Occurrence and pathogenicity of Puccinia coronata var avenae f. sp. avenae on oat in South Africa

2020 ◽  
Vol 133 ◽  
pp. 105144
Author(s):  
W.H.P. Boshoff ◽  
Z.A. Pretorius ◽  
T. Terefe ◽  
B. Visser
Plant Disease ◽  
2001 ◽  
Vol 85 (10) ◽  
pp. 1085-1090 ◽  
Author(s):  
B. D. van Niekerk ◽  
Z. A. Pretorius ◽  
W. H. P. Boshoff

Although crown rust (caused by Puccinia coronata f. sp. avenae) and stem rust (caused by Puccinia graminis f. sp. avenae) are generally considered to be the most widespread and damaging diseases of oat (Avena spp.) in South Africa, pathogenic variability has never been studied. During 1997 and 1998, one dominant crown rust pathotype (SBLL) was identified with virulence to resistance genes Pc40, Pc45, Pc46, Pc51, and Pc54. Four other pathotypes (SGLL, PBBB+Pc35, SDQL, and JBBM+Pc35), occurring at low frequencies and further rendering resistance genes Pc35, Pc39, Pc48, Pc50, Pc52, and Pc64 ineffective, were also detected. Resistance gene Pc40 was postulated in Wisconsin X1588-2; Pc51 in Euro, Maluti, Overberg, OX88I 075-106, Perdeberg, and Swartberg; and Pc39 was confirmed in the cultivar Fidler. During the same period, four stem rust pathotypes were identified with virulence to resistance genes Pg1, Pg2, Pg4, Pg8, Pg9, Pg12,Pg15, and Pga. Resistance gene Pga was postulated in Alpha, OX87 080-1, OX88I 075-106, Sederberg, and W94/4; Pg2 and/or Pg4 in Euro, Perdeberg, Potberg, and Swartberg; and Pg9 in Pallinup and Victorian. Collections of wild oat species Avena fatua, A. byzantina, A. sterilis, and A. barbata were susceptible to all crown rust patho-types, while the four stem rust pathotypes were virulent on all species except A. barbata.


1972 ◽  
Vol 1 ◽  
pp. 27-38
Author(s):  
J. Hers

In South Africa the modern outlook towards time may be said to have started in 1948. Both the two major observatories, The Royal Observatory in Cape Town and the Union Observatory (now known as the Republic Observatory) in Johannesburg had, of course, been involved in the astronomical determination of time almost from their inception, and the Johannesburg Observatory has been responsible for the official time of South Africa since 1908. However the pendulum clocks then in use could not be relied on to provide an accuracy better than about 1/10 second, which was of the same order as that of the astronomical observations. It is doubtful if much use was made of even this limited accuracy outside the two observatories, and although there may – occasionally have been a demand for more accurate time, it was certainly not voiced.


Author(s):  
Alex Johnson ◽  
Amanda Hitchins

Abstract This article summarizes a series of trips sponsored by People to People, a professional exchange program. The trips described in this report were led by the first author of this article and include trips to South Africa, Russia, Vietnam and Cambodia, and Israel. Each of these trips included delegations of 25 to 50 speech-language pathologists and audiologists who participated in professional visits to learn of the health, education, and social conditions in each country. Additionally, opportunities to meet with communication disorders professionals, students, and persons with speech, language, or hearing disabilities were included. People to People, partnered with the American Speech-Language-Hearing Association (ASHA), provides a meaningful and interesting way to learn and travel with colleagues.


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