间作对番茄黄化卷叶病毒病发生的影响

番茄黄化卷叶病毒的流行危害引起番茄产量大幅度下降，番茄间作其它作物，可减轻媒介昆虫传毒，是综合防治番茄黄化卷叶病毒的有效方法之一。番茄间作黄瓜、玉米、菜用大豆、黄秋葵、红薯后对发病情况及白粉虱虫口密度的影响试验结果表明，定植58d后，病害发生达高峰期；白粉虱成虫迁飞高峰在1月份，1月中旬至2月中旬白粉虱幼虫虫口密度最大；定植后37、47、58、78d，不同间作作物上白粉虱幼虫虫口密度有显著或极显著差异；黄瓜、菜用大豆是白粉虱偏爱的寄主植物；番茄间作菜用大豆、玉米、红薯、黄瓜对番茄黄化卷叶病毒有一定防效。     

Variation in Genotype and Aggressiveness of Ralstonia solanacearum Race 1 Isolated from Tomato in Taiwan

ABSTRACT A population of Ralstonia solanacearum race 1 from tomato (Lycopersicon esculentum) was analyzed for genetic polymorphism and aggressiveness on tomato. The 46 strains were collected from main tomato-growing areas in Taiwan. Genetic analysis was achieved by two polymerase chain reaction (PCR)-based methods: REP-, ERIC-, and BOX-PCR (collectively as rep-PCR) and random amplified polymorphic DNA (RAPD) techniques. RAPD (with three 10-mers) and rep-PCR revealed 35 and 30 haplotypes, respectively, that were grouped in 14 clusters and 3 clusters, respectively. Distribution of strains into genetic clusters did not appear related to biovar or geographic origin in considering RAPD, rep-PCR, or composite data. Although strains were more dissimilar based on RAPD data than on rep-PCR data, the two techniques gave complementary results for strain clustering. A set of 40 strains representing the main haplotypes was inoculated on six tomato cultivars differing in their bacterial wilt resistance. Six groups differing in general level of aggressiveness and cultivar specificity were detected. Although populations were highly diverse in both genotype and aggressiveness, no association was found between the two characteristics. Although the sample sizes in this study were not adequate to draw definite conclusions about population structure, these results will be valuable for future population genetic studies on R. solanacearum.     

绿豆白粉病的遗传

本文以白粉病敏感品种UT1和抗性品种组成的5个杂交组合为材料,研究了绿豆白粉病的遗传模式和遗传力。结果表明：UT1为白粉病高敏感品种,VC3528A和VC1560A为高抗品种,VC3890A和VC1482A为抗性品种,而VC3543A为中抗材料;白粉病在3个组合中由单个显性基因控制,但在一个组合中由两个显性基因控制,在组合3中,白粉病为多基因控制,遗传力为40.31%。     

Effect of Dietary Essential Fatty Acids and Vitamins on Egg Quality in Turbot Broodstocks

Varying egg quality is one of the main factors interfering with the reliable performance of marine fish hatcheries. As larval performance during the first period largely depends on the availability of essential nutrients, the endogenous provision of these nutrients through the egg stages, and possibly parental diet, might be an important tool in improving hatchery output. Therefore, several feeding experiments were conducted on turbot (Scophthalmus maximus) broodstock reared under production conditions at two commercial facilities in France: France Turbot (FT) and Sepia Conseil (SC). Diets varied mainly in essential fatty acids (-3 HUFA), Vitamins C and E, and were fed for 2–3 months prior to the reproductive season. Egg quality parameters, i.e. fertilization and hatching rate, egg and oil droplet diameter, and biochemical composition, were monitored for each female during its total reproductive phase.Egg size during the reproductive cycle showed a low variability among females receiving the same treatment, but became significantly smaller as the season progressed. The same occurred for the oil globule in the non-vitamin supplemented groups, whereas it significantly increased in the vitamin-supplemented groups. However, these observations could not be correlated with any of the hatching or fertilization characteristics. The egg dimensions also varied as a function of the diet supplied, i.e. high HUFA levels in the broodstock diet resulted in a significant increase of egg diameter, oil globule diameter as well as fertilization rate. Interestingly, the control groups, with the lowest fertilization rate, had the highest hatching percentage, significantly higher than the HUFA/non-vitamin enriched groups.Using non-selected sources of trash fish as a food source at SC resulted in low levels of ascorbic acid (AA) in the eggs compared to the administration of an optimal quality batch of mackerel at FT. Enrichment of the trash fish with ascorbate-2–polyphosphate (ApP) resulted in a tripling of the AA content. Extra enrichment of the FT control diet did not further increase the levels in the eggs, suggesting that a saturation level was obtained. The major fatty acids in turbot eggs as well as freshly hatched larva are 16:0, 18:1-9, 20:5-3 and 22:6-3, but no obvious changes in their pattern could be detected for the different broodstock treatments. However, the level of 20:4-6 was significantly higher in the control group of FT, and showed a high correlation with the hatching percentage of the eggs obtained from the various broodstock treatments.