西瓜抗枯萎病鉴定方法研究

STUDIES ON THE METHODS FOR IDENTIFYING WATERMELON RESISTANCES TO FUSARIUM WILT

试验比较了西瓜枯萎病(Fusarium oxysporum f.sp.niveum)苗期鉴定的4种接种方法和浸根法的不同浓度1×10~5、1×10~4、1×10~5、1×106、1×107孢子/ml的效果.以及杂交一代材料“85—26”的室内鉴定结果与疫区表现。结果表明:胚根法易出现于叶畸形(25.8%～47.2%)和烂籽(53.4%);灌根法潜育期长(16～18天);以浸根法最好,孢子培育法次之,潜育期一周,重复性好,结果稳定。浸根法最适浓度为1×10~5～1×10~6孢子/ml。“85—26”的疫区表现与室内鉴定相符。

Experiments were conducted to evaluate: (1)four inoculation methods for identifying resistance of watermelon varieties to fusarium wilt (F. oxysporum f. sp.niveum) at seedling stage: (2) the effects of different inoculum concentrations, i.e.l×10~3. 1×10~4, 1×10~5, 1×10~6, 1×10~7microconidia/ml under root dipping and to compare the results obtained from the nature field test with that of identification in the greenhouse. Results indicated that: embyro root dipping method made the cotyledons abnormal (25.8% 47.2%) and seeds rotten(53.4%); pouring of inoculum suspension had longer incubation period(16—18 days); root dippping was the best method, spore-culturing the second, their incubation periods were shorter (about one week) and the results were consistent. The most suitable inoculum concentrtion was 1×10~5—1×10~6microconidia/ ml. The performance of the hybrid '85 26' in the open field was identical to that in the greenhouse. The procedure which combines root dipping inoculation with spore-culturing method at seedling stage and further test for resistant materials in open field was recommended. It would show accurate and consistent results in comparatively shorter period, and accelerate the process of watermelon breeding resistant to fusarium wilt.