Factors responsible for levels of male sterility in photoperiod-sensitive cytoplasmic male sterile (PCMS) wheat lines

A `two-line system' using photoperiod-sensitivecytoplasmic male sterility (PCMS) caused by Aegilops crassa cytoplasm has been proposed as a newmeans of producing hybrid wheat. The PCMS line ismaintained by self-pollination under short-dayconditions (14.5 h light period), and F<sub>1</sub> seedscan be produced by outcrossing of the PCMS line witha pollinator under long-day conditions (15 h lightperiod). As the levels of male sterility in PCMSlines under the long-day conditions is a crucialfactor in determining hybrid purity of the F<sub>1</sub>seeds, a study was conducted into the effect ofseeding rate on male sterility in PCMS lines. Threedifferent density levels were tested using analloplasmic line of Japanese wheat cultivar `Norin 26'which exhibits PCMS. Levels of male sterility of thePCMS line increased at sparse planting, because tiller(ear) number per plant increased at low seedingdensity and late-appearing ears tended to exhibithigher levels of male sterility than early-appearingears. On the other hand, male sterility levels of thePCMS lines depended on genotype, e.g., the PCMS`Fujimikomugi' was completely male sterile, whereasthe PCMS `Norin 26' showed partial male sterility. APCMS line showing complete male sterility, such as thePCMS `Fujimikomugi', should produce F<sub>1</sub> seeds withhigh purity. However, the PCMS `Fujimikomugi' showeda lower female fertility. For practical use, it isnecessary to produce PCMS lines having high malesterility with high female fertility under long-dayconditions.     

玉米、小麦和高粱型日粮对肉仔鸡矿物元素沉积的影响

文章旨在研究不同日粮类型(玉米、小麦和高粱)对1～14 d肉仔鸡常量和微量元素沉积的影响。试验选择健康、体重一致的1日龄AA肉鸡540只,随机分为3组,每组6个重复,每个重复30只鸡。试验设计3种日粮,分别以玉米、小麦或高粱原料为主,3组日粮的代谢能、粗蛋白质和必需氨基酸水平维持一致,试验共进行14 d。结果表明:除了钙的含量例外,玉米、小麦或高粱型日粮其他矿物质元素的含量表现一致(P> 0.05)。14 d肉鸡各元素沉积系数的变化由0.24(镁)到0.64(钠),其中钠沉积系数在第3天最高(P <0.05);肉鸡日粮对各常量元素的影响表现为显著差异(P <0.05);3～7 d常量元素沉积系数显著降低(P <0.05);日粮类型显著影响3 d肉鸡钙的沉积系数,显著影响5 d肉鸡镁的沉积系数及磷的沉积系数(除了14 d)和钠的沉积系数(除了3 d)(P <0.05);小麦型日粮较玉米和高粱型日粮显著降低了钠的沉积系数(P <0.05);日粮类型和日粮对常量元素沉积系数的影响无显著交互作用(P> 0.05)。;肉鸡日粮对所有微量元素具有显著影响,其中在第3天表现为最高(P <0.05);日粮类型显著影响第7天铁、锌和锰的沉积系数(P <0.05),显著影响第9天铜的沉积系数(P <0.05);日粮类型和肉鸡日粮对微量元素的影响无显著交互作用(P> 0.05)。结论 :肉仔鸡对日粮无机矿物质的利用率较低,日龄对矿物元素的沉积量具有显著影响,但玉米、小麦或高粱型日粮对肉仔鸡常量和微量元素沉积量无显著影响。     

玉米‖花生茬口对冬小麦旗叶光化学活性的影响

为探明玉米‖花生茬口显著提高冬小麦旗叶的光合速率和产量的光反应机理,研究了玉米‖花生茬口(间作茬口,ICR)、玉米茬口(MCR)和花生茬口(PCR)及不同施磷水平对冬小麦播前土壤含水量、冬小麦花后旗叶的气体交换参数、光系统Ⅱ(PSⅡ)、光系统I(PSⅠ)及二者间的性能协调性的影响。结果表明,间作茬口较玉米茬口显著提高了冬小麦播前土壤含水量及旗叶的净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)和PSⅡ反应中心供(Wk)/受体侧(Vj)的活性,增强了单位面积吸收的光能(ABS/CSo)、捕获的能量(TRo/CSo)和进入电子传递的光能(ETo/CSo)。间作茬口较玉米茬口显著提高了冬小麦扬花期旗叶PSⅡ初级光化学最大量子产额(φpo)、转化效率(Ψo)、电子传递效率(δRo)及乳熟期的PSⅠ的性能(ΔI/Io)、PSⅡ与PSⅠ协调性(ΦPSⅠ/PSⅡ)和籽粒产量,较花生茬口显著提高了乳熟期的φpo和δRo值。施磷提高了Pn、ABS/CSo、TRo/CSo、ETo/CSo、φpo、Ψo、δRo、ΔI/Io和ΦPSⅠ/PSⅡ值。这说明间作茬口较玉米茬口提高了冬小麦旗叶光反应中心活性,从而提高净光合速率,重要原因可能是间作茬口能保持耕层较高的土壤含水量。     

Feeding value of enset (Ensete ventricosum), Desmodium intortum hay and untreated or urea and calcium oxide treated wheat straw for sheep

Feed intake, in vivo nutrient digestibility and nitrogen utilization were evaluated in male sheep fed different fractions (leaf, pseudostem, corm, whole plant) of enset, untreated or 2% urea‐ and 3% calcium oxide‐ (CaO or lime) treated wheat straw and Desmodium intortum hay as sole diets. All feeds, except D. intortum hay and enset leaf had low crude protein (CP) content. Non‐fiber carbohydrate contents were higher in enset fractions, especially in pseudostem and corm relative to other feeds. Enset leaf and pseudostem had high calcium, phosphorus and manganese contents. Corm, whole enset and D. intortum hay were rich sources of zinc. Daily dry matter and CP intakes were higher (p < 0.05) in sheep fed D. intortum hay (830 and 133 g, respectively) than those fed pseudostem (92 and 7.8 g, respectively). Organic matter digestibilities were highest for corm (0.780) and whole enset (0.776) and lowest for D. intortum hay (0.534) and untreated wheat straw (0.522). The CP digestibility ranged from 0.636 in D. intortum hay to 0.408 in corm. Nitrogen (N) balance was highest (p < 0.05) in D. intortum hay (10.4 g/day) and lowest in corm (?1.3 g/day). Enset leaf could be a useful protein supplement whereas the pseudostem and corm could be good sources of energy.     

冬小麦秸秆不同处理饲喂肉牛的效果观察

将冬小麦秸秆经微贮、氨化处理后进行饲喂肉牛增重育肥试验,对照牛喂自然干麦秸。48 头供试牛(每组16 头),试验结果为:喂微贮麦秸组头均日增重0.89kg,喂氨化麦秸组头均日增重0.84kg,对照组头均日增重0.57kg。试验组与对照组比较差异极显著(P< 0.01),两试验组差异不显著(P> 0.05)。将各组耗料(包括精料、粗料)、增重按市价进行效益分析,60 天试验期结束,微贮组平均每头获得114.00 元,氨化组平均每头获利63.13 元,对照组平均每头亏损14.36 元。冬小麦秸杆处理后饲喂肉牛效果明显。微贮法优于氨化法,成本低,易操作,饲喂效果好,在农区应大力推广。     

旱地栽培小麦及秸秆青贮饲料的发酵特性、营养成分及体外瘤胃降解特性

本研究总结了全珠小麦青贮饲料和小麦秸秆青贮饲料的保存和营养特性。选择25包来自4个不同田间的全珠小麦青贮饲料和10包小麦秸秆青贮饲料,分别进行了全株小麦青贮和秸秆青贮试验。全珠小麦青贮饲料保存良好,平均pH值为4.46,乳酸、乙酸和丁酸盐的浓度分别为19.2、10.4和4.7g/kg。小麦秸秆青贮饲料的平均pH值为5.46,由于干物质含量较高,发酵受到抑制,乳酸、乙酸和丁酸盐的浓度分别1.9、2.2和1.0g/kg。全株小麦青贮饲料粗蛋白含量为78g/kg,中性洗涤纤维含量为546g/kg,非纤维碳水化合物含量为306g/kg。全珠小麦青贮饲料中粗蛋白和非纤维碳水化合物含量变化较大,中性洗涤纤维含量变化相对较小,这与籽粒成熟度的差异有关。全株小麦青贮饲料和秸秆青贮饲料的体外有机质降解率分别为56.1%和29.3%。全株小麦青贮饲料的体外有机质降解与pH、乳酸和乙酸盐含量无显著相关性(P>0.05),与丁酸盐含量和氨氮比值有显著相关性的趋势(P=0.07)。瘤胃对全珠小麦青贮饲料的发酵早期体外气体生成的变异系数越高,相对于一些纤维组分,如中性洗涤纤维和酸性洗涤纤维,测定的非纤维碳水化合物变异系数也相应升高。综上所述,冬季旱地栽培的小麦可以作为全株青贮饲料在瘤胃中发酵提供能量,小麦秸秆也可以作为纤维原料进行青贮。     

组合型木聚糖酶对21日龄黄羽肉鸡器官指数、内源消化酶活性以及肠道吸收功能的影响

通过对21日龄黄羽肉鸡器官指数和胃蛋白酶、胰蛋白酶、胰脂肪酶、胰淀粉酶以及血清中木糖水平进行检测,研究酶制剂对动物内脏器官所产生的影响,以及组合酶和单酶之间的差异。木聚糖酶在小麦型日粮中添加,降低了肝脏、肌胃、腺胃、十二指肠、空肠和回肠的器官指数,增加了胰腺的器官指数;降低了胃蛋白酶和胰蛋白酶的分泌水平;组合酶比单酶降低小肠器官指数更明显,单酶增加了胰脂肪酶的分泌水平,组合酶降低了胰脂肪酶的分泌水平,差异不显著(P>0.05)。小麦型日粮饲喂组血清中木糖的水平高于玉米型日粮组和加酶组,酶制剂的添加降低了血液中的木糖水平,各处理组之间差异不显著(P>0.05)。     

甘肃陇南冬小麦条锈病气象等级预测模型的建立与应用

甘肃陇南地区是中国小麦（Triticum aestivum）条锈病菌核心越夏区,其越夏菌量对中国中东部来年春季小麦条锈病发生发展程度影响很大。本研究利用陇南冬麦区14个代表站点1990-2007年的气象资料和条锈病资料,依病田率将气象条件划分为5个等级,采用逐步回归方法建立了小麦条锈病气象等级预测模型。经历史回代检验,预测模型误差达2个等级的占12%,完全准确的为25%;对于实际病害等级为1~2级的气象等级拟合误差达2个等级的为23%,其他都在1个等级之内,预测效果良好。     

Ileal amino-acid digestibility of wheat, autoclaved wheat and spaghetti by-products for broiler chicks

An experiment was conducted to determine true and apparent ileal amino‐acid digestibility of a native cultivar of wheat (Mahdavi), autoclaved wheat (120°C for 30 min) and spaghetti by‐products available in Iran. One hundred 21‐day‐old broiler chickens were fed a standard corn–soybean meal starter diet from day 0 to 28 post hatch. At 28 days 80 chicks were distributed according to possessing very nearly the same average bodyweight to 20 wire cages. The experimental units were allocated at random to five dietary treatments with four replicates per treatment. The basal diet contained corn and soybean meal as the major ingredients. Three test diets were formulated containing wheat, autoclaved wheat and spaghetti by‐products as the sole source of dietary protein and each test diet was combined with a basal diet 50:50 on a weight basis to form three assay diets. The apparent and true digestibility of amino acid in the test ingredients were estimated from those in the assay diets basal/test diet mixtures, using the difference method. The apparent and true amino‐acid digestibility of the test ingredients were significantly different (P < 0.01). Autoclaving of wheat increase its amino‐acid digestibility (P < 0.01). Among the test ingredients, the average ileal amino‐acid digestibility of spaghetti by‐products was higher than wheat and autoclaved wheat but it was lower than values for the basal diet (P < 0.01).     

Evaluation of ground grain versus pre- and post-pellet whole grain additions to poultry diets via a response surface design

1. The objective of this study was to compare the effects of pre- and post-pellet whole grain wheat additions to diets on growth performance, gizzard and pancreas development, nutrient utilisation and starch and protein (N) digestibility coefficients in broiler chickens via an equilateral triangle response surface design.

2. The three apical treatments of the equilateral triangle comprised (1A) a standard diet containing 600 g/kg ground wheat, (2B) the same diet containing 600 g/kg pre-pellet whole wheat and (3C) the same diet containing 300 g/kg ground wheat and 300 g/kg post-pellet whole wheat. Seven blends of the three apical diets were located within the triangle to complete the design and a total of 360 male Ross 308 chicks were offered the ten experimental diets from 7 to 28 d post-hatch. Model prediction and response surface plots were generated with R 3.0.3 software.

3. The most efficient FCR of 1.466 was observed in birds offered an almost equal mixture of the pre- and post-pellet whole grain apical dietary treatments, which corresponded to 172 g/kg ground grain, 256 g/kg pre-pellet whole grain, 172 g/kg post-pellet whole grain in a diet containing 600 g/kg wheat.

4. The most efficient energy utilisation (ME:GE ratio of 0.766) was observed in birds offered a blend of the ground grain and pre-pellet whole grain apical dietary treatments which corresponded to a mixture of 384 g/kg pre-pellet whole grain and 216 g/kg ground grain.

5. Pre-pellet whole grain feeding generated the most pronounced responses in increased relative gizzard contents, reduced gizzard pH and increased relative pancreas weights. Consideration is given to the likely differences between pre- and post-pellet whole grain feeding.