Evaluation of heat tolerance potential in Capsicum annum L. genotypes under heat stress

2020 ◽  
Vol 1 (1) ◽  
pp. 16-22
Author(s):  
Mujahid Ali ◽  
Muhammad Imran Lodhi ◽  
Choudhary Muhammad Ayyub ◽  
Zahoor Hussain ◽  
Zaid Mustafa ◽  
...  

Summer vegetables are severely affected by high temperature above threshold level which ultimately results in serious losses of their production. To cope with these economic losses different strategies had been adopted. The present study was designed to screen out heat tolerant genotypes of bell pepper. For this purpose, experiment was conducted in plant growth room in Institute of Horticultural Sciences, University of Agriculture Faisalabad. Ten genotypes of bell pepper (C1G3, C3G5, C7G4, V6G4, C2-E, C5G4, C43-D, C4G3, C43-A, C2G3) were brought from Ayub Agriculture Research Institute Faisalabad (AARI) and were grown. Heat treatment up to 40 ̊C was given. Data regarding agronomic traits (number of leaves, root length, shoot length, seedling dry weight, seedling fresh weight, electrolyte leakage) and physiological (Stomatal conductance, photosynthetic rate, transpiration rate and water use efficiency) was collected. Proper statistical designs were used to analyze the data. The research findings proved that heat stress significantly affected physiology, morphology and mechanisms of screened genotypes which followed the order for the heat stress as C5G4, C1G3, C2G3, C43-A, C3G5, C43-D, V6G4, C4G3, C43-A and C2G3, respectively. The collective effects of all these changes under high temperature stress resulted in poor plant growth and productivity. On the basis of physical and physiological parameters, genotypes C5G4, C1G3 and C43-A were among the most tolerant group and the most resistant genotypes.

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1076B-1076
Author(s):  
Seenivasan Natarajan ◽  
Jeff Kuehny

One of the greatest impediments to the production of marketable ornamental herbaceous plants in the southern U.S. is high temperature stress. Exposure of plants to sublethal temperature (heat preconditioning) prior to sustained heat stress helps some plants to tolerate subsequent heat stress, a phenomenon often referred as acquired thermotolerance. The objective of this experiment was to examine various morphological, physiological, and anatomical responses of two red varieties of each of the `Vista' (heat tolerant) and `Sizzler' (heat sensitive) series of Salvia splendens to heat preconditioning (HC) and subsequent heat stress treatments [challenging temperatures (CT)]. Cultivars of salvia were subjected to short duration (3 hours) HC of 35 °C every third day until 5 weeks after germination and subsequent exposure to two CT treatments: 30/23 °C and 35/28 °C (day/night) cycles in growth chambers until flowering. Plant growth, marketable quality, stomatal conductance and net photosynthesis declined for `Sizzler' without HC treatment. Compared with nonpreconditioned plants, heat-preconditioned `Sizzler' had 38.28% higher root dry weight, 95% greater leaf thickness, and 50% higher marketable quality at 35/28 °C heat stress condition. Heat preconditioning helped both `Vista' and `Sizzler' to survive in both the heat stress treatments. `Vista' had greater heat-tolerant traits than `Sizzler'; these traits were enhanced with heat preconditioning treatment. The results demonstrated that heat preconditioning enhanced heat tolerance in varieties of salvia, which could be related to heat-tolerant traits, such as dense plant growth with shorter internodes, thicker stems, greater stomatal conductance, and extensive root growth that compensated for the transpiration water loss and cooling effect.


HortScience ◽  
2005 ◽  
Vol 40 (3) ◽  
pp. 874d-874
Author(s):  
Seenivasan Natarajan ◽  
Jeff S. Kuehny ◽  
James E. Board

One of the greatest impediments to production of marketable ornamental herbaceous plants in southern U.S. is high temperature stress. Exposure of plants to sub-lethal temperature (heat preconditioning) before sustained heat stress helps some plants to tolerate subsequent heat stress a phenomenon often referred as acquired thermotolerance. The objective of this research was to examine various morphological, physiological and anatomical responses of `Vista red' (heat tolerant) and `Sizzler red'(heat sensitive) cultivars of Salvia splendens to heat preconditioning (HC) and subsequent heat stress treatments (challenging temperatures, CT). Cultivars of Salvia were subjected to short duration HC of 35 °C for 3 hours every third day until 5 weeks after germination and subsequent exposure to two CT treatments 30/23 °C and 35/28 °C (D/N) cycles in growth chambers for the next five weeks. Plant growth, marketable quality, stomatal conductance and net photosynthesis declined for Sizzler Red without HC treatment. Compared with nonpreconditioned plants, heat preconditioned Sizzler Red had 38.28% higher root dry weight, 95% greater leaf thickness, 50% higher marketable quality at 35/28 °C heat stress condition. Heat preconditioning helped both Vista Red and Sizzler to survive in both the heat stress treatments. Vista Red had greater heat tolerant traits than Sizzler Red, these traits exacerbated with heat preconditioning treatment. The results demonstrated that heat preconditioning enhanced heat tolerance in cultivars of Salvia, which could be related to maintenance of dense plant growth with shorter internodes, thicker stems, greater stomatal conductance, extensive root growth that compensated the transpirational water loss and overall cooling of plants.


2020 ◽  
Author(s):  
Forouzan Bahrami ◽  
Ahmad Arzani ◽  
Mehdi Rahimmalek

AbstractThermal stress at the reproductive stage poses a substantial constraint on cereal production worldwide. A two-year field study was conducted to assess tolerance to terminal heat stress in cultivated (Hordeum vulgare ssp. vulgare L.) and wild (H. vulgare ssp. spontaneum L.) barley genotypes using phenological and agronomic traits as well as selection indices based on grain yield. A new heat-tolerance index was tested while a simultaneous study was also carried out of both phenological and grain yield-related variables as well as previously defined indices. Results of analysis of variance showed the significant genotypic and high-temperature stress (environment) effects on all the traits studied. In contrast to the cultivated genotypes, the wild ones were found less affected by high-temperature stress. Moreover, both cultivated and wild genotypes were observed to use the life cycle shortening as a mechanism to evade heat stress. In addition, supplementary tolerance mechanisms were also found likely to contribute to heat-stress evasion in the wild germplasm. Grain yield showed a strong relationship with both stress tolerance index (STI) and heat tolerance index (HTI) among the wild genotypes. However, multivariate analysis highlighted the feasibility of HTI to screen high-temperature tolerant wild genotypes under harsh environments with the most high-temperature tolerant wild genotypes identified originating from warm climates.


HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 698g-698
Author(s):  
Aref A. Abdul-Baki ◽  
S. A. Haroon ◽  
R. N. Huettel

Susceptibility of tomato (Lycopersicon esculentum Mill) genotpyes to the root-knot nematode Meloydogyne incognita and to heat stress can be evaluated in a single labor- and time-saving operation using a nondestructive in vitro excised root technique. Seeds are sterilized and germinated for 2 days on 1% water agar. Five-mm root sections are grown at 28 and 35 C for 30 days on Gamborg-B medium with and without nematode inoculum. Evaluation criteria include fresh and dry weight and the appearance of juveniles, adults, gulls, and egg masses. Evidence will be presented on the breakdown of resistance to M. incognita under high temperature stress.


2020 ◽  
Vol 21 (20) ◽  
pp. 7681
Author(s):  
Shufen Wang ◽  
Tixu Hu ◽  
Aijuan Tian ◽  
Bote Luo ◽  
Chenxi Du ◽  
...  

High temperature is a major environmental factor that adversely affects plant growth and production. SlBRI1 is a critical receptor in brassinosteroid signalling, and its phosphorylation sites have differential functions in plant growth and development. However, the roles of the phosphorylation sites of SIBRI1 in stress tolerance are unknown. In this study, we investigated the biological functions of the phosphorylation site serine 1040 (Ser-1040) of SlBRI1 in tomato. Phenotype analysis indicated that transgenic tomato harbouring SlBRI1 dephosphorylated at Ser-1040 showed increased tolerance to heat stress, exhibiting better plant growth and plant yield under high temperature than transgenic lines expressing SlBRI1 or SlBRI1 phosphorylated at Ser-1040. Biochemical and physiological analyses further showed that antioxidant activity, cell membrane integrity, osmo-protectant accumulation, photosynthesis and transcript levels of heat stress defence genes were all elevated in tomato plants harbouring SlBRI1 dephosphorylated at Ser-1040, and the autophosphorylation level of SlBRI1 was inhibited when SlBRI1 dephosphorylated at Ser-1040. Taken together, our results demonstrate that the phosphorylation site Ser-1040 of SlBRI1 affects heat tolerance, leading to improved plant growth and yield under high-temperature conditions. Our results also indicate the promise of phosphorylation site modification as an approach for protecting crop yields from high-temperature stress.


2019 ◽  
Vol 32 (1) ◽  
pp. 143-151 ◽  
Author(s):  
Luma Rayane de Lima Nunes ◽  
Paloma Rayane Pinheiro ◽  
Charles Lobo Pinheiro ◽  
Kelly Andressa Peres Lima ◽  
Alek Sandro Dutra

ABSTRACT Salinity is prejudicial to plant development, causing different types of damage to species, or even between genotypes of the same species, with the effects being aggravated when combined with other types of stress, such as heat stress. The aim of this study was to evaluate the tolerance of cowpea genotypes (Vigna unguiculata L. Walp.) to salt stress at different temperatures. Seeds of the Pujante, Epace 10 and Marataoã genotypes were placed on paper rolls (Germitest®) moistened with different salt concentrations of 0.0 (control), 1.5, 3.0, 4.5 and 6.0 dS m-1, and placed in a germination chamber (BOD) at temperatures of 20, 25, 30 and 35°C. The experiment was conducted in a completely randomised design, in a 3 × 4 × 5 scheme of subdivided plots, with four replications per treatment. The variables under analysis were germination percentage, first germination count, shoot and root length, and total seedling dry weight. At temperatures of 30 and 35°C, increases in the salt concentration were more damaging to germination in the Epace 10 and Pujante genotypes, while for the Marataoã genotype, damage occurred at the temperature of 20°C. At 25°C, germination and vigour in the genotypes were higher, with the Pujante genotype proving to be more tolerant to salt stress, whereas Epace 10 and Marataoã were more tolerant to high temperatures. Germination in the cowpea genotypes was more sensitive to salt stress when subjected to heat stress caused by the low temperature of 20°C or high temperature of 35°C.


Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 687
Author(s):  
Chan Seop Ko ◽  
Jin-Baek Kim ◽  
Min Jeong Hong ◽  
Yong Weon Seo

High-temperature stress during the grain filling stage has a deleterious effect on grain yield and end-use quality. Plants undergo various transcriptional events of protein complexity as defensive responses to various stressors. The “Keumgang” wheat cultivar was subjected to high-temperature stress for 6 and 10 days beginning 9 days after anthesis, then two-dimensional gel electrophoresis (2DE) and peptide analyses were performed. Spots showing decreased contents in stressed plants were shown to have strong similarities with a high-molecular glutenin gene, TraesCS1D02G317301 (TaHMW1D). QRT-PCR results confirmed that TaHMW1D was expressed in its full form and in the form of four different transcript variants. These events always occurred between repetitive regions at specific deletion sites (5′-CAA (Glutamine) GG/TG (Glycine) or (Valine)-3′, 5′-GGG (Glycine) CAA (Glutamine) -3′) in an exonic region. Heat stress led to a significant increase in the expression of the transcript variants. This was most evident in the distal parts of the spike. Considering the importance of high-molecular weight glutenin subunits of seed storage proteins, stressed plants might choose shorter polypeptides while retaining glutenin function, thus maintaining the expression of glutenin motifs and conserved sites.


1975 ◽  
Vol 84 (3) ◽  
pp. 525-528 ◽  
Author(s):  
I. C. Onwueme ◽  
S. A. Adegoroye

SUMMARYSeeds of Amaranthus, melon, cowpea and tomato were planted in moist soil at 1, 4 or 7·5 cm depth and subjected to a heat stress of 45 °C for 10 h on the day of sowing (day 0), 1 day after sowing or 2 days after sowing. Seedling emergence was retarded by heat stress, the most drastic retardation being due to heat stress on day 1 for cowpea and tomato, day 2 for melon, and day 0 for Amaranthus. Emergence also decreased with increasing depth of sowing. The interaction of depth and heat stress was also significant in all cases, such that the delay in emergence due to heat stress tended to be greater with increasing depth of sowing. The agronomic significance of the results is discussed.


2020 ◽  
Author(s):  
S MukeshSankar ◽  
C. Tara Satyavathi ◽  
Sharmistha Barthakur ◽  
S.P Singh ◽  
Roshan Kumar ◽  
...  

AbstractEnvironmental stresses negatively influence survival, biomass and grain yield of most crops. Towards functionally clarifying the role of heat responsive genes in Pearl millet under high temperature stress, the present study were carried out using semi quantitative RT- PCR for transcript expression profiling of hsf and hsps in 8 different inbred lines at seedling stage, which was earlier identified as thermo tolerant/susceptible lines through initial screening for thermo tolerance using membrane stability index among 38 elite genotypes. Transcript expression pattern suggested existence of differential response among different genotypes in response to heat stress in the form of accumulation of heat shock responsive gene transcripts. Genotypes WGI 126, TT-1 and MS 841B responded positively towards high temperature stress for transcript accumulation for both Pgcp 70 and Pghsf and also had better growth under heat stress, whereas PPMI 69 showed the least responsiveness to transcript induction supporting the membrane stability index data for scoring thermotolerance, suggesting the efficacy of transcript expression profiling as a molecular based screening technique for identification of thermotolerant genes and genotypes at particular crop growth stages. As to demonstrate this, a full length cDNA of Pghsp 16.97 was cloned from the thermotolerant cultivar, WGI 126 and characterized for thermotolerance. The results of demonstration set forth the transcript profiling for heat tolerant genes can be a very useful technique for high throughput screening of tolerant genotypes at molecular level from large cultivar collections at seedling stage.


2019 ◽  
Vol 13 ((04) 2019) ◽  
pp. 578-587 ◽  
Author(s):  
Muhammed Alsamir ◽  
Nabil Ahmad ◽  
Vivi Arief ◽  
Tariq Mahmood ◽  
Richard Trethowan

Tomato is a mild season crop and high temperature stress impacts productivity negatively. However, the development of cultivars with improved heat tolerance is possible as genetic variability has been consistently reported. This study aimed to identify candidate genes that impact various traits under heat stress. Genome-wide association studies (GWAS) were conducted on a diverse set of 144 tomato genotypes collected from various germplasm centers and breeding programs. The genotypes were grown under control and heat stress in poly tunnels having mean temperatures of 30°C and 45°C for two seasons and phenotypic data were collected on seven agro-physiological traits. All individuals were genotyped withthe80K DArTseq platform using 31237 SNP markers. Data were analysed using a mixed model based on restricted maximum likelihood (REML). Pattern analysis of the phenotypic data showed five primary clusters each with genotypes from multiple origins. Based on the genotypic data, three wild tomato genotypes showed a degree of un-relatedness with the other materials as they were distantly located from the rest of the genotypes in the scatter plot. Control treatment data were used to ascertain markers that are exclusively important under high temperature stress. A large number of markers were significantly associated with various traits under heat stress. These included strong marker associations for number of inflorescence/plant (IPP), number of flowers/inflorescence (FPI), fresh fruit weight (FFrW), and electrolyte leakage (EL). High association with EL was found due to two SNPs 7858523|F|0-25:G>A-25:G>A and 4705224|F|0-60:C>G-60:C>G located on Chr 6. Other less pronounced marker-trait associations were observed for plant dry weight (PDW), and number of fruit/plant (FrPP).


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