Werer Agricultural Research Center, Werer, Afar, Ethiopia.
International Wheat and Maize Improvement Center (CIMMYT), Addis Ababa, Ethiopia.
PLoS One. 2021 Sep 23;16(9):e0249507. doi: 10.1371/journal.pone.0249507. eCollection 2021.
Wheat is one of the high-value major crops in the world. However, wheat stem rust is considered one of the determinant threats to wheat production in Ethiopia and the world. So this study was conducted to assess the disease intensity, seasonal distribution dynamics pattern, the genetic variability of Puccinia graminis f. sp. tritici, and to determine the virulence spectrum in the irrigated ecology of the Awash River Basin. Totally 137 wheat farms were evaluated, from 2014/15-2019/20 in six districts representing the Upper, Middle, and Lower Awash River Basin. Farm plots were assessed, in every 5-10 km intervals, with 'X' fashion, and data on disease incidence, severity, healthy plants were counted and recorded. Diseased samples were collected from the diseased wheat stem by Puccinia graminis physiological and genetic race analysis. The seasonal trend of stem rust disease progress showed its importance to infer the future progresses of the disease for the country's potential production plan of irrigated wheat. The result revealed that the disease prevalence, disease incidence, and severity were significantly varied; among the different districts and seasons in the two regions. The survey results also indicated that about 71.7% of the wheat fields were affected by stem rust during the 2018/19 growing period. The disease's overall incidence and mean severity during the same season were 49.02% and 29.27%, respectively. In 2019/20, about 63.7% of the wheat fields were affected by stem rust, disease incidence 30.97%, and severity 17.22% were lower than the previous season. In 2019/20, even though seasonal disease distribution decreased, the spatial distribution was expanding in Afambo and Dubti districts. Four, stem rust dominant races were identified (TTTTF, TKTTF TKKTF, and TTKTF) by physiological and genetic race analysis during 2018/19 and one additional race (TKPTF) in 2019/20, production year. The result indicated that the races are highly virulent and affect most Sr genes except Sr31 and Sr24. From the race analysis result, TTTTF, and TKKTF have the broadest virulence spectrum race, which affects 90% of the Sr genes. Generally, we can conclude that the spatial and seasonal distribution of the disease is expanding. Most of the races in the irrigated areas in the Basin were similar to that of rain-fed wheat production belts in Ethiopia, so care must be given, to effective management of the diseases, in both production ecologies towards controlling the spore pressure than race variability. Therefore, these findings provide inputs for wheat producers to reduce the spread and disease' damage in the irrigated ecologies of Ethiopia. Also, it gives an insight for breeders to think about the breeding program in their crossing lines.
小麦是世界上高价值的主要作物之一。然而，小麦条锈病被认为是埃塞俄比亚乃至世界小麦生产的决定因素之一。因此，本研究旨在评估埃塞俄比亚灌溉生态系统中条锈病的发病强度、季节分布动态模式、小麦条锈菌生理小种和毒性谱的遗传变异。在 Awash 河流域的六个地区，从 2014/15 年到 2019/20 年，共评估了 137 个农场。在每个农场中，每隔 5-10 公里的距离，以“X”字形评估农田，统计并记录发病、严重度和健康植株的数据。通过小麦条锈菌生理小种和遗传小种分析，从发病的小麦茎秆上采集发病样本。条锈病季节进展趋势表明，它对推断该国灌溉小麦潜在生产计划的未来进展具有重要意义。结果表明，不同地区和季节的发病、发病率和严重度存在显著差异。调查结果还表明，在 2018/19 生长季节，约有 71.7%的麦田受到条锈病的影响。同一季节，病害总发病率和平均严重度分别为 49.02%和 29.27%。2019/20 年，约有 63.7%的麦田受到条锈病的影响，发病率为 30.97%，严重度为 17.22%，低于前一季节。尽管 2019/20 年的季节性病害分布有所减少，但在 Afambo 和 Dubti 地区，病害的空间分布仍在扩大。在 2018/19 年期间，通过生理和遗传小种分析鉴定出 4 个优势小种（TTTTF、TKTTF、TKKTF 和 TTKTF），在 2019/20 年生产年还鉴定出一个额外的小种（TKPTF）。结果表明，这些小种毒性很强，除 Sr31 和 Sr24 外，影响大多数 Sr 基因。从小种分析结果来看，TTTTF 和 TKKTF 是具有最广泛毒性谱的小种，影响 90%的 Sr 基因。一般来说，我们可以得出结论，病害的空间和季节性分布正在扩大。流域灌溉区的大多数小种与埃塞俄比亚雨养小麦生产带的小种相似，因此必须注意在这两种生产生态系统中对病害进行有效管理，以控制孢子压力而不是小种变异。因此，这些发现为小麦生产者提供了输入，以减少病害在埃塞俄比亚灌溉生态系统中的传播和损害。此外，它为培育者提供了在他们的杂交系中思考育成计划的思路。
