小麦秆锈菌不同小种间竞争能力的研究

本试验首次在小麦成株期把我国致病力较弱的优势小种21C3和致病力较强的低频或稀有小种34C2、34C4及116的新鲜夏孢子等量混合后,在长江流域选出的8个感病品种上继代转接。试验结果表明:温室转接5代与田间重复侵染3代后,小种21C3出现频率显著上升,小种34C2频率明显下降,小种34C4和116则下降更快,甚至完全消失。小种21C3与34C2、34C4和116相比或小种34C2与34C4和116相比,其出现频率都表现极显著差异。而小种34C4和116之间则差异不明显。说明小种21C3致病力虽不强,但竞争能力最强,故在自然界能维持优势;34C2竞争能力弱于21C3,但强于34C4和116,而且致病力较强,故在自然界也能维持一定数量。小种34C4和116致病力虽强,但竞争能力极弱,因此在自然界数量极少。     

Race-specific reaction of resistance to black rot in Brassica oleracea

Several black rot-resistant varieties of Brassica oleracea showed a race-specific hypersensitive response (HR) to inoculation with Xanthomonas campestris pv. campestris isolates of different races. In progenies of cabbage line PI436606, Portuguese kale ISA454 and Chinese kale SR1 the HR to race 1 of the pathogen was controlled by a dominant gene named R1, when a recessive gene r5 was responsible for the HR to race 5. Genes with a similar race-specific reaction were assumed on the basis of gene-for-gene interaction in black rot-resistant Japanese cabbage cultivars and double haploid lines obtained from them. Homology of gene r5 in cabbage lines PI436606, Fujiwase 01 and kale ISA454 was postulated in crosses between those lines or their progenies. In a cross between SR1 and PI436606, interaction between resistance to race 1 and non-specific resistance localized in the stem vascular system was found. On the basis of pedigree information and homology of resistance genes in the cultivars of East-Asian cabbage and Portuguese kales, the probable origin of race-specific resistance to black rot of cole crops was suggested to be in heading Mediterranean kale. Some evidence was found for a gene conferring resistance to race 4 in B. oleracea.     

黑龙江省稻瘟病菌生理小种监测研究

2001～2006年,广泛监测黑龙江省各主要稻区稻瘟病菌生理小种种类、分布及消长动态,鉴定了189个单孢分离菌株,共监测出7群28个中国小种.ZA、ZD、ZB菌群检出频率分别为42.3%、28.6%、17.5%,为黑龙江省目前主要菌群;ZA49、ZD1出现频率为21.7%、21.2%,为优势小种.ZA、ZD、ZB菌群呈明显上升趋势,ZE、ZF菌群迅速下降.     

阴山北麓地区向日葵列当生理小种的鉴定及种子的单株纯化

向日葵列当是一种全寄生的种子植物,对向日葵生产造成严重的影响,而选育抗列当品种是目前防控向日葵列当最为有效的防控措施。由于向日葵列当种群存在生理小种分化现象,因此明确不同地区的向日葵列当生理小种的类型以及分布对于抗列当品种的布局非常重要。本研究利用国际通用的向日葵列当生理小种鉴别寄主,对阴山北麓地区的武川县和四子王旗共计7个向日葵地块中采集的列当种子的生理小种进行了鉴定,结果表明除了呼和浩特市武川县头号村采集的向日葵列当样本为E小种外,其他6个不同地点采集到的向日葵列当样本均鉴定为G小种。为了更好地对向日葵品种抗列当水平进行准确的评价,本研究选择了已经鉴定为E、F和G三个小种类型的向日葵列当的样本进行了单株纯化以及扩繁。扩繁得到的列当的种子将用于准确评价向日葵不同的育种材料和品种对列当不同生理小种的抗性水平。     

Effect of annealing from traditional nixtamalisation process on the microstructural,thermal, and rheological properties of starch and quality of pozole

Eleven maize landraces were evaluated for pozole quality. The microstructural, thermal and rheological properties of annealed starch granules determine most of the quality of pozole. Annealed starch in traditional nixtamalisation has an important role in increasing gelatinisation onset (To), peak (Tp) and final (Tf) temperatures; peak, setback and final viscosity as well as the stability of the starch granule, all of which significantly affect pozole quality. Annealed starch in Cacahuacintle nixtamal (pozole end-use) increased temperatures To, Tp and Tf by >5.2, >3.8 and >4.1 °C respectively, and narrowed the range Tf − To from 13.78 to 12.62 °C. The enthalpy was reduced from 6.76 to 5.85 J/g, while the nixtamal starch in tortilla maize landraces presented fewer annealing effects. The annealing effect in nixtamal starch seems to stabilize the starch granules and avoid their collapse, compared to native starch, as shown by the X-ray diffraction peak intensity and pattern that is similar to unprocessed maize. Starch in nixtamal changes from Type A to Type V pattern in pozole. Kernel physical parameters, although important, affected the quality to a lesser extent, with the exception of the flotation index. Cacahuacintle maize landrace showed the best quality and yield as well as a short pozole cooking time.     

Taxonomy of Mexican landraces of maize,Zea mays,based on their resistance to European corn borer,Ostrinia nubilalis

Summary The resistance to the European corn borer, Ostrinia nubilalis (Hubner), of thirty-seven indigenous landraces of Mexican maize was examined. The relationship of resistance and existing taxonomy of maize according to Wellhausen et al., (1952), was subjected to numerical analyses. Variables examined were: seedling DIM-BOA content, the extent of leaf feeding damage by early instar larvae both in the field and in the laboratory, the extent of plant breakage and stalk tunneling by late instar larvae, plant height, and the extent of fungal damage by Gibberella zeae and Ustilago maydis. Significant differences in resistance among the major taxonomic groupings were reflected in the existing taxonomy of maize (Wellhausen et al., 1952). The most resistant landrace grouping was Wellhausen et al.'s Prehistoric Mestizos. Eighty-five percent of a series of modern inbred lines, pools, and Argentine landraces were found to have affinities with one of the more susceptible groupings, the Ancient Indigenous Races, based upon analysis of the resistance data.     

Estimation of the Isozymatic Genetic Variability of a Spanish A vena sativa Germplasm Collection

An analysis of Spanish land races of Avena sativa from the Germplasm Bank of the I.N.I.A. was carried out using starch gel electrophoresis. Samples of 15 seedlings per accession were used for estimating the intra- and interpopulational genetic variability. Electrophoretic analyses were performed with crude extracts from 15 day-old seedling leaflets by means of eight isozymatic systems representing a total of ten genetic loci. Two systems were mono-morphic in all the accessions, while the other six showed polymorphism both within and between populations. Intrapopulational variability was particularly high in this collection, only 16 out of the 137 accessions being uniform for all the isozyme systems. Thus the material was shown to represent a high potential of genetic variability for breeding programmes.     

我国小麦条锈菌对非小麦属植物的寄生专化性

供试的小麦条锈菌每一个中国生理小种都可以侵染多个非小麦属植物的种和属,并表现出与在小麦上相类似的寄生专化性。同一生理小种的寄生性,因供试植物的属,种或种内材料的不同而有差异。小麦条锈菌生理小种在小麦品种水平上的寄生范围,与在非小麦属植物属种水平上的寄生范围有关。     

Genetics of Resistance to Four Races of Xanthomonas campestris pv. oryzae in Some Rice Cultivars

Inheritance of resistance to four Philippine races of bacterial Might caused by Xanthomonas campestris pv. oryzae was investigated in four cultivars of rice, Oryza sativa L. Resistance to three races in ‘Benamuri’ and ‘Aus 192’ is governed by xa-5. In ‘Tepal Boro’ and ‘Bazail 975′, resistance to races 1, 2. and 3 is conferred by xa-5, but another recessive gene confers resistance to race 4. This recessive gene is closely linked to xa-5 and may be allelic to xa-13. Rice cultivars with xa-13 are resistant to prevalent races of bacteria] blight in the Indian subcontinent and should thus prove useful as donors for resistance to bacterial blight in rice breeding programs.     

Morphological diversity in sorghum germplasm from India

Summary Of the 5000 sorghum (Sorghum bicolor L. Monench) germplasm accessions assembled at ICRISAT Asia Center (IAC), over 4000 accessions from 11 major sorghum growing states in India were evaluated for morphological and agronomical characters at IAC during rainy and postrainy seasons.Considerable diversity was observed for all the characters studied. Diversity was more among states than within states. Variation among the seasons was also considerable. Days to flowering ranged from 42 to 129 days during postrainy and 33 to 180 days during the rainy season indicating their day length sensitivity. Plant height ranged from 65 to 330 cm during postrainy and 75 to 655 cm during rainy season. Panicle length ranged from 5 cm to 52 cm and panicle width from 1 to 51 cm. Erect and compact panicles are more frequent although all possible panicle shapes and compactness were found. In general, sorghums from India produce medium to large, lustrous grains in which the subcoat (testa) is absent. All the 5 basic and 10 intermediate sorghum races were found in India though durra or half-durra predominate. Racial diversity is maximal in the state of Andhra Pradesh followed by Maharashatra state. In the world collection a majority of the sources of resistance to shoot fly, stem borer, and striga are from India. Based on diversity for morphological and agronomical characters, India could be considered as the secondary center of diversity. Sorghum germplasm from India is useful for good quality large grain.