Chlorophyll Stability Index Research Articles

Screening and Variability Studies in Rice Genotypes for Drought Tolerance and Yield

In the present investigation, laboratory and field screening of nine rice genotypes, namely, TM 12061, TM 12077, TM 12012, TM 14035, TM 16017, Senthuram, Vandhana, TKM 12 and Anna (R) 4 was taken up to assess their drought tolerance potential. For laboratory screening, the effect of different levels of PEG concentration namely, -0.2, -0.4, -0.6 and -1.0 MPa on germination, shoot length and root length were studied. There was a considerable decrease in the germination potential among all the genotypes with increase in PEG concentration. The culture, TM 12077 showed higher level of tolerance to PEG induced drought stress showing 30.8% germination with 3.2 cm and 8.85 cm shoot and root length, respectively at higher level of PEG concentration (1.0 MPa). In field screening under managed stress condition, the cultures, TM 12077 and TM 12012 showed higher accumulation of proline (4.15 mg/g). Chlorophyll stability index was more than 80% in the genotypes, TM 12012, TM 12077, and TM 12061. The culture TM 14035, the varieties Anna (R) 4 and Vandhana matured early in 115 days. Plant height was found to be moderate in Vandhana (103.3 cm), TM 12077(105.4 cm), TM 12061 (108.2 cm) and TM 12012 (110.5 cm) under managed stress condition. The number of tillers per plant, number of panicles/sqm and yield/hectare were maximum in the culture, TM 12077 under managed stress condition. Based on laboratory and field screening, the cultures TM 12077, TM 12012, and TM 12061 were found promising for water stress environment and can be utilized as donors in the breeding programs for drought tolerance in rice. High heritability coupled with moderate to high GA as per cent of mean was recorded for plant height, tillers per plant, chlorophyll Stability index and total chlorophyll content indicating the presence of additive gene effects and scope for their improvement through direct selection.

Screening of mustard (Brassica juncea) varieties under different quality of saline water irrigation in semi-arid conditions of Haryana

Aim: Screening mustard varieties under saline water irrigation, and to evaluate the salt tolerant mustard varieties for semi-arid conditions of Haryana. Methodology: This study was conducted in permanent pucca plots measuring 2m x 2m with six mustard varieties (Kranti; NC, Kranti; Filler, CS2005-143,Giriraj,CS-54, and CS-60) and four quality of irrigation water, i.e., ECiw 0.36, 2.5, 5.0 and 7.5 dS m-1 in a Completely Randomised Design with three replications in sandy loam soil. Results: The data on seed yield, straw yield and other physiological parameters indicated decrease with increasing salinity of irrigation water. The interaction between varieties and saline water irrigation was in significant. Among six mustard varieties, variety CS 2005-143 showed significantly higher seed and straw yield (24.47 and 74.37 q ha-1) as compared to the remaining varieties. However, the variety Kranti (NC) attained the lowest seed and straw yield (15.47 and 45.53 q ha-1). The overall mean reduction in seed and straw yield at 2.5, 5.0 and 7.5 dS m-1 was 3.69, 12.42, 24.89 and 4.16, 14.85, 27.54% as compared to canal water (0.36 dS m-1), respectively. Physiological parameters like chlorophyll content, chlorophyll stability index (%), relative water content (%), assimilation rate declined under salinity stress. The maximum reduction was noticed at higher salinity level (7.5 dS m-1). Variety CS 2005-143 benefited higher among other varieties at each salinity levels. Interpretation: Among the six mustard varieties, CS 2005-143 performed better in terms of seed yield, straw yield, and other physiological parameter at higher salinity levels (7.5 dS m-1). Key words: Chlorophyll content, Mustard varieties, Saline water, Semi-arid areas

Comparative physiological and transcriptome analysis in cultivated and wild sugarcane species in response to hydrogen peroxide-induced oxidative stress

BackgroundSugarcane is an important energy crop grown worldwide,supplementing various renewable energy sources. Cultivated and wild sugarcane species respond differently to biotic and abiotic stresses. Generally, wild species are tolerant to various abiotic stresses. In the present study, the physiological and molecular responses of cultivated and wild sugarcane species to oxidative stress at the transcriptional levels were compared. Transcriptional responses were determined using RNAseq. The representative RNA-seq transcript values were validated by reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) and confirmed through physiological responses.ResultsOxidative stress causes leaf-rolling and -tip drying in cultivated sugarcane, but the wild species are tolerant. Higher chlorophyll fluorescence was observed in the wild species than that in the cultivated varieties under stress. Wild species can maintain a higher chlorophyll stability index than the cultivated species, which was confirmed by the lower transcripts of the chlorophyllase gene in the wild species than that in the cultivated variety. Transcription factor genes (NAC, MYB, and WRKY) were markedly expressed in response to oxidative stress, revealing their involvement in stress tolerance. The analysis revealed synchronized expression of acetyl-transferase, histone2A, cellulose synthase, and secondary cell wall biosynthetic genes in the wild species. The validation of selected genes and 15 NAC transcription factors using RT-qPCR revealed that their expression profiles were strongly correlated with RNA-seq. To the best of our knowledge, this is the first report on the oxidative stress response in cultivated and wild sugarcane species.ConclusionPhysiological and biochemical changes in response to oxidative stress markedly differ between cultivated and wild sugarcane species. The differentially expressed stress-responsive genes are grouped intothe response to oxidative stress, heme-binding, peroxidase activity, and metal ion binding categories. Chlorophyll maintenance is a stress tolerance response enhanced by the differential regulation of the chlorophyllase gene.There is a considerable difference in the chlorophyll stability index between wild and cultivated varieties. We observed a substantial regulation of secondary wall biosynthesis genes in the wild species compared with that in the cultivated variety, suggesting differences in stress tolerance mechanisms.

Exogenous application of carbon nanoparticles alleviates drought stress by regulating water status, chlorophyll fluorescence, osmoprotectants, and antioxidant enzyme activity in Capsicum annumn L.

Drought is one of the most important abiotic stresses that has a huge negative effect on crop yield. Carbon nanoparticles (CNPs) have received greater attention for their impact on the plants under abiotic stress conditions. However, it is urgently required to apply CNPs to the chili pepper (Capsicum annuum L. cv. Kaskada), which has not yet been studied. The goal of this study was to find out how CNPs affect the growth of chili pepper plants, chlorophyll pigments, proline content, and the activity of antioxidant enzymes when the plants are stressed by drought. Therefore, we synthesized and functionalized CNPs of oil fly ash by one-pot ball milling fabrication. X-ray photoelectron spectroscopy (XPS) was used to identify oxidative moieties on the CNPs surface after exposure to nitric and acetic acids. In the present study, functionalized CNPs were sprayed onto the leaves of 20-day-old plants at various concentrations (6 and 12mg L-1) to determine their effects. We demonstrate that drought stress considerably reduces the plant height, fresh weight (FW), and dry weight (DW). Nevertheless, the exogenous application of functionalized CNPs caused an increase in relative water content (RWC), chlorophyll stability index (CSI), and chlorophyll fluorescence (Fv/Fm) under drought stress. Exogenous functionalized CNPs dramatically increased proline content under drought by reducing abscisic acid (ABA) content in the leaves. When subjected to drought stress, functionalized CNPs boosted antioxidant activities such as superoxide dismutase (SOD) and catalase (CAT) activity. Overall, the positive effects of CNPs on chili pepper seedlings open up new possibilities for developing innovative agricultural techniques, especially when plants are grown in drought conditions.

Optimization of paclobutrazol dose for mitigation of water-deficit stress in rice (Oryza SativaL.)

The objective of the present study was to assess and optimize the paclobutrazol (PBZ) dose for mitigation of adverse effects of water deficit stress in rice. Paclobutrazol (PBZ), a triazole compound, has been proven to protect plants against abiotic stresses. As a result, an experiment was conducted with three rice varieties, namely N22, IR64 DTY1.1, and IR64, to identify the optimal dose under both mild and severe water deficit stress (WDS) at both vegetative and anthesis stages. Exogenous PBZ (30, 60, 90, and 120 ppm) was applied to plants just before imparting water deficit stress. The highest augmentation of relative water content (RWC), membrane stability index (MSI), total chlorophyll, chlorophyll stability index (CSI), and abscisic acid (ABA) was observed at 90 ppm of PBZ. Based on a curve-fitting analysis of the physiological responses of three rice cultivars to PBZ, the optimum dose was estimated to be around 100 ppm.

Physiological response of cocoa (Theobroma cacao L. ) genotypes to drought

Drought is one of the major environmental stresses affecting crop productivity worldwide. Climate change is expected to result in a rise in the number and intensity of drought events in the coming decades, so climate-resilient crops that can withstand this stress are in high demand. There are few genotypes in cocoa where it can tolerate water deficit conditions. The objective of the current investigation was to evaluate the effect of drought stress on the photosynthetic and physiological parameters of six cocoa genotypes (Theobroma cacao L.) with two irrigation regimes (100% field capacity and 40% field capacity) under greenhouse conditions at Cocoa Research Station, Kerala Agricultural University, Thrissur. The effect of water deficit conditions on gas exchange and physiological parameters such as relative water content, membrane stability index, chlorophyll stability index, and chlorophyll content were evaluated. Drought stress conditions resulted in reduced photosynthetic rate, relative water content, chlorophyll content, chlorophyll stability and membrane stability. All genotypes revealed significant differences for most parameters with two irrigation regimes. Among the cocoa genotypes, P.IV 19.9, which is classified as a highly tolerant genotype, recorded better results for all the parameters studied under water deficit conditions at 40 per cent FC. The findings of this study support the classification of these genotypes as highly tolerant, tolerant, and susceptible. These parameters may be used as the most promising indicators to screen for drought tolerance in cocoa. The results of the study revealed that photosynthetic and physiological parameters have a significant role in imparting drought stress tolerance to cocoa. Furthermore, these selected drought-tolerant genotypes can be used in future crop improvement programmes in cocoa.

Planting models and mulching materials management to improve anti-oxidant defense system, grain hormone balance and production of maize in semi-arid regions

The water shortage and weeds damage have become severe problems in the dry-land farming system of China, the farming commonly using mulching materials strategy as a water-saving and weeds precaution agricultural technology. However, it is still unclear whether various mulching applications under different cultivation models can improve the antioxidant defence system, herbicide tolerance, and grain hormone balance, photosynthetic capacity and grain yield of corn. Therefore, during 2018–2019, a two-year study was conducted, and the following six treatments were used: CT: traditional planting; SM: corn stalk mulch; FM: plastic mulch; RT: ridges cultivation without plastic mulch; RP: Plastic mulch covering ridges and furrows; RPS: Plastic covering on ridges and straw on furrows. The results revealed that the RPS treatment enhanced the soil water storage in the jointing and filling stages, and obtained a higher chlorophyll stability index, IAA, Z + ZR, ABA, corn yield and other plant hormone content, compared with the control plot. Furthermore, this improvement is attributed to the reduction of oxidative damage of malondialdehyde (MDA) content at different growth stages. The RPS and RP treatments considerably improved the superoxide dismutase (SOD) and catalase (CAT), also decreased considerably the MDA, H2O2 and O2− contents at various growth stages. The RPS treatment had a higher ability to reduce the H2O2 and O2−, and the better anti-oxidant enzyme activity due to the lower level of lipid peroxidation, which can efficiently protect the photosynthesis mechanism and significantly improve (54.8%) biomass, (49.5%), WUEg, (89.1%), WUEb and (98.0%) grain yield are higher than CT treatment. In conclusion, RPS treatment has a great potential in improving grain hormone balance, antioxidant defence system and corn production in semi-arid areas.

Screening and differential oxidative stress responses of hot pepper (Capsicum annuum L.) genotypes under cold stress

Cold stress (CS) anomalies have recently increased, major abiotic threat that delimit chilli production and yield. Cold tolerance is differing between genotypes, especially in commercial crops like hot pepper (chilli). specific investigations are required to understand biochemical and physiological changes in response to Cold stress (CS). Crop selection for increased tolerance needs traits with high sensitivity, fast and cost effective. This study aimed to select chilli genotypes which revealing differential tolerance to CS at seedling stage. Accordingly, 12 chilli genotypes were examined under two cold regimes including control (35/25 °C – day/night) and CS (10/8 °C – day/night). Multivariate cluster analysis of 14 traits grouped the genotypes into three clusters under stress condition, indicating that CS influencing physiology and oxidative potential of chilli seedlings. Chlorophyll, Membrane stability, Hydrogen peroxide content, lipid peroxidation and proline, phenolic contents are the influential traits for evaluating the impact of cold stress. ROS and ROS mediated traits showed a differential performance among the genotypes tested. Enzymatic antioxidants were significantly increased across all genotypes. Decrements of pungency levels in chilli fruits were significant only in CA-173 and F-02 genotypes. Altogether, the antioxidant profile has explored there is an association between capsaicinoid levels and antioxidant activities, antioxidants may involve preserving capsaicinoid metabolism to maintain the quality of chilli fruits during CS. Grouping of genotypes by cluster analysis is correlated with cold injury index and chlorophyll stability index under CS conditions. These indices can be employed as proper screening indices for cold tolerance in chilli genotypes. . • Simulated short-term cold stress has differential negative impacts among Chilli genotypes. • Differential levels of ROS generation and antioxidant potential among the genotypes tested. • ROS-induced oxidation of capsaicinoids was countered by antioxidant enzymes and chilli fruit quality was maintained under short-term cold stress. • 12 genotypes were grouped into 3 clusters: 1 – Sensitive; 2 – Moderately tolerant; 3 – Tolerant. • Cold injury index and Chlorophyll stability index can be used as cost-effective screening indices for selection of cold-tolerant chilli genotypes.

Evaluation of physio-biochemical criteria in maize inbred lines and their F1 hybrids grown under water-deficit conditions

Since the application of deficit water became a dominant tactic in crop irrigation, developing and surveying newly adapted genotypes should be adopted. In this study, we determined the physio-biochemical activities of 21 maize genotypes under 100 % and 70 % crop evapotranspiration irrigation conditions (normal and deficit irrigation, respectively) in sandy soil to determine which activities can identify drought-tolerant, high-yield genotypes. The experimental design was arranged in randomized complete blocks with three replicates. Results showed that the drought-tolerant parents and hybrids had the highest relative water content (RWC), membrane stability index (MSI), chlorophyll a and b (Chl. a, b), total chlorophyll (total Chl.), chlorophyll a/b ratio (Chl. a/b), chlorophyll stability index (CSI), proline, phenolic content, superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) levels. They also had the lowest malondialdehyde (MDA) content. The physio-biochemical traits were positively correlated with more tolerant inbred lines and hybrids that displayed a high yield under both irrigation treatments. Furthermore, maize parents that performed well under the 100 % and 70 % evapotranspiration levels were capable of producing high-performance hybrids under both conditions. Accordingly, the hybrids P1 x P6, P2 x P5, and P4 x P6 gave a high performance in sandy soil under both conditions, based on yield attributes estimation. It could be concluded that physio-biochemical traits can be used as effective selection criteria at the silking stage of maize plants to identify high-yield inbred lines and hybrids under stress and normal conditions. These findings will undoubtedly aid maize breeders in rapidly improving and developing new drought-tolerant varieties.

Biostimulation effects of linseed and citrus oils on growth, antioxidant enzymes activity, metabolic changes and water relations of Khaya senegalensis seedlings under drought stress

This study aim to use environmentally friendly material (Linseed and citrus oils) to reduce the harmful effect of water deficit on Khaya senegalensis plant due to its economic importance as a source of wood in addition to many uses of alternative medicine. Therefore, Khaya senegalensis plants were grown in green house with three irrigation intervals (5, 7 and 9 days) and oils foliar spray as linseed oil (Lin) at (0, 5, 7%) and citrus oils at (0, 1, 2%). The results indicated that the 9 days irrigation interval gave the lowest values of the most studied growth parameters, water relations (relative water content (RWC%), water retention capacity (WRC) and membrane stability index(MSI%), photosynthesis pigments, chlorophyll stability index (CSI%), minerals content, total free amino acid while increased values of electrolyte leakage (EL%), total sugar, total phenol, and antioxidant enzymes activities(Catalase (CAT), Peroxidase (POX), Superoxide dismutase (SOD)). Both oils treated especially linseed oil, at 7% increased values of all parameters and chemical composition compared with untreated plants plus different irrigation intervals, except EL% was decreased. The data provided evidence that linseed and citrus oils treatment reduces the adverse effect of water deficit on Khaya senegalensis plants and can play a role in providing stress tolerance.

Response of citrus (Citrus sps.) rootstock hybrids to PEG induced drought under hydroponic system

Present study was carried out at the glasshouse facility of the ICAR-Indian Agricultural Research Institute, New Delhi during 2020–21 using a simple hydroponic platform to assess the polyethylene glycol (PEG) induced drought impact on shoot-root morphology and physio-biochemical traits of 4 newly developed citrus (Citrus sps.) rootstock hybrids. Hybrid CRH 21-13/14 displayed superior shoot morphological performance in drought, articulated in terms of increment in plant height (4.5%), leaf numbers (9.5%), and dry weight of shoot (7.0%) with the lowest leaf wilting index (LWI). A contrasting pattern was noticed in CRH 23-5/15, CRH 23-9/17 akin to sensitive check Jatti khatti. Hybrid CRH 21-13/14 exhibited extensively, ramified and improved root system, and was able to sustain root growth under drought. It also showed an increment in root tips (116.1%) and forks (12.6%) during drought, whereas the rest hybrids along with sensitive check (Jatti khatti) exhibited a declining trend. The strong positive association of most root traits with relative water content (RWC) and membrane stability index (MSI) underscored the contribution of root traits towards drought avoidance by optimizing water resources. Although all tested hybrids declined total chlorophyll, chlorophyll a/b ratio and CSI (chlorophyll stability index) to varying degrees during drought, CRH 21- 13/14 exhibited minimum decline. Study postulate superior drought tolerance of CRH 21-13/14 conferred by the drought avoidance mechanism and moderate performance of CRH 21-14/14 (Pummelo × Troyer) as against CRH 23-5/15 and CRH 23-9/17 (Pummelo × Morton hybrids).

Rice CO 53: A high yielding drought tolerant rice variety for drought prone districts of Tamil Nadu

Early duration drought tolerant rice culture CB 06803, a derivative of the cross PMK (R ) 3 x Norungan was released as Rice CO 53 during the year 2020 as an alternate variety for Anna(R)4, with 115 -120 days duration. It possesses desirable features like high yield, drought tolerance and better physiological efficiency. This culture with semi dwarf stature has efficient tillering capacity, long droopy panicles with a highly acceptable plant characters and is a replacement for the rice variety Anna (R) 4 due to its grain yield and pest and disease resistance. In the overall yield analysis, the culture CB06803 recorded an overall mean grain yield of 3718 kg/ha which was 12.19 per cent increase over TKM (R) 12 and 14.08 per cent over Anna (R) 4 under dry condition. Under semi dry condition, it recorded 3866 kg/ha with 18.40 per cent increase over TKM (R) 12 and 8.67 per cent over Anna (R) 4. It is moderately resistant to WBPH, leaf blast, neck blast, sheath rot, brown spot and RTD under artificial condition. It has white short bold rice with high milling percentage (69.6), head rice recovery (59.6%) and suitable for idly making. The culture, CB 06803 had better  agronomic efficiency than TKM (R)12 and Anna (R) 4 by recording more number of productive tillers per plant and grain yield under control and drought. The culture CB 06803 had better physiological efficiency under drought than TKM (R) 12 and Anna (R) 4  having higher RWC, total chlorophyll content, chlorophyll stability index, photosynthetic rate, stomatal conductance and photo chemical efficiency. The culture had higher proline content than TKM (R) 12 and was on par with Anna (R) 4. It had higher catalase activity than Anna (R) 4. CB 06803 had better physiological efficiency under drought by showing partial closure of stomata as that of Sahbagidhan. CO 53 with higher grain yield under drought, disease resistance and short bold grains and suitable for cultivation in drought prone districts of Tamil Nadu as direct seeded rainfed or semi dry rice ecosystem. Keywords: Rice CO 53, bold grain rice, short duration, drought tolerance

Silicon Supplementation Alleviates the Salinity Stress in Wheat Plants by Enhancing the Plant Water Status, Photosynthetic Pigments, Proline Content and Antioxidant Enzyme Activities.

Silicon (Si) is the most abundant element on earth after oxygen and is very important for plant growth under stress conditions. In the present study, we inspected the role of Si in the mitigation of the negative effect of salt stress at three concentrations (40 mM, 80 mM, and 120 mM NaCl) in two wheat varieties (KRL-210 and WH-1105) with or without Si (0 mM and 2 mM) treatment. Our results showed that photosynthetic pigments, chlorophyll stability index, relative water content, protein content, and carbohydrate content were reduced at all three salt stress concentrations in both wheat varieties. Moreover, lipid peroxidation, proline content, phenol content, and electrolyte leakage significantly increased under salinity stress. The antioxidant enzyme activities, like catalase and peroxidase, were significantly enhanced under salinity in both leaves and roots; however, SOD activity was drastically decreased under salt stress in both leaves and roots. These negative effects of salinity were more pronounced in WH-1105, as KRL-210 is a salt-tolerant wheat variety. On the other hand, supplementation of Si improved the photosynthetic pigments, relative water, protein, and carbohydrate contents in both varieties. In addition, proline content, MDA content, and electrolyte leakage were shown to decline following Si application under salt stress. It was found that applying Si enhanced the antioxidant enzyme activities under stress conditions. Si showed better results in WH-1105 than in KRL-210. Furthermore, Si was found to be more effective at a salt concentration of 120 mM compared to low salt concentrations (40 mM, 80 mM), indicating that it significantly improved plant growth under stressed conditions. Our experimental findings will open a new area of research in Si application for the identification and implication of novel genes involved in enhancing salinity tolerance.

Alleviating Drought Stress in Brassica juncea (L.) Czern & Coss. by Foliar Application of Biostimulants-Orthosilicic Acid and Seaweed Extract.

Agricultural productivity is negatively impacted by drought stress. Brassica is an important oilseed crop, and its productivity is often limited by drought. Biostimulants are known for their role in plant growth promotion, increased yields, and tolerance to environmental stresses. Silicon in its soluble form of orthosilicic acid (OSA) has been established to alleviate deteriorative effects of drought. Seaweed extract (SWE) also positively influence plant survival and provide dehydration tolerance under stressed environments. The present study was conducted to evaluate the efficacy of OSA and SWE on mitigating adverse effects of drought stress on Brassica genotype RH-725. Foliar application of OSA (2ml/L and 4ml/L) and SWE of Ascophyllum nodosum (3ml/L and 4ml/L) in vegetative stages in Brassica variety RH 725 under irrigated and rainfed condition revealed an increase in photosynthetic rate, stomatal conductance, transpirational rate, relative water content, water potential, osmotic potential, chlorophyll fluorescence, chlorophyll stability index, total soluble sugars, total protein content, and antioxidant enzyme activity; and a decrease in canopy temperature depression, proline, glycine-betaine, H2O2, and MDA content. Application of 2ml/L OSA and 3ml/L SWE at vegetative stage presented superior morpho-physiological and biochemical characteristics and higher yields. The findings of the present study will contribute to developing a sustainable cropping system by harnessing the benefits of OSA and seaweed extract as stress mitigators.

Variation in biochemical, physiological and ecophysiological traits among the teak (Tectona grandis Linn. f) seed sources of India

Teak being an iconic timber species the studies on its physiological and biochemical traits are very limited in India and worldwide. As a result, the current study aimed to assess biochemical parameters such as chlorophyll a, chlorophyll b, total chlorophyll, carotenoids, chlorophyll ab ratio, proline content, and peroxidase activity, along with physiological parameters such as Chlorophyll stability index, relative water content, and leaf area, as well as ecophysiological traits such as net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci), transpiration rate (Tr), Leaf temperature, intrinsic water-use efficiency (iWUE), instantaneous water use efficiency and intrinsic carboxylation efficiency of thirty teak seed sources collected from different states of India. FCRITK 19, FCRITK 21, FCRITK 25, FCRITK 29, and FCRITK 05 were reported to have a greater photosynthetic rate (> 17 µmol m−2 s−1) coupled with a relative water content of more than 50% and a chlorophyll stability index of more than 60%, which could be used in a future genetic improvement programme. Correlation analysis indicated that water use efficiency was found to be strongly but negatively correlated with transpiration rate (−0.601) and stomatal conductance (−0.910). The proline content had a substantial positive correlation with the chlorophyll stability index (0.890), signifying that they are associated with abiotic stress conditions. Cluster analysis was attempted to discriminate the sources based on biochemical, physiological and ecophysiological traits. Eleven sources (FCRITK 25, FCRITK 27, FCRITK 29, FCRITK 14, FCRITK 30, FCRITK 16, FCRITK 05, FCRITK 13, FCRITK 02, FCRITK 17 and FCRITK 15) exhibited superior performance compared to rest of the sources.

Assessment of genetic variability in bread Wheat (Triticum aestivum) under heat stress

The present study was carried out during rabi 2017–18, at wheat research farm, Department of genetics and plant breeding, CCS Haryana Agricultural University, Hisar, Haryana to assess the genetic diversity of 64 genotypes of bread wheat (Triticum aestivum L.) under late sown conditions based on the morpho-physiological traits. Analysis of variance depicted significant differences for all morpho-physiological traits under heat stress. Mean sum of squares due to genotypes were found significant for all the traits, indicating the presence of sufficient genetic variability among the genotypes. High estimates of phenotypic coefficient of variation (PCV), genotypic coefficient of variation (GCV) and high heritability coupled with high genetic advance were observed for traits, viz. spike weight, relative stress injury, chlorophyll stability index and GGR28 indicating additive gene action in expression of the traits and simple selection will be effective for the improvement of these traits. Correlation coefficient analysis revealed that increased grain yield under heat stress conditions was significantly contributed by spike weight (0.699), spike length (0.646), harvest index (0.616), spikelets per spike (0.445), number of productive tillers (0.393), grains per spike (0.390), 1000-grain weight (0.364), biological yield (0.360), GGR14 (0.332) and chlorophyll stability index (0.330). Among the traits studied, biological yield per plot (0.8421) and harvest index (0.9686)recorded for highest positive direct effect on grain yield in late sown conditions. The grain yield is indirectly contributedby spike length, spike weight, spikelets per spike, CSI, GGR14 through harvest index and number of productive tillers permeter, spike weight, thousand grain weight, GGR14 through biological yield.

The synthesis of polysaccharide crude nanoparticles extracts from Taif rose petals and its effect on eggplant seedlings under drought and salt stress

ObjectivesNatural biopolymer nanoparticles are an emerging area of research in green electronic devices and biomedical and agricultural fields. However, because drought and salt are two keys environmental aspects that affect agricultural crop yields around the world, a new strategy has been suggested to valorize the waste of Taif rose petals (Rosa damascenaMiller var.trigintipetala) in the production of polysaccharide material on the nanoscale. In this study, we explore the effects of drought and salinity stress on the physiology of eggplants. MethodsThe key objectives of this research were to investigate the effect of polysaccharide crude nanoparticles extract (PCE) in the alleviation of drought and salinity stress in eggplants. ResultsReduced chlorophyll content, chlorophyll fluorescence (Fv/Fm), and chlorophyll stability index (CSI) were seen in the plants that had been subjected to drought and salt stress. Under drought and salt stress, proline, total soluble protein, and sugar levels were all shown to be higher. However, polysaccharide crude nanoparticles extract reverses the negative effects of drought and salt stress and increases the chlorophyll content, chlorophyll fluorescence (Fv/Fm), and chlorophyll stability index (CSI) in the presence of drought and salt stress. When PCE was supplemented, the accumulation of lipid peroxidation was reduced, and the activities of antioxidant enzymes (SOD, CAT, POX, GR) were raised. ConclusionIn summary, the results suggest that exogenous PCE can mitigate the detrimental effects of drought and salt stress in eggplants by modulating antioxidant systems. Furthermore, the findings of this study give experimental proof that PCE can be used to increase drought tolerance as well as production in eggplant plants.

Role of Biostimulant Priming Applications on Germination, Growth and Chlorophyll Content of Sunflower (Helianthus annuus L.) Cultivars under Salinity Stress

Salinity, which is one of the abiotic stresses, has become an important obstacle in agricultural areas. The use of humic acids (HA) as a biostimulant is increasing day by day and it is tried to increase the resistance of plants against stress. In this study, the effects of HA application of 0-15ml L-1 (4 concentrations) on the resistance to salt (S) 0-150 mM L-1 (4 concentrations) stress in 3 sunflower cultivars (Maximus (C1), Sirena (C2), Reyna (C3) were investigated under laboratory conditions. In the study; germination percentage (GP), mean germination time (MGT), salt tolerance percentage (STP), seeding length (SL), root length (RL), relative water content (RWC), real water content (GSI), total chlorophyll (Chl), chlorophyll stability index (CSI) parameters were examined. As a result of the study, HA applications played a role in reducing the negative effects of salt stress on the examined parameters. It was concluded that HA can be evaluated as an effective material that can be used to increase resistance and tolerance of plants against salt stress.

Phytostabilization of arsenic and associated physio-anatomical changes in Acanthus ilicifolius L

The carcinogenic attribute of arsenic (As) has turned the world to focus more on the decontamination and declining the present level of As from the environment especially from the soil and water bodies. Phytoremediation has achieved a status of sustainable and eco-friendly approach of decontaminating pollutants, and in the present study, an attempt has been made to reveal the potential of As remediation by a halophyte plant, Acanthus ilicifolius L. Special attention has given to analyse the morphological, physiological and anatomical modulations in A. ilicifolius, developed in response to altering concentrations of Na2AsO4.7H2O (0, 70, 80 and 90 μM). Growth of A. ilicifolius under As treatments were diminished as assessed from the reduction in leaf area, root length, dry matter accumulation, and tissue water status. However, the plants exhibited a comparatively higher tolerance index (44%) even when grown in the higher concentrations of As (90 μM). Arsenic treatment induced reduction in the photochemical activities as revealed by the pigment content, chlorophyll stability index (CSI) and Chlorophyll a fluorescence parameter. Interestingly, the thickness and diameter of the xylem walls in the leaf as well as root tissues of As treated samples increased upon increasing the As concentration. The adaptive strategies exhibited by A. ilicifolius towards varying concentrations of As is the result of coordinated responses of morpho-physiological and anatomical attributes, which make the plant a promising candidate for As remediation, especially in wetlands.

Antioxidant defence system induced by seed priming with nanoparticles to restrain Fusarium wilt in cumin (Cuminum cyminum L.)

An experiment comprising of persuade of seed priming with plant growth promoting rhizobacteria (PGPR) and nanoparticles was conducted to restrain fusarium wilt in cumin. Biochemical changes (chlorophyll stability index, membrane stability index, free amino acid, soluble protein, total phenols) and antioxidant enzymes (superoxide dismutase, guaiacol peroxidase, polyphenol oxidase and catalase) were determined during disease development stages and influenced by nanoparticle treatments. The chlorophyll stability index, free amino acids, soluble proteins, guaiacol peroxidase, polyphenol oxidase and catalase were found higher in seedling tissues of cumin treated with PGPR + chitosan nanoparticles. Membrane stability index, total phenol and superoxide dismutase enzyme activities were enhanced in chitosan nanoparticles + green silver nanoparticles treatment. Antioxidant enzymes activities were increased during disease development stages. The combination of chitosan nanoparticles either with green silver nanoparticles or PGPR for seed priming would be found better for boosting up the antioxidant/defence system to restrain Fusarium wilt infection in cumin.