Showing papers by "Ismail Cakmak published in 2016"

Biofortification of wheat, rice and common bean by applying foliar zinc fertilizer along with pesticides in seven countries

Abstract: Rice (Oryza sativa L.), wheat (Triticum aestivum L.) and common bean (Phaseolus vulgaris L.) are major staple food crops consumed worldwide. Zinc (Zn) deficiency represents a common micronutrient deficiency in human populations, especially in regions of the world where staple food crops are the main source of daily calorie intake. Foliar application of Zn fertilizer has been shown to be effective for enriching food crop grains with Zn to desirable amounts for human nutrition. For promoting adoption of this practice by growers, it is important to know whether foliar Zn fertilizers can be applied along with pesticides to wheat, rice and also common bean grown across different soil and environmental conditions. The feasibility of foliar application of zinc sulphate (ZnSO4.7H2O) to wheat, rice and common bean in combination with commonly used five fungicides and nine insecticides was investigated under field conditions at the 31 sites-years of seven countries, i.e., China, India, Pakistan, Thailand, Turkey, Brazil and Zambia. Significant increases in grain yields were observed with foliar Zn/foliar Zn + pesticide (5.2–7.7 % of wheat and 1.6–4.2 % of rice) over yields with no Zn treatment. In wheat, as average of all experiments, higher grain Zn concentrations were recorded with foliar Zn alone (41.2 mg kg−1) and foliar Zn + pesticide (38.4 mg kg−1) as compared to no Zn treatment (28.0 mg kg−1). Though the magnitude of grain Zn enrichment was lesser in rice than wheat, grain Zn concentrations in brown rice were significantly higher with foliar Zn (24.1 mg kg−1) and foliar Zn + pesticide (23.6 mg kg−1) than with no Zn (19.1 mg kg−1). In case of common bean, grain Zn concentration increased from 68 to 78 mg kg−1 with foliar Zn alone and to 77 mg kg−1 with foliar Zn applied in combination with pesticides. Thus, grain Zn enrichment with foliar Zn, without or with pesticides, was almost similar in all the tested crops. The results obtained at the 31 experimental site-years of seven countries revealed that foliar Zn fertilization can be realized in combination with commonly-applied pesticides to contribute Zn biofortification of grains in wheat, rice and common bean. This agronomic approach represents a useful practice for the farmers to alleviate Zn deficiency problem in human populations.

Magnesium applications to growth medium and foliage affect the starch distribution, increase the grain size and improve the seed germination in wheat

Abstract: Magnesium (Mg) has diverse functions in plants and plays a critical role in carbohydrate partitioning between source and sink tissues. There is, however, limited information available about the effects of Mg deficiency on grain starch accumulation, yield formation and seed quality in terms of seed germination and seedling establishment in wheat. In a solution culture experiment, bread wheat (Triticum aestivum) was grown to maturity with low or adequate Mg under greenhouse conditions, and a post-anthesis foliar Mg application was tested on low-Mg plants. The effects of these Mg treatments on i) yield parameters, ii) distribution of starch among sink and source organs, iii) tissue concentrations of Mg and other minerals and iv) seed germination and seedling development were investigated. Low Mg supply did not affect the vegetative biomass production; but substantially reduced the grain yield. Post-anthesis foliar Mg spray significantly minimized yield losses caused by Mg deficiency. Decreases in grain yield by Mg deficiency were due to decreases in individual seed weight rather than seed number per spike. Low Mg depressed the grain and root starch levels, while increasing the leaf starch. Foliar Mg spray largely reversed these effects of Mg deficiency. Seeds obtained from low-Mg plants exhibited severe impairments in germination and seedling establishment. These seed quality traits were also greatly improved by foliar Mg application to maternal plants. Magnesium deficiency reduces grain yield in wheat mainly by limiting the carbohydrate supply to developing seeds and thus by decreasing the seed weight. Since vegetative growth is far less affected than yield formation, Mg deficiency may remain latent until seed-filling. Therefore, foliar Mg application appears to be a promising tool to alleviate Mg deficiency during seed-filling and minimize its impact on yield and seed quality.

Zinc (Zn) concentration of bread wheat grown under Mediterranean conditions as affected by genotype and soil/foliar Zn application

Abstract: The combination of plant breeding and agronomic biofortification is the most reasonable approach to minimize zinc (Zn) deficiency-related problems in humans, but also in crop production. However, its efficiency and suitability under Mediterranean conditions and its effects on the grain yield and quality parameters are not well known. Field experiments were conducted over two years in south-eastern Portugal, where soils are deficient in Zn. Ten advanced breeding lines and three commercial varieties of bread-making wheat were fertilized with four Zn treatments as following: i) control, ii) soil Zn application, iii) foliar Zn application and iv) both soil and foliar Zn application. Low rainfall produced 46 % more of grain Zn concentration but about 67 % less of grain yield. Grain Zn concentration varied greatly across treatments and cultivars with INIAV-1, INIAV-6, INIAV-9 and the commercial varieties being the most efficient. There were no significant increases in Zn concentrations due to soil Zn application, but gains higher than 20 mg kg−1 were obtained both with foliar and soil+foliar Zn applications. Grain yield was not significantly higher in foliar application, but increased to about 10 % in soil, and about 7 % in soil+foliar applications, respectively. In soils with low Zn availability, the best strategy to improve grain Zn concentrations has been to select the most efficient cultivars for Zn accumulation with the added application of Zn in soil+foliar form.

Molecular speciation and tissue compartmentation of zinc in durum wheat grains with contrasting nutritional status

Abstract: Low concentration of zinc (Zn) in the endosperm of cereals is a major factor contributing to Zn deficiency in human populations. We have investigated how combined Zn and nitrogen (N) fertilization affects the speciation and localization of Zn in durum wheat (Triticum durum). Zn-binding proteins were analysed with liquid chromatography ICP-MS and Orbitrap MS(2) , respectively. Laser ablation ICP-MS with simultaneous Zn, sulphur (S) and phosphorus (P) detection was used for bioimaging of Zn and its potential ligands. Increasing the Zn and N supply had a major impact on the Zn concentration in the endosperm, reaching concentrations higher than current breeding targets. The S concentration also increased, but S was only partly co-localized with Zn. The mutual Zn and S enrichment was reflected in substantially more Zn bound to small cysteine-rich proteins (apparent size 10-30 kDa), whereas the response of larger proteins (apparent size > 50 kDa) was only modest. Most of the Zn-responsive proteins were associated with redox- and stress-related processes. This study offers a methodological platform to deepen the understanding of processes behind endosperm Zn enrichment. Novel information is provided on how the localization and speciation of Zn is modified during Zn biofortification of grains.

Magnesium deficiency decreases biomass water-use efficiency and increases leaf water-use efficiency and oxidative stress in barley plants

Abstract: In water-scarce agro-environments a clear understanding of how plant nutrients like magnesium (Mg) affect plant traits related to water-use efficiency (WUE) is of great importance. Magnesium plays a crucial role in photosynthesis and is thus a major determinant of biomass formation. This study investigated the effect of Mg deficiency on leaf and whole plant water-use efficiency, δ13C composition, hydrogen peroxide (H2O2) production and the activity of key enzymes involved in ROS scavenging in barley. Barley (Hordeum vulgare) was grown in hydroponic culture under three different levels of Mg supply (0.01, 0.1, 0.4 mM Mg). WUE was determined on the leaf-level (leaf-WUE), the biomass-level (biomass-WUE) and via carbon isotope discrimination (δ13C). Additionally, concentrations of Mg, chlorophyll and H2O2, and the activities of three antioxidative enzymes (ascorbate peroxidase, glutathione reductase and superoxide dismutase) in youngest fully expanded leaves were analyzed. Dry matter production was significantly decreased (by 34 % compared to control) in Mg deficient barley plants. Mg deficiency also markedly reduced leaf Mg concentrations and chlorophyll concentrations, but increased H2O2 concentrations (up to 55 % compared to control) and the activity of antioxidative enzymes. Severe Mg deficiency decreased biomass-WUE by 20 %, which was not reflected regarding leaf-WUE. In line with leaf-WUE data, discrimination against 13C (indicating time-integrated WUE) was significantly reduced under Mg deficiency. Mg deficiency increased oxidative stress indicating impairment in carbon gain and decreased biomass-WUE. Our study suggests that biomass-WUE was not primarily affected by photosynthesis-related processes, but might be dependent on effects of Mg on night-time transpiration, respiration or root exudation.

Planting seeds for the future of food

Abstract: The health and wellbeing of future generations will depend on humankind's ability to deliver sufficient nutritious food to a world population in excess of 9 billion. Feeding this many people by 2050 will require science-based solutions that address sustainable agricultural productivity and enable healthful dietary patterns in a more globally equitable way. This topic was the focus of a multi-disciplinary international conference hosted by Nestle in June 2015, and provides the inspiration for the present article. The conference brought together a diverse range of expertise and organisations from the developing and industrialised world, all with a common interest in safeguarding the future of food. This article provides a snapshot of three of the recurring topics that were discussed during this conference: soil health, plant science and the future of farming practice. Crop plants and their cultivation are the fundamental building blocks for a food secure world. Whether these are grown for food or feed for livestock, they are the foundation of food and nutrient security. Many of the challenges for the future of food will be faced where the crops are grown: on the farm. Farmers need to plant the right crops and create the right conditions to maximise productivity (yield) and quality (e.g. nutritional content), whilst maintaining the environment, and earning a living. New advances in science and technology can provide the tools and know-how that will, together with a more entrepreneurial approach, help farmers to meet the inexorable demand for the sustainable production of nutritious foods for future generations.