44份大豆微核心种质抗菌核病鉴定与评价

大豆菌核病又称白腐病，是一种真菌性病害。主要由真菌 Sclerotinia sclerotiorum (Lib.) de Bary侵染，是世界范围的大豆病害，也是我国大豆主产区的主要病害。本研究利用不同地区和寄主来源的4个菌核病分离物对44份大豆微核心种质进行连续2年的田间接种鉴定，筛选抗/耐菌核病的大豆种质资源，为大豆抗菌核病育种提供优异抗性种质。结果表明，(1)不同大豆种质对菌核病的抗性不同，在44份微核心种质中，中抗种质6份(13.64%)，中感种质27份(61.36%)，感病种质9份(20.45%)，高感I种质2份(4.55%)，其中合丰24、大天鹅蛋、倪丁花眉豆、牛毛黄、大黄豆和五月黄6个中抗种质可作为抗性亲本用于大豆抗菌核病育种。(2)不同地区和寄主来源的4个菌核病分离物致病性不同，分离物黑西5(黑龙江省，大豆)，病情指数49.32，病斑长度达到5.93 mm，致病性最强；黑饶24(黑龙江省，大豆)与Qin 24(青海省，油菜)致病性次之；Hef 50(安徽省，油菜)，病情指数为39.02，病斑长度为3.65 mm，致病性最弱。用黑西5鉴定和筛选抗菌核病大豆种质最为有效。

Identification and Evaluation for Resistance to Sclerotinia Stem Rot in 44 Soybean Mini Core Collections

Sclerotinia stem rot, also called white mould, is a fungal pathogen disease worldwide in soybean caused by Sclerotinia sclerotiorum (Lib.) de Bary. A total of 44 soybean cultivars were inoculated with four isolates of S. Sclerotiorum from different geographical regions and host plants in the two consecutive years experiment in the field to screen excellent germplasm for its resistance breeding. The results were as follows: (1) Different soybean cultivars had different resistance level to S. sclerotiorum. Among them, six cultivar (13.64%) were moderate resistant; twenty-seven (61.36%) were moderate susceptible; nine (20.45%) were susceptible; two (4.55%) were highly susceptible, showing that soybean cultivars with resistance to S. sclerotiorum are rare. Six soybean cultivars with moderate resistance, i.e. Hefeng 24, Big Swan egg, Nidinghuamei soybean, Niumaohuang, Big soybean and May soybean, could be used for soybean breeding for S. sclerotiorum resistance. (2) The pathogenicity of S. sclerotiorum isolates from different geographical regions and host plants is different. Isolate Heixi 5 from the soybean field of Heilongjiang had the strongest pathogenicity with 49.32 in DSI and 5.93 mm in lesion length. Isolate Heirao 24 from the soybean field of Heilongjiang and isolate Qin 24 from the oilseed rape field of Qinghai province had the moderate pathogenicity. Isolate Hef 50 from the oilseed rape field of Anhui province was the weakest in infection, with 39.02 in DSI and 3.65 mm in the lesion length. In conclusion, isolate Heixi 5 is the best one for effectively screening for the resistance to S. sclerotiorum in soybean breeding.