The frequency of natural cross-fertilisation in sequential sowings of winter barley

Summary Estimations of random mating frequency were computed for a series of sequential autumn sowings of populations of winter barley. The estimations were by means of the maximum likelihood scoring method and three varieties, each carrying a recessive genetic marker, provided three independent estimations for each population. High levels of out-crossing were found in sowings made early in September, and a trend towards absence of out-crossing in populations sown in late November was evident. Although fluctuations in this trend could be accounted for by fluctuations in meteorological factors, a more profound underlying effect was evident in that the three marker varieties behaved similarly, though to different degrees. It is postulated that the principle effect of sowing date, as it affects out-crossing, is upon the development of the flowering apex, and that environmental conditions at flowering time merely modify flowering behaviour.     

Genetical Studies of Resistance of Powdery Mildew in Barley Lines Derived from Hordeum spontaneum Collected from Israel

Genetical studies on mildew resistance were carried out with Hordem spontaneum derived lines. A total of 28 lines (66 %) showed monofactorial segregation for mildew resistance, For 14 lines, a bifactorial mode of inheritance was found. In total fifty six mildew resistance genes take part in the inheritance of mildew resistance of the H. spontaneum derived lines, while the presence of known genes for mildew resistance (i.e, Ml-a.9 and Ml-p) was established only in two cases. Independent segregation from the Ml-a locus was found in 10 mbnofaetorial segregating lines, The genes conditioning mildew resistance in barley lines derived from the accessions 1B-54B, RS 170-47, RS 20-1. 1B-86B, RS 145-39 and 1B–152B of H. spontaneum were closely linked or alleles to the Ml-a locus, but shown to be different from 15 previously identified Ml-a alleles. It is suggested that these genes should be designated Ml-a16, Ml-18, Ml-19 Ml-20 and Ml-a21 respectively. No recombinants were found in test crosses when both parents carried genes/alleles of the Ml-a locus. In addition, polymorphism has been observed also for the Ml-a locus. In 4 lines mildew resistance was conditioned by two dominant complementary genes. For one of the 2 genes, conditioning mildew resistance of line RS 42-8 × OrioL a new locus was found located near the centromere of the long arm of chromosome 5, and should be designated Ml-i The potential use of H. spontaneum genes for mildew resistance in barley breeding is discussed.     

Natural variation within the genus Beta and its possible use for breeding sugar beet: A review

Summary Sugar beet is a relatively young crop, which supposedly has a narrow genetic base. Natural variation occurring in primitive beet varieties and in wild Beta species has been used for breeding sugar beet. This paper reviews information on desirable characteristics in Beta germplasm and the attempts made for the introgression of such characters into commercial breeding material. After an introduction on the availability of germplasm and the possibilities of hybridisation, attention is focussed on the mating system (especially male sterility), on morphological and physiological characteristics, including yield and sugar content, and on resistances to diseases and pests.     

Genetic resources of wild cereals in Israel and vicinity. I. Phenotypic variation within and between populations of wild wheat,Triticum dicoccoides

Summary Populations of wild emmer wheat, Triticum dicoccoides, in Israel, originating from diverse habitats, and tested earlier for allozyme (Nevo et al., 1982) and disease resistance polymorphisms (Moseman et al., 1983a, 1983b; Nevo et al., 1984a, 1984b), were compared and contrasted for performance in agronomically important phenotypic traits. The traits compared involved 10 variables comparing germination, earliness, biomass and yield variables. The field experiments were conducted in 1980, 1981 and 1982 in two relatively standardized and contrasting environments: mesic (Mount Carmel, Haifa) and xeric (Acedat Farm, and Sede Boqer, in the northern Negev desert). The experimental design involved 12 population quadrangles at Avedat Farm in 1980, and rows of randomized genotypes of five populations in both Haifa and Sede Boqer in 1981 and 1982.The results indicate that the characters studied are partly genetically determined. Striking genetic variation was found between and, at least in some characters, also within populations in each site, whereas remarkable environmental variation including genetic-environmental interaction was found between the mesic and the xeric sites. We conclude that natural populations of wild emmer wheat in Israel vary not only in genetic polymorphisms of allozymes and disease resistance, but also in quantitative traits of agronomic importance. These traits are economically significant and should be conserved and utilized in wheat crop improvement.     

天然抗氧化剂茶多酚在肉制品上的应用

茶多酚是一种新型的天然抗氧化剂,具有抗氧化能力强、使用安全、无副作用和防腐保鲜等优点。将茶多酚应用于肉制品,可以预防和减缓其腐败变质。目前茶多酚的应用虽然仍存在一些问题,但是它具有广阔的发展前景。     

荒漠草原自然恢复中植物群落组成及物种多样性

摘要：通过调查封育3、4、5、6、7年及未封育荒漠草原群落的特征,研究了不同封育年限下草原植物群落组成及生物多样性的变化,以期探明封育对荒漠草原群落恢复的影响。结果表明,封育改变了草原植物群落组分,表现为随封育年限延长,多年生草本植物,特别是短花针茅(Stipa breviliora)等一些地带性物种比例增加;封育草原的Shannon Wiener指数、Pielou指数、Simpson指数均比未封育草地高,封育5年草原的多样性指数最大。     

自然低温胁迫下腰果幼苗抗寒生理指标的研究

以腰果FL30幼苗为试材,测定在自然低温胁迫下相对电导率、丙二醛、可溶性糖、脯氨酸等生理指标,探索腰果在低温胁迫下的生理响应机制。结果表明:随着低温胁迫时间的延长,腰果叶片的脯氨酸含量持续上升;相对电导率、丙二醛和可溶性糖含量表现出先上升后下降又上升的变化规律,而下降所持续的时间不同。     

张家口市观花植物主要害虫和天敌种类调查

2010年采用定期定点调查的方法,调查了张家口市11种草本花卉、4种花灌木的害虫种类和天敌种类其危害情况,以期完善张家口市观花植物害虫名录,为园林植保工作提供理论基础.结果表明:所调查的草本花卉、花灌木及地被植物均受到不同程度的为害,其中在草本花卉上共调查到害虫26种,天敌10种;在花灌木及地被植物上共调查到害虫25种,天敌10种.     

中国甜柿及其在世界甜柿基因库中的地位

 柿（Diospyros kaki Thunb.）原产中国,但绝大多数为完全涩柿,中国原产完全甜柿（简称中国甜柿）仅在湖北、河南和安徽三省交界的大别山区有分布。主要介绍中国甜柿的栽培历史、地理分布及其变异类型,并重点对其生物学特性、自然脱涩特点及遗传规律等进行总结;此外,还对中国甜柿在世界甜柿的起源与进化、自然脱涩机理和遗传改良研究中的价值进行了阐述。     

松林自然控制松干蚧、松毛虫效应的研究

80年代以来,人们越来越重视以营林为基础的综合防治措施。山东昆嵛山林场多年来全面实行封山育林,把全部林地改造为混交林,松干蚧和松毛虫的危害程度逐年下降,连续16年有虫不成灾。为了探索其原因,寻求长期控制虫害的途径,在以前研究基础上,进一步研究了日本松干蚧发生和松树死亡的环境因子,以及影响这些因子的相互关系,试图通过营林保护措施,在松林里造成一种有利于有益生物生存繁衍,提高松树速生丰产的生境;抑制主要虫害的发生,从而促进松林自然控制松于蚧[Matsucoccus matsumurae(Kuwana)]、松毛虫(Dendrolimus spectabilis Butler)的生态效应。现将1987～1989年的研究结果报道如下。