Zn Concentration In Grain Research Articles

KNACking on heaven’s door: how important are NAC transcription factors for leaf senescence and Fe/Zn remobilization to seeds?

Senescence is a coordinated process where a plant, or a part of it, engages in programmed cell death to salvage nutrients by remobilizing them to younger tissues or to developing seeds. As Fe and Zn deficiency are the two major nutritional disorders in humans, increased concentration of these nutrients through biofortification in cereal grains is a long-sought goal. Recent evidences point to a link between the onset of leaf senescence and increased Fe and Zn remobilization. In wheat, one member of the NAC (NAM, ATAF, and CUC) transcription factor (TF) family (NAM-B1) has a major role in the process, probably regulating key genes for the early onset of senescence, which results in higher Fe and Zn concentrations in grains. In rice, the most important staple food for nearly half of the world population, the NAM-B1 ortholog does not have the same function. However, other NAC proteins are related to senescence, and could be playing roles on the same remobilization pathway. Thus, these genes are potential tools for biofortification strategies in rice. Here we review the current knowledge on the relationship between senescence, Fe and Zn remobilization and the role of NAC TFs, with special attention to rice. We also propose a working model for OsNAC5, which would act on the regulation of nicotianamine (NA) synthesis and metal–NA remobilization.

Characterization of oxygen defect and zinc segregation in the dense tin dioxide ceramics added with zinc oxide

We investigated the effect of zinc oxide addition for the defects in the dense SnO2 ceramics. Cathode and photoluminescence properties revealed the luminescence originated to oxygen vacancies in SnO2 grains and the presence of non-radiative defect at the grain boundaries. The oxygen diffusion profile showed that the oxygen diffusion was controlled by the limited process at the surface and uniform concentration of 18O at the grain boundaries inner side of sample. This sample exhibited a low Zn concentration in grains and a high Zn concentration at grain boundaries. We conclude that segregation of Zn at grain boundaries prevents SnO2 from decomposing at high temperatures, enabling dense SnO2 ceramics to be obtained.

Increasing iron and zinc in rice grains using deep water rices and wild species - identifying genomic segments and candidate genes

Large genetic variation exists for grain iron and zinc in rice germplasm including wild species and deep water rices. Conventional breeding is an easy and acceptable approach to biofortify rice. Analysis of 126 rice accessions using atomic absorption spectrophotometry showed that Fe concentration in brown rice ranged from 6 ppm in Athira to 72 ppm in O. nivara and Zn concentration from 27 ppm in Jyothi to 67 ppm in O. rufipogon. Quantitative trait loci (QTL) for high Fe and Zn concentration in grains were mapped from 3 wild progenitors and 2 deep water rices with the aim of gene discovery and also to develop iron/zinc-rich lines of two widely grown, popular rice varieties Swarna (MTU7029) and Samba Mahsuri (BPT5204) through conventional breeding approaches. Three advanced backcross mapping populations were developed using 3 wild accessions: Swarna x O.nivara IRGC81832, Swarna x O.nivara IRGC81848 and Samba Mahsuri x O.rufipogon WR119. In addition, F7 recombinant inbred lines (RILs) were developed from two crosses: Madhukar x Swarna and Jalmagna x Swarna. Madhukar and Jalmagna are deep-water rice varieties with high grain iron and zinc. Overall, Fe concentration ranged from 0.2 to 224 ppm and Zn concentration from 0.4 to 104 ppm in the 5 mapping populations. QTLs for Fe and Zn concentration in polished rice were mapped from two Swarna x O. nivara BC2F3 mapping populations using accession IRGC81848- 227 families, 100 SSR markers and accession IRGC81832- 245 families, 75 SSR markers. qFe2.1, qFe3.1, qFe8.1 and qFe8.2 coincided in the two populations. QTLs for Fe and Zn concentration coincided on chromosomes 2, 3, 8 and 12. Five QTLs for Fe and 3 QTLs for Zn each explained more than 15% phenotypic variance. QTLs were also mapped for Fe and Zn concentration in brown rice from Madhukar x Swarna F7 RILs using 110 SSR markers including 9 gene specific markers. Seven QTLs for Fe and six QTLs for Zn were identified each explaining >30% phenotypic variance. QTLs for Fe and Zn concentration coincided on chromosomes 7 and 12. Madhukar allele increased Fe in qFe7.1 and qFe7.2 and Swarna allele increased Zn in qZn12.1 and qZn12.2. Only two QTL flanking markers RM243 for qFe1.1 and RM517 for qZn3.1 were common in the 3 mapping populations. Genotyping of 2 populations is in progress. Candidate genes OsYSL1, OsNAC, OsYSL16, OsZIP4, OsYSL17 and OsNAAT1 underlie the Fe or Zn QTLs mapped in the Swarna x O.nivara mapping population. Likewise, OsYSL1, OsMTP1, OsNAS1, OsNAS3, OsNRAMP1, heavy metal ion transporter, OsAPRT underly QTLs for Fe and Zn mapped in the Madhukar x Swarna mapping population. In all, 20 elite lines with >80 ppm iron and >50ppm zinc in brown rice were identified from 5 mapping populations. These non-transgenic rice lines with high iron, high zinc or both are a useful resource for functional genomics and biofortification programmes.

Grain cadmium and zinc concentrations in wheat as affected by genotypic variation and potassium chloride fertilization

Thirteen bread wheat ( Triticum aestivum L.) and two durum wheat (Triticum turgidum L. var. durum) cultivars were grown over six site-years to identify differences in grain Cd and Zn concentrations, as affected by genotypic variation and soil application of potassium chloride (KCl) fertilizer. Application of KCl fertilizer did not consistently affect grain Cd concentration of wheat cultivars, but increased average grain yield and decreased average grain Zn in 4 of 6 site-years. However, soil type and year had significant effects on grain Cd and Zn, indicating a strong environmental effect on grain quality. Grain concentrations of Cd and Zn were generally lower for the clay loam (CL) than the fine sandy loam (FSL) soils. The wheat cultivars showed significant genotypic differences in grain concentrations of Cd and Zn, suggesting the potential of breeding to reduce Cd and increase Zn concentrations in grain. The two durum cultivars contained high concentrations of Cd but not Zn compared to the bread wheat. The interaction between cultivars and site-years was significant for grain Zn, but not for grain Cd, suggesting that grain Cd is a more stable trait than grain Zn across environments. Grain Zn and Cd were not related to each other but they both correlated negatively with grain yield. The lack of relationship between Zn and Cd suggests that breeding for enhanced Zn concentration can be attained without necessarily affecting grain Cd concentration. The negative relationship between Cd and Zn concentration and dry matter yield was likely the result of biological dilution, suggesting that genetic improvement leading to increased yield may concurrently decrease mineral concentration. Results of this study are useful to improve the mineral composition of wheat used for human consumption through the development of cultivars and use of agronomic management practices that increase Zn and/or reduce Cd concentrations in wheat grain.

Zinc Fertilization Methods on Zinc Absorption and Translocation in Wheat

To increase grain Zn concentration of wheat grown on calcareous soil, field and hydroponic culture experimentswere conducted to investigate the effects of various Zn fertilization methods on Zn absorption and translocationin wheat. A completely randomized block design was used in the field experiment comprising five Zn treatments(0, 7.5, 15, 30, and 45 kg Zn/ha as ZnSO4·7H2O) and wheat cultivar (Zhengmai 9023). The hydroponic experiment used a completely randomized block design with two factors (Zn supplementation to root and foliarspray of Zn). Results showed that in the field experiment, Zn fertilization significantly increased the amount ofsoil diethylene triamine penlaacetic acid-Zn (DTPA-Zn), whereas there was no significant effect on Znconcentration in grain. Furthermore, the utilization rate of Zn fertilizer was only 0.98%, 0.64%, 0.29%, and0.14% with treatments of 7.5, 15, 30, and 45 mg Zn ha-1, respectively. In contrast, the hydroponic experimentshowed that both foliar spray and Zn supplied to roots significantly increased Zn concentration in grain, with thegreatest concentration found in shoots. Results suggested that lower absorption and translocation were theinhibitory factors to increase grain Zn concentration in calcareous soil. Consequently, Zn fertilization topotentially Zn-deficient calcareous soils is not effective method to increase grain Zn concentration.

GENOTYPIC VARIATION FOR PRODUCTIVITY, ZINC UTILIZATION EFFICIENCIES, AND KERNEL QUALITY IN AROMATIC RICES UNDER LOW AVAILABLE ZINC CONDITIONS

Zinc (Zn) has emerged as the plant nutrient limiting rice growth in several parts of the world. About 50% of world soils are deficient in Zn and this is also true for India. An analysis of 0.233 million samples taken from different states showed that 47% of Indian soils are deficient in Zn. In India, Zn deficiency is widespread, especially in the rice–wheat cropping system belt of North India, which has high pH calcareous soils. Zinc is also now recognized as the fifth leading health risk factor is developing Asian countries, where rice is the staple food and Zn nutrition of humans and animals has recently received considerable attention. However, no reports are available on the effect of Zn fertilization on kernel quality of aromatic rices. The present study was therefore undertaken to study the effect of Zn fertilization on yield attributes, grain, and straw yield, Zn concentrations in grain and straw, Zn uptake, Zn use indices and kernel qualities of the aromatic rices. A field study at the Indian Agricultural Research Institute, New Delhi, India showed that Pusa Sugandh 4 (‘PS 4’) is a better than the earlier developed aromatic rice variety Pusa Basmati 1 (‘PB 1’) in terms of grain yield (4.08 tonnes ha−1), kernel quality, zinc (Zn) concentrations in grain and Zn uptake (1,396.9 g ha−1), recovery efficiency (5.2%), agronomic efficiency (122.7 kg grain increase kg−1 Zn applied), partial factor productivity (1,064.7 kg grain kg−1 Zn applied) and physiological efficiency (39,625 kg grain kg−1 Zn uptake) of applied Zn. From the grain yield (4.64 tonnes ha−1) viewpoint an application of 5 kg Zn ha−1 was found sufficient for the aromatic rices grown on ustochrepts of north Indian rice-wheat cropping system belt. Application of 7.5 kg Zn ha−1 increased Zn concentrations in the grain (37.0 mg kg−1 DM) and straw (117.3 mg kg−1 DM) of aromatic rices studied and this is important from the human and animal nutrition viewpoint under Indian conditions.

Response of Wheat Plants to Zinc, Iron, and Manganese Applications and Uptake and Concentration of Zinc, Iron, and Manganese in Wheat Grains

This experiment was conducted at Zahak Agricultural Research Station in the Sistan region in southeast Iran. A factorial design with three replications was used to determine the effects of zinc (Zn), iron (Fe), and manganese (Mn) applications on wheat yield, Zn, Fe, and Mn uptakes and concentrations in grains. Four levels of Zn [soil applications of 0, 40, and 80 kg ha−1 and foliar application of 0.5% zinc sulfate (ZnSO4) solution], two levels of iron sulfate (FeSO4; 0 and 1%) as foliar application, and two levels of Mn (0 and 0.5%) also as foliar application were used in this study. Results showed that the interactive effects of Zn and Mn were significant on the number of grains in each spike. The highest number of grains resulted from the application of 80 kg ZnSO4 ha−1 and foliar Mn. The interactive effects of Zn and Fe were significant on weight of 1000 grains. The highest weight of 1000 grains resulted from application of 80 kg Zn and foliar Fe. Application of 80 kg ZnSO4 ha−1 alone and 80 kg ZnSO4 ha−1 with foliar application of Mn significantly increased grain yield in 2003. The 2‐year results showed that foliar application of Zn increased Zn concentration and Fe concentration in grains 99% and 8%, respectively. Foliar application of Fe resulted in a 21% increase in Fe concentration and a 13% increase in Zn concentration in grains. The foliar application of Mn resulted in a 7% increased in Mn concentration in grains.

Variation of grain Cd and Zn concentrations of 110 hybrid rice cultivars grown in a low-Cd paddy soil

Enhanced Cd uptake and Zn depletion in rice grains and high potential for food Cd exposure by the high-yielding hybrid cultivars of China had been addressed. A field experiment was conducted in 2006 to determine the difference in grain Cd and Zn between cultivars. Total 110 cultivars including super rice and common hybrid rice cultivars were grown on a single paddy soil (Entic Haplaquept) with a neutral reaction and low total Cd content. Grain Cd and Zn concentrations were determined with graphite atomic adsorption spectrophotometer (GFAAS) and flame atomic adsorption spectrophotometer (AAS) respectively. Wide variation of Cd content in grain was found in a range of 0.004-0.057 mg/kg, while the Zn content in a range of 10.25-30.06 mg/kg among the cultivars. Higher Cd but lower Zn concentration in grains of super rice cultivars was observed compared to the common hybrid ones. A highly significant positive linear correlation of grain Cd/Zn with grain Cd was found for super rice and common hybrid cultivars, meanwhile much higher slope for these hybrid cultivars than the reported non-hybrid cultivars was also observed. Using the limit value of the Chinese chemical guidelines for foods (MOHC and SSC, 2005), calculated potential risk of food Cd exposure with "Zn hungry" through diet intake was prominent with all the studied 110 hybrid rice cultivars, possessing high potential health problems for rice production in South China using the super rice cultivars. Breeding of genotypes of rice cultivars with low grain Cd and low Cd/Zn ratio is needed for rice production in acidic red soils where Cd bioavailability is prevalently high.

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.

Enrichment of cereal grains with zinc: Agronomic or genetic biofortification?

Zinc deficiency is a well-documented problem in food crops, causing decreased crop yields and nutritional quality. Generally, the regions in the world with Zn-deficient soils are also characterized by widespread Zn deficiency in humans. Recent estimates indicate that nearly half of world population suffers from Zn deficiency. Cereal crops play an important role in satisfying daily calorie intake in developing world, but they are inherently very low in Zn concentrations in grain, particularly when grown on Zn-deficient soils. The reliance on cereal-based diets may induce Zn deficiency-related health problems in humans, such as impairments in physical development, immune system and brain function. Among the strategies being discussed as major solution to Zn deficiency, plant breeding strategy (e.g., genetic biofortification) appears to be a most sustainable and cost-effective approach useful in improving Zn concentrations in grain. The breeding approach is, however, a long-term process requiring a substantial effort and resources. A successful breeding program for biofortifying food crops with Zn is very much dependent on the size of plant-available Zn pools in soil. In most parts of the cereal-growing areas, soils have, however, a variety of chemical and physical problems that significantly reduce availability of Zn to plant roots. Hence, the genetic capacity of the newly developed (biofortified) cultivars to absorb sufficient amount of Zn from soil and accumulate it in the grain may not be expressed to the full extent. It is, therefore, essential to have a short-term approach to improve Zn concentration in cereal grains. Application of Zn fertilizers or Zn-enriched NPK fertilizers (e.g., agronomic biofortification) offers a rapid solution to the problem, and represents useful complementary approach to on-going breeding programs. There is increasing evidence showing that foliar or combined soil+foliar application of Zn fertilizers under field conditions are highly effective and very practical way to maximize uptake and accumulation of Zn in whole wheat grain, raising concentration up to 60 mg Zn kg−1. Zinc-enriched grains are also of great importance for crop productivity resulting in better seedling vigor, denser stands and higher stress tolerance on potentially Zn-deficient soils. Agronomic biofortification strategy appears to be essential in keeping sufficient amount of available Zn in soil solution and maintaining adequate Zn transport to the seeds during reproductive growth stage. Finally, agronomic biofortification is required for optimizing and ensuring the success of genetic biofortification of cereal grains with Zn. In case of greater bioavailability of the grain Zn derived from foliar applications than from soil, agronomic biofortification would be a very attractive and useful strategy in solving Zn deficiency-related health problems globally and effectively.

Rice grain zinc concentrations as affected by genotype, native soil-zinc availability, and zinc fertilization

The development of rice (Oryza sativa L.) cultivars with a higher Zn content in their grains has been suggested as a way to alleviate Zn malnutrition in human populations subsisting on rice in their daily diets. This study was conducted to evaluate the effects of native soil Zn status and fertilizer application on Zn concentrations in grains of five rice genotypes that had previously been identified as either high or low in grain Zn. Genotypes were grown in field trials at four sites ranging in native soil-Zn status from severely deficient to high in plant available Zn. At each site a −Zn plot was compared to a +Zn plot fertilized with 15 kg Zn ha−1. Results showed that native soil Zn status was the dominant factor to determine grain Zn concentrations followed by genotype and fertilizer. Depending on soil-Zn status, grain Zn concentrations could range from 8 mg kg−1 to 47 mg kg−1 in a single genotype. This strong location effect will need to be considered in estimating potential benefits of Zn biofortification. Our data furthermore showed that it was not possible to simply compensate for low soil Zn availability by fertilizer applications. In all soils fertilizer Zn was taken up as seen by a 50–200% increase in total plant Zn content. However, in more Zn deficient soils this additional Zn supply improved straw and grain yield and increased straw Zn concentrations by 43–95% but grain Zn concentrations remained largely unchanged with a maximum increase of 6%. Even in soils with high Zn status fertilizer Zn was predominantly stored in vegetative tissue. Genotypic differences in grain Zn concentrations were significant in all but the severely Zn deficient soil, with genotypic means ranging from 11 to 24 mg kg−1 in a Zn deficient soil and from 34 to 46 mg kg−1 in a high Zn upland soil. Rankings of genotypes remained largely unchanged from Zn deficient to high Zn soils, which suggests that developing high Zn cultivars through conventional breeding is feasible for a range of environments. However, it may be a challenge to develop cultivars that respond to Zn fertilizer with higher grain yield and higher grain Zn concentrations when grown in soils with low native Zn status.

Relative yield and zinc uptake by rice from zinc sulphate and zinc oxide coatings onto urea

Zinc (Zn) deficiency is prevalent worldwide and is a barrier to achieving yield goals in crops. It is also now recognized as a leading risk factor for disease in humans in developing countries. In general, soil application of 5–17 kg of Zn ha−1 year−1 as zinc sulphate (ZnSO4) or more is recommended. However, in developing rice growing countries of Asia, ZnSO4 of desired quality is not readily available and is also quite expensive, so the farmers generally fail to apply Zn, resulting in rice crop yield loss. Availability of Zn-coated urea guarantees not only the availability of quality Zn but also ensures its application. Field experiments were therefore conducted during the rice seasons of 2005 and 2006 at the Indian Agricultural Research Institute, New Delhi, to evaluate the relative efficiency of 0.5, 1.0, 1.5 and 2.0% Zn as ZnSO4- or zinc oxide (ZnO)-coated ureas for rice. Soil application of ZnSO4 was also compared in 2006. Rice grain and straw yields, Zn concentrations in grain and straw, and Zn uptake by rice increased with the level of Zn coating onto urea. Crop response was the highest with 2.0% ZnSO4-coated urea, and higher than with the same rate of ZnO-coated urea, possibly related to the higher water solubility of Zn in ZnSO4. Crop response with ZnSO4-coated urea was also higher than with the same rate of ZnSO4 and urea applied separately to the soil. However, apparent recovery data suggest that 1.0% coating with ZnSO4 may be a better choice from the point of view of the utilization of applied Zn. Increased Zn concentrations in rice grain due to application of Zn-coated urea is important from the point of view of Zn nutrition of humans, since rice is the staple food in developing countries of Asia. Also, increased Zn concentrations in rice straw is of importance as regards cattle nutrition since in developing countries of Asia rice straw is the major feed for farm cattle.

Yield response of crops amended with sewage sludge in the field is more affected by sludge properties than by final soil metal concentration

SummaryAdverse effects on crop yield or quality have been reported in sewage‐sludge treated soils at soil total metal concentrations below those of the current EU directives. A field trial was set up in Belgium (2002–2004) to assess crop response to the application of sewage sludge below these soil thresholds but with sludge metal concentrations either above (high‐metal) or below (low‐metal) sludge metal limits. Two lime‐stabilized and two raw, dewatered sludges were applied annually at rates of 10, 25 and 50 t dry matter (dm) ha−1 for 3 years with four rates of N‐fertilizer as a reference. Final soil metal concentrations increased to maximums of 1.6 mg Cd kg−1 and 225 mg Zn kg−1 through sludge applications. Maize yield was marginally affected by treatments in year 1, whereas wheat and barley grain yields in subsequent years increased up to threefold with increasing sludge or fertilizer rates and were mainly explained by grain‐N. However, the grain yield of winter wheat in year 2 was reduced by about 14% in lime‐stabilized high‐metal sludge treatments compared with wheat receiving N‐fertilizer at equivalent grain‐N. Wheat grain and straw analysis showed no nutrient deficiencies but Zn concentrations in grain and straw were greater than in N‐fertilizer and lime‐stabilized, low‐metal sludge treatments, suggesting Zn toxicity. Sludge properties other than Cd concentration (e.g. electrical conductivity) affected crop Cd in the first year (maize), whereas significant correlations between Cd application and wheat grain Cd were found in the second year. Wheat grain Cd concentrations reached the international trade guideline of 0.1 mg Cd kg−1 fresh weight in the plots amended with lime‐treated, high‐metal sludge even though soil Cd remained below EU limits. In the third year, barley grain Cd remained largely below EU limits. We discuss the possibility that sludge properties rather than soil total metal concentrations are related to effects on crops in the initial years after sludge applications. In none of the 3 years were any adverse effects on crops found for sludge meeting current EU regulations.

Trace Element Concentrations in Soil, Corn Leaves, and Grain after Cessation of Biosolids Applications

From 1974 to 1984, 543 Mg ha(-1) of biosolids were applied to portions of a land-reclamation site in Fulton County, IL. Soil organic C increased to 5.1% then decreased significantly (p < 0.01) to 3.8% following cessation of biosolids applications (1985-1997). Metal concentrations in amended soils (1995-1997) were not significantly different (p > 0.05) (Ni and Zn) or were significantly lower (p < 0.05) (6.4% for Cd and 8.4% for Cu) than concentrations from 1985-1987. For the same biosolids-amended fields, metal concentrations in corn (Zea mays L.) either remained the same (p > 0.05, grain Cu and Zn) or decreased (p < 0.05, grain Cd and Ni, leaf Cd, Cu, Ni, Zn) for plants grown in 1995-1997 compared with plants grown immediately following termination of biosolids applications (1985-1987). Biosolids application increased (p < 0.05) Cd and Zn concentrations in grain compared with unamended fields (0.01 to 0.10 mg kg(-1) for Cd and 23 to 28 mg kg(-1) for Zn) but had no effect (p > 0.05) on grain Ni concentrations. Biosolids reduced (p < 0.05) Cu concentration in grain compared with grain from unamended fields (1.9 to 1.5 mg kg(-1)). Biosolids increased (p < 0.05) Cd, Ni, and Zn concentrations in leaves compared with unamended fields (0.3 to 5.6 mg kg(-1) for Cd, 0.2 to 0.5 mg kg(-1) for Ni, and 32 to 87 mg kg(-1) for Zn), but had no significant effect (p > 0.05) on leaf Cu concentrations. Based on results from this field study, USEPA's Part 503 risk model overpredicted transfer of these metals from biosolids-amended soil to corn.

Effect of variety and zinc application on yield, profitability, protein content and zinc and nitrogen uptake by chickpea (Cicer arietinum)

A field experiment was conducted during the winter seasons of 201112 and 201213 at New Delhi, to study the effect of varieties (desi types Pusa 372 and Pusa 5028 and Kabuli type Pusa 2024) and levels of zinc (Zn) (0, 2.5, 5.0 and 7.5 kg/ha) on the yields, protein content, Zn and nitrogen uptake by chickpea ( Cicer arietinum L.). Pusa 372 chickpea recorded the highest grain yield (2.13 tonnes/ha), Zn concentration in grain and straw (42.9 mg/kg grain and 36.8 mg/kg straw respectively), total Zn uptake (229.0 g/ha), protein yield (480.6 kg/ha) and pro- tein content (22.7%) in chickpea grains. Kabuli type Pusa 2024 chickpea had the lowest protein content (19.9%). Application of Zn significantly increased grain and straw yields, Zn concentration in grain and straw and its total uptake and protein yield, protein content in grain, nitrogen uptake and gross and net returns. It also increased the efficiency of applied fertilizer (NPK), being significantly highest (26.6 kg grain/kg applied NPK) with 7.5 kg Zn/ha and lowest (22.3 kg grain/kg applied NPK) with the control (no Zn).

Dual purpose summer legumes and zinc fertilization for improving productivity and zinc utilization in aromatic hybrid rice (Oryza sativa)

Field experiments were conducted during 2007-08 at New Delhi, to study the effect of dual purpose summer le- gumes and zinc (Zn) fertilization on productivity and Zn-use efficiency of aromatic hybrid rice cv Pusa Rice Hybrid 10 (PRH 10). The experiment was carried out in split plot design with 3 treatments of legume residue in main plots and seven treatments of Zn fertilization in sub-plots. The tallest plant height, number of tillers/m2, dry matter accumulation/hill, leaf area index (LAI), yield attributes and grain yield of aromatic hybrid rice was recorded with incorporation of cowpea residue followed by mungbean residue. Zinc fertilization in aromatic hybrid rice increased growth parameters, yield attributes, grain and straw yields. Application of 2% ZEU (ZnSO .7H O) was found to be 4 2 the best in terms of all the yield attributes, grain yield of aromatic hybrid rice, 2% ZEU (ZnO) was found very close to it. In respect to Zn concentrations in grain and straw of aromatic hybrid rice, 2% ZEU (ZnSO .7H O) recorded 4 2 higher Zn concentrations in grain as well as in straw of aromatic hybrid rice. The highest agronomic efficiency (AE) was obtained with the application of 2% ZEU (ZnSO .7H O). Physiological efficiency (PE) and Zn harvest index 4 2 (ZnHI) of applied Zn were also significantly influenced due to dual purpose summer legumes and various Zn fertili- zation treatments applied in aromatic hybrid rice. Cooking quality parameters were significantly improved by le- gume residue incorporation and with the application of ZEU. The highest net returns and B:C ratios of the legume- rice sequence were recorded with the legume residue incorporation and with the application of ZEU in the aro- matic hybrid rice. Thus, growing of cowpea or mungbean as dual purpose summer legumes along with Zn fertiliza- tion as 2% ZEU either with ZnSO .7H O or ZnO to aromatic hybrid rice led to higher productivity, cooking quality 4 2 and Zn-use efficiency in aromatic hybrid rice and higher net returns of this sequence.

Residual effects of summer green manure crops and zinc applied to rice (Oryza sativa) on succeeding durum wheat (Triticum durum) under basmati ricewheat cropping sequence

Field experiments were conducted for two consecutive years (2009-11) at the research farm of Indian Agricul- tural Research Institute, New Delhi, to determine the direct and residual effects of summer green manuring crops [Sesbania aculeata (Dhaincha), Crotalaria juncea (Sunhemp) and Vigna unguiculata (Cowpea)] and zinc fertilizer sources [EDTA-chelated Zn (12% Zn), ZnSO .7H O (21% Zn), ZnSO .H O (33% Zn), ZnO (82% Zn) and 4 2 4 2 ZnSO .7H O + ZnO (50% + 50%)] on productivity, Zn uptake and economics of basmati rice (Oryza sativa L.)du- 4 2 rum wheat (Triticum durum Desf.) cropping sequence. In this paper information pertaining to residual effect of treatments on durum wheat is given. Significant residual effects of Zn fertilizer sources and summer green manur- ing crops were observed on durum wheat in comparison with control (no Zn application or summer fallow in pre- ceding Basmati rice). With residual effect of Sesbania incorporation, grain and straw yields of durum wheat were 4.5 and 5.16 t/ha, which were 15.9 and 10.0% higher compared to fallow. Among the different Zn fertilizer sources, residual effect of EDTA-chelated Zn was found to be the best with respect to growth, yield attributes, grain, straw, Zn content and uptake and economics. The residual effect of application of EDTA-chelated Zn resulted in the high- est durum wheat grain (4.78 t/ha) and straw yields (5.38 t/ha) compared to control. Highest Zn concentration in grain (43.0 mg/kg) and straw (126.6 mg/kg) and its uptake was recorded with residual effect of Sesbania incorpo- ration compared with sunhemp, cowpea and summer fallow. Highest total Zn uptake (936.6 g/ha) in durum wheat was recorded with residual effect of EDTA-chelated Zn application, followed by ZnSO .7H O, ZnSO .H O, 4 2 4 2 ZnSO .7H O + ZnO (50% + 50%), ZnO and control. The best economical returns were obtained with residual ef- 4 2 fect of Sesbania incorporation and EDTA-chelated Zn combination.

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.

Effect of different zinc application methods on grain yield and zinc concentration in wheat cultivars grown on zinc‐deficient calcareous soils

The effect of six different zinc (Zn) application methods on grain yield and concentrations of Zn in whole shoots and grain was studied in wheat cultivars (Triticum aestivum, L. cvs. Gerek‐79, Dagdas‐94 and Bezostaja‐1 and Triticum durum, Desf. cv. Kunduru‐1149) grown on severely Zn‐deficient calcareous soils (DTPA‐extractable Zn: 0.12 mg‐kg‐1 soil) of Central Anatolia which is the major wheat growing area of Turkey. Zinc application methods tested were: a) control (no Zn application), b) soil, c) seed, d) leaf, e) soil+leaf, and f) seed+leaf applications. Irrespective of the method, application of Zn significantly increased grain yield in all cultivars. Compared to the control, increases in grain yield were about 260% with soil, soil+leaf, and seed+leaf, 204% with seed and 124% with leaf application of Zn. In a similar manner, biomass production (dry weight of above‐ground parts) was increased by Zn treatments. The highest increase (109%) was obtained with the soil application and the lowest increase (40%) with the leaf application. Significant effects of Zn application methods were also found on the yield components, i.e., spike number.m‐2, grain number‐spike‐1, and thousand kernel weight. Spike number.m‐2 was affected most by Zn applications, particularly by soil and soil+leaf applications. Concentrations of Zn in whole shoots and grain were greatly affected by different Zn treatments. In plants without added Zn, concentrations of Zn were about 10 mg‐kg‐1 both in shoots and grain and increased to 18 mg‐kg‐1 dry weight (DW) by soil application of Zn, but not affected by seed application of Zn. Soil+leaf application of Zn had the highest increase in concentration of Zn in shoot (82 mg‐kg‐1 DW) and grain (38 mg‐kg‐1 DW). Soil application of Zn was economical and had long‐term effects for enhancing grain yield of wheat grown on Zn deficient soils. When high grain yield and high Zn concentration in grains are desired, soil+leaf application of Zn was most effective method of Zn application.

Diagnosing zinc deficiency in rapeseed and mustard by seed analysis

Abstract Zinc (Zn) deficiency in crops, including rapeseed and mustard, is a widespread nutritional disorder especially in alkaline soils. However, plant analysis diagnostic criteria for interpreting Zn analysis in rapeseed and mustard are scarcely reported in the literature. Use of seeds for diagnosing Zn fertility status of soils has certain advantages over foliar analysis—ease of sampling, processing, and chemical analysis. Despite this, mature seeds of these species were hardly evaluated as an index tissue for this purpose. Our study determined Zn requirement in foliar tissues and also evaluated Zn composition of mature seeds as an index of Zn status of soils and plants. Zinc concentration in mature seeds of the test crops reflected the Zn status of the soil where plants were grown. In fact, the range of Zn concentration in grains was almost comparable with the ranges in foliar plant parts. Critical Zn concentration (mg/kg) in diagnostic plant parts of rapeseed was: whole shoots, 29; leaves, 33; and s...