施氮量对稻茬麦土壤速效磷质量分数及磷素平衡的影响

以宁麦9号和豫麦34为材料,研究施氮量(0、75、150、225、300kg·hm-2)对土壤速效磷质量分数变化、植株磷素吸收、土壤磷素平衡的影响。结果表明,各处理植株磷素吸收均以拔节至开花期为积累高峰期,且随施氮量增加,磷素吸收呈先增后降的趋势,以N225处理最高。磷肥施用显著提高0~40cm土层速效磷质量分数,随施氮量的增加,土壤速效磷质量分数呈降低趋势。土壤-小麦系统磷素平衡呈明显的阶段性,播种至拔节期磷素出现大量的盈余,拔节至成熟期磷素出现不同程度的表观亏缺。在全生育期,2品种磷素表观盈余量均以N225处理最低,N0处理最高。综合考虑小麦产量和磷素平衡特征,宁麦9号和豫麦34在105kg·hm-2的施磷量基础上可分别再降低P2O5用量7kg·hm-2和10kg·hm-2,配施225kg·hm-2施氮量,能够获得较高的小麦产量并减少磷素损失。     

西北干旱区农田春小麦蒸散量的空间插值方法

综合运用传统统计分析方法和地质统计分析方法,研究了西北旱区春小麦蒸散量在不同生育阶段的时空变异特征,并分析了试验区表层土壤储水量和叶面积指数对春小麦蒸散量的影响关系,通过分析比较,筛选表层土壤储水量为协同因子,并将其应用到试验区春小麦蒸散量的空间插值研究中。研究结果表明:在所研究的条件下,即使外观较为均匀、面积相对较小的农田,春小麦蒸散量仍具有较高的空间变异(变异系数范围0.328~0.495);当降雨入渗深度小于20 cm时,表层土壤储水量(0~20 cm)是影响研究区春小麦蒸散量变异的主要因子,春小麦不同生育期累积蒸散量与表层土壤储水量变化的相关系数在0.8~0.9之间,远大于春小麦累积蒸散量与叶面积指数的相关系数;基于表层土壤储水量的蒸散量协同克里金空间插值分析与地面实测结果相比,仅42个蒸散量地面采样数据即可保证研究区春小麦蒸散量估计精度高于90%。     

不同混合比例对甘薯蔓、酒糟及稻草混合青贮品质的影响

本试验旨在研究不同混合比例对甘薯蔓、酒糟及稻草混合青贮品质的影响。试验设5个组:对照组(鲜甘薯蔓单一青贮)、凋萎组(经2 d自然晾晒处理的甘薯蔓)、40%组(40%鲜甘薯蔓+40%酒糟+20%稻草混贮)、55%组(55%鲜甘薯蔓+25%酒糟+20%稻草混贮)、70%组(70%鲜甘薯蔓+10%酒糟+20%稻草混贮),每个组10个重复,压实密封后室温贮藏60 d,取样分析青贮品质。结果表明:1)甘薯蔓与酒糟和稻草混合以及凋萎处理后青贮均改善了其感官品质;2)与对照组相比,凋萎组干物质、粗蛋白质、乳酸含量极显著增加(P<0.01),氨态氮/总氮、丙酸、丁酸含量及p H极显著降低(P<0.01);3)与对照组和凋萎组相比,3个混贮组干物质、中性洗涤纤维、酸性洗涤纤维、乳酸含量都极显著增加(P<0.01),氨态氮/总氮、粗蛋白质、粗灰分含量及p H极显著降低(P<0.01);4)随着混贮组中甘薯蔓比例的升高,干物质含量极显著降低(P<0.01),粗蛋白质含量显著降低(P<0.05),氨态氮/总氮、丙酸含量极显著增加(P<0.01);5)与青贮前各组原料相比,对照组和凋萎组干物质、粗蛋白质损失较多,40%组损失最少。综上所述,鲜甘薯蔓、酒糟及稻草混合比例为40∶40∶20青贮品质最优。     

酒糟营养成分检测及其酶水解研究

文章测定了采自甘肃世纪金徽酒业集团公的酒糟营养成分,并对其进行了酶水解研究.结果表明：酒糟中蛋白质、淀粉和粗脂肪含量分别为14.03％、13.7％和3.4％,并富含维生素B族,其中维生素B6含量高达0.3 g/kg.矿物质元素钙、镁、锌、铁含量均远远高于其他常见粮食.含有的18种氨基酸中,必需氨基酸占总氨基酸的30.27％,必需氨基酸与非必需氨基酸的比值43.40％.氨基酸比值系数法评价表明,该酒糟中必需氨基酸种类齐全,比值系数分（SRC）63.37,比例均衡.酶解结果表明,蒸汽加热处理（121℃,10 min）后酒糟的酶解效果优于超声波（400 W,15 min）处理,酶添加顺序为先加纤维素酶,后加糖化酶,酶添加量分别为纤维素酶（2 000 U/g纤维素）和糖化酶（1 000 U/g淀粉）,该条件下还原糖含量达49.75 mg/mL.     

中国长江流域冬麦区小麦品种试验精确度回溯分析

为全面评价长江流域小麦品种区域试验精确度的发展水平,分析了2011—2021年度中国长江流域冬麦区单年单点和一年多点小麦区域试验的试验精确度和品种比较精确度,对产量、穗数、穗粒数、千粒重、生育期、株高、基本苗和最高茎数等性状的试验精确度差异进行了比较。结果表明,长江流域冬麦区单年单点品种试验精确度较好,试验误差变异系数(CEV)在5%和10%以下的试点数占比分别在60%和95%以上,但品种比较精确度(RLSD_0.05)在3%以下的试验比例不到10%,长江上游和中下游单点品种试验RLSD_0.05在10%以下的试点数分别占比约60%和90%。一年多点区域试验精确度和品种比较精确度显著优于单年单点试验,上游和中下游试验平均CEV分别在8%和5%以下。采用试点固定模型时,长江上游和中下游试验平均RLSD_0.05分别为2.19%和1.49%,符合国家小麦品种审定标准对品种比较精确度的要求;但采用试点随机模型时,小麦品种试验尚无法鉴别出品种间3%的产量差异。试验对生育期、株高、基本苗、千粒重和穗数的RLSD_0.05优于产量性状,而最高茎数和穗粒数的RLSD_0.05较低。     

2019-2023年度陕西省科企联合体小麦区试品种抗病性鉴定与评价

为掌握陕西省科企联合体小麦区试品种抗病性水平,对2019—2023年度连续5年参加联合体区试的114份品种,采用大田人工接种的方法进行小麦条锈病、白粉病、赤霉病、叶锈病和纹枯病等5种病害的抗性鉴定与评价。结果表明,供试的114份品种对鉴定的5种病害抗性程度差异较大,表现为对条锈病抗性水平较高,对白粉病和赤霉病抗性水平最差。供试品种中,对条锈病表现免疫-中抗的品种61份,占供试品种的53.51%;对白粉病表现免疫-中抗的品种27份,占供试品种的23.68%;对赤霉病表现抗-中抗的品种21份,占供试品种的18.42%;同时鉴定出2份对5种病害均表现抗病的品种,分别为西农968和金麦207。对21份高感条锈病的品种均按陕西省区试品种试验要求终止了试验。     

Amino acid digestibility of heat damaged distillers dried grains with solubles fed to pigs

The primary objective of this experiment was to determine the effects of heat treatment on the standardized ileal digestibility(SID) of amino acids(AA) in corn distillers dried grains with solubles(DDGS) fed to growing pigs. The second objective was to develop regression equations that may be used to predict the concentration of SID AA in corn DDGS. A source of corn DDGS was divided into 4 batches that were either not autoclaved or autoclaved at130°C for 10, 20, or 30 min. Four diets containing DDGS from each of the 4 batches were formulated with DDGS being the only source of AA and CP in the diets. A N-free diet also was formulated and used to determine the basal endogenous losses of CP and AA. Ten growing pigs(initial BW: 53.5 ± 3.9 kg) were surgically equipped with a T-cannula in the distal ileum and allotted to a replicated 5 × 4 Youden square design with 5 diets and 4 periods in each square. The SID of CP decreased linearly(P 0.05) from 77.9% in non-autoclaved DDGS to 72.1, 66.1, and 68.5% in the DDGS samples that were autoclaved for 10, 20, or 30 min, respectively. The SID of lysine was quadratically reduced(P 0.05) from 66.8% in the non-autoclaved DDGS to 54.9, 55.3, and 51.9% in the DDGS autoclaved for 10, 20, or30 min, respectively. The concentrations of SID Arginine, Histidine, Leucine, Lysine, Methionine, Phenylalanine, or Threonine may be best predicted by equations that include the concentration of acid detergent insoluble N in the model(r2= 0.76, 0.68, 0.67, 0.84, 0.76, 0.73, or 0.54, respectively). The concentrations of SID Isoleucine and Valine were predicted(r2= 0.58 and 0.54, respectively) by the Lysine:CP ratio, whereas the concentration of SID Tryptophan was predicted(r2= 0.70) by the analyzed concentration of Tryptophan in DDGS. In conclusion, the SID of AA is decreased as a result of heat damage and the concentration of SID AA in heat-damaged DDGS may be predicted by regression equations developed in this experiment.     

Genetic resistance to and effect of leaf rust and powdery mildew on yield and its components in 50 soft red winter wheat cultivars

Effects of leaf rust (caused by Puccinia triticina f. sp. tritici Eriks.) and powdery mildew [caused by Blumeria graminis (DC.) E. O. Speer f. sp. tritici Em. Marchal], on performance of 50 soft red winter (SRW) wheat (Triticum aestivum L) cultivars were evaluated under natural field conditions. Widely grown cultivars released from 1919 to 2009 with varying disease resistance were grown in split-plot experiments in 2010 and 2011. Treated replications received seed treatments of triadimenol, captan and imidacloprid and foliar applications of propiconazole and prothioconazole + tebucanazole fungicides. Non-treated replications received only tebucanazole + metalaxyl + imazalil seed treatments. Final mean disease severity, agronomic, yield-related traits, yield components and spike characteristics were analyzed to determine individual and combined effects of leaf rust and powdery mildew on the cultivars. Yield losses as high as 54% were observed in the susceptible cultivar Red May. Average yield losses ranged from 1% to 21%. Yield losses primarily due to powdery mildew were as high as 14%, and losses primarily due to leaf rust were as high as 33%. Powdery mildew had the largest negative correlation with harvest index and seeds/spike. Leaf rust was most negatively correlated with plant biomass and harvest index, with a less consistent negative relationship with kernel weight.     

Temperature variations during grain filling obtained in growth tunnel experiments and its influence on protein content,polymer build-up and gluten viscoelastic properties in wheat

The aim of this study was to investigate effects of temperature during grain filling on gluten quality characteristics at a lower to moderate temperature range. Experiments with two wheat varieties grown in field covered by polypropylene tunnels during grain filling were performed in two seasons. Mean day temperature differences achieved within the tunnel were approximately 2–2.5 °C from the open to the closed end. There were significant effects of temperature on grain maturity time, thousand grain weight and protein content. The resistance to stretching of the gluten doughs increased with the increasing day temperatures. This was reflected in the proportion of unextractable polymeric proteins (UPP). The results suggest that increases in temperature within this temperature range affect the polymerization of polymeric proteins, giving higher molecular weights, and hence increased Rmax and stronger gluten. The two varieties differed in their response to temperature. In addition, there were seasonal variations in gluten functionality that may be associated with fluctuations in day temperatures between the seasons.     

Manufacture and characterization of pasta made with wheat flour rendered gluten-free using fungal proteases and selected sourdough lactic acid bacteria

Wheat flour, which was rendered gluten-free by sourdough lactic acid bacteria fermentation and fungal proteases, was used for manufacturing experimental gluten-free pasta (E-GFp), according to a traditional process with low temperature drying cycle. Chemical, technological, structural, nutritional and sensory features were characterized and compared with those of commercial gluten-free (C-GFp) and durum wheat pasta (C-DWp). As shown through immunological analyses, the residual concentration of gluten of the hydrolyzed wheat flour was below 10 ppm. E-GFp showed rapid water uptake and shorter optimal cooking time compared to the other pastas. Despite the absence of the gluten network, the supplementation with pre-gelatinized rice flour allowed structural properties of E-GFp, which were comparable to those of C-GFp. The in vitro protein digestibility of E-GFp resulted the highest. Probably due to proteolysis during sourdough fermentation; chemical scores, essential amino acid profile, biological value and nutritional index of E-GFp were higher than those of C-DWp. The hydrolysis index (HI) of E-GFp was ca. 30% lower than that found for C-GFp. As shown by sensory analysis, the characteristic of E-GFp were acceptable. The manufacture of E-GFp should be promising to expand the choice of gluten-free foods, which combine sensory and nutritional properties.