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.     

GENETICALLY MODIFIED AND CONVENTIONAL DRY BEAN GENOTYPE RESPONSES TO SOIL FERTILITY

Dry bean is important pulse for the diet of South American population and results related to comparison of genetically modified and conventional dry bean genotypes to soil fertility are limited. A greenhouse experiment was conducted to compare genetically modified and conventional dry bean genotypes to soil fertility. Genotypes evaluated were Olathe Pinto, Olathe 5.1 (genetically modified), BRS Pontal, BRS Pontal 5.1 (genetically modified), Pérola and Pérola 5.1 (genetically modified). Fertility levels were 1 g fertilizer (5-30-15) kg^?1 soil (low fertility level) and 2 g fertilizer (5-30-15) per kg soil (high fertility level). These fertility levels were designated as low and high, respectively. Grain yield, number of pods per plants, and seed per pod were significantly increased with the increase in soil fertility. Shoot dry weight, seed per pod, and 100 seed weight were also significantly influenced by genotype treatment. Fertility X genotypes interaction was significant for maximum root length and root dry weight, indicating genotypes responded differently at two fertility levels in relations to these two traits. Shoot dry weight, number of pods per plant, and grain harvest index had significant association with grain yield, indicating that increase in these three traits grain yield can be increased. Grain yield efficiency index (GYEI) was having significant linear association with grain yield. Hence, on the basis of GYEI, genotypes were classified as efficient (E), moderately efficient (ME), and inefficient in nutrient use. Three conventional genotypes (Olathe Pinto, BRS Pontal and Pérola) and one genetically modified genotype (Olathe Pinto 5.1) were classified as moderately efficient and two genetically modified genotypes (Pérola 5.1 and BRS Pontal 5.1) were classified as efficient. None of the genotypes fall into the inefficient group.     

Yield and Yield Components of Dry Bean Genotypes as Influenced by Phosphorus Fertilization

Dry bean is an important legume for South American population, and phosphorus (P) deficiency is the most yield-limiting nutrient for crop production in South American soils. A greenhouse experiment was conducted with the objective of evaluating influence of P fertilization on grain yield and yield components of 30 dry bean genotypes. The P levels used were 0 mg P kg^?1 (natural level of the soil) and 200 mg P kg^?1 applied with triple superphosphate fertilizer. Yield and yield components were significantly influenced with P as well as genotype treatments. The P?×?genotype interactions were significant for yield as well as yield components, indicating different responses of genotypes at two P levels. Root dry weight and maximum root length were also significantly increased with the addition of P fertilization. There were also significant differences among the genotypes in the growth of root system. Based on grain yield efficiency index (GYEI), genotypes were classified as P efficient, moderately efficient, and inefficient. Among 30 genotypes, 17 were classified as efficient, 12 were classified as moderately efficient, and 1 was classified as inefficient. Yield components such as pods per plant and seeds per pod were having significant positive association with grain yield. In addition, grain harvest index (GHI) was also having significant linear association with grain yield. Hence, it is possible to improve grain yield of dry bean in Brazilian Oxisol with the addition of adequate rate of P fertilization as well as use of P-efficient genotypes.     

Agronomic Evaluation of Dry Bean Genotypes for Potassium Use Efficiency

Dry bean is an important legume worldwide, and potassium (K) deficiency is one of the important constraints for bean production in most of the bean growing regions. A greenhouse experiment was conducted with the objective to evaluate fifteen dry bean genotypes grown on a Brazilian lowland (Inceptisol) United States Soil Taxonomy classification and Gley humic Brazilian Soil Classification system), locally known as “Varzea” soil. The K rate used was 0 mg kg^?1 (low, natural soil level) and 200 mg kg^?1 (high, applied as fertilizer). Straw yield, seed yield, pods per plant, seeds per pod, 100 seed weight, and seed harvest index were significantly increased with the addition of K fertilizer. These traits were also significantly influenced by genotypic treatment. Similarly, root length and root dry weight were also influenced significantly by K and genotype treatments. The K X genotype interactions for most of these traits were also significant, indicating variation in these traits with the variation in K level. Based on seed yield efficiency index (SYEI), genotypes were classified as efficient, moderately efficient, and inefficient in K use efficiency. Maximum grain yield was obtained with 74 mg K kg^?1 extracted by Mehlich 1 extracting solution. Similarly, K saturation required for maximum grain yield was 1.1%.     

播期对高蛋白大豆新品种(系)农艺性状、品质及产量的影响

为明确高蛋白大豆新品种(系)在黄淮海区的适宜播期,本研究以黄淮海地区高蛋白大豆新品种(系)圣豆18、圣豆24、菏豆37、菏豆38为试验材料,设置不同播期试验,研究不同播期对各大豆品种(系)生育期、农艺性状、干物质积累、籽粒品质及产量的影响。结果表明,播期推迟,出苗至始花期缩短幅度较大,大豆全生育期缩短;大豆株高、底荚高、主茎节数随播期推迟均逐渐降低;各大豆品种植株有效分枝、有效荚数、单株粒数、单株粒重、百粒重、根干重、茎干重、豆荚干重、植株总干重、籽粒蛋白质和脂肪含量以及产量均随着播期推迟呈先升后降的趋势,且随着播期推迟,豆荚干重变化幅度较大,根、茎干重所占比例均逐渐缩小,豆荚干重所占比例均逐渐增大;播期对籽粒蛋白质和脂肪含量、产量的影响均占主导地位;圣豆18、圣豆24、菏豆37、菏豆38均在6月15日播种时产量最高,分别为3 940.95、3 750.24、 3 252.37、3 905.54 kg·hm^-2,且单株粒重与产量相关性最大。综上可知,只有适期播种,大豆营养生长和生殖生长才能实现合理过渡,促使植株生长、干物质积累及分配等达到最佳状态,从而保证大豆优质高产,进而推动大豆及高蛋白大豆产业发展。     

Nutrient Uptake in Dry Bean Genotypes

Dry bean is an important legume for human consumption in South America. A greenhouse experiment was conducted to evaluate uptake and use efficiency of macro- and micronutrients by six dry bean genotypes at two P levels (25 and 200 mg kg^?1 soil). Shoot dry weight and grain yield varied significantly among genotypes and significantly increased with increasing phosphorus (P) levels. Grain harvest index (GHI) and 100-grain weight also differ significantly among genotypes and significantly increased with the increasing P levels. Based on grain yield efficiency index (GYEI), genotypes were classified as efficient and inefficient. The most efficient genotype was CNFP 10104, and inefficient genotypes were CNFP 10103 and CNFP 10120. Number of pods per plant and number of seeds per pod increased significantly with the addition of 200 mg P kg^?1 of soil compared to the low level of P (25 mg P kg^?1). Similarly, nitrogen (N), P, calcium (Ca), magnesium (Mg), sulfur (S), zinc (Zn), copper (Cu), and manganese (Mn) concentrations and uptake in the shoot and grain also significantly varied among genotypes. Uptake of macro- and micronutrients was greater under the greater P rate compared to the low P rate. This may be related to greater shoot or grain yield at 200 mg P kg^?1 soil compared to 25 mg P kg^?1 of soil.     

DYNAMICS OF FABA BEAN GROWTH AND NUTRIENT UPTAKE AND THEIR CORRELATION WITH GRAIN YIELD

Growth parameters and nutrient uptake of faba bean with 12 different genotypes were studied at the end of four subsequent growth periods, viz. first vegetative (V1), second vegetative (V2), first reproductive (R1) and second reproductive (R2) periods for two years and correlated with final grain yield. All parameters including plant height, leaf number, leaf area index (LAI), above ground plant dry matter (DM) and root DM, nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg) uptake and concentration of N, P, K, Ca, and Mg showed different patterns with advancement of the growth period. All the mentioned parameters were fitted in either quadratic or linear equations. Significant correlations were found among nutrients, growth parameters and grain yield during different growth stages. On the basis of these experiments it was clear that nutrient uptake was directly related to biomass. In V2 and R1 biomass production was greatest resulting in high nutrient uptake. Among the growth parameters, biomass and LAI showed the highest significant correlation with grain yield. The findings especially models derived from two year data across twelve genotypes can be used for better fertilizer management of faba bean.     

Optimum Soil Acidity Indices for Dry Bean Production on an Oxisol in No‐Tillage System

Abstract

Soil acidity is one of the major yield constraints to crop production in various parts of the world. Quantifying optimum soil acidity indices is an important strategy for achieving maximum economic crop yields on acid soils. Five field experiments were conducted for three consecutive years using dry bean as a test crop on an Oxisol. The lime rates used were 0, 12, and 24 Mg ha^?1 for creating a wide range of soil acidity indices in a no‐tillage cropping system. Grain yield of dry bean was significantly increased by improving soil pH, base saturation, calcium (Ca), magnesium (Mg), and potassium (K) saturation and reducing aluminum (Al) saturation. These soil acidity indices were higher in the 0‐ to 10‐cm soil layer than the 10‐ to 20‐cm soil layer for maximum grain yield. Across two soil depths, optimum values for maximum bean yield were pH 6.5, base saturation 67%, Ca saturation 48%, and Mg saturation 19%. Bean yield linearly increased with increasing K saturation in the range of 1.5 to 3% across two soil depths. There was a significant linear decrease in grain yield with increasing Al saturation in the range of 0 to 8% across two soil depths. Optimal values of soil indices for maximum bean yield can be used as a reference for liming and improving yield of bean crop on Oxisols in a no‐tillage cropping system. Yield components, such as pod number, grain per pod, and 100‐grain weight were significantly improved with liming, and bean yield was significantly associated with these yield components.     

PHOSPHORUS UPTAKE AND USE EFFICIENCY IN FIELD CROPS

Phosphorus (P) is required by crop plants for many physiological and biochemical functions. Knowledge of phosphorus uptake and its use by crop plants is essential for adequate management of this essential nutrient. A field experiment was conducted during four consecutive years to determine P uptake and use efficiency by upland rice, dry bean, corn and soybean grown in rotation on a Brazilian Oxisol. Plant samples were taken at different growth stages during the growth cycle of each crop for phosphorus analysis. Phosphorus concentration (content per unit dry matter) significantly decreased in a quadratic fashion with the advancement of plant age in four crop species. Phosphorus concentration was higher in legumes compared to cereals. Phosphorus uptake in shoot, however, significantly increased in an exponential quadratic fashion with the advancement of plant age of crop species. At harvest, P uptake was higher in grain compared to shoot, indicating importance of this element in improving crop yields. Phosphorus use efficiency (grain or straw yield per unit P uptake) was higher in cereals compared to legumes. The P use efficiency for grain production was 465 kg kg^?1 for upland rice, 492 kg kg^?1 for corn, 229 kg kg^?1 for dry bean and 280 kg kg^?1 for soybean. The higher P use efficiency in cereals was associated with higher yield of cereals compared to legume species.     

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.     

红芸豆养分限制因子及养分吸收、积累和分配特征研究

研究红芸豆养分限制因子、植株干物质和氮、磷、钾养分积累及分配规律,可为红芸豆合理施肥及高产栽培提供理论依据。大田试验条件下,以‘英国红’红芸豆为试材,设置缺素试验,采集全施肥区植株样品,分析研究红芸豆不同生育时期各器官干物质量、养分含量及积累量。结果显示,氮磷钾配合全施显著提高红芸豆产量;缺氮、缺磷、缺钾处理与全施肥处理相比,产量分别降低14.2%、8.0%和11.3%,表明影响红芸豆产量的限制因子为氮钾磷。在整个生育期,红芸豆干物质累积速率先升高后降低;根、茎、荚皮和豆粒干物质累积量呈上升趋势,叶干物质在收获期有下降趋势,收获时不同部位干物质量为豆粒茎≈荚皮叶片根。随生育期推进,茎、叶和荚皮中氮含量呈递减趋势,豆粒中氮含量呈递增趋势,而各器官磷、钾含量呈递减趋势。盛花期到结荚期是养分累积最大期,其氮、磷、钾吸收量分别占整个生育期吸收总量的28.14%、49.22%和56.20%;不同器官吸收累积氮、磷、钾量不同,成熟期豆粒、叶、茎和根中均为累积氮最多、钾次之、磷最少,荚皮中累积钾最多、氮次之、磷最少。每生产100 kg红芸豆需供给N 4.37 kg、P2O5 2.38 kg、K2O 3.53 kg,比例为1∶0.54∶0.81。     

Influence of Nitrogen on Growth,Yield, and Yield Components and Nitrogen Uptake and Use Efficiency in Dry Bean Genotypes

Dry bean is an important legume and nitrogen (N) deficiency is one of the most yield-limiting factors in most of the bean-growing regions. A greenhouse experiment was conducted with the objective to determine influence of N on growth, yield, and yield components and N uptake and use efficiency of 23 dry bean genotypes. Straw yield, grain yield, yield components, maximum root length, and root dry weight were significantly increased with the addition of N but varied with genotypes. The N × genotype interactions were also significant for most of these traits, indicating variation in responses of genotypes with the variation in N levels. There was significant difference in N uptake and use efficiency among genotypes. Most of growth and yield components were significantly and positively associated with grain yield. Based on grain yield efficiency index (GYEI), genotypes were classified into efficient, moderately efficient, or inefficient group in N-use efficiency. Nitrogen concentration was greater in grain compared to straw, indicating greater N requirement of dry bean genotypes.     

Genotypic Differences in Dry Bean Yield and Yield Components as Influenced by Nitrogen Fertilization and Rhizobia

Dry bean (Phaseolus vulgaris L.) is an important legume worldwide and nitrogen (N) is most yield limiting nutrients. A field experiment was conducted for two consecutive years to evaluate response of 15 dry bean genotypes to nitrogen and rhizobial inoculation. The N and rhizobia treatments were (i) control (0 kg N ha^?1), (ii) seed inoculation with rhizobia strains, (iii) seed inoculation with rhizobia strains + 50 kg N ha^?1, and (iv) 120 kg N ha^?1. Straw yield, grain yield, and yield components were significantly influenced by N and rhizobial treatments. Grain yield, straw yield, number of pods m^?2, and grain harvest index were significantly influenced by year, nitrogen + rhizobium, and genotype treatments. Year × Nitrogen + rhizobium × genotype interactions were also significant for these traits. Hence, these traits varied among genotypes with the variation in year and nitrogen + rhizobium treatments. Inoculation with rhizobium alone did not produce maximum yield and fertilizer N is required in combination with inoculation. Based on grain yield efficiency index, genotypes were classified as efficient, moderately efficient, and inefficient in nitrogen use efficiency (NUE). NUE defined as grain produced per unit N applied decreased with increasing N rate. Overall, NUE was 23.17 kg grain yield kg^?1 N applied at 50 kg N ha^?1 and 13.33 kg grain per kg N applied at 120 kg N ha^?1.     

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.     

Response of Soybean to Phosphorus Fertilization in Brazilian Oxisol

Soybean is an important grain crop for Brazil, and phosphorus (P) plays an important role in improving yield of this crop in Brazilian Oxisols. Data are limited on influence of P sources and rate on soybean yield, yield components, and P-use efficiency. A field experiment was conducted for 3 consecutive years to determine response of soybean to three fertilizers (single superphosphate, Yoorin, and Arad) with 0, 17.5, 35, and 52.5 kg P ha^?1 (0, 40, 80 and 120 kg P₂O₅ ha^?1). Grain yield was significantly influenced by phosphorus fertilization. Overall, maximum grain yield was produced by application of single superphosphate, followed by Yoorin and Arad. Number of grains per pod and 100-grain weights were also influenced significantly by P fertilization. Shoot dry weight, number of pods per plant, and grain harvest index had a significant positive association with grain yield. Phosphorus uptake in grain was about six times more than uptake in shoots, and P uptake in grain had a significant positive association with grain yield. Phosphorus-use efficiency (kg grain/kg P applied or uptake) decreased with increasing P rate, and it was greater for single superphosphate than for Yoorin and Arad sources of P fertilization. However, P-utilization efficiency (kg grain plus straw yield / P uptake in grain plus straw) was greater under Yoorin treatment compared to the two other sources of P.     

Growth,Nutrient Uptake,and Use Efficiency in Dry Bean in Tropical Upland Soil

Dry bean (Phaseolus vulgaris L., cv. ‘BRS Requinte’) is an important legume crop and nutrient availability is one of the most yields limiting factors for bean production in tropical upland soils. A greenhouse experiment was conducted in Brazilian Oxisol to study growth, nutrient uptake, and use efficiency of macro- and micronutrients during growth cycle of bean plant. Plants were harvested at 15, 30, 45, 60, 73, and 99 days after sowing for determination of growth parameters and uptake of nutrients. Root dry weight, shoot dry weight and leaf trifoliate increased significantly (P< 0.01) in a quadratic fashion with the advancement of plant age. However, root-shoot ratio decreased significantly with increasing plant age. Concentrations of nitrogen (N), calcium (Ca), magnesium (Mg), and zinc (Zn) decreased with the advancement of plant age. However, concentrations of phosphorus (P), potassium (K), copper (Cu), and manganese (Mn) increased significantly with the advancement of plant age. Accumulation of macro- and micronutrients significantly increased with the increasing plant age. Accumulation of N, P, K and Cu was higher in the grain compared with root and shoot, indicating relatively higher importance of these nutrients in improving grain yield of dry bean. Nitrogen, P and Cu use efficiency was higher for shoot weight compared to grain weight. For grain production, nutrient use efficiency was in the order of Mg > Ca > P > K > N for macronutrients and Cu > Zn = Mn for micronutrients.     

NITROGEN HARVEST INDEX AND ITS ASSOCIATION WITH CROP YIELDS

Nitrogen (N) is one of the most yield-limiting nutrients in crop production around the world. The main reasons of N deficiency are low recovery efficiency (RE) of applied N fertilizers. The RE efficiency of N by most crop plants is lower than 50%. The lower RE of this element is associated with losses by volatilization, leaching, denitrification, and soil erosion. Some part of N is also immobilized in undecomposed organic materials and by soil microbial population. Nitrogen harvest index (NHI) is a ratio between N accumulated in grain to N accumulated in grain plus straw. The NHI is an important index in determining crop yields because it is positively associated with grain yield. Relationship between GHI and crop grain yield may be positive linear or quadratic depending on crop genotypes and soil and crop management practices adopted. In cereals retranslocation of previously assimilated N in the vegetative parts is the predominant source of N for the grain. The most important practices that can improve NHI are liming acid soils, use of adequate N rates, source and timing, planting N efficient crop species or genotypes within species, and use of appropriate crop rotation.     

Spectral assessments of phenotypic differences in spike development during grain filling affected by varying N supply in wheat

Single plant traits such as green biomass, spike dry weight, biomass, and nitrogen (N) transfer to grains are important traits for final grain yield. However, methods to assess these traits are laborious and expensive. Spectral reflectance measurements allow researchers to assess cultivar differences of yield‐related plant traits and translocation parameters that are affected by varying amounts of available N. In a field experiment, six high‐yielding wheat cultivars were grown with N supplies of 0, 100, 160, and 220 kg N ha^–1. Wheat canopies were observed spectrally throughout the grain‐filling period, and three spectral parameters were calculated. To describe the development of the vegetative plant parts (leaves + culms) and the spikes, plants were sampled four times during grain filling. Dry weights and the relative dry‐matter content were recorded for leaves + culms and spikes. The N status of the plants was assessed by measuring the total N concentration and by calculating the aboveground N uptake. Good correlations were found between spectral indices and single plant traits throughout grain filling but varied with N supply and development stage. The normalized difference vegetation index, NDVI, was strongly affected by the saturation effects of increased N concentration. The red‐edge inflection point, REIP, predicted plant traits with r² values up to 0.98. However, in plants with advanced senescence, the REIP was less efficient in describing plant traits. The NIR‐based index R₇₆₀/R₇₃₀ was closely related to yield‐related plant traits at early grain filling. Compared to the REIP, the R₇₆₀/R₇₃₀ index was resistant to strong chlorophyll decays being able to predict plant traits at late grain filling, with r² values of up to 0.92. Spectral reflectance measurements may represent a promising tool to assess phenotypic differences in yield‐related plant traits during grain filling.     

Nitrogen relations in winter wheat cultivars differing in grain protein percentage and stature

Accumulation of reduced nitrogen and its partitioning between vegetative tissue and grain are two important aspects of the nitrogen economy of wheat (Triticum aestivum L.). The objectives of this study were to 1) determine the range of nitrogen harvest index (NHI) among four hard red winter wheat cultivars differing in grain protein percent (GPP) and the influence of NHI on grain protein percent, and 2) to contrast the partitioning of nitrogen and dry matter to the component parts of the plant throughout growth and development. Plants were grown in a nutrient solution and nitrogen salts were withheld from the solution when the wheat reached anthesis. High nitrogen percentage of plant parts tended to correlate positively with grain protein percentage at first node and anthesis stages, but correlated negatively at latter stages. Dry weight was important in the accumulation of nitrogen; however, neither dry weight nor total plant nitrogen was correlated with GPP. Nitrogen harvest index was correlated strongly and positively with GPP and was independent of plant stature. The selection of parents with high NHI could be an important criterion in breeding programs to increase GPP of wheat.     

不同产量水平小麦的氮吸收利用差异

在土培盆栽条件下,以130份小麦为材料,测定了不同生育时期小麦的干物质量、氮素含量和籽粒产量,将供试品种按籽粒产量由低到高低依次分为I、II、III、IV、V、VI等6类型,研究了各类型氮素吸收利用的差异。结果表明：（1）供试品种籽粒产量差异较大（CV=3316%）,氮素籽粒生产效率随籽粒产量水平提高呈增加的趋势(r=02740**),提高氮素吸收量和籽粒氮素利用效率均可提高籽粒产量。（2）不同生育时期,不同籽粒产量水平类型小麦植株含氮量存在显著或极显著差异,但与籽粒产量的相关性不密切。抽穗期和成熟期植株吸氮量与籽粒产量极显著相关(r=02890**、09175**)。（3）不同生育时期氮素干物质生产效率在类型间的差异均达到显著水平,但其与籽粒产量相关性不显著。提高氮素收获指数和拔节期氮素干物质生产效率均可提高籽粒产量。（4）拔节期-成熟期不同类型间小麦干物质量随籽粒产量的增加而增加,成熟期表现尤为突出。籽粒产量水平较高的品种在拔节期后有较强干物质和籽粒产量形成能力。（5）氮素吸收量和氮素籽粒生产效率是影响籽粒产量的重要因素。