<div>Background: Chickpea at seedling stage is highly sensitive to salinity and high temperature stress. Many studies explained plant responses under independent salinity and high temperature stress, but very little findings had revealed the combined effects of these two stresses on plants. So, the present experiment was aimed to study the response of chickpea genotypes for growth parameters and stress tolerance indices at seedling stage under individual and combined salinity and high temperature stress. 
 
Methods: A laboratory experiment during rabi season of 2018-2019 was conducted with thirty chickpea genotypes by comparing their responses under different salinity stresses i.e. EC 4.0 dSm-1 and 8.0 dSm-1 and high temperature (37&deg;C). Seedling growth parameters i.e. germination percentage, vigour index and seedling dry weight along with stress tolerance indices like yield stability index and tolerance index were measured for 10-day-old seedlings. 
 
Result: The results revealed genotypic variations for all the parameters, based on which the genotypes KPG-59, IPC 2013-74 and NDG 15-6 were identified as tolerant, whereas KWR-108, BG-3075 and BG-3076 as susceptible. Interestingly, the results also showed that the tolerant genotypes exhibited maximum cross-tolerance at highest level of stress (T5) for germination percentage and vigour index, over control (T0), which might be attributed to their acclimatization while facing different stresses during early growth. So, the genotypic variations in chickpea for these parameters at germination stage might be good criteria for selection of tolerant genotypes under salinity and high temperature individually and also when combined.</div>

<div>Cross-tolerance Physiology of Chickpea (Cicer arietinum L.) Genotypes under Combined Salinity and High Temperature Stress Condition</div>

<div>Background: Drought and high temperature stress limits the crop production. Development of drought and high temperature tolerant cultivars that can withstand and yield better under adverse conditions is very much important to ensure the food and nutritional security. Green gram is one of the important pulse crops with high nutritional and economic value. Among the various stages of plant growth and development, reproductive stage is highly sensitive to drought and high temperature stress across all species. The main objective of this study was to evaluate green gram germplasm collection and identification of elite greengram genotypes that can withstand drought and high temperature stresses at reproductive stage.&nbsp; 
 
Methods: The experiment was conducted during March-April, 2019, at National Pulses Research Centre, Vamban, Pudukottai district, Tamil Nadu. To study the influence of combined drought and high temperature stress during reproductive stage, the green gram genotypes were sown in pots. Six pots were maintained for each genotype of which three were maintained at 100% field capacity (control) and for another three; drought stress (50% field capacity for 5 days) was imposed combined with high temperature stress (36 &plusmn; 2&deg;C) during reproductive phase (35 Days after sowing). At the end of stress period, physiological and biochemical analysis were carried out to identify the tolerant green gram genotypes against drought and high temperature stresses. 
 
Result: In the present study, drought and high temperature stress has negative impact on green gram physiology. Among the genotypes screened for their tolerance at reproductive stage, the following green gram genotypes viz., TARM 1, VGG 15029, VGG 17003, VGG 17004, VGG 17006, VGG 17010 and VGG 17019 were found to withstand drought and high temperature stress and maintain high total chlorophyll content, relative water content and chlorophyll stability index. These green gram gramplasm can be used in pulse breeding program to evolve resilient green gram varieties. Screening of 29 green gram genotypes for drought and high temperature stress during reproductive stage were carried out by maintaining the drought stress (50% field capacity for 5 days) combined with high temperature stress (36 &plusmn; 2&deg;C) during reproductive stage (35 days after sowing) by pot culture experiment. Total chlorophyll, relative water content, chlorophyll stability index (CSI), oxidants and antioxidant activity were quantified to identify the tolerant green gram genotypes&nbsp;against drought and high temperature stresses. Based on physiological and biochemical parameters, the following green gram genotypes viz., TARM 1, VGG 15029, VGG 17003, VGG 17004, VGG 17006, VGG 17010 and VGG 17019 were found to withstand and tolerate combined drought and high temperature stresses at flowering stage.</div>

Physiological Divergence in Green Gram [Vigna radiata (L.) Wilczek] Genotypes for Drought and High Temperature Stress Tolerance During Flowering Phase

<div>Background: High temperature is an important abiotic stress affecting the productivity of rice. Early morning flowering trait is an escape mechanism from heat. This trait is present in wild rice cultivars. Here we tried to induce early morning flowering trait by the application of methyl jasmonate. 
 
Methods: A pot culture experiment was conducted during Rabi, 2017 and 2018 to study the effect of foliar application of methyl jasmonate on high temperature stress (more than 35&deg;C) mitigation in rice was conducted in the Department of Plant Physiology, College of Agriculture, Vellayani during 2017-2019. The variety used was Uma (MO 16). Methyl jasmonate was applied as foliar spray to the spikelet in varying concentration with different time. Physiological observations were taken at 50% flowering stage and yield parameters were taken at harvest stage.&nbsp; 
 
Conclusion: There was significant variation for physiological and yield components among treatments. 4mM L-1 methyl jasmonate at 7am treatment exhibited increase in pollen viability, spikelet fertility percentage, yield per plant and 1000 grain weight. Hence, it is found that methyl jasmonate can advance anthesis time and thereby plants can escape from the severity of temperature experiencing at the normal flowering time in rice.</div>

<div>Manipulation of Flowering Time to Mitigate High Temperature Stress in Rice (Oryza sativa L.)</div>

<div style="text-align: justify;">High temperature above the optimum has a drastic effect on the stomatal activity and gaseous exchange which ultimately affect the yield and yield attributing traits. In this study, the Net photosynthetic rate (An), stomatal conductance (gs), transpiration rate (E), and intrinsic water use efficiency (iWT) on flag leaves of 100 recombinant inbred lines of bread wheat derived from the cross of WH1021 (heat-tolerant) and WH711 (heat-sensitive) were evaluated. Recombinant inbred lines and both parents were assessed for various gas attributes under two sowing dates i.e., normal (17.11.2015) and late sowing (27.12.2015). The temperature persisted normal from December, 2015 to February, 2016 and there was a consistent rise in temperature in the last week of March. Measurements were made at anthesis and 10 days after anthesis. Average An, E, gs and iWT decreased as the temperature increase. A contrasting difference was observed in timely sown and late sown at 10 days after anthesis for photosynthetic rate and transpiration &nbsp;rate. Decrease in stomatal conductance and water use efficiency was found with delayed sowing and high temperature. There results may prove useful in the selection of physiologically efficient heat-tolerant genotypes with higher rate of photosynthesis.</div>

Variability in gas exchange attributes of wheat RILs subjected to high temperature stress

<div style="text-align:justify">Background: In this decade, increasing temperatures and adverse environmental factors are expected to influence the crop yield, seed quality and germination ability. Prolonged heat stress affects the pod setting, seed morphology and alters the starch granules. Methods: In this study, Scanning Electron Microscopy (SEM) and Light microscope was used to investigate the variations of morphological and ultra-structural characteristics in blackgram genotypes grown under high temperature (38+2&deg;C) stress (HTS). Nineteen blackgram genotypes were evaluated under open top temperature controlled chamber (OTC) and the genotypes were classified into three categories such as heat tolerant, moderately heat tolerant and heat susceptible genotypes based on the Temperature Induction Response (TIR) and yield reduction percentage under HTS. Two genotypes were selected and examined the seed size, surface pattern, starch granule size and hilum from the each category. Result: Seed coat morphology was captured using SEM and light microscope showed that the tolerant genotype VBG-07-001 had a clear shiny surface, thin and reduced cotyledon fissures, compact surface devoid of surface deposits and pits whereas rest of the genotypes (VBG-06-001, VBN-6, CoBg-11-02, CoBg-11-03 and VBG-08-003) had a rough surface. A bold and well-structured starch granule was observed in heat tolerant lines whereas, unstructured and pleated granules were observed in moderately tolerant and heat stress lines. These morphological and ultra-structural studies revealed remarked diversity among different genotypes that can be regarded as useful to screen the genotypic tolerant characters for HTS.&nbsp;</div>

<div style="text-align: justify;">Morphological and Ultra-Structural Characterization of Blackgram [Vigna mungo (L.) Hepper] Genotypes Grown under High Temperature Stress</div>

Background: Blackgram is one of the important short duration pulse crop which is sensitive to high temperatures. The rising global temperatures are threatening the yield of blackgram by altering the physiological processes at cellular level. Keeping this in view, the present investigation was carried out for better understanding of genotypic variability and the physiological mechanisms governing heat stress tolerance which can help in identifying heat tolerant blackgram genotypes that can yield better under climate change scenarios.&nbsp; 
 
Methods: 30 blackgram genotypes selected from temperature induction response technique were evaluated for physiological efficiency under natural high temperature conditions during summer, 2022 and 2023. Field experiment was conducted at Agricultural College Farm, Acharya N.G Ranga Agricultural University, Agricultural College, Bapatla. Physiological and yield parameters were recorded at flowering and the data were analyzed statistically and pooled. 
 
Result: Significant genetic variability was observed among the blackgram genotypes with respect to all the physiological traits under high temperature stress conditions. Among the 30 genotypes tested for thermotolerance, the genotypes TBG-129, PU-1804, LBG-1015, PU-31 and TBG-104 were found to withstand high temperature stress at reproductive stage by maintaining higher total chlorophyll, carotenoids, chlorophyll stability index, total biomass production, cooler canopies resulting into higher canopy temperature depression, less membrane injury index values and higher yield. Correlation analysis revealed a strong positive correlation for all the physiological traits with seed yield except membrane injury index under heat stress conditions. The PCA results revealed considerable variability among the traits accounting for 82.65% of total variability. The genotypes TBG-129, PU-1804, LBG-1015 and TBG-104 can be potentially used as donors in the breeding programmes for the development of heat tolerant genotypes.

Variation in Physiological Traits of Blackgram (Vigna mungo L.) Genotypes under High Temperature Stress

<div>Background: Vitamin C (VitC) is a widely used antioxidant in poultry production. However, there is some ambiguity about the effects of VitC in reducing oxidative stress in poultry when they are under heat stress. Therefore, the objective of this study was to investigate the effects of VitC on reducing oxidative stress and nitric oxide (NO) formation which affects the viability of the broiler finisher blood cells (BFBC).&nbsp; 
 
Methods: BFBC were maintained at temperature at 41&deg;C and the temperature increasing from 41&deg;C to 45&deg;C. At 41&deg;C to 45&deg;C, BFBC supplemented with VitC solution at concentrations of 0, 25, 50 and 75 &micro;mol. Then, total antioxidant power (FRAP), malondialdehyde (MDA), hydrogen peroxide (H2O2), NO in supernatant and the viability of BFBC were measured. 
 
Result: It was found that MDA and NO levels were increased at high ambient temperature (P&lt;0.05). At the same time, the viability of BFBC was decreased (P&lt;0.05). Vitamin C at the concentration of 50 &micro;mol could reduce MDA and NO better than at other concentrations (P&lt;0.05)&nbsp; and increased the viability of BFBC (P&lt;0.05). This phenomenon indicated that VitC reduced oxidative stress and NO levels, which were important factors for BFBC viability at high ambient temperature.</div>

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The Effect of Vitamin C on Oxidative Stress, Nitric Oxide Formation and Viability of Broiler Finisher Blood Cells Subjected to High Ambient Temperature

<div>Background: High temperatures adversely affect the growth and development of plants at vegetative, reproductive and maturity stages of their life cycle. The maximum air temperature of higher than 25oC frequently encountered in lentil at the reproductive stage mainly in West Bengal rice-lentil cropping pattern. Such high temperatures in rabi season impair the crop growth and productivity. Added to this, future climate predictions are indicating 27-28oC during this period.&nbsp; 
 
Methods: The field-laboratory experiment was conducted during 2014, with 20 genotypes of lentil. The field experiment was laid in split plot design with 3 different windows of sowing, while the laboratory investigation was carried out in completely randomized design with pollen collected from the field experiment. 
 
Result: The present investigation reveals that high air temperature &gt;25oC resulted in the failure of pollen germination, increase in abnormal pollen tube and aborted pollen. A drastic effect in seed filling and pod development in lentil was observed. Out of 20 lentil genotypes studied, ILL-10893 and L-13-113 emerged as tolerant genotypes while, BM-6 and L-4076 as susceptible with special emphasis on physiological characters.</div>

<div>High-temperature Stress and the Fate of Pollen Germination and Yield in Lentil (Lens culinaris Medikus)</div>

Background: In the present climate change scenario, the rising temperatures are imposing severe threat to blackgram production leading to marked reduction in yield potential.The reduction in the yield potential is mainly due to reproductive failures caused by heat stress. Keeping this in view, the present study was carried out to find out the reasons behind reproductive failures and identify the genotypes that yield better under heat stress. 
 
Methods: Thirty blackgram genotypes selected from temperature induction response technique were evaluated for reproductive efficiency under natural high temperature conditions. Field experiment was conducted at Agricultural College Farm, Acharya N.G Ranga Agricultural University, Agricultural College, Bapatla. Dry matter partitioning, reproductive efficiency and yield traits were recorded at flowering and the data were analyzed statistically and pooled. 
 
Result: Genetic variability was observed among the blackgram genotypes with respect to dry matter partitioning, reproductive efficiency and yield traits under high temperature stress conditions. Among the 30 genotypes tested for thermotolerance, the genotypes TBG-129, PU-1804 and LBG-1015 were found to withstand high temperature stress at reproductive stage by possessing higher dry matter, number of flowers per plant, pollen viability, pollen germination percentage, pollen load on stigma, stigma receptivity, flower to pod setting percentage and higher yield. Correlation analysis revealed a strong positive association of total dry matter and all the reproductive efficiency characteristics with seed yield under heat stress conditions. The PCA results revealed considerable variability among the traits accounting for 86.6% of total variability. The genotypes TBG-129, PU-1804 and LBG-1015 can be potentially used as donors in the breeding programmes for the development of heat tolerant genotypes.

Evaluation of Blackgram (Vigna mungo L.) Genotypes for Dry Matter Partitioning, Reproductive Efficiency and Yield under High Temperature Stress

Background: Blackgram is a short duration pulse crop which is sensitive to high temperatures. Raising global temperatures are becoming a serious threat to the production of blackgram by altering biochemical processes at cellular level. Hence, the present investigation was carried out for better understanding of genotypic variability and the biochemical mechanisms governing heat stress tolerance which can help in identifying heat tolerant blackgram genotypes that can yield better under climate change scenarios. 
 
Methods: Thirty blackgram genotypes selected from temperature induction response technique were evaluated for biochemical efficiency under natural high temperature conditions during summer, 2022 and 23. Field experiment was conducted at Agricultural College Farm, Acharya N.G Ranga Agricultural University, Agricultural College, Bapatla. Biochemical and yield parameters were recorded at flowering and the data were analyzed statistically and pooled. 
 
Result: The results of the study revealed that the genotypes TBG-129, LBG-1015, PU-1804 and PU-31 recorded higher seed yield indicating their ability to withstand high temperatures by up-regulating various biochemical pathways involved in increased production of proline, carotenoids and antioxidant defense enzymes that might have scavenged the free radicals that were produced due to high temperature stress, thereby preventing lipid peroxidation. Lower seed yield was recorded in TBG-125 and LBG-1023 which might be due to oxidative damage caused by higher accumulation of free radicals and poor scavenging activity of antioxidant enzymes. Moreover, the results of correlation analysis revealed that all the biochemical traits such as proline, carotenoids and antioxidant defense enzymes showed positive association with seed yield except free radicals and malondialdehyde. The principal component analysis results revealed considerable variability among the traits accounting for 80.0%.&nbsp;The genotypes TBG-129, LBG-1015, PU-1804 and PU-31 can be used in breeding programmes for development of heat tolerant genotypes.