Krupnik Timothy J, Harun-Or-Rashid Md, Pandit Dinabandhu, Islam Rabiul, Hossain Md Khaled, Fernandes José Mauricio Cunha, Roy Krishna Kanta, Kabir Muhammad Rezaul, Stuerz Sabine, Singh Pawan Kumar, Faruq Golam
International Maize and Wheat Improvement Center (CIMMYT), Dhaka, Bangladesh.
Independent Consultant, Dhaka, Bangladesh.
Crop Prot. 2024 Oct;184:106831. doi: 10.1016/j.cropro.2024.106831.
Originating in South America, wheat blast disease has spread to both Asia and Africa and is considered a significant threat to food security. Bangladesh experienced the first outbreak of wheat blast outside of the Americas in 2016. Shortly thereafter, the blast-resistant variety BARI Gom 33 was released. Seeds of this variety are however not as widely available as required, although the disease threat remains. While varietal mixtures have been shown to mitigate some symptoms and yield losses associated with other fungal diseases in wheat, there is a complete research gap on this topic as it pertains to wheat blast. As such, we evaluated the potential of using BARI Gom 33 as a component of a variety mixture under high disease pressure in Bangladesh. During three cropping seasons, blast symptoms and yield were determined in a field experiment for the highly blast-susceptible variety BARI Gom 26, the moderately susceptible BARI Gom 30, the resistant BARI Gom 33, and seven mixture combinations of the three varieties using artificial inoculation to increase disease pressure. In addition to wheat blast, leaf blight (BpLB) symptoms were observed and evaluated. While yields of the susceptible varieties were severely affected by blast even after fungicide application, disease-inflicted yield loss without fungicide was only 15% for sole BARI Gom 33 and did not differ significantly from yield losses in BARI Gom 33 and BARI Gom 30 mixtures. Furthermore, in the mixture containing 67% BARI Gom 33 and 33% BARI Gom 30, blast incidence and severity were reduced by 25% and 16%, respectively, in comparison to weighted values in sole stands. Conversely, mixing varieties tended to increase the symptoms of BpLB. Under high wheat blast pressure, fungicide protection against blast was relatively weak, underscoring the importance of resistant varieties. Although variety mixtures did not increase yield, the yield advantage of BARI Gom 33 was maintained when its seeds were mixed with the less resistant BARI Gom 30. This study confirms recommendations that farmers should use BARI Gom 33 as a first line of defense against wheat blast in Bangladesh. Yet where farmers cannot access sufficient BARI Gom 33 seed for planting, our data suggest that agricultural extension services can recommend this variety with non-resistant cultivars as interim strategy without significant risk of yield loss.
小麦条锈病起源于南美洲，已蔓延至亚洲和非洲，被视为对粮食安全的重大威胁。2016年，孟加拉国经历了美洲以外的首次小麦条锈病疫情爆发。此后不久，抗条锈病品种BARI Gom 33被推出。然而，尽管病害威胁依然存在，但该品种的种子供应并未达到所需的广泛程度。虽然品种混合已被证明可减轻与小麦其他真菌病害相关的一些症状和产量损失，但在小麦条锈病这一主题上仍存在完全的研究空白。因此，我们评估了在孟加拉国高病害压力下，将BARI Gom 33用作品种混合物成分的潜力。在三个种植季节中，通过人工接种增加病害压力，在田间试验中测定了高感条锈病品种BARI Gom 26、中感品种BARI Gom 30、抗病品种BARI Gom 33以及这三个品种的七种混合组合的条锈病症状和产量。除了小麦条锈病，还观察并评估了叶枯病（BpLB）症状。尽管即使施用杀菌剂后，感病品种的产量仍受到条锈病的严重影响，但单独种植BARI Gom 33时，不使用杀菌剂时病害造成的产量损失仅为15%，与BARI Gom 33和BARI Gom 30混合种植的产量损失没有显著差异。此外，在含有67%BARI Gom 33和33%BARI Gom 30的混合物中，与单独种植的加权值相比，条锈病发病率和严重程度分别降低了25%和16%。相反，品种混合往往会增加叶枯病的症状。在高小麦条锈病压力下，杀菌剂对条锈病的防治效果相对较弱，凸显了抗病品种的重要性。虽然品种混合并未提高产量，但当BARI Gom 33的种子与抗性较弱的BARI Gom 30混合时，其产量优势得以保持。本研究证实了相关建议，即孟加拉国的农民应将BARI Gom 33作为抵御小麦条锈病的第一道防线。然而，当农民无法获得足够的BARI Gom 33种子用于种植时，我们的数据表明，农业推广服务机构可以建议将该品种与非抗病品种混合作为临时策略，而不会有显著的产量损失风险。
