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65 result(s) for "Ul-Allah, Sami"
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The fingerprints of climate warming on cereal crops phenology and adaptation options
Growth and development of cereal crops are linked to weather, day length and growing degree-days (GDDs) which make them responsive to the specific environments in specific seasons. Global temperature is rising due to human activities such as burning of fossil fuels and clearance of woodlands for building construction. The rise in temperature disrupts crop growth and development. Disturbance mainly causes a shift in phenological development of crops and affects their economic yield. Scientists and farmers adapt to these phenological shifts, in part, by changing sowing time and cultivar shifts which may increase or decrease crop growth duration. Nonetheless, climate warming is a global phenomenon and cannot be avoided. In this scenario, food security can be ensured by improving cereal production through agronomic management, breeding of climate-adapted genotypes and increasing genetic biodiversity. In this review, climate warming, its impact and consequences are discussed with reference to their influences on phenological shifts. Furthermore, how different cereal crops adapt to climate warming by regulating their phenological development is elaborated. Based on the above mentioned discussion, different management strategies to cope with climate warming are suggested.
Exogenous application of silicon improves the performance of wheat under terminal heat stress by triggering physio-biochemical mechanisms
Due to climate change, temperature in late February and early March raised up which cause heat stress at reproductive stage (terminal growth phase of wheat crop) which has become the major causative factor towards low wheat production in arid and semiarid regions. Therefore; strategies need to be adopted for improving terminal heat stress tolerance in wheat. In this study, we assessed whether foliar application of silicon (Si) (2 and 4 mM) at terminal growth phase i.e. heading stage of wheat imposed to heat stress (37 ± 2 °C) under polythene tunnel could improve the performance of wheat. Results of the study revealed that heat stress significantly reduced the photosynthetic pigments (chlorophyll a, b and a + b and carotenoids) leading to a lower grain yield. However, a 4 mM Si application (foliar applied) at heading stage prominently increased the chlorophyll a, b and a + b and carotenoids of flag leaf by improving the activities of enzymatic antioxidants (catalase, peroxidase and superoxide dismutase) and osmoprotectants (soluble sugar protein and proline) under terminal heat stress. Improvements in the performance of wheat (chlorophyll contents, carotenoids, soluble sugar and proteins and proline and yield) with foliar application of Si were also observed under control conditions. Correlation analysis revealed strong association ( r  > 0.90) of chlorophyll contents and carotenoids with grain and biological yield. Negative correlation (−0.81 <  r  > −0.63) of physio-biochemical components (antioxidants, proline, soluble sugars and proteins) with yield revealed that under heat stress these components produced in more quantities to alleviate the effects of heat, and Si application also improved these physio biochemical components. In crux, foliar application of Si alleviates the losses in the performance of wheat caused by terminal heat stress by improving the antioxidant mechanism and production of osmoprotectants.
Terminal drought and heat stress alter physiological and biochemical attributes in flag leaf of bread wheat
Heat stress along with low water availability at reproductive stage (terminal growth phase of wheat crop) is major contributing factor towards less wheat production in tropics and sub-tropics. Flag leaf plays a pivotal role in assimilate partitioning and stress tolerance of wheat during terminal growth phase. However, limited is known about biochemical response of flag leaf to combined and individual heat and drought stress during terminal growth phase. Therefore, current study investigated combined and individual effect of terminal drought and heat stress on water relations, photosynthetic pigments, osmolytes accumulation and antioxidants defense mechanism in flag leaf of bread wheat. Experimental treatments comprised of control, terminal drought stress alone (50% field capacity during reproductive phase), terminal heat stress alone (wheat grown inside plastic tunnel during reproductive phase) and terminal drought stress + terminal heat stress. Individual and combined imposition of drought and heat stresses significantly (p≤0.05) altered water relations, osmolyte contents, soluble proteins and sugars along with activated antioxidant defensive system in terms of superoxide dismutase (SOD), peroxidase (POD) and ascorbate peroxidase (APX). Turgor potential, POD and APX activities were lowest under individual heat stress; however, these were improved when drought stress was combined with heat stress. It is concluded that combined effect of drought and heat stress was more detrimental than individual stresses. The interactive effect of both stresses was hypo-additive in nature, but for some traits (like turgor potential and APX) effect of one stress neutralized the other. To best of our knowledge, this is the first report on physiological and biochemical response of flag leaf of wheat to combine heat and drought stress. These results will help future studies dealing with improved stress tolerance in wheat. However, detailed studies are needed to fully understand the genetic mechanisms behind these physiological and biochemical changes in flag leaf in response to combined heat and drought stress.
Zinc biofortification potential of diverse mungbean Vigna radiata (L.) Wilczek genotypes under field conditions
Zinc (Zn) is an important micronutrient for crop plants and essential for human health. The Zn-deficiency is an important malnutrition problem known globally. Biofortified foods could overcome Zn deficiency in humans. Mungbean [ Vigna radiata (L.) Wilczek] is an important, pulse crop frequently grown in arid and semi-arid regions of the world. Mungbean could provide essential micronutrients, including Zn to humans. Therefore, it is very important to investigate the impact of Zn fertilization on the yield and grain biofortification of mungbean. Twelve mungbean genotypes (i.e., NM-28, NM-2011, NM-13-1, NM-2006, NM-51, NM-54, NM-19-19, NM-92, NM-121-25, NM-20-21, 7006, 7008) were assessed for their genetic diversity followed by Zn-biofortification, growth and yield under control (0 kg ha -1 ) and Zn-fertilized (10 kg ha -1 ) conditions. Data relating to allometric traits, yield components, grain yield and grain Zn contents were recorded. Zinc fertilization improved entire allometric and yield-related traits. Grain yield of different genotypes ranged from 439 to 904 kg ha -1 under control and 536 to 1462 kg ha -1 under Zn-fertilization. Zinc concentration in the grains varied from 15.50 to 45.60 mg kg -1 under control and 18.53 to 64.23 mg kg -1 under Zn-fertilized conditions. The tested genotypes differed in their Zn-biofortification potential. The highest and the lowest grain Zn contents were noted for genotypes NM-28 and NM-121-25, respectively. Significant variation in yield and Zn-biofortification indicated the potential for improvement in mungbean yield and grain Zn-biofortification. The genotypes NM-28 and NM-2006 could be used in breeding programs for improvement in grain Zn concentration due to their high Zn uptake potential. Nonetheless, all available genotypes in the country should be screened for their Zn-biofortification potential.
Genetic basis of ion exclusion in salinity stressed wheat: implications in improving crop yield
Productivity of food crops like wheat, a staple food of major portion of the world, is hampered due to salinity stress, thereby threatening food security. With the advancements in plant physiology and molecular biology based techniques, a number of structural and regulatory genes (transcription factors, miRNA, siRNA etc.) have been identified that contribute to inducing salinity tolerance responses. Location of these salt tolerant genes or genetic loci on specific chromosomes has also been partially characterized through QTL mapping. This information helps in efficient transfer of these genes into other crop cultivars through molecular breeding tools. Although plant salt tolerance mechanisms include osmotic adjustment, ion exclusion, ion inclusion, efficient antioxidant system, hormonal signaling etc., ion exclusion has long been recognized as central to salinity tolerance in wheat. Ion exclusion involves highly coordinated activity of a variety of channels, pumps and antiporters at parenchyma cells in root, stem and leaves associated with xylem. A number of molecular markers have been identified which are associated with ion exclusion or Na+ exclusion. However, some of them are associated with undesirable traits thereby producing lower crop productivity, e.g. Kna1. Thus, it is imperative to assess novel sources of ion exclusion with subsequent characterization before their introgression into other crop cultivars. In this review, recent advancements in identifying novel sources of ion exclusion in wheat have been discussed at length. In addition, up to what extent marker assisted breeding using these ion exclusion sources will help improve crop salt tolerance in wheat, thereby reducing global food security threat. An effective new paradigm is the targeted identification of specific genetic determinants of stress adaptation that have evolved in nature and their precise introgression into elite varieties.
Efficacy of fertilizing method for different potash sources in cotton (Gossypium hirsutum L.) nutrition under arid climatic conditions
Precise choice of potassium (K) source and application method does matter for its cost-effectiveness. This study was aimed to evaluate the best source and method of K fertilizer application to improve cotton productivity and profitability under an arid climate. Three different K sources (KNO3, K2SO4 and KCl) were applied at 100 kg ha-1 by four methods, i.e. a) basal application, b) side dressing, c) fertigation and d) foliar application of 2% K2SO4. The highest productivity and profitability were recorded with K2SO4 applied as foliar application. Total boll weight per plant was similar in foliar applied K2SO4 and basal application of KNO3. Better boll opening in foliar applied K2SO4, perhaps, played decisive role for increased seed-cotton yield. For basal application and side dressing, KNO3 produced the highest seed-cotton yield, but the benefit cost ratio was better for foliar applied K2SO4. In crux, foliar application of K2SO4 might be opted to improve the seed cotton yield, fiber quality and net returns under the arid climate. However, soil K application through K2SO4 and/or KNO3 is essential to balance the K removal from soil.
Synergistic effects of PGPRs and fertilizer amendments on improving the yield and productivity of Canola (Brassica napus L.)
Background Organic fertilizers are safer and more eco-friendly than chemical fertilizers; hence, organic fertilizers can be used to support sustainable farming. The effects of PGPRs are manifold in agriculture, especially in monoculture crops, where the soil needs to be modified to increase germination, yield, and disease resistance. The objective of this study was to assess the effects of PGPRs combined with fertilizer on the yield and productivity of canola. Canola was chosen for its global importance as an oilseed crop and its responsiveness to soil amendments, making it ideal for evaluating the synergistic effects of PGPRs and fertilizers on yield and soil health. Methodology This research, which was carried out over two years, was aimed at establishing the effectiveness of PGPRs together with organic and inorganic fertilizers on canola yields and was performed with a two-factorial RCBD design under field conditions. We applied Azotobacter salinestris and Bacillus subtilis with biochar, compost, animal manure, poultry manure, and NPK fertilizer. Insect pest management and other agronomic practices were carried out to maintain the experiment. Results Canola yield and agronomic traits were enhanced by the combination of Bacillus subtilis with the fully recommended N: P:K ratio (140:55:40 kg/ha). Additionally, the application of Bacillus subtilis with biochar at 2 tons/ha improved the yield and quality of canola, as well as the structure and nutrient regulation of the soil. Conclusion In light of these results, we recommend the application of Bacillus subtilis to canola seeds along with either 2 t/ha biochar or the entire recommended dose of N: P:K (140:55:40 kg/ha). These strategies are sustainable and help producers and the environment increase the productivity of canola. Combining PGPRs with fertilizers for canola enhances nutrient efficiency, promotes sustainable growth, and boosts stress resilience, addressing agricultural and environmental challenges. Clinical trial number Not Applicable.
Conservation tillage improves productivity of sunflower (Helianthus annuus L.) under reduced irrigation on sandy loam soil
Sunflower production is significantly lower in arid and semi-arid regions due to various crop management problem. Conservation of tillage provides the most excellent opportunity to reduce degradation of soil reserves and increase soil productivity. The main objective of this study was to investigate the combined effects of conservation tillage and drought stress on growth and productivity of different sunflower hybrids. Experimental treatments included two sunflower hybrids (‘NK-Senji’ and ‘S-278’), two drought stress treatments (i.e., well-watered and drought stress at flowering and grain filling stages) and three tillage practices (i.e., conservation, minimum and deep tillage). The results indicated that morphological and physiological parameters, and yield-related traits were significantly ( P≤0 . 05 ) affected by all individual factors; however, their interactive effects were non-significant. Among sunflower hybrids, ‘NK-Senji’ performed better for morphological, physiological, and yield-related traits than ‘S-278’. Similarly, conservation tillage observed better traits compared to the rest of the tillage practices included in the study. Nonetheless, conservation tillage improved growth and yield-related traits of hybrid ‘NK-Senji’ under drought stress. Hence, it is concluded that conservation tillage can improve the productivity of sunflower under low moisture availability. Therefore, conservation tillage could be suggested in the areas of lower water ability to improve sunflower production. Nonetheless, sunflower hybrids or varieties need thorough testing for their adaptability to conservation tillage and low moisture availability before making recommendations.
Phenotypic characterization of exotic tomato germplasm: An excellent breeding resource
Tomato production in Pakistan faces significant problems of low yields due to various biotic and abiotic stresses primarily because of a narrow genetic base of the cultivars being used. Therefore, Introduction and evaluation of the exotic tomato germplasm has become necessary to acquire elite material to develop future breeding programs. To this end, the present study was conducted for the phenotypic characterization of twenty exotic tomato genotypes along with two locally grown cultivars in semi-arid subtropical climate. Data were collected for morphological, fruit quality and fruit yield traits. A significant (p<0.05) phenotypic variation was observed for all the studied traits. Maximum yield was obtained from “Rober” i.e., 1508.31 g per plant. The maximum shelf life was observed in the Cromco, with the least weight loss (2.45%) and loss in the firmness of fruit (22.61%) in 4 days. Correlation analyses revealed a strong genetic association among morphological and yield related traits. High estimates of the heritability (ranged from 79.77% to 95.01% for different traits), along with a high genetic advance (up to 34%) showed the potential usefulness of these traits and genotypes to develop breeding programs to improve the tomato yield and fruit quality.
Combined application of zinc and silicon alleviates terminal drought stress in wheat by triggering morpho-physiological and antioxidants defense mechanisms
Wheat is an important global staple food crop; however, its productivity is severely hampered by changing climate. Erratic rain patterns cause terminal drought stress, which affect reproductive development and crop yield. This study investigates the potential and zinc (Zn) and silicon (Si) to ameliorate terminal drought stress in wheat and associated mechanisms. Two different drought stress levels, i.e., control [80% water holding capacity (WHC) was maintained] and terminal drought stress (40% WHC maintained from BBCH growth stage 49 to 83) combined with five foliar-applied Zn-Si combinations (i.e., control, water spray, 4 mM Zn, 40 mM Si, 4 mM Zn + 40 mM Si applied 7 days after the initiation of drought stress). Results revealed that application of Zn and Si improved chlorophyll and relative water contents under well-watered conditions and terminal drought stress. Foliar application of Si and Zn had significant effect on antioxidant defense mechanism, proline and soluble protein, which showed that application of Si and Zn ameliorated the effects of terminal drought stress mainly by regulating antioxidant defense mechanism, and production of proline and soluble proteins. Combined application of Zn and Si resulted in the highest improvement in growth and antioxidant defense. The application of Zn and Si improved yield and related traits, both under well-watered conditions and terminal drought stress. The highest yield and related traits were recorded for combined application of Zn and Si. For grain and biological yield differences among sole and combined Zn-Si application were statistically non-significant ( p> 0.05). In conclusion, combined application of Zn-Si ameliorated the adverse effects of terminal drought stress by improving yield through regulating antioxidant mechanism and production of proline and soluble proteins. Results provide valuable insights for further cross talk between Zn-Si regulatory pathways to enhance grain biofortification.