Gonzalez M
Catedra de Fitopatologia, Facultad de Ciencias Agrarias Universidad Nacional de Rosario, C.C.14. (2123) Zavalla, Argentina.
Plant Dis. 2000 Aug;84(8):921. doi: 10.1094/PDIS.2000.84.8.921A.
Common rust (Puccinia sorghi) is a chronic disease of corn (Zea mays L.) in Argentina. Factors contributing to the disease include relatively susceptible germ plasm, planting late in the season, and variability within populations of P. sorghi. Several genes for race-specific resistance to common rust (i.e., Rp genes) were identified based on virulence in populations of P. sorghi in the United States (1). The objective of this research was to examine the virulence of Argentine populations of P. sorghi against 24 alleles at four Rp loci that condition race-specific resistance to common rust. Rp genes in an R168-inbred background were planted in trials at two locations in the central corn belt of Argentina. In the 1996-97, 1997-98, and 1999-2000 seasons, trials were planted in Pergamino (Province of Buenos Aires). In the 1998-99 season, the trial was planted in Zavalla (Province of Santa Fe). Plants were exposed to naturally occurring local populations of P. sorghi. About 3 to 4 weeks after anthesis, rust severity (percentage of leaf tissue with uredinia) and infection type were rated for all plants. Four categories of infection type were: 1-no rust, necrotic or chlorotic flecks, 2-small uredinia with or without necrotic flecks, 3-large uredinia, and 4-large uredinia with banding. Three lines with Rp genes (Rp1-N, Rp3-A, and Rp3-C) had infection type 1 with necrotic flecks and severity of 0%. Lines with other Rp genes (Rp1-A, Rp1-B, Rp1-C, Rp1-D, Rp1-E, Rp1-F, Rp1-G, Rp1-H, Rp1-I, Rp1-J, Rp1-K, Rp1-M, Rp1-N, Rp3-A, Rp3-B, Rp3-C, Rp3-D, Rp3-E, Rp4-A, Rp4-B, and Rp5) had infection types 2 to 4 and severity ranged from 5 to 35%. Severity was affected by the virulence of the populations and the environmental conditions in each trial. These results are evidence of a wide spectrum of virulence in P. sorghi populations in Argentina. Reference: (1) W. Hagan and A. Hooker. Phytopathology 55:193, 1965.
普通锈病（Puccinia sorghi）是阿根廷玉米（Zea mays L.）的一种常见病害。导致该病的因素包括种质相对易感、季节后期播种以及P. sorghi种群内的变异性。基于美国P. sorghi种群的毒性，鉴定出了几个对普通锈病具有小种特异性抗性的基因（即Rp基因）(1)。本研究的目的是检测阿根廷P. sorghi种群对四个Rp位点上24个等位基因的毒性，这些位点决定了对普通锈病的小种特异性抗性。在阿根廷中部玉米带的两个地点进行了试验，种植了R168自交系背景下的Rp基因。在1996 - 97、1997 - 98和1999 - 2000季节，试验在佩尔加米诺（布宜诺斯艾利斯省）进行。在1998 - 99季节，试验在萨瓦利亚（圣菲省）进行。植株暴露于自然存在的当地P. sorghi种群中。在开花后约3至4周，对所有植株的锈病严重程度（有夏孢子堆的叶片组织百分比）和感染类型进行评级。感染类型分为四类：1 - 无锈病，坏死或褪绿斑点；2 - 有或无坏死斑点的小夏孢子堆；3 - 大夏孢子堆；4 - 有条纹的大夏孢子堆。三条带有Rp基因的品系（Rp1 - N、Rp3 - A和Rp3 - C）感染类型为1，有坏死斑点，严重程度为0%。带有其他Rp基因的品系（Rp1 - A、Rp1 - B、Rp1 - C、Rp1 - D、Rp1 - E、Rp1 - F、Rp1 - G、Rp1 - H、Rp1 - I、Rp1 - J、Rp1 - K、Rp1 - M、Rp1 - N、Rp3 - A、Rp3 - B、Rp3 - C、Rp3 - D、Rp3 - E、Rp4 - A、Rp4 - B和Rp5）感染类型为2至4，严重程度在5%至35%之间。严重程度受每个试验中种群毒性和环境条件的影响。这些结果证明了阿根廷P. sorghi种群中存在广泛的毒性。参考文献：(1) W. Hagan和A. Hooker。植物病理学55:193, 1965。
