Wheat stripe rust in China

2007 ◽  
Vol 58 (6) ◽  
pp. 605 ◽  
Author(s):  
A. M. Wan ◽  
X. M. Chen ◽  
Z. H. He

China has the largest stripe rust epidemic region in the world in terms of wheat acreage affected by the disease. Extensive studies on the epidemiology and management of stripe rust have been carried out since the widespread occurrence of the disease in the 1950s. Fifteen epidemic zones were classified, based on factors influencing the occurrence of wheat stripe rust. The disease can spread inter-regionally, mainly from west to east and from south to north. Winter-wheat growing regions in the north-west, south-west, and north, and spring-wheat growing regions in the north-west are the major epidemic areas. Hotspots of wheat stripe rust are mainly located in south-eastern Gansu and north-western Sichuan, and these areas constitute the inoculum base, centre of diversity, and major over-summering areas of the pathogen. Successful control in over-summering areas is the key to achieving sustainable management of stripe rust in China. Pathogen variability and race virulence have been monitored continuously, and the resistance genetics and background of Chinese wheat cultivars analysed. Effective management of stripe rust includes resistance breeding and application, diversification and deployment of various resistance genes, use of chemicals, adoption of appropriate agricultural practice, and integrated disease management in ‘hotspot’ regions. Collaboration of scientists among various organisations and disciplines is vital. We discuss the progress and challenges of wheat stripe rust management in China.

2020 ◽  
Vol 23 ◽  
pp. 01006
Author(s):  
Ekaterina L. Shaydayuk ◽  
Elena I. Gultyaeva

Wheat yellow rust (causative agent Puccinia striiformis West.) is a widespread disease of common wheat in the North-West Russia. A comparative analysis of P. striiformis populations, collected in the Leningrad region in 2019 on wheat and triticale, by virulence and racial composition was carried out for the first time. Virulence and racial composition of P. striiformis were studied using international and European sets of differentiating varieties and isogenic lines of “Avocet” with 20 Yr genes. A total of 55 single-pustule isolates of P. striiformis were studied, including 31 from common wheat, 10 from durum wheat and 14 from triticale. Using differentiating varieties, 2 races (111E247, 110E247) were identified among isolates from common wheat, 3 races from durum wheat (111E213, 111E231, 111E247), and 5 races from triticale (111E247, 78E209, 79E209, 111E231, 78E215). Using “Avocet” isogenic Yr lines, all isolates were avirulent to lines with the Yr5, Yr10, Yr11, Yr12, Yr15, Yr24, Yr26 genes and virulent to Yr6, Yr7, Yr8, Yr9, Yr18, YrSp, YrJr(18), YrAS genes. Isolates virulent to Yr17 were revealed on triticale; avirulent to YrSk (27) – on durum wheat. and avirulent to YrAR – on triticale. Highly effective Yr genes can be recommended for wheat resistance breeding to to yellow rust.


Author(s):  
Daryl A. Cornish ◽  
George L. Smit

Oreochromis mossambicus is currently receiving much attention as a candidater species for aquaculture programs within Southern Africa. This has stimulated interest in its breeding cycle as well as the morphological characteristics of the gonads. Limited information is available on SEM and TEM observations of the male gonads. It is known that the testis of O. mossambicus is a paired, intra-abdominal structure of the lobular type, although further details of its characteristics are not known. Current investigations have shown that spermatids reach full maturity some two months after the female becomes gravid. Throughout the year, the testes contain spermatids at various stages of development although spermiogenesis appears to be maximal during November when spawning occurs. This paper describes the morphological and ultrastructural characteristics of the testes and spermatids.Specimens of this fish were collected at Syferkuil Dam, 8 km north- west of the University of the North over a twelve month period, sacrificed and the testes excised.


2014 ◽  
Author(s):  
Roald Amundsen ◽  
Godfred Hansen
Keyword(s):  

2003 ◽  
pp. 136-146
Author(s):  
K. Liuhto

Statistical data on reserves, production and exports of Russian oil are provided in the article. The author pays special attention to the expansion of opportunities of sea oil transportation by construction of new oil terminals in the North-West of the country and first of all the largest terminal in Murmansk. In his opinion, one of the main problems in this sphere is prevention of ecological accidents in the process of oil transportation through the Baltic sea ports.


Author(s):  
Angelina E. Shatalova ◽  
Uriy A. Kublitsky ◽  
Dmitry A. Subetto ◽  
Anna V. Ludikova ◽  
Alar Rosentau ◽  
...  

The study of paleogeography of lakes is an actual and important direction in modern science. As part of the study of lakes in the North-West of the Karelian Isthmus, this analysis will establish the dynamics of salinity of objects, which will allow to reconstruct changes in the level of the Baltic Sea in the Holocene.


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