Hybrid grass-clump dwarfness in wheat: Physiology and genetics

Summary The growth of all grass-clump dwarfs is sensitive to temperature with low temperature giving rise to the grass-clump phenotype and high temperature producing normal phenotype. A continuous temperature of 26°C is required for normal growth of Type 1 dwarfs, a continuous temperature of 21°C is required for normal growth of Ty[e 2 dwarfs and a continuous temperature of 16°C is required for normal growth of Type 3 dwarfs.Genetic studies show that the inheritance of the grass-clump characteristic is due to three complementary dominant genes.The grass-clump growth habit is produced as a result of the temperature sensitivity of the apical meristem. In grass-clump plants low temperature treatment results in the cessation of cell division, DNA synthesis and phospholipid synthesis in the apical meristem. The primary temperature lesion has not been identified. Prolonged low temperature treatment of grass-clump plants results in extensive cell necrosis in a region just below the apical meristem; this cell death results in the permanent inactivation of the apical meristem.Supported in part by the National Research Council of Canada.     

Effect of Phosphorus in Alleviation of Adverse Impacts of Salinity on Wheat Grown on Different Soils

Fertilization management is an important technique to alleviate the adverse effects of salinity stress on plants. A pot experiment was conducted to evaluate the ameliorative role of inorganic phosphorus (P) and organic P sources on wheat grown under salt stress in three soil types deficient in available P. Wheat (Triticum asetivum L. cv. Shakha 93) was grown on alluvial, sandy, and calcareous soils under salinity levels of 4, 8, and 12 dS m^?1 of saturated paste extract (EC_e) and supplied with constant rate of 30 mg P₂O₅ kg soil^?1 as superphosphate (SP), cattle manure (CM), and 1:1 mixture of SP and CM. The results revealed that plants grown on the sandy soil were more susceptible to the adverse effects of salinity compared with those planted on the alluvial one, especially at zero P. Plants grown on the calcareous soil were moderately affected. Varying soil type caused significant differences in the aboveground biomass and uptake of nitrogen (N), potassium (K), P, and zinc (Zn). It was obvious that P ameliorated wheat growth under salt stress, and this role was greater under moderate and high salinity. The increases in N, P, K, and Zn uptake appeared driven by P application were more conspicuous in the sandy and calcareous soils. Results also indicated that combined application of inorganic and organic P sources surpassed both when applied solely under all soil types and salinity levels.     

Influence of race and post infection temperature on two components of partial resistance to wheat leaf rust in seedlings of wheat

Summary Components of partial resistance, infection frequency and latency period, were determined in 71 winter and spring wheat genotypes in the seedling stage, after infection with three races of leaf rust (Felix 3B, Clement B and Betuwe 85C) at three different day/night temperature regimes (24/18°C, 18/12°C and 12/6°C). The genotypes were split into two groups and two separate experiments were carried out. Five genotypes, SVP 84039, Akabozu, Banco, BH 1146 and Orso, conferred a low infection frequency and a long latency period and Westphal 12A a long latency period, indicating a relatively high level of partial resistance. The correlation coefficient between infection frequency and latency period was low. Race-specificity was not found. There was a significant temperature effect on the latency period. In the second experiment the temperature x genotype interaction was significant. Temperature-response functions of transformed data demonstrated that the latency periods of four relatively resistant genotypes, Westphal 12A, Banco, BH 1146 and Orso and of Sarno and Mirela were most sensitive to temperature. The range between the genotypes with the longest and the shortest latency period was highest at 12°C. Therefore, low temperature regimes are preferred to distinguish differences in level of partial resistance.     

The association of genes for purple coleoptile with chromosomes of the wheat variety Mironovskaya 808

Summary The association of genes for purple pigment in the coleoptile with the chromosomes of the winter wheat variety Mironovskaya 808 was investigated using monosomic F₂ analysis. The segregation ratio for F₂ hybrids of Chinese Spring monosomics x Mironovskya 808 seems to indicate that the purple colour of the coleoptile is determined by two dominant genes, Rc₃ and Rc₄, which are located on the chromosomes 7D and 6B respectively, and which reinforce each other. Apart from these two genes, suppressors found on the chromosomes 2A, 2B, 2D, 4B and 6A also play a role in the intensity of the purple colour.With the aid of a Chinese Spring telocentric chromosome marker it was observed that the Rc₃ gene is located on the chromosome arm 7DS, at a distance of 16±4.23 crossover units from the centromere.     

早春短命植物绵果荠愈伤组织诱导相关因素研究

绵果荠是分布在新疆北部准噶尔荒漠中的十字花科一年生早春短命植物。本研究为探讨绵果荠愈伤组织诱导条件,以无菌苗子叶为外植体,研究了不同苗龄、培养基种类、蔗糖浓度和培养条件对愈伤组织的诱导及其生长的影响。结果表明,1)愈伤组织诱导的最佳条件为:苗龄14 d、培养基为MS+1.0 mg/L IBA+0.1 mg/L BAP、含糖量3%、温度25℃和光照为黑暗。2)愈伤组织生长的适宜条件是光照16 h/d和温度25℃。     

Isolation of Salmonella Organisms from Commercial Layer Houses Where the Flocks Were Molted with a Wheat Bran Diet

To develop an alternative method to feed withdrawal for molting layers, 2 flocks consisting of approximately 26,000 commercial laying hens each at 478 (68 wk, flock 1) and 466 (67 wk, flock 2) d of age were reared in an environmentally controlled windowless house and were fed wheat bran (WB) diet. Flock 1 hens were fed WB for 25 d, and flock 2 hens were fed WB for 21 d and then fed a mixture of WB and layer feed (1:1, wt:wt) for the last 4 d of the treatment. After that, the birds in both flocks were fed a normal layer feed. The photoperiod was reduced from 16 to 9 h in both flocks. Most of the birds in both flocks ceased egg production by 10 to 15 d of feeding the WB diets. Egg production in flock 1 gradually increased to 11.4% by 31 to 40 d and 71.4% by 41 to 50 d of the treatment, whereas the egg production in flock 2 hens lagged behind by almost 10 d. The mean egg production from 61 to 140 d exceeded 86% in both flocks. The houses in the farm were naturally contaminated with several serovars of Salmonella, not Enteriditis or Typhimurium. In both flocks with the WB treatment, no marked increase in Salmonella isolation from environmental samples was observed postmolt relative to premolt levels. The study demonstrated that feeding hens WB could be successfully used as an alternative to feed withdrawal to force-rest aging hens while not exacerbating a Salmonella problem in a commercial egg-production setting.     

中草药添加剂提高密蜂春繁效果的研究

在早春繁殖期,以中草药作为饲料添加剂,观察蜜蜂群势变化和蜂群健康情况.结果表明,试验组A和对照组CK的蜂群繁殖效果差异极显著,试验组蜂群健康、活动正常,蜂群繁殖率提高了12.1%.     

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。     

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。     

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.