG 6000 (5%, 7.5%, 10%, 15%) along with control (distilled water) in petri plates. For identification of contrasting genotypes, seedling parameters viz. emergence percentage, biomass of seedling, seedling length, seedling vigour index I and seedling vigour index II were recorded in 10 days old wheat seedlings. On the basis of growth performances one set of contrasting wheat genotypes were identified (HD-2733, relatively tolerant for stress and DBW-187 relatively stress sensitive). Similarly, BRs concentration was chosen by taking EBL in 4 concentrations along with control and 0.01mM EBL stood best among all. Taking all these results in to consideration, second experiment was performed, where two genotypes along with four treatments (well-watered, water deficit, EBL treated and EBL + water deficit) were maintained for other two objectives. Different physio-biochemical parameters were compared across the treatments and genotypes. The results are indicating that the tolerant genotype (HD-2733) showed better tolerance across all most all morphophysiological and biochemical parameters as of sensitive genotypes (DBW-187). It was clear that low moisture stress had a detrimental impact on the growth, development, physiology, and yield of wheat plant, and that a lower dose of EBL was effective against water deficit condition. Under conditions of water scarcity, EBL increase the relative water content, membrane stability index, root length, chlorophyll content, and carbohydrate and protein content. Furthermore, the application of EBL positively balanced the osmolyte such as proline, controlled the amount of phenol and malondialdehyde (MDA) content under stress condition. The growth response of HD- 2733 was higher than that of DBW-187 when exposed to EBL under low moisture, over all the EBL play a major role in enhancement of growth biomass, yield and decrease membrane damage in wheat under water deficit. However further investigations with EBL are needed to understand the mechanism of its action.ThesisItem Open Access Effect of zinc nano particle on physiology of finger millet [Eleusine coracana (L.)] under saline condition(DRPCAU, PUSA, 2022) SHAILENDRA, BUTE PARESH; Kumar, ShaileshNumerous abiotic stressors have significantly impacted crop development and productivity, Salinity is one of them which affect around 50% of irrigated area as well as 20-33% of cultivated areas all around the world. Therefore, creating fresh methods for crop improvement against several stresses has now taken precedence. However, the majority of crop development efforts are focused on major cereals like rice, wheat, maize, and others, while attention to minor cereals like finger millet [Eleusine coracana (L.).] lags significantly. It is a vital staple with good nutraceutical characteristics in many semi-arid and tropical regions of the world, ensuring food security even in hard environments.Nanotechnology has been shown to be an emerging trend to alleviate salinity stress. Zinc nanoparticles due to its unique properties acts as fertiliser releasing Zn, a potential micronutrient through which negative effects of salinity could be mitigated, potentially increasing crop productivity and fostering growth and development. The present research is termed, “Effect of zinc nano particle on physiology of finger millet [Eleusine coracana (L.)] under saline condition”, was performed with aim to determine how salt affects the development and growth of finger millet seedlings and to recognise ZnO nanoparticle’s ameliorative effects on morpho-physiological characteristics of finger millet seedling. 7 In first objective, thirty genotypes of finger millet viz., RAUF-1, RAUF-2, RAUF-3, RAUF-4, RAUF-5, RAUF-6, RAUF-7, RAUF-8, RAUF-9, RAUF-10, RAUF-11, RAUF-12, RAUF-13, RAUF-15, STF-1, STF- 2, STF-3, STF-4, STF-5, STF-6, STF-7, STF-8, STF-9, STF-10, STF- 11, STF- 12, RAU-8, RAU-3, BR-407 and Rajendra Mandua-1 were tested at salinity level at 4.30 dSm-1 EC. Based on emergence percentage, seedling length and seedling dry weight in 12-day-old plants, genotype screening was carried out, and contrasting genotypes were chosen. Salinity has significantly decreased the aforementioned parameters, with BR-407 experiencing the lowest percentage reductions and higher in RAU 8.In the second goal, seeds of a chosen set of genotypes were primed using ZnO nanoparticles at various concentrations (50, 100, 250, 500 and 1000 ppm). The genotypes were grown in both normal and saline soil conditions, and 14-day-old seedlings of both genotypes were evaluated for morpho-physiological parameters as emergence percentage, shoot and root length, shoot and root dry weight, and SPAD value. The findings showed that in both normal and saline soil conditions, ZnO nanoparticles at 250 ppm concentration have an enhancing effect on those previously mentioned parameters. Additionally, there was a promoting impact at doses of 50 and 100 ppm; however it was not quite as effective as at the higher dosage. High quantities of nanoparticles have shown harmful effects that point to phytotoxicity. Thus, the consequences of salinity stress were mitigated to their greatest extent at 250 ppm concentration.In the third goal, ZnO nanoparticles' effects on morphological (plant height, dry matter accumulation, root study), physiological (RWC, MSI, photosynthetic pigments, SPAD value, chlorophyll stability index, lipid peroxidation) and biochemical parameters (antioxidant enzymes like Super oxide dismutase, Ascrobate peroxidase, catalase and proline content) of 21-day-old finger millet seedlings of both genotypes are characterized. All of the aforementioned characteristics were negatively impacted by salinity stress, which ZnO nanoparticles could help to reduce or lessen. ZnO has better relieving potential at a concentration of 250 ppm. According to the current research, salt had negative impacts on the development and growth of finger millet seedlings, which might be mitigated by seed priming with ZnO nanoparticles. When applied to finger millet, ZnO nanoparticles at a concentration of 250 ppm had a positive influence on the plant's morpho-physiological and biochemical parameters. As a result, nanoparticles may soon be used more effectively as fertilizers or stress relievers.ThesisItem Open Access STUDIES ON PHYSIO-BIOCHEMICAL RESPONSE OF BIOSTIMULANTS APPLICATION TO TERMINAL HEAT TOLERANCE IN LENTIL (Lens culinaris Medik.)(DRPCAU, PUSA, 2022) Nandkishor, Ingle Rahul; Kavita, Dr.Day by day temperature is increasing due to climate change and their adverse impact on crop cultivation and agricultural productions. According to IPCC report 2022, world is facing various climatic vulnerabilities such as heat wave, cyclones, drought, flood etc. Heat wave is one of the most important climatic vulnerability which is mainly affecting agriculture at global level. Temperature required for most crop plant generally ranges between 20-30 °C (min/max) but in case of high temperature (above 30 °C), plant growth may be stuck because of enzyme denaturation or inactivation resulting in early maturity thereby reducing crop yield. Heat stress mainly affects reproductive stage such as flower abortion and grain filling thereby causing drastic reduction in yield. Biostimulant application may prove useful in reducing the adverse effect.In this research, major focus is on terminal heat stress tolerance of lentil and their amelioration through humic acid and seaweed extract with the objectives i) to understand alterations in morpho-physio-biochemical characters by biostimulants application that leads to thermo tolerance in lentil and ii) to assess yield attributes and yield of lentil crop influenced by biostimulant application The experiment was conducted with two genotypes of lentil viz. IPL 220 and KLS 218 in pots with two different sowing dates i.e. normal (control) and late sown (to expose the plants to terminal heat stress) in CRD with three replications. Late sown crops were given different treatments viz. seed priming with humic acid (SPHA), seed priming with seaweed extract (SPSWE), foliar spray (40+60 DAS) with humic acid (FSHA), foliar spray(40+60 DAS) with seaweed extract (FSSWE), SPH+FSHA and SPSWE+FSSWE. It was observed that there was significant reduction in leaf area, specific leaf weight, relative water content, membrane stability index, total chlorophyll content, yield attributes (no. of flowers per plant, no. of pod per plant, no. of seed per pod) and seed yield per plant in lentil genotypes subjected to terminal heat stress condition over control but was improved by application of humic acid and seaweed extract. However, lipid peroxidation, proline content and activities of antioxidative enzymes (catalase, peroxidase and superoxide dismutase) increased during heat stress condition but application of humic acid and seaweed extract decreased it. Among all the treatments, SPSWE+FSSWE treatment was significantly superior in reducing the adverse effects of terminal heat stress in lentil. Hence, it can be concluded that application of humic acid and seaweed extract either as seed priming or foliar spray or their combination may be useful for ameliorating terminal heat stress in late sown lentil crop.ThesisItem Open Access Response of mustard [Brassica juncea (L.) Czern and Coss] to moisture stress and its amelioration by microbes(DRPCAU, Pusa, 2021) Mohan, Krishna; KavitaMustard [Brassica juncea (L.) Czern and Coss] is an important oilseed crop belonging to family Brassicaceae (Syn. Cruciferae) which is sensitive to moisture and is adversely affected by moisture stress in terms of growth and yield. Inoculation of plants with microbes such as Trichoderma viride and Bacillus subtilis can enhance plant growth under moisture stress conditions, which is an eco-friendly approach to sustainable agriculture. The present investigation entitled “Response of mustard [Brassica juncea (L.) Czern and Coss] to moisture stress and its amelioration by microbes.” was conducted with two objectives viz., to identify contrasting set of mustard genotypes against moisture stress and to study the response of microbes on morpho-physiological and biochemical traits in contrasting mustard genotypes under moisture stress. For the identification of contrasting set of mustard genotypes to moisture stress, experiment was performed in Petri dishes with 30 genotypes of mustard viz., NPJ 214, LES 54, NPJ 210, NPJ 210, RB 100, 81J0117, RGN-444, DRMRHJ1118 (Hybrid), DRMRCI 95, NPJ-225, RH 1424, RH 1584, PM-29, PM-30, RB-102, TM 179, PDZ 9, RH 1555, NPJ 211, LES 57, NPJ 212, NPJ 216, RLC 7, DRMR 541-44, DRMRCI 114, RGN 229, DRMR CI70, Kranti, RGN 73, RCH 1## and RLC 3#. All the genotypes were subjected to control (0.0 MPa) and moisture stress (-0.6 MPa and -0.8 MPa) for 7 days and germination percent, seedling length, shoot dry weight, root dry weight, vigour index-І and vigour index-II were recorded. Results showed that mustard genotypes on exposure to different moisture stress levels (-0.6 and -0.8 MPa) experienced significant reduction in germination per cent and seedling growth parameters (seedling length, dry weight of shoot and root and vigour index) over control. At maximum moisture stress i.e. -0.8 MPa, genotype NPJ-214 had the minimum reduction while TM-179 showed the maximum reduction in these parameters and hence rated as relatively tolerant and susceptible genotypes, respectively. These two genotypes were further used to study the response of microbes on morpho-physiological and biochemical traits Plant height, relative water content, membrane stability index, total chlorophyll content and leaf area remarkably decreased due to moisture stress and conversely increased in all the microbial treatments over control (without microbial inoculation), whereas lipid peroxidation, proline, antioxidative enzymes viz. catalase and peroxidase were remarkably increased due to moisture stress but decreased by microbial application. On the basis of present study it was concluded that, moisture stress adversely affected morpho-physiological and biochemical attributes of mustard genotypes. These parameters were best improved under control as well as moisture stress with the soil application of Trichoderma viride at 35 DAS. Hence, this treatment can be used in ameliorating moisture stress.ThesisItem Open Access Response of mustard [Brassica Juncea (l.) Czern and Coss] to terminal heat stress and its amelioration by Brassinosteroid(DRPCAU, Pusa, 2021) Kumar, Deepak; KavitaMustard [Brassica juncea (L.) Czern and Coss] is an important oilseed crop belonging to family Brassicaceae (Syn. Cruciferae) which is sensitive to heat and is adversely affected by terminal heat stress in terms of growth and yield. Brassinosteroid treatment of plants can enhance the growth under terminal heat stress condition, which is an eco-friendly approach to sustainable agriculture. The present investigation entitled “Response of mustard [Brassica juncea (L.) Czern and Coss] to terminal heat stress and its amelioration by Brassinosteroid.” was conducted with two objectives viz., to identify contrasting set of mustard genotypes against terminal heat stress, and to study the response of brassinosteroid on morphophysiological and biochemical traits in contrasting mustard genotypes under terminal heat stress. For the identification of contrasting set of mustard genotypes to terminal heat stress, experiment was conducted with two sowing dates i.e. normal and late sown at Research farm, Tirhut College of Agriculture, Dholi, Muzaffarpur, Bihar in RCBD, replicated thrice with 20 genotypes viz., NPJ-213, DRMR 15-9, DRMR 1191-2, DRMR 1C192, DRMR 2017-15, PRO 5222, RGN 368, JD 6, NRCHB 101, DRMR 2300, DRMR 1616-47, RH 749, DRMRIC16-39, RLC 7, RH 1599-41, DRMR 1153- 12, DRMR 2059, RH 919, RMWR 09-1 and LES 54. On the basis of percent reduction in seed yield, one set of mustard genotypes i.e. tolerant (DRMR 15-9) and susceptible (RH 1599-41) were taken for evaluating the effect of brassinosteroid on morphophysiological and biochemical parameters viz., plant height, number of branches per plant, relative water content, membrane stability index, total chlorophyll content, chlorophyll stability index and antioxidative enzymes (catalase, peroxidase) and biochemical (proline) under normal and late sown conditions. The selected cultivars were sown in pots in CRD and foliar application of brassinosteroid (24- epibrassinolide) i.e. control, 10 ppm and 20 ppm were applied at flowering stage. Results showed that mustard genotypes on exposure to terminal heat stress, experienced reduction in quantity of yield at harvest. Genotype DRMR 15-9 had the minimum reduction in yield while RH 1599-41 showed the maximum reduction in yield and hence rated as relatively tolerant and susceptible genotypes, respectively. Morphological (plant height, number of branches per plant) and physiological parameters (relative water content, membrane stability index, total chlorophyll content, chlorophyll stability index) remarkably decreased due to terminal heat stress and conversely increased in all the brassinosteroid treatments over control (without brassinosteroid), whereas biochemical (proline) and antioxidant enzymes (catalase, peroxidase) were remarkably increased due to terminal heat stress which was further increased by foliar application of brassinosteroid. On the basis of present study it was concluded that, terminal heat stress adversely affected morpho-physiological and biochemical attributes of mustard genotypes. These parameters were best improved under control as well as terminal heat stress with the foliar application of brassinosteroid @ 20 ppm during flowering stage. Hence, this treatment can be used in ameliorating terminal heat stress.
