Iron and zinc variation along the grain length of different Thai rice varieties

ABSTRACT: This study examined the distribution of iron (Fe) and zinc (Zn) along the grain length of seven rice varieties. The experiment was conducted in a completely randomized design with two factors (variety and grain fraction) and three independent replications. Samples of brown and white rice of six common Thai rice varieties and a high Fe and Zn variety, IR68144, were transversely cut into three fractions per grain (basal, middle, and distal) with approximately the same length in each fraction. The concentration of Fe and Zn was determined by the dry ashing method and quantified using atomic absorption spectrometry. The middle grain fraction of brown rice was found to have the lowest Fe and Zn with greater concentration of Fe and Zn in the basal (embryo end) than the other fractions. The rice varieties differed in the amount of Fe and Zn allocated to different fractions of the endosperm (white rice). The potential for loss of Fe and Zn during milling due to their uneven distribution along the grain length will become more significant when higher nutrient concentrations are involved, such as those achieved by biofortification efforts. Micronutrient distribution needs to be taken into consideration to ensure that rice consumers benefit from Fe and Zn biofortification

Application of Silicon Influencing Grain Yield and Some Grain Quality Features in Thai Fragrant Rice

Silicon (Si) is a beneficial nutrient that has been shown to increase rice productivity and grain quality. Fragrant rice occupies the high end of the rice market with prices at twice to more than three times those of non-fragrant rice. Thus, this study evaluated the effects of increasing Si on the yield and quality of fragrant rice. Also measured were the content of proline and the expression of the genes associated with 2AP synthesis and Si transport. The fragrant rice varieties were found to differ markedly in the effect of Si on their quality, as measured by the grain 2AP concentration, while there were only slight differences in their yield response to Si. The varieties with low 2AP when the Si supply is limited are represented by either PTT1 or BNM4 with only slight increases in 2AP when Si was increased. Si affects the gene expression levels of the genes associated with 2AP synthesis, and the accumulation of 2AP in fragrant rice mainly occurred through the upregulation of Badh2, DAO, OAT, ProDH, and P5CS genes. The findings suggest that Si is a potential micronutrient that can be utilized for improving 2AP and grain yield in further aromatic rice breeding programs.</p

The impact of foliar applied zinc fertilizer on zinc and phytate accumulation in dorsal and ventral grain sections of four thai rice varieties with different grain zinc

© 2017 Elsevier Ltd. This manuscript version is made available under the CC-BY-NC-ND 4.0 license: http://creativecommons.org/licenses/by-nc-nd/4.This study investigated the effect of foliar applied zinc (Zn) on the distribution of Zn and phytate in rice grain between four Thai rice varieties that differ in grain Zn. Foliar Zn application at 0.5% ZnSO4 was applied at flowering and the early milky stage compared with non-foliar applied Zn. Among the high-yielding, low grain Zn varieties (CNT1 and RD21), foliar applied Zn increased Zn concentration in both dorsal and ventral sections of unpolished rice by up to 17.7 and 14.3%. In the low-yielding, high grain Zn varieties (KPK and NR), Zn concentration increased by 11% in the dorsal section of NR, but no effect was found in both sections of KPK. In polished rice, the Zn concentration increased by 20% in both sections but it was increased only in the ventral section of KPK and CNT1 by 21.0% and 25.0% respectively, while there was an increase of 12.5% in the dorsal section of RD21. The phytate in the seed fractions was measured as an indication for Zn bioavailability within humans. A lower phytate concentration was observed after foliar Zn application in both unpolished and polished rice, indicating the potential for a higher bioavailability of Zn in the rice grain

Improving Grain Zinc Concentration in Wetland and Upland Rice Varieties Grown under Waterlogged and Well-Drained Soils by Applying Zinc Fertilizer

The objective of this study was to evaluate the responses in grain yield and zinc concentration of wetland and upland rice varieties to Zn fertilizer application and different growing conditions. The wetland (Chainat 1; CNT1) and upland (Kum Hom CMU; KH CMU) rice varieties were grown under waterlogged and well-drained soil conditions with or without Zn fertilizer application. Zinc fertilizer (ZnSO4) was applied at 0 and 60 kg ha−1 in three stages at tillering, booting, and flowering. In the wetland variety, CNT1, grain yield decreased by 18.0% in the well-drained soil compared to the waterlogged conditions, but there was an 8.9% decrease in grain yield in the waterlogged soil compared to the well-drained soil in the upland variety, KH CMU. Applying Zn fertilizer affected yields differently between the varieties, decreasing grain yield by 11.9% in CNT1 while having no effect in KH CMU. For grain Zn concentrations in brown rice, applying Zn fertilizer increased Zn concentration by 16.5–23.1% in CNT1 and KH CMU under both growing conditions. In the well-drained soil, applying Zn fertilizer increased straw Zn concentration by 51.6% in CNT1 and by 43.4% in KH CMU compared with the waterlogged conditions. These results indicated that the wetland and upland rice varieties responded differently to Zn fertilizer application when grown in different conditions. Applying Zn fertilizer in the appropriate rice variety and growing conditions would help farmers to improve both the desirable grain yield and Zn concentration in rice

Silicon Application Promotes Productivity, Silicon Accumulation and Upregulates Silicon Transporter Gene Expression in Rice

Rice has been shown to respond positively to Si fertilizer in terms of growth and productivity. The objective of this study was to evaluate the effect of a series of Si application rates on grain yield, Si concentration, and the expression of the OsLsi6 gene among three Thai rice varieties. The varieties CNT1, PTT1, and KDML105 were grown in a pot experiment under six levels of Si (0, 100, 150, 200, 250, and 300 kg Si/ha). Grain yield was the highest at 300 kg Si/ha, being increased by 35%, 53%, and 69% in CNT1, PTT1, and KDML105, respectively, compared with the plants grown without added Si. For Si concentrations in rice plants, rising Si fertilizer application up to 150 kg/ha significantly increased the Si concentration in straw, flag leaf, and husk in all varieties. The Si concentration in all tissues was higher under high Si (300 kg Si/ha). Applying Si fertilizer also increased the expression level of OsLsi6 in both CNT1 and PTT1 varieties. The highest expression level of OsLsi6 was associated with 300 kg Si/ha, being increased by 548% in CNT1 and 326% in PTT1 compared with untreated plants. These results indicate that Si application is an effective way to improve rice yield as well as Si concentration, and that the effect is related to the higher expression of the OsLsi6 gene

Key factors affecting Fe density in Fe-fortified-parboiled rice: Parboiling conditions, storage duration, external Fe-loading rate and genotypic differences

The present study evaluated the key factors affecting the efficiency of iron (Fe) penetration into the endosperm in parboiled rice of different varieties. It also investigated effects of storage time on Fe bio-accessibility, rice colour and Fe retention after rinsing. Rice grains of three varieties were fortified with an increasing range of Fe-fortification rates during the parboiling process, under two typical parboiling conditions, which are ambient soaking temperature for 24h and 60°C soaking temperature for 6h at neutral (6.0-6.5) and acidic pH (3.0-3.5). Soaking of paddy rice, at 60°C in acidic water for 6h before steaming, was found to be better for maximising the Fe concentration in white-parboiled rice than the former ambient soaking. Under this parboiling condition, adding 250mgFekg of paddy rice, at soaking, produced the most desirable Fe concentration in white rice, ranging from 17.5 to 25.4mgkg among the rice varieties tested. The concentrations of Fe in parboiled white rice exhibited an exponential increase with increasing concentrations of Fe in the soaking water in all varieties, which were linearly related to Fe concentration of brown rice (r=0.96**,

Efficacy of Nitrogen and Zinc Application at Different Growth Stages on Yield, Grain Zinc, and Nitrogen Concentration in Rice

Zinc (Zn) is an essential element involved in human metabolism, which can be supplied by an appropriate diet. Enhancing Zn enrichment in rice grains through agronomic biofortification is advocated as an immediate and effective approach to combat micronutrient malnutrition in hu-man. It has been well-documented that high grain Zn accumulation in rice can be achieved by Zn fertilizers management. This study evaluated the effects of foliar nitrogen (N) and Zn applied at the flowering and milky stages of brown rice plants with and without soil Zn application. A glasshouse pot experiment was conducted using a completely randomized design with four replicates. Soil Zn in the form of ZnSO4 was applied at 0 and 50 kg ha−1. Foliar fertilizer of 1% urea along with 0.5% ZnSO4 was applied and assigned as (1) nil foliar N and Zn (N0Zn0), (2) foliar N with nil Zn (N+Zn0), (3) nil foliar N with foliar Zn (N0Zn+), and (4) foliar N and Zn (N+Zn+) at flowering and milky stages. Foliar application of N and Zn increased grain yield and yield components in both soil Zn conditions. Grain Zn concentration in brown rice was the highest when foliar N and Zn were applied under nil soil Zn conditions; however, grain N concentration decreased by 13.1–28.5% with foliar application at flowering and 18.8–28.5% with application at the milky stage. The grain Zn content was increased by foliar application of N0Zn+ and N+Zn+ at flowering and milky stages. Applying foliar N and Zn at flowering or milky stages tended to increase the grain N content when Zn was applied to the soil, while nil soil Zn decreased the N content by 26.8% at flowering and milky stages under N0Zn+. The results suggest that the milky stage is the most suitable for foliar application of Zn for increasing (i) grain yield and (ii) N and Zn concentrations in brown rice without having a dilution effect

Zinc fortification of whole rice grain through parboiling process

Chanakan Prom-u-thai1*, Benjavan Rerkasem1, Ismail Cakmak2, Longbin Huang3 1Agronomy Department, Faculty of Agriculture, Chiang Mai University, Chiang Mai 50200, Thailand 2 Faculty of Engineering and Natural Sciences, Sabanci University, Istanbul 34956, Turkey 3 The University of Queensland, Center for Mined Land Rehabilitation, St Lucia, QLD 4072, Australia Abstract The present study evaluated the effectiveness of Zn fortification in parboiling process for improving Zn density in parboiled-polished rice and its potential bioavailability in rice-based human diet. The result showed that fortification of Zn in the whole paddy rice grain during parboiling process with 50-400 mg Zn kg-1 paddy rice increased Zn concentration in polished-parboiled rice from 1.3 to 4.5 times of those in unfortified parboiled rice. The added Zn rapidly penetrated into parboiled rice grains in the initial soaking process before saturation. There was an exponential correlation between Zn concentrations in unpolished (r= 0.63) (p< 0.01) and polished rice (r= 0.30) (p< 0.05) and soaking time. Zinc concentrations in unpolished rice were linearly correlated with Zn concentration in the polished rice (r= 0.60) (p< 0.01). Moreover, more than half of the added Zn is retained after a simulated washing process before cooking, ranging from 64-100%. In the Zn fortified parboiled rice, 57-100% of Zn in polished rice grain was soluble in dilute acid, indicating a high potential Zn bioavailability for human intake, but further in vivo investigations are required to confirm this potential. The results suggest that the established parboiling technique in parboiled rice industry has a great potential for Zn fortification to improve the density of Zn in parboiled rice grain and nutritional value for human base diets, in addition to Fe fortification as reported previously (Prom-u-thai et al., 2008, 2009). The benefit of Zn fortification in parboiled rice can be rapidly deployed to populations in South Asia who are major consumers of parboiled rice. Keyword: Zinc deficiency, Zinc fortification, Parboiled ric

Iron, Zinc and Total Antioxidant Capacity in Different Layers of Rice Grain among Different Varieties

Iron, Zinc and Total Antioxidant Capacity in Different Layers of Rice Grain among Different Varietie