饲用玉米品种类型对饲草产量和品质的影响

为筛选适宜在新疆北疆地区种植的饲用玉米新品种,采用随机区组设计测定并评价了2种青贮玉米、1种普通玉米和2种饲草玉米的产草潜力和主要营养价值。经过测定,各饲用玉米生育期相近。每hm~2干草产量玉草3号最高,为40875kg,新饲玉12号、雅玉8号、金玉818和墨西哥玉米干草产量依次为36675kg、35910kg、33495kg和26325kg。粗蛋白含量玉草3号最高为10.98%DM,中性洗涤纤维和酸性洗涤纤维表现最优为雅玉8号,分别为53.6%DM和33.6%DM。结果表明饲用玉米品种类型对干草产量和品质有极显著影响。远缘杂交合成的玉草3号和具有热带玉米血缘的雅玉8号是优质、高产的饲用作物类型,具有广泛的生态适应性,也可作为优质饲用作物在北疆推广。     

种植密度对不同类型玉米青贮产量和营养价值的影响

为明确不同类型青贮玉米在临沂地区最佳种植密度,设置了4个密度梯度（60 000、75 000、90 000、105 000株/hm ²）,研究种植密度对专用型青贮玉米雅玉8号和粮饲兼用型玉米登海605饲用产量和营养价值的影响。结果表明：密度对不同类型青贮玉米鲜草、干草产量影响显著,密度增加,青贮玉米鲜草产量和干草产量均先增加后减少,在密度75 000株/hm ²时均获得最高鲜草、干草产量。密度对不同类型青贮玉米粗脂肪、粗灰分、酸性洗涤纤维含量和子粒产量、粗蛋白产量、粗脂肪产量、可消化干物质、相对饲喂价值、无氮浸出物含量和总能量影响显著,密度增加,雅玉8号粗蛋白、粗脂肪含量和可消化干物质、干物质采食量、相对饲喂价值和无氮浸出物含量下降,粗灰分、中性洗涤纤维和酸性洗涤纤维含量呈上升趋势,子粒产量、粗蛋白、粗脂肪产量和总能量先增加后减少,在密度75 000株/hm ²均获得最高子粒、粗蛋白、粗脂肪产量。从饲料总能量来说,专用型青贮玉米雅玉8号和粮饲兼用型玉米登海605在山东临沂地区饲用的最佳种植密度均为75 000株/hm ²。     

鲁南地区青贮玉米品种的聚类分析

为筛选适宜鲁南地区种植的青贮玉米品种,采用SPSS软件对13个青贮玉米品种的11个农艺和品质性状进行系统聚类分析。结果表明,参试的13个品种分为3个类群,类群Ⅰ:京科青贮516、饲玉1号、饲玉2号、诺达1号和登海605,平均干草、鲜草产量较高,高抗锈病,平均粗蛋白含量中等,平均中性洗涤纤维含量较低;类群Ⅱ:京科青贮301、北农青贮208、北农青贮356、鲁单9066和宇玉30,平均干草和鲜草产量较低,高感锈病,平均粗蛋白含量较低,平均中性洗涤纤维含量较低;类群Ⅲ:北农青贮308、BN 2932和鲁单6076,平均干草和鲜草产量中等,中感锈病,平均粗蛋白含量较高,平均中性洗涤纤维含量较高。京科青贮516、饲玉1号、饲玉2号、诺达1号和登海605等5个品种农艺性状较好、品质优,适宜作为全株青贮玉米在鲁南地区种植。     

不同饲用玉米品种产量及青贮品质比较分析

为筛选出适宜安徽省种植的饲用玉米品种,进行了10个饲用玉米品种的产量及青贮品质比较研究。结果表明：品种间产量和青贮品质存在显著差异。其中,‘玉草3号’的产量最高,YA473182的产量仅次于‘玉草3号’;YA473182的氨态氮(NH3-N)含量略低于‘玉草3号’,乳酸(LA)含量显著高于‘玉草3号’,发酵品质较好;YA473182的可溶性碳水化合物(WSC)含量及粗蛋白(CP)含量显著高于其他品种,且中性洗涤纤维(NDF)及酸性洗涤纤维(ADF)含量相对较少,饲用品质较好。综合考虑各玉米品种的产量及青贮品质,YA473182和‘玉草3号’最适合安徽省种植利用,‘瑞德2号’和‘豫青3230’也有推广价值。     

适宜十堰市种植的青贮玉米品种筛选

为促进十堰市种植业结构调整,带动畜牧养殖业发展,筛选出适宜十堰地区种植的青贮玉米品种,引进郑青贮1号、豫青贮23和雅玉青贮8号3个青贮玉米品种,选取湖北省自育国审青贮玉米品种华玉11以及湖北省生产上种植面积较大的7个籽粒玉米品种进行青贮玉米品种筛选试验。以雅玉青贮8号为对照,对各品种的物候期、农艺性状、抗逆性、生物产量、干物质产量等方面进行比较分析。结果表明, 华玉11、华玉12、金与669持绿性好,抗逆性好,生物产量显著高于对照品种雅玉青贮8号,适宜十堰地区作青贮玉米种植。     

不同类型饲用作物营养成分的比较研究

对3种类型饲用作物杂交苏丹草皖草2号、墨西哥玉米和粮饲兼用玉米农大108进行了比较。结果表明,鲜、干物质产量以皖草2号最高,墨西哥玉米其次,农大108最低。皖草2号和墨西哥玉米叶片是干物质产量构成的主体,对农大108茎秆是主体。皖草2号粗蛋白(CP)、无氮浸出物(NFE)、酸性洗涤纤维(AWF)、粗脂肪(EE)、粗灰分(CA) 5大养分产量均显著高于墨西哥玉米和农大108,其粗蛋白和粗灰分含量均低于墨西哥玉米高于农大108。皖草2号总能量(GE)极显著高于墨西哥玉米和农大108,分别高出1 448.024×10⁶ J·hm^-2和2 339.687×10⁶ J·hm^-2。农大108干物质和粗蛋白降解率最高,分别为57.880%和12.424%。墨西哥玉米粗纤维的降解率显著高于皖草2号,但它们的干物质和粗蛋白降解率差异不显著。3种类型饲用作物营养价值差异来自其生物学特性的显著差异。     

粮饲兼用型玉米青贮产量形成与生理特性的研究

本试验选用在四川当地适合作青贮的粮饲兼用型玉米品种川单21、成单22、雅玉8号和燎原青贮玉米2号及从新疆引进的专用青贮玉米品种新青2号为材料，研究了不同青贮玉米的产量形成及其光合生理特性。结果表明，鲜物质、干物质产量以及果穗产量均以粮饲兼用型玉米较高，其中以雅王8号表现最优。粮饲兼用型品种在抽丝后的叶面积指数(LAI)、群体光合势(LAD)和净光合率(NAR)等几个重要生理指标上均表现出明显优势，叶面积指数、群体光合势持续期长、净光合速率高而衰减速率慢是粮饲兼用型品种产量高的重要生理原因。     

推广青贮玉米品种提高饲喂饲料单位

为了尽快建设宝鸡畜牧大市,宝鸡市九丰农业科技有限公司在 2004年推广了青贮玉米品种雅玉 8号和粮饲兼用品种农大 108、济单 7号等高蛋白、高脂肪、高赖氨酸、高糖分的品种 6700hm2.据调查测产,一般每 667m2生物产量 4 5～ 6 0t、子粒总产量 400～ 600kg.特别是雅玉 8号品种,受到了畜农的好评,为推广开拓了道路.为了进一步推广青贮玉米品种,促进畜牧业发展,现将存在问题、概念、特点作以下介绍,以便对青贮玉米有进一步的了解.     

海河低平原区14个玉米品种青贮性状评价及适应性分析

为筛选适宜海河低平原种植的优良青贮玉米品种。采用随机区组设计对14个玉米品种进行了生物产量、农艺性状、品质及抗逆性筛选评价。结果表明,参试品种株高、穗位高度分别为246.7~322.8 cm和86.2~148.9 cm,雅玉青贮79491株高最高,郑单958株高最低;参试品种生物产量为14.46~22.19 t/hm2,品种间差异极显著(P0.01),其中雅玉青贮79491、中地175、北农青贮308和北农青贮2932生物产量较高,分别较郑单958增产28.35%,20.43%,20.06%和10.09%;玉米乳熟期-蜡熟期收获,其生长天数与生物产量相关极显著,R=0.77**,株高与生物产量间相关显著,R=0.62*;品种间饲用品质差异极显著(P0.01),中地175、郑单958、先玉335、衡玉321及兼用型品种巡青518作为普通玉米、其余为青贮玉米进行统计,普通玉米中性洗涤纤维及酸性洗涤纤维含量较青贮玉米低2.59%和4.58%,可溶性糖及淀粉含量较青贮玉米高2.06%和2.12%;参试品种收获时绿叶数11.1~13.8,鲜干比30.23%~39.15%。除北农308、雅玉青79491和先玉335倒伏率+倒折率15%外,其他11个玉米品种各项测定指标符合国家分级标准,青贮品质达2级以上,其中恩喜爱298、中农大青贮Y4515、辽单青贮625和巡青518等4个杂交种符合国家青贮品质1级标准。为促进玉米种植业结构的调整,中地175等普通玉米品种同时作为普通玉米、全株青贮、粮饲兼用型多用途开发推广应用具有好的发展前景。     

不同饲料作物产量与品质比较研究

对引进的7个高大饲草品种的产量和品质进行了初步研究.结果表明,鲜草产量和干草产量最高的品种均为玉草2号,其次为龙草1号.品质最好的为晋草系列品种;粗蛋白产量最高的品种是龙草1号和玉草2号.分析表明,青贮利用可选玉草2号,青饲利用可选龙草1号.     

Breeding forage grasses for organic conditions

Herbage yield trials are necessary to test if candidate varieties are well suited for organic conditions. In order to elucidate a particular suitability for organic conditions, we run such trials in parallel under both organic and conventional conditions. Here, we report on second and third year results of the sowings 2004 and 2005. These trials are part of a targeted breeding programme for organic conditions. Irregular colonisation of pure grass plots with adventitious plants, in particular white clover, was recognized as a major constraint to the quality of the results obtained under organic conditions. The coefficients of variance in dry matter yield almost doubled when compared to conventional trials, and significant differences in annual yield among varieties were rare. However, when herbage yield was corrected for the estimated fraction of adventitious plant colonization at each cut, the number of instances with statistically significant differences for annual yield among varieties increased more than fourfold. Dry matter yields under organic and conventional conditions were significantly and positively correlated. However, analysis of variance showed a significant culture type by variety interaction for annual dry matter yield in 12 out of 24 trials. When diploid and tetraploid varieties of the same Lolium species were tested in one common trial, only tetraploid varieties were identified as being particularly well suited for organic conditions, while in these trials, the great majority of apparently poorly suited varieties were diploid. This suggests that breeding tetraploid Lolium varieties is promising when aiming at a favourable response to organic agriculture.     

Half-sib family selection for forage yield in orchardgrass

Genetic variation for forage yield of orchardgrass is abundant, but there are few reports of progress from selection for increased forage yield. The objective of this study was to estimate direct effects of selection from one cycle of half‐sib family selection for forage yield in orchardgrass. Eleven selected populations were compared with their parent populations within three maturity groups. Populations were evaluated under hay management at three locations and management‐intensive rotational grazing at two locations. Nine of the 11 selected populations differed, by an average of 7.4%, from their parent population in forage yield. Nine of the selected populations also showed changes in Drechslera leafspot reaction, all indicating a negative genetic correlation with forage yield. Selection for high forage yield tended to result in greater ground cover and later relative maturity. However, changes in net herbage accumulation (NHA) under rotational grazing were generally not significant and were uncorrelated with changes in forage yield, indicating that forage yield of hay plots is not correlated with the NHA of grazed plots. Although genetic gains in forage yield measured under hay management were very favourable relative to other reports from the literature, the lack of correlated progress under grazing management indicates that directed selection for NHA of orchardgrass should be conducted under grazing management.     

Recurrent phenotypic selection for forage yield in rye

Summary Cultivars of Cucurbita pepo and other Cucurbita species were characterized by RFLP analysis using different fragments of the ribosomal intergenic spacer (IGS) of Cucurbita pepo as hybridization probes. Several cultivars could be distinguished by a specific rDNA restriction pattern, whereas some cultivars showed an identical RFLP pattern suggesting a closer relationship. Other species of the genus Cucurbita exhibited strong cross-reaction with the C. pepo spacer probes, in contrast to DNA of Cucumis species which did not cross-hybridize.Abbreviations IGS intergenic spacer - ITS internal transcribed spacer - kbp kilo base pairs - rDNA ribosomal DNA - RFLP restriction fragment length polymorphism - rRNA ribosomal RNA     

Prospects for genomic selection in forage plant species

Genomic selection (GS) is a powerful method for exploitation of DNA sequence polymorphisms in breeding improvement, through the prediction of breeding values based on all markers distributed genome‐wide. Forage grasses and legumes provide important targets for GS implementation, as many key traits are difficult or expensive to assess, and are measured late in the breeding cycle. Generic attributes of forage breeding programmes are described, along with status of genomic resources for a representative species group (ryegrasses). Two schemes for implementing GS in ryegrass breeding are described. The first requires relatively little modification of current schemes, but could lead to significant reductions in operating cost. The second scheme would allow two rounds of selection for key agronomic traits within a time period previously required for a single round, potentially leading to doubling of genetic gain rate, but requires a purpose‐designed reference population. In both schemes, the limited extent of linkage disequilibrium (LD), which is the major challenge for GS implementation in ryegrass breeding, is addressed. The strategies also incorporate recent advances in DNA sequencing technology to minimize costs.     

饲草玉米品种的引进比较试验

为选出适合遵义地区栽培的优良品种,本试验对引进的一批饲草玉米品种进行比较试验,结果显示：不同饲草玉米品种的表现不同,收割青草产量由高到低依次为玉草3号＞玉草4号＞玉草5号＞玉草2号＞雅玉8号;玉草4号分蘖最多平均每株有2个分蘖,而玉草5号和雅玉8号没有分蘖;玉草5号和雅玉8号比玉草4号和玉草2号刈割期提前。这些饲料玉米品种在贵州遵义地区具有良好的气候适应性,产量高,品质好,可以根据采收期的不同进行不同品种的搭配种植。     

Thiocyanate in forage kale (Brassica oleracea L.)

Summary An improved technique has been used for the determination of thiocyanate ion (^-SCN) released on enzymatic hydrolysis of kale (B. oleracea) inbred lines and F₁ hybrids. Considerable heritable variation has been found. Grazing trials have shown a relationship between ^-SCN in the crop and in the blood plasma of grazing sheep.     

Nitrogen response models for winter cereals grown for forage

Forage double cropping can increase production, reduce erosion risk and improve soil health. Farmer experience in the north‐eastern USA shows that winter cereals can, in 3–4 weeks (Feekes 9 harvest), produce high quality forage given sufficient N at dormancy break. Here, we evaluate crop response models to determine the most economic rate of N (MERN) for forage winter cereals. Sixty‐three on‐farm N‐rate trials (0, 34, 67, 101, 135 kg N/ha) were conducted in New York from 2013 to 2016. Trials were divided into four categories: (a) no yield response to N (group 1; 20 trials); (b) yield plateau exceeded the highest N rate (group 2; one trial); (c) the MERN was below the lowest N rate (group 3; seven trials) and (d) all other N‐responsive trials (group 4; 35 trials). For group 4, three statistical models were compared (quadratic plateau, exponential and square root plateau). Statistical, environmental and economic criteria showed that the quadratic plateau fits the data best and had the most stable predictions across scenarios. The four‐category analysis is effective in determining MERNs of individual trials, and the quadratic plateau is best for determining forage winter cereal MERNs and yields at MERNs for individual trials in the north‐eastern USA.     

Genetic variation within eight populations of perennial forage grasses

Information on both mean performance and genetic variation is important in determining the value of germplasm for breeding via recurrent selection. The objectives of this experiment were to evaluate different methods of controlling spatial variation for forage yield, and to estimate genetic variances and heritability in eight perennial forage grass populations. Polycross families of two populations of smooth bromegrass (Bromus inermis Leyss.), two populations of hybrid wheatgrass (Elytrigia×muctonata (Opiz ex. Bercht.) Prokud.), and four populations of orchardgrass (Dactylis glomerata L.) were field tested for 2 years. Spatial variation was present in all three progeny tests, but was well accounted for by either the incomplete block design or a nearest neighbour analysis (NNA) of yield potentials. Low rank correlations between adjusted family means for the incomplete block design vs. the NNA created the unanswered question of which would provide a more appropriate estimate of family mean performance. Genetic variation was detected in six out of eight populations for forage yield, four out of six populations for ground cover, all four orchardgrass populations for maturity and one of four orchardgrass populations for leafspot reaction (caused by Drechslera spp.). Excessive year-family interactions prevented detection of genetic variation for leafspot reaction in the other populations. Heritability estimates ranged from 0.30 to 0.42 for forage yield. In all three species, there was a trend toward a negative relationship between population mean and genetic variance, suggesting that less elite populations may need to contribute other traits to be useful in the short term.     

The economic benefits of forage improvement in the United States

The United States is a large country with a diversity of forage ecosystems and forage species to fill the varied management options within each ecosystem. For example, the American Seed Trade estimates seed of 5,500 varieties representing 1,500 grass and 4,000 legume species are produced annually. The economic benefits of forage improvement are both direct (seed and hay sales) and indirect (saleable animal products, nitrogen fixation and conservation uses). The benefits of improving forages through breeding are likewise important due to the current use of improved varieties to underpin these systems and their direct and indirect products. Because of the diversity of species and management systems, only a few case studies were examined in this paper to estimate these benefits. These were the alfalfa (Medicago sativa L.) industry (economic value of US$8.1 billion per year), the forage and livestock systems of the southeastern USA (economic value estimated overall at US$11.4 billion per year), and switchgrass (Panicum virgatum L.) and its potential use as bio-energy feedstock (economic value of needing an additional 28 million acres of production to supply the estimated future feedstock needs). The overall conclusion is that the economic benefits from forage improvement in the USA have been, and continue to be, immense. However, future resources are going to fewer crops, and these crops are the ones that have greater economic value and where biotechnology can be applied. This will favor alfalfa and penalize forage grasses. Even for crops with an identifiable path to market, this concentration of resources in fewer hands requires development of consortia where organizations can leverage their resources with others who possess complementary resources. The Consortium for Alfalfa Improvement is a good example of how this could work.