四川省小麦条锈菌群体遗传结构和流行传播规律研究

Wheat stripe rust, a threat to the safety production of wheat , is one of the important biological disasters of food security in China. It has important theoretical significance and economic value to understand stripe rust population genetic structure to control the disease effectively and ensure the security of wheat production. Sichuan Province is the major oversummering area, important overwintering area and the origin place of new race to wheat stripe rust in China, which connect Southwest epidemiological region and Northwest and North epidemiological region in China. It is critical to understand where the rust in Sichuan oversummering area come from and the communication relationship of the rust in oversummering areas between Sichuan Province and neighbouring Provinces. Wheat stripe rust can spread in Sichuan regional and interregional wheat area, which form a local small cycle and the annual major cycle in Sichuan Province. But it still need to further confirm how stripe rust spread in Sichuan Province and whether the rust source in Sichuan overwintering area affect it in neighboring spring epidemics. Through gathering the large-scale rust samples from Sichuan Province and neighbouring Provinces, analyzing the population genetic structure of the rust by SSR markers to confirm the population genetic structure of the rust in different regions of Sichuan Province. Integrating geographic meteorological data, analyzing comprehensively the rule of epidemc and spread of wheat stripe rust in Sichuan and the rust origin in its oversummering area, discussing the exchange relation of the rust between Sichuan Province and neighboring Provinces. This is significant to manage the national stripe rust from original place, and which can be considered as a foundation to lastingly control the disease.

小麦条锈病威胁我国小麦安全生产，是粮食安全的重大生物灾害之一。探明条锈菌自然群体遗传结构对病害有效控制及保障小麦安全生产具重要理论意义和经济价值。四川省是我国小麦条锈菌主要越夏区、新小种策源地和重要冬繁区，连接西南流行区系与华北西北流行区系。探明四川省小麦条锈菌越夏区菌源来源问题以及与邻近越夏区间菌源交流关系至关重要。小麦条锈菌可在四川麦区的地区内和地区之间传播，形成省内局部小循环和周年大循环。四川省条锈病如何流行传播及其冬繁区的菌源是否对邻近省份春季流行造成影响仍需要进一步研究确认。从四川麦区和临近省份麦区大规模追踪采样，用SSR标记方法分析条锈菌群体遗传结构，明确条锈菌在四川省不同区域群体遗传结构。综合地理气象等资料，全面分析四川省小麦条锈菌流行传播规律和其越夏区菌源来源，探讨四川省小麦条锈菌与临近省份菌源交流关系。将对全国小麦条锈病的源头治理具重要意义，为持久控制该病害奠定基础。

四川省是我国小麦条锈菌主要越夏区、新小种策源地和重要冬繁区，连接西南流行区系与华北西北流行区系。探明四川省小麦条锈菌冬繁区菌源来源与邻近省份菌源交流关系至关重要。利用SSR方法分析条锈菌在四川省不同区域群体遗传结构，综合地理、气象、田间和分子数据等资料，分析四川省小麦条锈菌流行传播规律、冬繁菌源来源和与临近省份菌源交流关系。研究结果如下：（1）基于高空风场数据分析，在四川盆地条锈病发病时期，950hPa（约海拔700米）及以下高空气流风向与田间发病路线较为一致。700hpa（约海拔3000米）及以上高主要空气流风向为西南气流可能有利于夏孢子远距离传播。（2）梓潼地区小麦条锈病存在2个流行高峰；每年3-4月是冬繁区的梓潼小麦条锈病流行主要时期；3月上旬以前，发病前10天气温影响梓潼条锈病发病面积，日照和降水次之；发病前第二旬降水比发病前10天的降水更能影响发病面积；（3）除重庆、内江地区遗传多样性较低，其它地区遗传多样性水平较高。基于遗传距离发现南充和绵阳地区群体最近，广元、德阳群体次之，重庆和内江群体聚为一类，资阳群体距离最远。遗传距离能呈现出显著地理区域性，表明不同地理群体间具有明显遗传距离，不同群体基因来源可能不一致。利用Structure软件对7个地理群体小麦条锈病进行聚类分析，广元、南充、绵阳、德阳的小麦条锈病菌遗传结构趋于多样化，内江、重庆、资阳的趋于一致。其中德阳、广元单个样品基因来源较为一致，绵阳和南充单个样品所呈现的基因来源较多。（4）综合地理气象等资料，分析小麦条锈菌在四川盆地及周边地区的菌源交换关系。结果表明，四川盆地可能存在不同时间段多个外来传播路径，川西北、陇南越夏区由北向南传播，陕西汉中方向由广元向西南方向传播，以及发病后期由湖北、贵州和云南等省份传播至重庆、川东南地区。绵阳、南充条锈菌源可能来自川西北高原、甘肃陇南和陕西汉中等地区，导致该地区成为外来菌源的汇合区域。

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