村规民约对牧民减畜决策行为的影响

牧民的减畜行为在草原退化过程中起着关键的作用。村规民约作为一种基层自治方式,在一定程度上,对实现草原环境治理的制度化和法制化具有积极作用。因此,本研究通过探讨村规民约对牧民减畜决策行为的影响,以期从非正式制度视角,提出控制牧民超载过牧行为的政策建议。本研究在对村规民约对牧民草原保护决策行为影响机制进行分析的基础上,以内蒙古和新疆193户牧民的实地调研数据为依据,运用Double-Hurdle模型,实证分析村规民约对牧民草原生态保护决策行为的影响。研究发现,以书面形式制定,且近5年内容未发生变化的村规民约,可显著提高牧民的减畜意愿;宗教信仰对牧民的减畜意愿有显著的制约作用;汉语水平越好的牧民,其减畜意愿越高。本研究认为村规民约对其生产生活影响程度越高的牧民,其减畜比例越高;牧民的受教育水平和家庭收入水平与其减畜比例均显著负相关。因此,重视村规民约制定形式的规范性和内容的稳定性,提高牧民对村规民约的遵守程度和认可程度,定期开展牧民汉语培训工作,提高牧民的汉语水平等方式对引导牧民做出有利于保护草原生态的决策行为有积极作用。     

Production of mutants with high cold tolerance in spring canola (<Emphasis Type="Italic">Brassica napus</Emphasis>)

A major factor affecting spring canola (Brassica napus) production in Canada is killing frosts during seedling development in the spring and seed maturation in the fall. The objective of this study was to explore the possibility of producing spring canola lines with mutations that have altered biochemical pathways that increase cold tolerance. The approach was to generate UV point mutations in cultured microspores followed by chemical in vitro selection of individual mutant microspores or embryos resulting in measurable alterations to various biochemical pathways with elevated levels of key defense signaling molecules such as, salicylic acid (SA), p-Fluoro-d,l-Phenyl Alanine (FPA), and jasmonic acid (JA). In addition, since proline (Pro) is known to protect plant tissues in the cold-induced osmotic stress pathway, mutants that overproduce Pro were selected in vitro by using three Pro analogues: hydroxyproline (HP), azetidine-2-carboxylate (A2C); and, 3,4-dehydro-d,l-proline (DP). Of the 329 in vitro selected mutant embryos produced, 74 were identified with significant cold tolerance compared to their donor parents through indoor freezer tests at −6°C, and 19 had better winter field survival than winter canola checks. All chemically selected mutant doubled haploids with increased cold tolerance compared well with parent lines for all seed quality and agronomic parameters. Development of increased frost tolerant cultivars should allow for spring canola to be produced in western Canada without compromising seed quality.     

A rapid extensigraph protocol for measuring dough viscoelasticity and mixing requirement

The extensigraph is particularly useful in characterizing dough viscoelastic properties; however, testing throughput for standard method is low due to the prerequisite for farinograph water absorption, long dough resting and milling to prepare large amounts of flour. Therefore, a rapid extensigraph method was developed that reduced sample size (165 g wheat) for milling and more than tripled throughput. Wheat is milled in Quadrumat Junior mill with a modified sieving system. The resulting flour (100 g) was mixed with a pin mixer at constant water absorption to allow the evaluation of wheat genotypes at the absorption level they are expected to perform. Dough was subsequently stretched by an extensigraph after 15 min of floor time and 30 min resting. Strong correlations for extensigram R_max (r > 0.93), extensibility (r > 0.64) and area (r > 0.88) were found for the proposed method compared to the standard method. Mixing parameters (time and energy) obtained during dough preparation provided further information about dough strength and mixing requirement. By significantly reducing sample size requirement and increasing testing throughput, this rapid extensigraph method can be widely adopted in milling and baking industry and meets the need for a fast evaluation of dough strength in breeding trials.     

低温播种对春玉米出苗及苗期生理参数的影响

以金产5号为试验材料,在培养箱中进行盆栽模拟试验,设定5℃、7℃、9℃、11℃4个播种温度处理,测定出苗率和3叶期相关生理参数,研究金产5号最适播种温度。结果表明,5℃~9℃播种春玉米能够出苗,5℃播种出苗率偏低(86.42%),7℃~9℃播种出苗较好(89.38%~96.88%)。5℃、7℃、9℃处理的植株脯氨酸含量和还原糖含量显著高于11℃处理;5℃处理PEPC活性高于7℃、9℃、11℃处理;5℃、7℃处理的过氧化物酶活性显著高于9℃、11℃处理,可溶性蛋白含量随播种温度的降低而降低,说明土壤温度在7℃以上是金产5最适播种温度。     

利用隶属函数值法对玉米成熟期抗旱性的综合评价

以10个不同基因型玉米为试验材料,在宁夏中部干旱带,通过测定不同品种成熟期的K~+/Na~+、光合气体交换参数、农艺性状及产量性状等指标进行抗旱性鉴定,并利用主成分分析和隶属函数法对其抗旱性强弱进行综合评价。结果表明,干旱胁迫地和对照田中,各参试品种的光合特征参数、K~+/Na~+及形态性状等均有明显差异,且干旱胁迫条件下的净光合速率(P_n)、株高、产量均显著低于对照(P0.05)。同一品种不同器官的K~+/Na~+值表现为茎基茎叶根,表明植株体内的离子吸收和运输具有选择性,茎基具有贮存K~+的作用,根具有贮存Na~+的功能。不同基因型玉米品种的抗旱能力根据综合评价值(D值)大小,综合评价其抗旱性强弱顺序为A111-3/H242HoViY1北21/A58A3/A18高WY2宁3/1522H237/A18桂青贮1号H237/1506A3/A18。     

吉林省玉米推荐施肥指标体系的建立

通过总结2004~2014年间课题组在吉林省开展的田间试验及2005~2013年吉林省玉米"3414"田间肥效和校验试验资料,按土壤养分(播前耕层土壤硝态氮、速效磷、速效钾及10叶期0~90 cm土层土壤硝态氮)含量对土壤进行分级,进一步结合目标产量,初步建立以根层硝态氮调控为核心的总量控制、分期实时实地精确监控的玉米氮肥推荐施肥指标体系以及基于养分平衡和土壤测试的磷、钾肥恒量监控推荐施肥指标体系,为吉林省玉米合理科学施肥提供一定参考。     

缓释型玉米专用肥不同氮源配比对玉米生长的影响

以春玉米大丰30和缓效氮源硫包膜尿素为试材,采取盆栽方式,设不施氮为对照,研究缓效氮不同添加比例下缓效氮的释放速率,春玉米干物质积累量、吸氮量、氮素利用率及产量,土壤p H值的动态变化。结果表明,配施缓效氮能有效提高玉米对氮素的利用,增加产量。随着缓效氮添加比例增加,玉米干物质积累量、吸氮量及产量均呈先增加后减少的趋势,其中添加33%缓效氮处理为最优处理。添加33%缓效氮处理中缓效氮累积释放率和玉米对氮素的吸收规律更加吻合,与普通尿素处理相比,产量增加73.83%,成熟期玉米地上部吸氮量和干物质积累量分别增加15.40%和20.10%,地下部吸氮量和干物质重分别增加21.11%和13.09%。配施缓效氮显著提高玉米氮素利用率,缓效氮添加比例为33%和50%处理分别比普通尿素处理提高14.76%和12.46%。     

An economically based evaluation index for perennial and short‐term ryegrasses in New Zealand dairy farm systems

Grazed pastures based on ryegrass species provide most of the feed for dairy cattle in New Zealand. There are many cultivars of perennial (Lolium perenne), annual and Italian (L. multiflorum), and hybrid (L. boucheanum) ryegrasses available for dairy farmers to use in pasture renewal. This study describes an index which ranks ryegrass cultivars relative to a genetic base according to the estimated economic value (EV) of seasonal dry matter (DM) traits. A farm system model was used to derive EVs (Grazed pastures based on ryegrass species provide most of the feed for dairy cattle in New Zealand. There are many cultivars of perennial (Lolium perenne), annual and Italian (L. multiflorum), and hybrid (L. boucheanum) ryegrasses available for dairy farmers to use in pasture renewal. This study describes an index which ranks ryegrass cultivars relative to a genetic base according to the estimated economic value (EV) of seasonal dry matter (DM) traits. A farm system model was used to derive EVs ($ ha^?1 calculated as change in operating profit divided by unit change of the trait) for additional DM produced in different seasons of the year in four regions. The EV of early spring DM was consistently high across all regions, whereas EV for late spring DM was moderate to low. Genotype × environment analysis revealed significant reranking of DM yield among ryegrass cultivars across regions. Hence, separate performance values (PVs) were calculated for two mega‐environments and then combined with the corresponding season and region EV to calculate the overall EV for twenty‐three perennial ryegrass and fifteen short‐term ryegrass cultivars. The difference in operating profit between the highest ranked and lowest ranked perennial ryegrass cultivar ranged from $556 ha^?1 to $863 ha^?1 year^?1 depending on region. For short‐term ryegrasses used for winter feed, the corresponding range was $394 to $478 ha^?1 year^?1. Using PV for DM yield, it was estimated that plant improvement in perennial ryegrass has added $12–$18 ha^?1 year^?1 (depending on region) operating profit on dairy farms since the mid‐1960s.     

A new lean no time test baking method with improved discriminating power

In response to customer concerns related to gluten strength in commercial baking, the Canadian Grain Commission assessed whether the Canadian Short Process (CSP) test bake method was generating useful data related to intrinsic strength of wheat varieties. Assessment of CSP loaf volume data for Canadian variety trials spanning 2003 to 2013 showed very little correlation with dough strength parameters as measured by farinograph and extensigraph. A lean no time (LNT) test baking method was developed that can better discriminate genotypes and provide objective indicators of the effect of intrinsic dough strength on baking quality. From early method development, through method validation and verification using diverse sets of samples targeting different Canadian wheat classes and grown in three different crop years, results showed the LNT method to be more discriminating and easily adopted by other laboratories. In 2015, the LNT method was adopted as the method of choice in future Canadian variety registration trials. The LNT method is fast, simple and well-suited to high throughput test baking conditions encountered in the evaluation of large numbers of breeder lines. A new objective parameter, loaf top ratio, was also introduced and found to correlate well with dough strength and dough handling properties.     

灌水量对不同年代宁夏春小麦光合特性及产量构成因素的影响

为揭示不同灌水量对不同年代春小麦光合特性及产量的影响,以5 个不同年代宁夏春小麦品种（系）为试验材料,在宁夏灌区4 种水分处理条件下,研究了灌水时期对不同年代宁夏春小麦品种光合生理指标及产量因子的影响。结果表明,不同时期灌水对春小麦叶绿素含量、净光合速率(Pn)、蒸腾速率(Tr)、水分利用率(WUE)等生理指标均产生明显影响;T1、T2 处理,‘毛火麦’和‘宁春27 号’的叶绿素含量、Pn、WUE较高,在T1、T2 和T3 处理下其产量与其他品种（系）差异不显著。随着灌水量的增加,灌区品种（系）‘宁春4 号’、‘宁春50 号’和‘J63’的叶绿素含量、Pn、WUE高于‘毛火麦’和‘宁春27 号’且产量正常灌水条件下显著高于其他处理。因此,宁夏灌区在保证分蘖期和拔节期灌水,增加抽穗期灌水,各品种（系）既保持较高水分利用效率,又可以获得较高的产量。