Mian M A R, Boerma H R, Phillips D V, Kenty M M, Shannon G, Shipe E R, Blount A R Soffes, Weaver D B
Department of Crop and Soil Sciences, University of Georgia, Athens 30602-7272.
Department of Plant Pathology, Georgia Experiment Station, Griffin 30223.
Plant Dis. 1998 Sep;82(9):1017-1021. doi: 10.1094/PDIS.1998.82.9.1017.
Frogeye leaf spot (FLS) caused by Cercospora sojina Hara is a disease of soybean (Glycine max (L.) Merr.) that causes significant seed yield losses in warm, humid environments of southeastern United States. The Rcs gene in soybean has been reported to condition resistance to all known races of C. sojina. The objectives of this study were to determine the effectiveness of Rcs in limiting seed yield loss due to FLS and to compare the seed yield of the resistant and susceptible near-isolines (NILs) in the absence of significant FLS disease. Four pairs of NILs-Colquitt/Colquitt-Rcs, Gordon/Gordon-Rcs, Thomas/Thomas-Rcs, and Wright/Wright-Rcs -were evaluated in 23 field experiments in Alabama, Florida, Georgia, Louisiana, Mississippi, and South Carolina during 1992 to 1994. The amount of damage to susceptible soybean caused by FLS was dependent on the specific environment. All four of the Rcs NILs were resistant to the prevalent races of FLS in all environments. In the absence of significant FLS disease, each of the Rcs NILs was at least equal to the respective susceptible line in its seed yield. In the presence of FLS infestation, the susceptible lines suffered significant seed yield loss (up to 31%) compared to their Rcs NILs. The effect of FLS on seed yield was dependent on cumulative disease severity over the growing season. Thus, the area under disease progress curve was more useful than percent of leaf area infected at the end of the growing season (R7 stage of development) in explaining the seed yield loss due to FLS.
由大豆尾孢菌（Cercospora sojina Hara）引起的蛙眼叶斑病（FLS）是大豆（Glycine max (L.) Merr.）的一种病害，在美国东南部温暖潮湿的环境中会导致显著的种子产量损失。据报道，大豆中的Rcs基因对所有已知的大豆尾孢菌小种都具有抗性。本研究的目的是确定Rcs在限制因蛙眼叶斑病导致的种子产量损失方面的有效性，并比较在没有严重蛙眼叶斑病的情况下抗性和感病近等基因系（NILs）的种子产量。1992年至1994年期间，在阿拉巴马州、佛罗里达州、佐治亚州、路易斯安那州、密西西比州和南卡罗来纳州的23个田间试验中，对四对NILs——科尔奎特/科尔奎特-Rcs、戈登/戈登-Rcs、托马斯/托马斯-Rcs和赖特/赖特-Rcs进行了评估。蛙眼叶斑病对感病大豆造成的损害程度取决于具体环境。在所有环境中，所有四个Rcs NILs对蛙眼叶斑病的流行小种都具有抗性。在没有严重蛙眼叶斑病的情况下，每个Rcs NILs的种子产量至少与各自的感病品系相当。在有蛙眼叶斑病侵染的情况下，与它们的Rcs NILs相比，感病品系的种子产量遭受了显著损失（高达31%）。蛙眼叶斑病对种子产量的影响取决于整个生长季节的累积病害严重程度。因此，在解释因蛙眼叶斑病导致的种子产量损失方面，病害进展曲线下的面积比生长季节结束时（发育的R7阶段）感染叶面积的百分比更有用。
