Mian Rouf, Bond Jason, Joobeur Tarek, Mengistu Alemu, Wiebold William, Shannon Grover, Wrather Allen
United States Department of Agriculture-Agricultural Research Service (USDA-ARS), The Ohio State University, Wooster 44691.
Southern Illinois University, Carbondale 62901.
Plant Dis. 2009 Apr;93(4):408-411. doi: 10.1094/PDIS-93-4-0408.
Frogeye leaf spot (FLS) of soybean, caused by Cercospora sojina, has been a problem in the southern United States for many years and has recently become a greater problem in the northern United States. Cultivars resistant to FLS have been developed for planting in the southern United States and resistance in many of these cultivars is conditioned by the Rcs3 gene. This gene conditions immunity to all known races and isolates of the pathogen. Resistance to C. sojina in soybean genotypes (cultivars and breeding lines) adapted to north-central U.S. production region is unknown. The objectives of this study were to (i) identify maturity group (MG) III, IV, and V soybean genotypes resistant to C. sojina race 11 by field screening at multiple locations over years and (ii) determine whether FLS resistance in these genotypes is likely to be conditioned by the Rcs3 gene. In total, 1,350 genotypes were evaluated for resistance to race 11 in field trials, and 13 MG III, 45 MG IV, and 15 MG V genotypes did not develop symptoms of FLS. Of these, 54 were subsequently tested for the possible presence of Rcs3 using five molecular markers located within 2 centimorgans (cM) of the gene. None of the MG III genotypes tested had the Rcs3 haplotype of cv. Davis, the source of Rcs3; six of the MG IV genotypes and seven of the MG V genotypes had the Rcs3 haplotype. This is the first report of the presence of the Rcs3 haplotype in LN 97-15076 and S99-2281. The soybean genotypes predicted to have the Rcs3 gene and other genotypes with no FLS symptoms in field trials may be useful in developing soybean cultivars with broad resistance to FLS and adapted to the northern United States.
由大豆尾孢菌引起的大豆蛙眼病（FLS）多年来一直是美国南部的一个问题，最近在美国北部也成为了一个更严重的问题。美国南部已培育出抗FLS的品种用于种植，其中许多品种的抗性由Rcs3基因决定。该基因对病原体的所有已知小种和分离株具有免疫作用。适应美国中北部生产地区的大豆基因型（品种和育种系）对大豆尾孢菌的抗性尚不清楚。本研究的目的是：（i）通过多年在多个地点进行田间筛选，鉴定对大豆尾孢菌11号小种具有抗性的成熟组（MG）III、IV和V大豆基因型；（ii）确定这些基因型中的FLS抗性是否可能由Rcs3基因决定。在田间试验中，总共对1350个基因型进行了对11号小种的抗性评估，13个MG III、45个MG IV和15个MG V基因型未出现FLS症状。其中，随后使用位于该基因2厘摩（cM）范围内的五个分子标记对54个进行了Rcs3可能存在情况的检测。所检测的MG III基因型中没有一个具有Rcs3基因供体品种Davis的单倍型；6个MG IV基因型和7个MG V基因型具有Rcs3单倍型。这是在LN 97 - 15076和S99 - 2281中存在Rcs3单倍型的首次报道。预计具有Rcs3基因的大豆基因型以及在田间试验中无FLS症状的其他基因型，可能有助于培育对FLS具有广泛抗性且适应美国北部的大豆品种。
