达县分葱田甜菜夜蛾发生规律初步研究

采用系统调查方法研究了达县地区分葱田甜菜夜蛾的生活史、发生与环境的关系。甜菜夜蛾在达县分葱田1a发生6代,以三至五代为害最重,世代重叠。其数量消长与虫源、夏秋季气候、天敌、栽培管理等因素密切相关。通过调查分析提出本县初始虫源非本地虫源。     

Seed production of Chenopodium album in competition with field vegetables

Total weed control within a crop is both difficult and expensive to achieve, so that some weeds will often remain to set seed. The seed production resulting from these weeds will ultimately affect the sustainability of the weed control strategy. If too much is allowed to return each season there could be a gradual, but significant, increase in the potential weed flora over a number of seasons. Field trials were carried out in 2000 and 2001 to quantify the potential magnitude of this weed seed return from Chenopodium album L., grown at two planting densities either in pure stands or in competition with one of two crops (cabbage or onion). Crop and weed weights and weed seed production were notably greater in 2001. Both dry weight and seed production of C. album were suppressed by increasing planting density or by the presence of crop, with cabbage having a more suppressive effect. Despite the plasticity in seed production, a linear relationship was demonstrated between log weed seed production and log weed biomass that was robust over a range of competitive situations with onion and cabbage, at different planting densities and in growing seasons. The study also demonstrated that the relationship could be combined with an existing simple competition model to allow the consequences of incomplete weed control to be assessed in terms of potential weed seed return.     

一种脱水洋葱制品中微生物菌落总数的检测方法

建立一种准确检测脱水洋葱制品中菌落总数的方法.利用离心法对出口脱水洋葱制品中沙门氏菌进行预富集,以提高国标检测方法的致病菌检出率,弥补国标方法的不足,并对该方法的准确度进行评价.试验结果表明,样液中菌体经过高速离心后,99％以上的菌体可以从样液分离.与标准方法比对,高速离心法很好地解决了脱水洋葱粉样液中的抑菌成分的干扰,结果可靠准确,基本满足国标中食品安全标准要求,具有一定的实际推广意义.     

辽葱5号的选育

辽葱5号是以玉田县五叶齐大葱为母本、朝阳鳞棒葱为父本进行有性杂交，对杂交后代进行季节穿梭选择的方法，即用3年时间进行了3个世代的以株为单位的混合选择及以株系为单位的选择，最后留选1个经济性状整齐、生殖性状稳定的雄性可育母系，经系内混合授粉育成的大葱新品种。该葱生长旺盛、秋葱产量高、葱白较长、叶片直立性好、抗紫斑病能力较强，适合长季节栽培，生育期在120d以上，属中晚熟品种。冬贮干葱可食用率高，适宜北方各省、区种植。     

红皮洋葱新品种‘西葱1号’的“一道清”高效栽培技术研究

将“一道清”的高产长效施肥技术在激光诱变选育出的红皮洋葱新品种‘西葱1号’上施用，通过与’常规施肥试验的对比，得出使用这种施肥技术可显著提高肥料利用率25％左右，能满足洋葱生长全过程的需要；还能降低洋葱早期抽薹率50％左右，改善洋葱品质，产量提高5％以上，施肥上用工减少5／4以上。在生产应用上有极好的前景。     

New mite-borne virus isolates from rakkyo,shallot and wild leek species

Flexuous viruses were transmitted from rakkyo (Allium chinense) and wild leek species (especiallyA. commutatum) to plants of crow garlic (A. vineale), by transfer of dry bulb mites. By electron microscope decoration tests using three antisera and by inoculations onto test plants, it was concluded that from each of the two natural host species at least two viruses were isolated. The viruses from wild leeks are both pathogenic onAllium spp. and may be of economic importance. Decoration tests on a virus mixture from shallot obtained earlier, revealed another new mite-borne virus in this species. The mite-borne viruses ofAllium spp. appear to be very common; they are largely diverse and their identification remains difficult.     

Effects of cultural methods and physical weed control on intrarow weed numbers, manual weeding and marketable yield in direct-sown leek and bulb onion

Manual weeding of intrarow weeds in direct-sown leek and bulb onion crops grown organically can be very labour-intensive. Four field experiments, two in direct-sown leek and two in direct-sown bulb onion were made in this investigation to study the effects of physical and cultural methods on intrarow weed numbers, time consumption for hand-weeding and marketable yield parameters. The physical methods considered were: pre-emergence flaming and harrowing, and post-emergence hoeing close to the row (only leek) and vertical brush weeding. The cultural methods were: seed priming, slurry placement and cultivar choice (only leek). Generally, flaming plus brush weeding gave the highest intrarow weed control at 92% and 87%, respectively, in the two leek experiments and 39% (only brush weeding was effective) and 74%, respectively, in the two onion experiments. Time consumption for hand-weeding after the different treatments was linearly related to the remaining numbers of intrarow weeds, with no significant influences of the experimental factors on the general relationship. Generally, the cultural methods had no significant influence on the effects of physical weeding in terms of their effect against intrarow weeds. They did not affect the tolerance or robustness of the crop plants against negative impact from the physical control methods. However, generally, seed priming and cultivar choice did improve yield in the leek experiments and seed priming also did so in the one experiment with onion.     

Effects of a juvenile hormone analog,pyriproxyfen, on Thrips tabaci (Thysanoptera: Thripidae)

Effects of a juvenile hormone analog, pyriproxyfen, on various developmental stadia of the onion thrips, Thrips tabaci Lindeman, were determined on cabbage leaves in the laboratory. Pyriproxyfen was applied at 0.064 or 0.128 g AI liter(-1) on leaves (residual contact-ingestion), thrips (direct contact) and leaf-thrips (residue contact-ingestion-direct contact). Pyriproxyfen did not have any significant lethal effects on thrips pupae in any treatment. Lethal effects on thrips larvae varied depending on application method and dosage. In the leaf and the leaf-thrips treatments, few larvae and pre-pupae molted to the next stage, and none developed to adults. In contrast, in the thrips-only treatment, pyriproxyfen did not show any significant lethal effects. The developmental times of larvae and pre-pupae were prolonged when larvae were treated with pyriproxyfen, and those of pre-pupae and pupae were shortened when pre-pupae and pupae were treated. The longevity and survival rates of thrips adults were generally shorter when they contacted and ingested pyriproxyfen-treated leaves than those in water control. Significantly fewer progeny (0.22-1.15 larvae per female) were produced by females that had fed on and been in contact with the pyriproxyfen-treated leaves than by those in the water control (11.94 larvae per female). However, the number of progeny produced by the thrips females increased significantly (3.32-7.28 larvae per female) when the females were transferred to untreated leaves after feeding on treated leaves for 5 days; the daily larval hatching pattern was similar to those in water control, indicating that female adults were able to produce viable eggs when untreated food was offered.     

The use of vegetable phytometers in the evaluation of the potential response of understorey crops to the aerial environment in an interculture system

Carrots, onions, radishes and peas, growing in pots were placed at various locations in a pear orchard and used as phytometers to characterise the aerial environment. The growth of plants growing beneath the orchard canopy was not significantly less than that of phytometers grown in the open. However, the bulb diameter of radish and onion was significantly reduced when growing immediately beneath pear trees. Radish was selected as a suitable phytometer for further research.     

大葱种子人工老化与膜脂过氧化的研究

大葱种子经过人工老化处理后,其发芽率、发芽指数、活力指数下降,活力指数较发芽率和发芽指数下降明显,种子老化6天后活力指数比对照下降70％。脱氢酶、SOD、POD活性和GSH含量也呈下降趋势,而浸出液可溶性糖、MDA、自由基、H2O2的含量增加,GSH、H2O2、自由基、可溶性糖含量与种子活力显著相关,并且较其他指标变化更为显著。说明大葱种子人工老化过程中膜脂过氧化加剧,膜结构和功能遭到破坏。因此,大葱种子人工老化与膜脂过氧化直接相关。