草莓花瓣脱落对果实灰霉病的影响

Effect of Petals Fall off on Botrytis Fruit Rot in Strawberry

【目的】明确衰老花瓣在草莓果实灰霉病中的作用以及草莓花瓣脱落早晚与果实灰霉病发病的关系,为果实灰霉病的防控和抗(耐)灰霉病品种选育提供理论依据。【方法】试验1:以草莓品种‘甜查理’为材料,进行田间试验,摘除至少2 000个果实表面的衰老花瓣,以不摘除花瓣的处理为对照。保持塑料棚内高湿度8 d后,调查不同处理草莓果实灰霉病发病率。试验2:分别在2013、2014和2015年3月草莓盛花期,对11个草莓品种的田间花瓣脱落动态进行调查,每个品种选择20朵刚现蕾的花,记录现蕾后第7、14、21和28天果实上残留的花瓣数量,计算花瓣脱落率;于果实灰霉病发病高峰期,调查不同草莓品种果实灰霉病的发病率,分析现蕾后第7天花瓣脱落率与果实灰霉病发病率的相关性。试验3:对33个草莓品种现蕾后不同天数的花瓣脱落率与果实上残留花瓣数量进行调查,并分析两者的相关性。【结果】试验开始前棚内的草莓果实灰霉病发病率为4.2%;利用自然雨雪天气保持塑料棚内高湿度8 d后,摘除果实上残留衰败花瓣的处理,果实灰霉病的平均发病率为7.3%,对照小区果实灰霉病的平均发病率为25.3%,大部分果实均从与花瓣接触的地方开始感染。在不同试验年份,草莓品种之间的花瓣脱落趋势始终一致。所有草莓品种在花朵现蕾后,随时间延长,花瓣脱落率不断提高,但是不同草莓品种的花瓣脱落速度却有显著差异。不同年份草莓品种‘晶瑶’在现蕾后7 d的花瓣脱落率分别为99.0%、79.8%和94.4%,显著高于‘晶玉’(61.0%、24.0%和62.5%)和‘甜查理’(26.0%、3.8%和31.9%)。2013年调查的5个草莓品种的果实灰霉病发病率与花朵现蕾后第7天花瓣脱落率显著负相关(P<0.05);2014年调查的6个草莓品种,2015年调查的11个草莓品种的果实灰霉病发病率与花朵现蕾后第7天花瓣脱落率都显著负相关(P<0.01)。对33个草莓品种的调查发现,不同草莓品种现蕾后第7天花瓣脱落率与果实上残留花瓣数量显著负相关(P<0.01)。【结论】衰老花瓣是灰葡萄孢(Botrytis cinerea)侵染果实的主要途径,摘除草莓果实上衰老花瓣可显著降低果实灰霉病的发病率。现蕾后第7天的草莓花瓣脱落率与果实灰霉病的发生具有显著负相关性,利用这种避病性,在选育抗灰霉病草莓品种时可优先考虑花瓣脱落早的材料。

【Objective】The role of petal senescence in Botrytis fruit rot（BFR） of strawberry was defined and the relationship between the speed of petal fall and the incidence of BFR was analyzed. The results will provide a practical basis for BFR control and the evaluation of strawberry resistance or tolerance to BFR.【Method】Trial 1： Field trials were conducted on the strawberry cv. ‘Sweet Charlie＇. Senescent petals on the surface of at least 2 000 fruits were removed. The incidences of BFR were evaluated after 8 days with high humidity in plastic greenhouses. Trial 2： Field trials were conducted in Mar. 2013,2014 and 2015 on 11 cultivars. For each cultivar,numbers of senescent petals left on the strawberry surface were recorded at 7,14,21 and 28 days after white bud（DAB）,20 petals per cultivar. Percentages of fallen petals were calculated. The BFR incidences were investigated at the peak of BFR. The correction between the fallen petal rates and the BFR incidences were analyzed using Excel 2007. Trial 3： The petal fall rates and the number of residual petals on fruits of 33 cultivars were investigated and the correction between the two was analyzed.【Result】The BFR incidence was 4.2% at the beginning of the investigation. After 8 days,the average BFR incidence increased to 7.3% and 25.3% for the treatment of deblossoming and control,respectively. For most fruits,the infection origin was the overlap of senescent petals and fruits. For each cultivar,the trend of petal fall rates from year to year was consistent. The fallen petals of all cultivars increased with time; however,the petal-off speeds among cultivars were significantly different. For example,the fallen petal rates of ‘Jingyao＇ at 7 DAB in the year 2013,2014 and 2015 were 99.0%,79.8% and 94.4%,which were significantly higher than ‘Jingyu＇（61.0%,24.0% and 62.5%） and ‘Sweet Charlie＇（26.0%,3.8% and 31.9%）. The results of the correlation analysis showed that the BFR incidences were significantly negatively related with the fallen petal rates at the 7 DAB in different years（P〈0.05 in 2013; P〈0.01 in 2014 and 2015）. The fallen petal rates at the 7 DAB was significantly negatively correlated with the number of residual petals on fruits（P〈0.01）. 【Conclusion】Senescent petals is the main way for Botrytis cinerea to infect the strawberry fruit,therefore,removal of the senescent petals can significantly reduce the BFR incidences. There was significant correlation between fallen petal rates and BFR incidences on strawberry. Strawberry resources which petals fall off early are potential varieties with BFR resistance for the trait of disease escape.