Groth J V, Ozmon E A, Busch R H
Department of Plant Pathology.
Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul 55108.
Plant Dis. 1999 Nov;83(11):1033-1038. doi: 10.1094/PDIS.1999.83.11.1033.
Breeders of hard red spring wheat (Triticum aestivum) are attempting to incorporate resistance to scab, caused by Fusarium graminearum. In artificially inoculated, replicated field plots, 37 wheat entries (inbred lines or cultivars) were evaluated for 3 years and an additional 60 entries for 2 of the 3 years for incidence (percent spikes infected), severity (percent infected spikelets within infected spikes), and disease index (percent infected spikelets in 50-spike sample). From year to year, entries had similar index values, with coefficients of determination (r ) ranging from 0.59 to 0.78, with a mean of 0.73. Entries appeared slightly more similar from year to year for incidence than for severity, although both measures of disease had highly significant r values. Incidence and severity were highly correlated in the wheat germ plasm examined; r values in single years ranged from 0.51 to 0.67, with a mean of 0.64. A representative subset of 22 entries was included for a fourth year. None of the measures of disease in year 4 correlated with their counterparts in any of the first 3 years. This loss of repeatability may have been caused by severe lodging or by high temperatures during the evaluation period that accelerated disease progress and wheat maturity during year 4. Incidence and severity remained correlated in year 4 (r = 0.60).
硬红春小麦（普通小麦）育种者正试图培育对禾谷镰刀菌引起的赤霉病具有抗性的品种。在人工接种、重复设置的田间小区试验中，对37个小麦品系（自交系或品种）进行了3年的评估，另外60个品系在3年中的2年进行了评估，评估指标包括发病率（感染穗的百分比）、病情严重程度（感染穗中感染小穗的百分比）和病情指数（50穗样本中感染小穗 的百分比）。年复一年，各品系的病情指数值相似，决定系数（r²）范围为0.59至0.78，平均值为0.73。尽管两种病害指标的r²值都非常显著，但各品系的发病率逐年之间的相似性略高于病情严重程度。在所检测的小麦种质中，发病率和病情严重程度高度相关；单年的r²值范围为0.51至0.67，平均值为0.64。选取了22个有代表性的品系作为第四年的研究对象。第四年的任何病害指标均与前三年中的对应指标不相关。这种重复性的丧失可能是由于严重倒伏或评估期内的高温加速了第四年的病害发展和小麦成熟。发病率和病情严重程度在第四年仍然相关（r² = 0.60）。
