Zn distribution and bioavailability in whole grain and grain fractions of winter wheat as affected by applications of soil N and foliar Zn combined with N or P

A two-year field experiment was conducted to investigate the effects of foliar Zn combined with N or P on Zn concentration and bioavailability in wheat grain and its milling fractions under different soil N levels. At maturity, grains were harvested and fractionated into flour and bran for nutrient analysis. Both high soil N supply and foliar Zn-enriched fertilizer applications greatly increased Zn concentration and bioavailability in both whole grain and grain fractions. Compared with foliar Zn alone, foliar Zn combined with N increased Zn concentration and bioavailability, whereas foliar Zn combined with P decreased Zn concentration and bioavailability. However, foliar Zn combined with P slightly increased the protein concentration compared to foliar Zn alone. Protein concentration significantly increased, whereas phytate concentration decreased, in whole grain and flour, both in soil N and foliar Zn-enriched N treatments. Therefore, foliar Zn plus N (with appropriate soil N management) may be a promising strategy for addressing dietary Zn micronutrient deficiencies, especially in countries where flour is a significant component of the daily diet.     

碳氮供给对小麦离体穗培养粒重、微量元素及蛋白质含量的影响

为了解碳氮供给与小麦粒重、Fe、Zn、Mn、Cu等微量元素以及蛋白质含量的关系,在离体穗培养条件下研究了灌浆初期和灌浆中期不同浓度C(蔗糖)、N(硝酸铵)供给对小麦粒重、微量元素(Fe、Zn、Mn、Cu)和蛋白质含量的影响.结果表明,随着培养基糖浓度的增大,粒重和Fe、Mn含量都表现为先升高后降低的趋势,在4%糖浓度时,均达到最高值;籽粒Zn、Cu和蛋白质含量表现为随糖浓度增大而持续降低.随着培养基N浓度的增加,粒重和Fe、Zn、Mn、Cu含量多表现为先升高后降低的趋势,且多在N浓度为0.07%时达到最高值,尤以灌浆中期开始的培养表现明显;籽粒蛋白质含量表现为随N浓度增大而持续增加.由此可见,外源C、N供给对粒重、微量元素和蛋白质含量有明显的调控效应.一定的糖供给可同时提高粒重和Fe、Mn含量,一定的N供给可同时提高粒重及微量元素和蛋白质含量.     

氮、磷、锌营养对水稻籽粒植酸含量的影响及与几种矿质元素间的相关性

以协青早、秀水110及其辐射诱变获得的低植酸突变系（HIPi1和HIPj1）为材料,通过水培试验对不同氮、磷、锌浓度处理下水稻籽粒植酸含量差异及与几种矿质元素间的相关性进行了比较分析。高水平氮、磷、锌浓度处理的籽粒植酸含量较同一品种的低氮、磷、锌处理均有所降低,但在水稻生育期间,籽粒植酸含量对磷、锌处理浓度变化的敏感性,则因品种的植酸类型特征而异;氮、磷浓度增加能分别提高铁或降低铜在籽粒中的积累,但在高锌处理下,籽粒铁含量明显降低、而钾和镁的含量等却有所升高; 籽粒植酸含量一般与K、Mg、Fe、Cu 4种矿质元素含量呈正相关、与籽粒Zn含量呈负相关,但统计显著水平因品种而异。低植酸突变体籽粒中的K、Mg、Fe、Zn等含量虽略有下降,但可以通过适当的介质营养条件来调节有关矿质营养在水稻籽粒中的积累。     

Influence of long-term nitrogen fertilization on micronutrient density in grain of winter wheat (Triticum aestivum L.)

A long-term (1999–2007) field experiment was conducted to investigate the effects of three nitrogen (N) fertilization rates (0, 130, and 300 kg N/ha) on micronutrient density in wheat grain and its milling fractions. At maturity, grains were harvested and fractionated into flour, shorts, and bran for micronutrient and N analysis. N fertilization increased iron (Fe), zinc (Zn), and copper (Cu) density in wheat grain compared to the control. Increase of N application rate from 130 to 300 kg N/ha, however, did not further increase the three micronutrient densities in grain. Micronutrient concentrations were usually highest in the bran and lowest in the flour. High N application increased Zn and Cu densities in all three milling fractions and increased Fe concentration in shorts and bran but not in flour. N application did not affect the manganese (Mn) concentration in grain. N fertilization changed the proportions of Fe and Cu in flour and bran but did not affect the distribution of Zn. Because N fertilization increased micronutrient accumulation in wheat grain, proper management of N fertilization has the potential to enhance the nutritional quality of this important food.     

Grain yield,starch, protein,and nutritional element concentrations of winter wheat exposed to enhanced UV-B during different growth stages

In order to alleviate the damage of UV-B on plants, it is important to determine at which growth stages are plants more sensitive to enhanced UV-B. The objective of the study was to evaluate the effects of UV-B on wheat yield and quality during different growth stages. Enhanced UV-B during heading, flowering and the whole growth stages (UCK, from seedling to grain filling) decreased yield by 6.6, 4.4 and 9.6%, respectively. Protein content in grain was decreased by enhanced UV-B during flowering and UCK over the control. Amylose, amylopectin and total starch content were not affected by UV-B treatments. UCK treatment resulted in a decrease of nitrogen (N), phosphorus (P) and iron (Fe) concentrations, while zinc (Zn) and manganese (Mn) concentrations increased. Enhanced UV-B during tillering, heading and flowering stages reduced Fe concentration, but increased Mn, copper (Cu) and Zn (except for flowering) concentrations. The results indicated that the changes in wheat yield and quality induced by enhanced UV-B during the whole growth stage were probably from the effects of UV-B radiation during heading and flowering stages. Therefore, to better defend the damage of UV-B to wheat, some methods should be undertaken during heading and flowering stages.     

氮锌肥配施对小麦籽粒不同类型混合粉锌营养品质的影响

为明确氮、锌肥配施对小麦籽粒不同类型混合粉锌营养品质的影响规律，采用田间试验，研究了氮、锌肥配施对小麦籽粒产量、不同类型混合粉中氮、锌含量及其累积量的影响及混合粉中植酸含量、植酸与锌的摩尔比（PA/Zn）和锌日吸收量的变化规律。结果表明，锌肥处理对小麦籽粒产量、各类型混合粉中的氮含量及其累积量无显著影响；与不施氮对照比较，施氮处理小麦籽粒产量提高93.7%，各类型混合粉中氮含量及其累积量显著提高，以施氮量240 kg·hm^-2处理最高。喷锌处理下，各类型混合粉中锌含量显著增加，精制粉、标准粉、通粉和全粉中锌累积量较对照依次提高了63.3%、58.0%、48.6%和50.9%；施氮后，各类型混合粉的锌含量及其累积量显著增加，以喷施锌肥处理更为明显。全粉和通粉中的植酸含量显著高于精制粉和标准粉，但PA/Zn低于精制粉和标准粉。喷锌后，精制粉、标准粉和全粉中植酸含量增加13.0%~ 15.4%，但PA/Zn下降23.8%~34.7%；施氮降低了精制粉、通粉和全粉中的植酸含量和PA/Zn。全粉中锌日吸收量为0.98 mg·d^-1，显著高于其他各混合粉；喷施锌肥后，各类型混合粉的锌日吸收量提高了 35.9%~61.0%；施氮显著提高了各类型混合粉的锌日吸收量。     

氮肥用量对苏中冬小麦地上部主要矿质元素含量的影响

为了明确施氮量对苏中地区冬小麦主要矿质元素含量的影响,以扬麦11和扬麦13为材料,在江苏丹阳设置3个氮素水平(0、150、300kg.hm-2),研究不同施氮量对冬小麦籽粒、茎鞘和叶片中Fe、Zn、Mn、Cu、Ca、Mg和P等矿质元素含量的影响。结果表明,增施氮肥能显著提高冬小麦籽粒、茎鞘、叶片、面粉和麸皮中的Fe、Zn、Mn、Cu和Ca含量,但P含量明显下降。与对照(N0)相比,施氮量达300kg.hm-2时,扬麦11籽粒中的Fe、Zn、Mn、Cu和Ca含量分别增加了11.74%、32.20%、31.78%、66.87%和53.75%,P含量降低23.06%,茎鞘中Zn、Cu和Ca含量增加106.34%、136.97%和51.15%,P含量降低46.46%;扬麦13籽粒中Zn、Cu和Ca含量分别比对照(N0)增加33.03%、59.67%和56.63%,Mg和P含量分别降低14.10%和25.41%,叶片中Mn、Cu、Ca和Mg分别增加174.54%、27.15%、41.66%和29.95%。随着氮肥用量增加,籽粒中Mg含量呈下降趋势,但茎鞘和叶片中Mg含量呈递增趋势。籽粒、茎鞘和叶片中不同矿质元素含量对氮肥的响应存在品种间差异。在本试验条件下,适量施氮可以提高冬小麦籽粒中微量元素的含量。但是,氮肥用量过高可能降低籽粒中P和Mg的含量,不利于籽粒矿质营养品质的提高。     

Variation in mineral micronutrient concentrations in grain of wheat lines of diverse origin

150 lines of bread wheat representing diverse origin and 25 lines of durum, spelt, einkorn and emmer wheat species were analysed for variation in micronutrient concentrations in grain. A subset of 26 bread wheat lines was grown at six sites or seasons to identify genetically determined differences in micronutrient concentrations. Substantial variation among the 175 lines existed in grain Fe, Zn and Se concentrations. Spelt, einkorn and emmer wheats appeared to contain higher Se concentration in grain than bread and durum wheats. Significant differences between bread wheat genotypes were found for grain Fe and Zn, but not Se concentration; the latter was influenced more by the soil supply. Grain Zn, but not Fe, concentration correlated negatively with grain yield, and there was a significant decreasing trend in grain Zn concentration with the date of variety release, suggesting that genetic improvement in yield has resulted in a dilution of Zn concentration in grain. Both grain Zn and Fe concentrations also correlated positively and significantly with grain protein content and P concentration, but the correlations with kernel size, kernel weight or bran yield were weak. The results from this study are useful for developing micronutrient biofortification strategies.     

氮肥对不同玉米品种子粒微量元素含量和生物有效性的影响

研究田间施用氮肥对吉林省4个玉米品种子粒中Zn、Fe、Mn、Cu含量以及Zn与Fe生物有效性的影响。结果表明,施用氮肥可增加玉米子粒中Zn、Fe含量,过量施氮玉米子粒中Zn和Fe含量不再增加甚至呈下降趋势;子粒中Mn含量随氮肥增加而提高,Cu含量随氮肥增加而降低,4个品种中只有吉四单19在过量施氮时子粒Mn含量呈下降趋势。随氮肥水平提高,玉米子粒中Zn、Fe和Mn累积量呈递增趋势,Cu累积量变化不显著。全磷与这些矿物质元素的比值(P/Zn、P/Fe)表明,氮肥施用将显著降低玉米子粒中Zn和Fe的生物有效性。     

氮磷钾肥对稻米铁、锌、铜、锰、镁、钙含量和产量的影响

 采用田间试验，在四川省西昌市用两个水稻品种研究了氮、磷、钾肥施用量对稻米中铁、锌、铜、锰、镁、钙含量和产量的影响。结果表明，稻米中铁、锌、铜、锰、镁、钙含量均随着施氮量增加先上升后下降，滇屯502的铁、锌、铜、锰、镁、钙含量和产量都以施用90 kg/hm2 N最高，稻谷产量以施用180 kg/hm2 N最高；而合系39的铁、锌、铜、锰、镁、钙的含量以施用180 kg/hm2 N最高，稻谷产量以施用270 kg/hm2 N最高，说明供试籼型品种滇屯502对氮肥的敏感性较粳型品种合系39强；磷肥明显降低了稻米中铁、铜、锰、钙的含量和产量，适量增施磷肥有利于增加稻米中镁的含量和产量；适量施用钾肥有利于提高稻米中铁、锌、铜、锰含量和产量，两供试品种铁、锌、铜、锰含量均以90 kg/hm2 K2O时最高，而钾肥明显降低了稻米中镁、钙的含量和产量。     

Grain yield,zinc efficiency and zinc concentration of wheat cultivars grown in a zinc-deficient calcareous soil in field and greenhouse

Field experiments were carried out to study grain yield, zinc (Zn) efficiency and concentrations of Zn in shoot and grain of 37 bread wheat (Triticum aestivum) and three durum wheat (Triticum durum) cultivars grown in a Zn-deficient calcareous soil with (23 kg Zn ha⁻¹), and without, Zn fertilization in 1993–1994 and 1994–1995. The same Zn-deficient soil was used in greenhouse experiments to study shoot dry weight, Zn efficiency and shoot Zn concentrations of 21 bread and three durum wheat cultivars (same cultivars used in the field experiments). Zinc fertilization of cultivars in the field enhanced grain yield on average by 30% in both years. Increases in grain yield to Zn fertilization varied substantially between cultivars from 8% to 76%. Accordingly, there was large variability in Zn efficiency of cultivars, expressed as the ratio of grain yield or shoot dry-matter yield produced under Zn deficiency compared to that under Zn fertilization. On average, Zn efficiency values ranged from 57% to 92% for grain yield in field experiments and from 47% to 83% for shoot dry weight in greenhouse experiments. Most of the cultivars behaved similarly in their response to Zn deficiency in the field and greenhouse. The cultivars selected from local landraces had both, a high Zn efficiency and high yield under Zn-deficient conditions. The bread wheat cultivars, improved for irrigated conditions, had generally low Zn efficiency and low yield, both in the field and greenhouse. All durum wheat cultivars in this study also showed low levels of Zn efficiency, grain yield and shoot dry weight under Zn deficiency. Overall, there was no relation between Zn efficiency values and Zn concentrations in grain or shoot dry matter. The results presented here demonstrate the existence of substantial variation in Zn efficiency among wheat cultivars, particularly bread wheat cultivars, and suggest that wheat landrace populations are a valuable source of genes to improve high Zn efficiency of wheat for Zn-deficient soils.     

叶面锌肥对紫粒小麦产量及品质的影响

为明确叶面施锌肥对紫粒小麦产量及品质的影响,选用小麦山农紫（紫粒）和山农129（红粒）为试验材料,采用大田试验,设置不施锌肥（Zn₀,对照）、叶面喷施锌肥10 kg·hm^-2（Zn_{10）、20 kg·hm^-2（Zn20）、30 kg·hm^-2（Zn30）、40 kg·hm^-2（Zn40）5个处理,分析了不同施锌量下紫粒小麦产量和品质相关指标的异同。结果表明,与不施锌肥比较,叶面施锌肥后山农129和山农紫分别增产1.4%~4.7%和2.3%~5.2%;随着施锌量的增加,山农129和山农紫的籽粒锌含量、总蛋白含量及蛋白质产量均表现出先增后降的趋势,分别在Zn30和Zn20处理下达到最高值,比Zn0分别提高25.8%、1.2%、16.8%和44.1%、2.1%、20.1%。两品种叶面施锌肥较其对照显著提高了籽粒蔗糖含量、湿面筋含量、面筋指数（P<0.05),但总淀粉和可溶性糖含量无显著性差异;总体上,山农紫小麦增幅大于山农129。综上所述,本试验条件下,叶面喷施锌肥可提高紫粒小麦产量、锌含量以及营养品质,以喷施锌肥20 kg·hm^-2较佳。}     

Biofortification strategies to increase grain zinc and iron concentrations in wheat

Micronutrient deficiencies, especially those arising from zinc (Zn) and iron (Fe), pose serious human health problems for more than 2 billion people worldwide. Wheat is a major source of dietary energy and protein for the world's growing population, and its potential to assist in reducing micronutrient-related malnutrition can be enhanced via integration of agronomic fertilization practices and delivery of genetically-manipulated, micronutrient rich wheat varieties. Targeted breeding for these biofortified varieties was initiated by exploiting available genetic diversity for Zn and Fe from wild relatives of cultivated wheat and synthetic hexaploid progenitors. The proof-of-concept results from the performance of competitive biofortified wheat lines showed good adaptation in target environments without compromising essential core agronomic traits. Agronomic biofortification through fertilizer approaches could complement the existing breeding approach; for instance, foliar application of Zn fertilizer can increase grain Zn above the breeding target set by nutritionists. This review synthesizes the progress made in genetic and agronomic biofortification strategies for Zn and Fe enrichment of wheat.     

Mineral element distributions in milling fractions of Chinese wheats

Malnutrition related to micronutrient deficiency can create immense economic and societal problems. The objective of this study was to quantify the mineral element concentration distribution in milled fractions, using 43 common wheat (Triticum aestivum L.) cultivars sown in Jinan, China during the 2005–2006 crop season. All 43 cultivars had low Fe (average 28.2 mg Kg⁻¹) and Zn (28.6 mg Kg⁻¹) concentrations, and wide ranges of variation for mineral element concentrations. Highly significant effects among milling fractions and cultivars on all traits were observed, with fraction effect being the larger. There was an uneven distribution of mineral element concentrations in wheat grain. Shorts and bran fractions had the highest mineral element concentrations, whereas flours from break and reduction had low concentrations. Compared with those in the central endosperm, the concentration of inorganic phosphorus (Pi) decreased the most with decreasing flour yield, whereas the concentration of phytic acid P (PAP), phytase activity, and Ca decreased the least. Pi was the most concentrated element in the aleurone, whereas PAP, phytase activity, and Ca were the least, compared to those in the central endosperm. Milling technique through adjusting flour yield can be used to improve the element composition of flour.     

Mineral element distributions in milling fractions of Chinese wheats

Malnutrition related to micronutrient deficiency can create immense economic and societal problems. The objective of this study was to quantify the mineral element concentration distribution in milled fractions, using 43 common wheat (Triticum aestivum L.) cultivars sown in Jinan, China during the 2005–2006 crop season. All 43 cultivars had low Fe (average 28.2 mg Kg⁻¹) and Zn (28.6 mg Kg⁻¹) concentrations, and wide ranges of variation for mineral element concentrations. Highly significant effects among milling fractions and cultivars on all traits were observed, with fraction effect being the larger. There was an uneven distribution of mineral element concentrations in wheat grain. Shorts and bran fractions had the highest mineral element concentrations, whereas flours from break and reduction had low concentrations. Compared with those in the central endosperm, the concentration of inorganic phosphorus (Pi) decreased the most with decreasing flour yield, whereas the concentration of phytic acid P (PAP), phytase activity, and Ca decreased the least. Pi was the most concentrated element in the aleurone, whereas PAP, phytase activity, and Ca were the least, compared to those in the central endosperm. Milling technique through adjusting flour yield can be used to improve the element composition of flour.     

离体穗培养条件下C、N供给对小麦穗粒数、粒重及蛋白质含量的影响

为探究C、N供给时期和供给水平对小麦籽粒建成及蛋白质含量的影响,以冬小麦品种济麦22为材料,采用离体穗培养的方法,设置了三个蔗糖浓度(C1:20 g·L~(-1);C2:40g·L~(-1);C3:80g·L~(-1))和四个硝酸铵水平(N1:0.57g·L~(-1);N2:1.14g·L~(-1);N3:2.28g·L~(-1);N4:4.56g·L~(-1)),比较分析了开花期和花后7d培养的小麦穗粒数、粒重及籽粒蛋白质含量对C、N供响应的差异。结果表明,1)开花期增加C、N供给可明显提高小麦穗粒数,C3的穗粒数相比于C1、N3的穗粒数相比于N1分别增加23.5%和8.2%,且弱势粒增幅显著高于强势粒,高氮(N4)下穗粒数显著下降,N4的强、弱势粒数相比于N3分别降低4.8%和29.6%;花后7 d增加C、N供给对穗粒数无显著影响;两个时期比较,以开花期培养的小麦穗粒数更高。2)开花期和花后7 d增加C供给均能显著提高小麦粒重,C3的粒重相对于C1分别提高84.9%和41.5%,且弱势粒增幅大于强势粒;开花期适当增加N供给也能提高小麦粒重,N3的粒重相对于N1增加10.2%,花后7 d适当增加N供给对粒重无显著影响,高氮(N4)下粒重显著下降,且以弱势粒降幅较大;两个时期比较,以花后7 d培养的小麦粒重较高。3)小麦穗粒重随培养基C、N浓度的增加而增加,但高氮下穗粒重显著降低,且穗粒重受粒重的影响较大。4)小麦籽粒蛋白质含量和蛋白质积累量随C浓度的增加而持续降低,随N浓度的增加而持续增加。综上可知,离体穗培养条件下C、N供给水平对小麦穗粒数、粒重及蛋白质含量的调控作用明显,其中开花期增加C、N供给的增粒增重效果更显著,以弱势粒反应更敏感;另外,穗粒数与粒重、粒重与蛋白质含量的调控具有一定矛盾性,其平衡协调仍需进一步研究。     

Effect of drought and elevated temperature on grain zinc and iron concentrations in CIMMYT spring wheat

Abiotic stress caused by increasing temperature and drought is a major limiting factor for wheat productivity around the world. Wheat plays an important role in feeding the world, but climate change threatens its future harvest and nutritional quality. In this study, grain iron (Fe) and zinc (Zn) concentrations of 54 wheat varieties, including CIMMYT derived historic and modern wheat varieties grown in six different environmental conditions, were analyzed. The objective of the study was to evaluate the effect of water and heat stress on the nutritional value of wheat grains with a main emphasis on grain protein content, Zn and Fe concentrations. Significant effects of environment on protein content and grain micronutrients concentration were observed. The protein and Zn concentrations increased in the water and heat stressed environments, whereas Zn and Fe yield per unit area was higher in non-stress conditions. The results suggest that genetic gains in the yield potential of CIMMYT derived wheat varieties have tended to reduce grain Zn, in some instances; however, environmental variability might influence the extent to which this effect manifests itself.     

Mineral and protein content,test weight,and yield variations of hard red spring wheat grain as influenced by fertilization and cultivar

Among the complex factors affecting grain nutritional quality, protein and mineral content are highly important. A two-year study was conducted in eastern North Dakota to determine the influence of fertility on the protein and mineral content, test weight, and yield of two hard red spring wheat (Triticum aestivum L.) cultivars. Zero, medium (56, 12, and 47 kg/ha), and high (280, 122, and 465 kg/ha) rates of N, P, and K, respectively, were applied in a complete factorial arrangement to ‘Era’ (a semi-dwarf) and ‘Waldron’ wheat (a tall type) in 1977. Seven of these treatments were repeated in 1978. Micronutrients and S were also applied to most treatments in 1977, and micronutrients but no S to all treatments in 1978. In 1977 on a site with high residual NO₃-N, additions of N reduced yields and test weight but increased protein, P, Ca, Zn, Mn, and Fe content. At this site application of P increased grain yield, P, K, and Mg contents but reduced protein and Zn; fertilizer K increased Mn and Fe content and reduced yield, P, K, and Mg. In 1978, N additions increased grain yield, protein, Ca, and Fe but reduced Zn. The application of P and K had little influence on the composition of the grain in 1978. The two cultivars acted the same both years, with Waldron exceeding Era grain in protein (15%), P (12%), Mg (12%), Mg (12%), Zn (17%), Mn (30%), and Fe (12%). Era surpassed Waldron in test weight (2%), K (2%), and Ca (27%). Era proved to be more responsive to fertilizer additions for most grain parameters. Drier weather conditions and lower soil N status for the 1978 experiment produced grain higher in test weight and P, K, Ca, Mg, and Fe content but lower in yield, protein, and Zn. Many highly significant fertilizer-grain and grain-grain interactions were observed. Since wheat grain composition may often be altered by fertilizers and cultivars, the range of these changes should become known through investigations by soil scientists, agronomists, and nutritionists; additional research should be conducted to determine if their changes are of nutritional significance.     

Factors Contributing to the Benefits of Foliar Nitrogen Application for Wheat in a Sub-Tropical Winter Environment

Abstract

Beneficial effects of foliar N application to cereal crops have been widely believed to rely on subsequent rainfall or irrigation in the semi-arid region where in-crop rain is insufficient and unreliable. To verify this, factors contributing to the effects of foliar N application were assessed by implementing foliar N application in trials on three farmers' properties in central Queensland, Australia. Solutions of CRN35 (30 kg N ha^?1 at 1.94 N % w v^_1), urea and UAN (both 26, 2.25%), and urea (20, 20%; 40, 20%) and UAN (20, 20%; 40, 40%), were applied to wheat at anthesis respectively at the three properties (sites). Adjuvant chemical agents were also applied in mixture form with the N at the latter two sites. At the first site, with foliar N (CRN35) application, grain protein content on average increased by 1.07 percentage points, and by 1.6 in the presence of basal superphosphate. Superphosphate alone also increased grain yield. At the second site, while the applications of UAN and urea increased grain protein content by 1.3 and 0.9 percentage points, respectively, UAN showed superiority to urea in N recovery.

At the third site, foliar N applications with or without chemical adjuvant did not affect grain protein content, but due to the higher concentration in the N solution, some of them (excluding UAN40) had negative effects on grain yield, compared to the water only control.

Based on our data and supporting literature, to ensure the positive effect on wheat grain protein content, subsequent irrigation or rainfall may not be critical provided that foliar N concentration is lower than 5%. It is also suggested that UAN is superior to urea as an N source for foliar application. For alkaline/sodic soils, while the application of basal superphosphate increased grain yield, the added foliar N ensured an increase of grain protein content.     

Effect of foliar treatments to durum wheat on flag leaf senescence, grain yield, quality and deoxynivalenol contamination in North Italy

Since the production of durum wheat in the drier areas of the Mediterranean Basin is characterized by high variability in terms of yield and grain quality, there is also considerable interest in developing durum wheat in the northern regions, where the pedo-climatic conditions can offer the possibility of obtaining grain yields with higher technological quality and stability. However, the climatic conditions in the northern regions make durum wheat more prone to fungal foliar disease, particularly to Septoria Tritici Blotch (Septoria tritici Rob.) and to Fusarium Head Blight (Fusarium graminearum Petch and Fusarium culmorum Sacc.), with the consequent occurrence of DON in grains.Field experiments have been conducted over two growing seasons at four sites in North West Italy to evaluate the effect of fungicides and foliar nitrogen fertilizer application on durum wheat yield and grain quality. Five combinations of foliar application were compared at each site and each year (untreated control, azole fungicide application at heading, strobilurin fungicide at the stem elongation stage and/or at heading, the addition of a foliar N fertilizer to a fungicide programme). The following parameters were analysed: Septoria Tritici Blotch (STB) severity, flag leaf greenness using a chlorophyll meter, grain yield, test weight, grain protein content, ash content, vitreousness, Fusarium Head Blight (FHB) incidence and severity and deoxynivalenol (DON) contamination. The collected data underline that the cultivation of durum wheat at the climatic conditions of North Italy is actually risky and needs a direct control of fungal disease, which would be able to reduce the development of both foliar and head attacks. The double treatment, with a strobilurin application during the stem elongation stage and azole at heading, results to be an essential practice and showed advantages in terms of the delay of flag leaf senescence (+27%), STB control (+31), FHB control (+11%), yield (+32%) and DON contamination (−45%), compared to the untreated control. Other foliar treatments at heading, such as strobilurin or foliar N fertilizer applications, do not seem to provide any further advantage, for either grain yield or quality. No significant effect of fungicide or foliar N fertilizer application was recorded on the protein or ash concentration or vitreousness.