Hed Bryan, Ngugi Henry K, Travis James W
Department of Plant Pathology, Penn State University, Lake Erie Regional Grape Research and Extension Center, North East, PA 16428.
Department of Plant Pathology, Penn State University, Fruit Research and Extension Center, Biglerville, PA 17307.
Plant Dis. 2009 Nov;93(11):1195-1201. doi: 10.1094/PDIS-93-11-1195.
The impact of cluster compactness and debris retention on harvest bunch rot of Vitis interspecific hybrid 'Vignoles' was investigated between 2001 and 2005 near Lake Erie, in Pennsylvania. Cluster compactness was characterized subjectively based on the OIV code 204 standard and objectively by determining the number of berries per centimeter of rachis. In 2001, 2002, and 2004, the median number of berries per centimeter for loose clusters was 6.3, 7.0, and 6.4 compared with 10.2, 12.7, and 12.4 for the compact clusters, respectively. Kolmogorov-Smirnoff and the Mann-Whitney U two-samples tests confirmed that the distribution of the berries per centimeter was significantly (90 ≤ χ ≤ 184.3; P < 0.0001) different between the two subjective compactness categories. Cluster compactness was strongly correlated with bunch rot incidence (χ = 73.1 and 62.2 for 2001 and 2002, respectively; P < 0.0001), whereby disease incidence was higher in compact than in loose clusters. Logistic regression analysis indicated that every additional berry per centimeter unit of compactness almost doubled the likelihood of a cluster becoming infected with bunch rot (odds ratio = 1.828, 95% confidence interval [CI] = 1.392 to 2.399 in 2001 and odds ratio = 1.705, 95% CI = 1.394 to 2.085 in 2002). In 2004, bunch rot severity in compact clusters was nearly four times that of loose clusters. Linear regression analysis revealed that berries per centimeter accounted for >89% of the variation in bunch rot severity (R = 0.893, P < 0.0001, n = 30) and >74% in cluster weight (R = 0.745, P < 0.0001, n = 30). Accumulations of dehiscent floral debris contributed to greater bunch rot severity, and the effect was more pronounced in compact clusters than in loose clusters. Removal of basal leaves at trace bloom reduced berries per centimeter by 13% in 2004 and >25% in 2005, with corresponding reductions in bunch rot severity of 60% in 2004 and 62.5 to 82% in 2005. These results indicate that berries per centimeter is a good indicator of cluster compactness in Vignoles, and that practices that reduce cluster tightness would be effective in an integrated program for control of bunch rot on this cultivar.
2001年至2005年期间，在宾夕法尼亚州伊利湖附近，研究了葡萄种间杂种‘维诺’的果穗紧密度和残屑留存对采收时果穗腐烂的影响。果穗紧密度根据国际葡萄与葡萄酒组织（OIV）代码204标准进行主观评定，并通过测定每厘米穗轴上的浆果数量进行客观评定。2001年、2002年和2004年，松散果穗每厘米的浆果数量中位数分别为6.3、7.0和6.4，而紧密果穗分别为10.2、12.7和12.4。柯尔莫哥洛夫-斯米尔诺夫检验和曼-惠特尼U双样本检验证实，两种主观紧密度类别之间每厘米浆果的分布存在显著差异（90≤χ≤184.3；P<0.0001）。果穗紧密度与果穗腐烂发生率密切相关（2001年和2002年的χ分别为73.1和62.2；P<0.0001），紧密果穗的病害发生率高于松散果穗。逻辑回归分析表明，紧密度每增加一个浆果/厘米单位，果穗感染果穗腐烂的可能性几乎翻倍（2001年的优势比=1.828，95%置信区间[CI]=1.392至2.399；2002年的优势比=1.705，95%CI=1.394至2.085）。2004年，紧密果穗的果穗腐烂严重程度几乎是松散果穗的四倍。线性回归分析表明，每厘米浆果数量占果穗腐烂严重程度变异的比例>89%（R=0.893，P<0.0001，n=30），占果穗重量变异的比例>74%（R=0.745，P<0.0001，n=30）。开裂的花残屑积累导致果穗腐烂严重程度增加，且在紧密果穗中的影响比在松散果穗中更明显。在始花期摘除基部叶片，2004年使每厘米浆果数量减少了13%，2005年减少了>25%，相应地，2004年果穗腐烂严重程度降低了60%，2005年降低了62.5%至82%。这些结果表明，每厘米浆果数量是维诺果穗紧密度的良好指标，减少果穗紧密度的措施在该品种果穗腐烂综合防治计划中是有效的。
