LOWLAND RICE GENOTYPES EVALUATION FOR PHOSPHORUS USE EFFICIENCY IN TROPICAL LOWLAND

Lowland rice is a staple food for more than 50% of the world's population and phosphorus (P) deficiency is one of the main constraints in rice production in tropical lowlands. A field experiment was conducted for two years consecutive with the objective to evaluate 12 lowland rice genotypes for P use efficiency. The P rates used were 0, 22, 44, 66, and 88 kg P ha^?1 (0, 50, 100, 150 and 200 kg P₂O₅ ha^?1) applied to an Inceptisol. The genotypes used were BRS Jaçanã, CNAi 8860, BRS Fronteira, CNAi 8879, CNAi 8880, CNAi 8886, CNAi 8885, CNAi 8569, BRSGO Guará, BRS Alvorada, BRS Jaburu and BRS Biguá. There were significant and quadratic responses of genotypes to phosphorus fertilization. Adequate P rates for maximum grain yield varied from genotype to genotype. However, across 12 genotypes, maximum grain yield was obtained with the application of 54 kg P ha^?1. Genotype BRS Jaçanã was most efficient and genotype CNAi 8569 was most inefficient in P use efficiency. Shoot dry weight and panicle number was also increased significantly and quadratically with increasing P rates in the range of 0 to 88 kg P ha^?1. These two plant parameters were positively associated with grain yield. Agronomic efficiency (kg grain produced per kg P applied) was significantly decreased with increasing P rates in the range of 22 to 88 kg P ha^?1.     

ROOT GROWTH OF UPLAND RICE GENOTYPES AS INFLUENCED BY NITROGEN FERTILIZATION

The plant root system is an important organ which supplies water and nutrients to growing plants. Information is limited on influence of nitrogen fertilization on upland rice root growth. A greenhouse experiment was conducted to evaluate influence of nitrogen (N) fertilization on growth of root system of 20 upland rice genotypes. The N rate used was 0 mg kg^?1(low) and 300 mg kg^?1(high) of soil. Nitrogen X genotype interactions for root length and root dry weight were highly significant (P < 0.01), indicating that differences among genotypes were not consistent at two N rates. Overall, greater root length, root dry weight and tops-roots ration were obtained at an N fertilization rate of 300 mg kg^?1compared with the 0 mg N kg^?1soil. However, genotypes differ significantly in root length, root dry weight and top-root ratio. Nitrogen fertilization produced fine roots and more root hairs compared with absence of N fertilizer treatment. Based on root dry weight efficiency index (RDWEI) for N use efficiency, 70% genotypes were classified as efficient, 15% were classified as moderately efficient and 15% were classified as inefficient. Root dry weight efficiency index trait can be incorporated in upland rice for improving water and nutrient efficiency in favor of higher yields.     

NITROGEN USE EFFICIENCY IN UPLAND RICE GENOTYPES

Nitrogen (N) deficiency is one of the most yield-limiting nutrients in upland rice growing regions word wide. A greenhouse experiment was conducted with the objective to evaluate nineteen upland rice (Oryza sativa. L.) genotypes for N use efficiency. The soil used in the experiment was an Oxisol and two N levels used were without N application (low level) and an application of 400 mg N kg^?1 of soil (high level). Grain yield and yield components and N uptake parameters were significantly affected by N and genotype treatments. Regression analysis showed that plant height, shoot dry weight, number of panicles per pot, number of grains per panicle, grain harvest index, N uptake in shoot and grain were having significant positive relation with grain yield. Nitrogen concentration of 6.4 g kg^?1 in the shoot is established as deficient level and 9.5 g kg^?1 as sufficient level at harvest. Agronomic efficiency of N (grain yield/unit of N applied) and N utilization efficiency (physiological efficiency X apparent recovery efficiency) were significantly different among genotypes. These two N use efficiencies were having significant quadratic relationship with grain yield. Soil pH, exchangeable soil Ca and base saturation were having significantly positive association with grain yield. However, soil extractable phosphorus (P), potassium (K), hydrogen (H⁺), aluminum (Al) and cation exchange capacity were having significantly negative association with grain yield.     

DRY BEAN GENOTYPES EVALUATION FOR GROWTH,YIELD COMPONENTS AND PHOSPHORUS USE EFFICIENCY

Dry bean along with rice is a staple food for the population of South America. In this tropical region beans are grown on Oxisols and phosphorus (P) is one of the most yield limiting factors for dry bean production on these soils. A greenhouse experiment was conducted to evaluate P use efficiency in 20 elite dry bean genotypes grown at deficient (25 mg P kg^?1 soil) and sufficient (200 mg P kg^?1) levels of soil P. Grain yields and yield components were significantly increased with P fertilization and, interspecific genotype differences were observed for yield and yield components. The grain yield efficiency index (GYEI) was having highly significant quadratic association with grain yield. Based on GYEI most P use efficient genotypes were CNFP 8000, CNFP 10035, CNFP10104, CNFC 10410, CNFC 9461, CNFC 10467, CNFP 10109 and CNFP 10076 and most inefficient genotypes were CNFC 10438, CNFP 10120, CNFP 10103, and CNFC 10444. Shoot dry weight, number of pods per plant, 100-grain weights and number of seeds per pod was having significant positive association with grain yield. Hence, grain yield of dry bean can be improved with the improvement of these plant traits by adopting appropriate management practices. Soil pH, extractable P and calcium (Ca) saturation were significantly influenced by P treatments. Based on regression equation, optimum pH value in water was 6.6, optimum P in Mehlich 1 extraction solution was 36 mg kg^?1 and optimum Ca saturation value was 37% for dry maximum bean yield.     

LOWLAND RICE GENOTYPES EVALUATION FOR PHOSPHORUS USE EFFICIENCY

ABSTRACT

Phosphorus (P) deficiency is the most yield-limiting factor in lowland rice production in Inceptisols of Brazil. A greenhouse experiment was conducted to evaluate 12 genotypes of lowland rice (Oryza sativa L.) using an Inceptisol (Typic Haplaquepts). The P treatments were: low (0?mg?P?kg^?1), medium (100?mg?P?kg^?1), and high (400?mg?P?kg^?1). Significant (P<0.01) genotypes differences in P-use efficiency were found. On the basis of P-use efficiency, genotypes were classified as efficient and responsive, efficient and non-responsive, non-efficient and responsive, and non-efficient and non-responsive. From a practical point of view, efficient and responsive and efficient and non-responsive genotypes are the most desirable ones. Among the 12 genotypes tested, none were found to be efficient and responsive and genotypes CNA7553, CNA7591, CNA7601, and Aliança were found to be efficient and non-responsive. Among the yield components, panicle length and harvest index were significantly affected by P levels and genotypes and P and genotypes interactions were significant for these two parameters. However, panicle number was significantly influenced only by P treatment. Among the yield components, panicle number, harvest index, and panicle length were significantly (P<0.01) related to grain yield.     

YIELD AND YIELD COMPONENTS OF UPLAND RICE AS INFLUENCED BY NITROGEN SOURCES

Ammonium sulfate and urea are main sources of nitrogen (N) for annual crop production in developing countries. Two greenhouse experiments were conducted using ammonium sulfate and urea as N sources for upland rice grown on a Brazilian Oxisol. The N rates used were 0, 50, 100, 150, 3000, and 400 kg N kg^?1 of soil. Yield and yield components were significantly increased in a quadratic fashion with increasing N rate. Ammonium sulfate X urea interaction was significant for grain yield, shoot dry matter yield, panicle number, plant height and root dry weight, indicating a different response magnitude of these plant parameters to two sources of N. Based on regression equation, maximum grain yield was achieved with the application of 380 mg N kg^?1 by ammonium sulfate and 271 mg N kg^?1 by urea. Grain yield and yield components were reduced at higher rates of urea (>300 mg kg N) but these plant parameters’ responses to ammonium sulfate at higher rates was constant. In the intermediate N rate range (125 to 275 mg kg^?1), urea was slightly better compared to ammonium sulfate for grain yield. Grain yield was significantly related with plant height, shoot dry weight, panicle number, grain harvest index and root dry weight. Hence, improving these plant characteristics by using appropriate soil and plant management practices can improve upland rice yield.     

Nitrogen,Phosphorus and Potassium Interactions in Upland Rice

Upland rice is an important crop in South America, including Brazil. Nutrient interactions are important in determining crop yields. A greenhouse experiment was conducted to evaluate interaction among nitrogen (N), phosphorus (P), and potassium (K) in upland rice production. The treatments applied to upland rice grown on an Oxisol were three levels of N (N₀, N₁₅₀ and N₃₀₀ mg kg^?1), three levels of P (P₀, P₁₀₀ and P₂₀₀ mg kg^?1) and three levels of K (K₀, K₁₀₀ and K₂₀₀ mg kg^?1). These treatments were tested in a 3 × 3 × 3 factorial arrangement. Grain yield, shoot dry weight, plant height, root dry weight, maximum root length, panicle number, 1000-grain weight, and grain harvest index were significantly influenced by N, P, and K treatments. The treatment that did not receive P fertilization did not produce panicle or grain. Hence, P was most yield-limiting nutrient compared to two other nutrients. At the N₀P₀K₀ treatment, rice did not produce grains, indicating severe deficiency of these nutrients in Brazilian Oxisols. Maximum grain yield was obtained with the N₃₀₀P₂₀₀K₂₀₀ treatment. Grain yield had significant positive association with plant height, shoot dry weight, root dry weight, maximum root length, 1000-grain weight, panicle number, and grain harvest index. Among these growth and yield components, shoot dry weight had the highest positive association with grain yield and root length minimum positive association with grain yield. Hence, adopting adequate soil and crop management practices can improve growth and yield components and increase grain yield of upland rice.     

Zinc,Copper, Boron and Iron Requirement of Upland Rice Grown on a Brazilian Oxisol

Deficiency of micronutrients increasing in field crops, including upland rice in recent years. The objective of this study was to determine requirement of zinc (Zn), copper (Cu) boron (B) and iron (Fe) for upland rice grown on a Brazilian Oxisol. The levels used were: Zn (0, 10, 20, 40, and 80 mg kg^?1), Cu (0, 5, 10, 20 and 40 mg kg^?1), B (0, 5, 10, 20 and 40 mg kg^?1) and Fe (0, 250, 500, 1000, and 2000 mg kg^?1). Plant height, straw yield, grain yield, panicle number and grain harvest index (GHI) were significantly improved with the addition of these micronutrients. Root growth was also improved with the application of micronutrients, except with the addition of B. Maximum grain yield was obtained with the addition of 51 mg Zn, 24 mg Cu, 5 mg B kg^?1, and 283 mg Fe kg^?1 soil. Similarly, maximum straw yield was obtained with the addition of 38 mg Zn, 17 mg Cu, 6 mg B kg^?1, and 1500 mg Fe kg^?1 soil. Maximum plant height was obtained with the addition of 54 mg Zn, 10 mg B kg^?1, and 1197 mg Fe kg^?1 soil. Copper did not affect plant height significantly. Maximum panicle number was obtained with the addition of 22 mg Cu kg^?1, 3 mg B kg^?1, and 1100 mg Fe kg^?1 soil. Zinc did not affect panicle number significantly. Maximum GHI was obtained with the addition of 61 mg Zn kg^?1, and 8 mg B kg^?1. Zinc was had a linear increase in GHI in the range of 0 to 80 mg kg^?1, and Fe showed a negative relationship with GHI.     

NITROGEN USE EFFICIENCY IN DRY BEAN GENOTYPES

Dry bean is an important legume crop for Latin American people and nitrogen is one of the most yields limiting nutrients for bean crop. A greenhouse experiment was conducted to evaluate nitrogen (N) use efficiency of 20 dry bean genotypes. Genotypes were grown on an Oxisol and two N levels used were without N application (low level) and an application of 400 mg N kg^?1 (high level). Shoot dry weight, grain yield and yield components, N concentration and uptake in shoot and grain were significantly affected by N and genotype treatments. Grain yield had a highly significant (P < 0.01) association with shoot dry weight, pod number, grains per pod and 100 grain weight. Among the 20 genotypes tested, Perola, CNFR 7847, CNFR 7865, CNFP 7777 and CNFM 6911 were found to produce reasonably good yield at low N rate as well as responded well to applied N. Whereas, some genotypes like BRS Radiante, CNFP 7624, CNFM 7875, CNFM 7886, CNFC 7813, CNFC 7827, CNFP 7677 and CNFP 7775 produced very good yields at higher N rate but very low yields at lower N rate. Hence, these genotypes are good for farmers using higher technology. Nitrogen concentration and uptake were higher in dry bean grains compared with shoot and 63% of N accumulated at zero N rate and 75% N accumulated at 400 mg N rate were translocated to grain across 20 genotypes. Nitrogen uptake efficiencies were having highly significant (P < 0.01) quadratic relationship with grain yield. This indicates that improving N uptake in dry bean plants can increase grain yield.     

Phosphorus Use Efficiency in Upland Rice Genotypes Under Field Conditions

Phosphorus (P) deficiency is one of the most yield limiting factors for crop production in South American soils. Upland rice (Oryza sativa L.) is an important crop in South American cropping systems, including Brazil. A field experiment was conducted with the objective to evaluate 20 upland rice genotypes for phosphorus (P) use efficiency. The P rate used was low (0 kg P ha^?1) and high [87 kg P ha^?1 or 200 kg phosphorus pentoxide (P₂O₅) ha^?1]. Plant height, shoot dry weight, grain yield, panicle number, 1000 grain weight, spikelet sterility, and grain harvest index were significantly influenced by P and genotype treatments. The P X genotype interaction was significant for grain yield, indicating that genotypes responded differently under two P rates. Overall, grain yield increased by 12% with the addition of P fertilization. Based on grain yield efficiency index, genotypes were classified into efficient, moderately efficient, and inefficient group. The genotypes that were classified as efficient in P use were BRA032048, BRA042094, BRA02601, BRA032051, BRA032033, BRA052015, BRA042156, BRA01600, BRA01506, BRA052023 and BRA042160. The inefficient genotypes in P us efficiency were BRS Primavera, BRA052045, BRA01596, and BRS Sertaneja. Grain harvest index had a significant positive association with grain yield and spikelet sterility had a significant negative association with grain yield, as expected. Average, P-use efficiency of five genotypes was about 17 kg kg^?1 (kg grain yield per kg P applied).     

Effect of calcium sprays,time of harvest,cold storage,and ripeness on fruit quality of ‘anjou’ pears 1

Calcium chloride (CaCl₂), increased Ca concentrations in fruit cortex and peel of ‘Anjou’ pears (Pyrus communis L.). Calcium sprays reduced the fruit disorders: brown core, cork spot and superficial scald. Fruit size (weight) increased while fruit Ca concentrations decreased with fruit at the later harvest dates. The earliest harvest date was associated with a lower incidence of fruit disorders. Superficial scald increased in fruit held longer in cold storage and in ripened fruit. Shelf‐life and fruit quality of Ca‐sprayed fruit was improved due to higher Ca concentrations in fruit peel and cortex resulting in overall enhancement of fruit appearance, and in improvement in the control of the incidences of cork spot, scald, brown core, and external and internal rots, and in amelioration of fruit juiciness and fruit color.     

Lowland Rice Genotypes Evaluation for Potassium-Use Efficiency

Lowland rice significantly contributes to world as well as Brazilian rice production and information on genotypes potassium-use efficiency is limited. A greenhouse experiment was conducted with the objective to evaluate lowland rice genotypes for potassium (K)–use efficiency. Ten genotypes were evaluated at 0 mg K kg^?1 (low) and 200 mg K kg^?1 (high) of soil. Grain yield and shoot dry weight were significantly affected by K as well as genotype treatments. Genotypes CNAi 8860, CNAi 8859, BRS Fronteira, and BRS Alvorada were the best in relation to K-use efficiency because they produced best grain yield at low as well as at higher K levels. Shoot dry weight, number of panicles per pot, and 1000-grain weight had highly significant (P < 0.01) association with grain yield. Spikelet sterility, however, had significant negative association with grain yield. These plant parameters were mainly influenced by genotypes, indicating importance of selecting appropriate genetic material for improving grain yield. Soil K depletion was significant at harvest, suggesting large amount of K uptake by lowland rice genotypes.     

Comparison of Conventional and Polymer Coated Urea as Nitrogen Sources for Lowland Rice Production

Nitrogen (N) is one of the most yield limiting nutrients in lowland rice production. Improving N use efficiency is essential to reduce cost of crop production and environmental pollution. A greenhouse experiment was conducted with the objective to compare conventional and polymer coated urea for lowland rice production. Grain yield, straw yield, panicle density, maximum root length, and root dry weight were significantly increased in a quadratic fashion with the increase of N rate from 0 to 400 mg kg^?1 soil. Nitrogen source X N rate interactions for most of these traits were not significant, indicating that lowland rice responded similarly to change in N rates of two N sources. Based on regression equations, maximum grain yield was obtained with the application of 258 mg N kg^?1 soil and maximum straw yield was obtained with the addition of 309 mg N kg^?1 soil. Nitrogen use efficiency (grain yield per unit of N applied) was maximum for polymer coated urea compared to conventional urea. Root length and root dry weight improved at an adequate N rate, indicating importance of N fertilization in the absorption of water and nutrients and consequently yield. Polymer coated urea had higher soil exchangeable calcium (Ca) and magnesium (Mg), Ca saturation, Mg saturation, base saturation, and effective cation exchange capacity compared to conventional urea. There was a highly significant decrease in soil exchangeable potassium (K) with increasing N rates at harvest of rice plants.     

Nitrogen-Use Efficiency in Lowland Rice Genotypes under Field Conditions

Rice is staple food for more than 50% of the world's population. Nitrogen (N) is one of the most yield-limiting nutrients for lowland rice production around the world. Two field experiments were conducted at two locations for two consecutive years to evaluate N-use efficiency of 12 lowland rice genotypes. Growth, grain yield, and yield components were significantly influenced by N as well as genotype treatments. Location?×?year?×?genotype and location?×?year?×?N interactions were significant for most of the growth, yield, and yield components, indicating influence of these factors on yield and yield components. Overall, the most N-efficient genotypes measured in terms of grain yield were BRA 031032, BRA 031044, and BRA 02654 and the most inefficient genotypes were BRS Jaçana, BRS Fronteira, and BRA 02674. Genotypes had linear and quadratic responses to added N in the range of 0 to 200 kg ha^?1. Nitrogen significantly influenced plant height, shoot dry weight, panicle number, and 1000-grain weights. Nitrogen-use efficiency (kg grain per kg N applied) varied from 33 to 49 kg grain per kg N applied, with an average value of 40 kg grain per kg N applied. The genotype BRA 031044 produced the greatest N-use efficiency, and the lowest N-use efficient genotype was BRS Fronteira. There was a significant linear association between N-use efficiency and grain yield.     

Comparative Efficiency of Nitrogen Sources for Lowland Rice Production

Rice (Oryza sativa L.) is the staple food for more than 50% world population and nitrogen (N) is one of the most yield-limiting nutrients for rice production worldwide. A greenhouse experiment was conducted to evaluate the efficiency of three N sources for lowland rice production. The N sources used were ammonium sulfate, common urea, and polymer-coated urea. There were three N rates, i.e. 100, 200, and 400 mg N kg^?1 applied with three sources plus one control treatment (0 mg N kg^?1). Growth, yield, and yield components were significantly increased either in a linear or quadratic fashion with the addition of N fertilizers in the range of 0–400 mg kg^?1 soil. Maximum grain yield was obtained with the addition of ammonium sulfate at 100, 200, and 400 mg kg^?1 of soil. Common urea and polymer-coated urea were more or less similar in grain production at 100 and 200 mg N kg^?1. However, at 400 mg N kg^?1 treatments, polymer-coated urea produced the lowest grain yield. Most of the growth and yield components were positively related to grain yield, except spikelet sterility which was negatively related to grain yield. Nitrogen use efficiency decreased with increasing N rate in all the three N sources. Maximum N use efficiency was obtained with the addition of ammonium sulfate at lower as well as at higher N rates compared with other two N sources.     

粳稻伞穗型突变体的诱发与特性评价

采用60Coγ射线200Gy辐照处理晚粳稻密穗型材料U5纯系干种子,经加代筛选后,获得了粳稻伞状穗型突变体,取名为ET2。与原亲本比较,ET2穗部形态发生了明显变异,其一次枝梗着生角度显著增大,与穗轴的张开角达30°~40°;其未成熟粒、垩白粒率和垩白度分别减少41.8%、39.8%和59.1%;其籽粒产量提高4.15%。分析ET2穗部不同部位籽粒特性表明,在未成熟粒和垩白改良方面,其穗下部显著优于穗中部,而穗中部又优于穗上部。ET2的诱发可能是培育籽粒优良、密穗型高产晚粳稻品种的一条有效途径。     

不同基因型冬小麦冠层温度与产量和水分利用效率的关系

通过研究水分利用效率和产量之间的相关性,证明冠层温度在筛选小麦品种(系)时也是一个重要的指标。利用红外测温仪,于2006-2007年在甘肃陇东旱原研究了来自中国北方和美国的40个小麦品种(系)不同生育时期冠层温度的差异及其与产量、水分利用效率的关系。结果表明,不同基因型小麦在籽粒灌浆结实期存在着冠层温度高度分异现象,其分异程度随生育期的推后明显加大,到灌浆中后期达到最大。无论拔节期、灌浆初期还是中后期,旱地冬小麦产量、水分利用效率与冠层温度均呈极显著的负相关,并且随着生育期推移,相关性增大。灌浆中期以后不同基因型小麦冠层温度保持较高的一致性,冠层温度偏低的品种具有较高的产量和水分利用效率。灌浆中后期的冠层温度在评价小麦产量和水分利用效率上具有较高的可靠性,可作为田间选择的一个指标应用。     

水稻氮效率基因型差异及其机理研究进展

提高氮效率是当前水稻生产中亟待解决的问题。针对水稻基因型间氮效率差异的客观事实,从根系、叶片光合与衰老、库容量、氮代谢、物质生产与分配、产量及其构成等方面,详细阐述了水稻氮效率基因型差异的机理。对研究中存在的问题进行了探讨,并对水稻氮效率与高产的协同进行了展望。     

水稻细胞质雄性不育恢复性的等位基因分化

选用WA型、Y型和DA型3种细胞质的4个不育系(博白A、珍汕97A、协青早A和Y华农A)对6个单片段代换系、8个双片段聚合系和华粳籼74的恢复力进行测交鉴定,结果表明:(1)6个单片段代换系、8个双片段聚合系和华粳籼74对于4个不育系的恢复力存在显著的不同,携带有Rf3基因座位的单片段代换系的恢复力均低于携带有Rf4基因座位的单片段代换系,并且低于对照品种(华粳籼74);单片段代换系S6对这3种不育细胞质均具有较强的恢复力,单片段代换系S5对珍汕97A(WA)、协青早A(DA)具有较强的恢复力。(2)在华粳籼74的遗传背景下,4个不育系可恢复性存在差异,程度依次为:协青早A>博白A>珍汕97A>Y华农A,即Y华农A的不育性最难恢复,而协青早A的不育性最易恢复。(3)在恢复基因Rf3和Rf4基因座分别鉴定出4个等位基因,由弱到强依次命名为Rf31、Rf32、Rf33、Rf34和Rf41、Rf42、Rf43、Rf44,受体亲本华粳籼74的基因型为Rf34Rf34Rf42Rf42,即华粳籼74携带的Rf3基因的恢复性很强,携带的Rf4基因恢复性却比较弱。(4)携带有较弱恢复性基因(Rf3和Rf4)的单片段代换系聚合为双片段聚合系后恢复力有减小的趋势。本研究结果将为水稻三系的选育和恢复基因的转移奠定基础。     

Growth and Zinc Uptake and Use Efficiency in Food Crops

Zinc (Zn) deficiency in annual crops is very common in Brazilian Oxisols. Data are limited on Zn uptake and use efficiency during crop growth cycles. A field experiment was conducted during two consecutive years with the objective to determine shoot dry weight and Zn uptake and use efficiency in upland rice, dry bean, corn, and soybean during growth cycles. Shoot dry weight of four crops was significantly increased in an exponential quadratic fashion with increasing plant age. Rice and corn had higher shoot dry weights and grain yields than dry bean and soybean. Zinc concentration in rice and corn decreased in a quadratic fashion with increasing plant age. However, in dry bean and soybean, Zn concentration had a quadratic increase. Zinc uptake followed an exponential quadratic response in four crops, and it was higher in corn and upland rice than in dry bean and soybean. Zinc use efficiency in shoot dry‐weight production had significant quadratic responses in upland rice and soybean with increasing plant age. In corn, Zn use efficiency for shoot dry‐weight production was linear as a function of plant age. Zinc use efficiency for grain production was maximum for corn and minimum for soybean. Hence, cereals had higher Zn use efficiency than legumes.

Zinc concentration in grain of dry bean and soybean was higher than in upland rice and corn, which is a desirable quality factor for human consumption so as to avoid Zn deficiency.