Fine mapping of the gene for susceptibility to black spot disease in Japanese pear (Pyrus pyrifolia Nakai)

Black spot disease, which is caused by the Japanese pear pathotype of the filamentous fungus Alternaria alternata (Fries) Keissler, is one of the most harmful diseases in Japanese pear cultivation. We mapped a gene for susceptibility to black spot disease in the Japanese pear (Pyrus pyrifolia Nakai) cultivar ‘Kinchaku’ (Aki gene) at the top of linkage group 11, similar to the positions of the susceptibility genes Ani in ‘Osa Nijisseiki’ and Ana in ‘Nansui’. Using synteny-based marker enrichment, we developed novel apple SSR markers in the target region. We constructed a fine map of linkage group 11 of ‘Kinchaku’ and localized the Aki locus within a 1.5-cM genome region between SSR markers Mdo.chr11.28 and Mdo.chr11.34. Marker Mdo.chr11.30 co-segregated with Aki in all 621 F₁ plantlets of a ‘Housui’ × ‘Kinchaku’ cross. The physical size of the Aki region, which includes three markers (Mdo.chr11.28, Mdo.chr11.30, and Mdo.chr11.34), was estimated to be 250 Kb in the ‘Golden Delicious’ apple genome and 107 Kb in the ‘Dangshansuli’ Chinese pear genome. Our results will help to identify the candidate gene for susceptibility to black spot disease in Japanese pear.     

1.2%阿维菌素微囊悬浮剂防治松材线虫试验

松材线虫病是松树的一种流行性病害。此病1982年中国在南京市中山陵首次发现,在短短的30多年里,在我国南方很多省市相继发生并流行成灾。通过选用黑龙江省平山林业制药厂生产的1.2%阿维菌素微囊悬浮剂对松材线虫进行防治试验,结果表明:使用该药剂,最佳施药量为每cm胸径施药1.2mL,施药60d后,防治效果达91.67%。     

川滇地区主汛期暴雨洪水灾害风险评价

[目的]对川滇地区主汛期暴雨洪水灾害风险等级分布及特征进行研究,以期为区域暴雨洪水灾害的防御提供理论参考。[方法]采用反距离加权空间插值(IDW),自然灾害风险指数等方法。[结果]暴雨洪水灾害的高、较高风险区主要集中在川东盆地和云南省南部边缘地区;中度风险区主要分布在川西南山地和云南省的大部分地区;较低灾害风险区零星分布在滇东高原、滇西北地区和川西高原东北部等地;低风险区主要位于川西高原地区。[结论]大气环流、降水量、地形地貌、河网水系是影响川滇地区主汛期暴雨洪水灾害的主要因素,人类活动对区域下垫面性质的改变,是加剧暴雨洪水灾害的触动因素。     

Increased frequency of phytosanitary pod removal in cacao (Theobroma cacao) increases yield economically in eastern Peru

Diseases caused by Moniliophthora roreri (moniliasis), Crinipellis perniciosa (witches’ broom) and Phytophthora palmivora (black pod) are the most important factors limiting cocoa production in Peru and cultural management is considered to be the only practical means of control for the smallholder. The objective of this study was to develop an epidemiologically and economically sound control recommendation based on the frequency of phytosanitary pod removal. Weekly removal of diseased pods reduced the incidence of diseases significantly in comparison with fortnightly removal. In three fields, moniliasis was decreased by 26–41%, black pod by 35–66% and witches’ broom on pods by 14–57%. The cumulative effect was a consistent yield increase from an average of 504–660 kg ha⁻¹ yr⁻¹. Returns compensated for increased labour costs. Weekly pod removal was 32% more profitable. Time-course analyses indicated that weekly removal should be practised throughout the year under field conditions of eastern Peru.     

新城疫活疫苗对控制鸡大肠杆菌病的效果观察

为了研究鸡新城疫活疫苗紧急免疫控制鸡大肠杆菌病的效果,通过大肠杆菌人工感染30日龄蛋鸡,待出现病症后,紧急免疫新城疫La-sota弱毒苗(Ⅳ系)4羽份.免疫后5～17 d,通过血凝抑制试验测定血清新城疫抗体水平,试验组新城疫抗体水平逐步提高,对照组抗体略有下降,免疫后17 d两组抗体水平差异显著(P＜0.05);对照组...     

东江中上游3种造林树种的光合-光响应特征

 以东江中上游6年生的山乌桕、枫香和南酸枣为材料,采用LI-COR公司L i-6400光合作用测定系统测定光合、蒸腾、水分利用效率等生理参数及其光响应过程,探讨3树种在自然生境条件下的光合-光响应特征。结果表明:3树种光合-光响应曲线均符合非直角双曲线模型(R2>0.98)和指数模型(R2>0.98);3树种表观量子效率和暗呼吸速率均表现为山乌桕>南酸枣>枫香,山乌桕在弱光下光合能力要高于枫香和南酸枣,但对光合产物消耗大;山乌桕最大净光合速率与枫香、南酸枣间差异显著(0.05);3树种介于阴生植物和阳生植物之间,山乌桕对强光的适应能力较好,对光照强度表现出一定的适应性和可塑性,具有较宽的光照生态幅,对弱光与强光的利用能力较高;3树种净光合速率光响应均值表现为山乌桕>南酸枣>枫香,耗水能力表现为山乌桕>南酸枣>枫香,而水分利用效率表现为枫香>山乌桕>南酸枣。