Analysis of correlation between seed-associated fungi and seed vigor of sweet corn

Chinese. 明确甜玉米种子携带真菌种类，探讨真菌与种子活力的相关性。采用洗涤检测法和PDA平板法对市售7个甜玉米品种和2个普通玉米品种进行种子携带真菌检测，同时以滤纸卷法对种子活力进行测定。供试种子外部带菌量差异显著，主要菌群为镰刀菌属（Fusarium spp.）、青霉属 ( Penicillium spp.)、曲霉属(Aspergillus spp.)和枝孢属(Cladosporium sp.)；种子内部带菌率在品种间差异显著，以甜玉米442最高，达到99.3%，普通玉米农大108最低，仅为4.4%；甜玉米种子内部寄藏优势菌群为镰刀菌属、青霉属、曲霉属、链格孢属(Alternaria spp.)、平脐蠕孢属(Bipolaris spp.)和黑孢属(Nigrospora sp.)，其中甜玉米种子内部寄藏平脐蠕孢属真菌为首次报道。除甜单22外，其余6个品种的甜玉米种子内部总体带菌率和带镰刀菌率均显著高于普通玉米品种。甜玉米种子多项活力指标显著低于普通玉米种子。种子内部带镰刀菌率与种子活力相关性分析表明，种子内部寄藏镰刀菌是影响甜玉米种子活力的重要因素之一。

English. The aim of this study is to identify the seed-associated fungi of sweet corn and discuss the correlation between seed-associated fungi and seed vigor. Seed samples of seven sweet corn cultivars and two dent corn cultivars were collected and analyzed for seed-associated fungi by washing test and PDA test, meanwhile seed vigor of all cultivars were evaluated by rolled towel test. The result indicated that Fusarium spp., Penicillium spp., Aspergillus spp, Cladosporium sp. were main species of seed associated fungi on seed surface. The rates of seeds with fungi and seeds with Fuasrium of nine cultivars were significantly different. Sweet corn 442 had the highest rate of seeds with fungi, 99.3%, and Nongda108 had the lowest, 4.4%. The mainly isolated fungi inside seeds were Fusarium sp., Penicillium spp., Aspergillus spp, Alternaria spp., Bipolaris spp., Nigrospora sp. Except for Tiandan22, other six cultivars of sweet corn had significant higher rates of seeds with fungi and seeds with Fusarium than that of dent corn cultivars. Based on the analysis of correlation between the rate of seeds with Fusarium and seed vigor, it was presumed that the seed-born Fusarium might have anegative effect on seed vigor.