影响甘蔗茎尖组培苗假植成活质量的几个因素分析

将假植成活率和成活植株的形态特征结合起来,作为评价指标,摸索分析了不同消毒处理、不同苗床基质、不同浓度NAA(萘乙酸)蘸根处理对甘蔗茎尖组培苗假植成活质量的影响。试验表明:两种不同消毒处理方式对甘蔗组培苗假植成活率的影响较小,但对成活植株质量的影响较大;不同苗床基质对甘蔗茎尖组培苗假植成活质量有一定影响;不同浓度NAA蘸根处理对甘蔗茎尖组培苗假植成活质量影响较大,成活植株的根长、株高、叶长、叶宽等性状,随着NAA浓度的变化,呈现出一定的规律性。     

甘蔗脱毒健康种苗田间繁育技术研究

通过对甘蔗脱毒健康种苗进行原种苗假植、假植苗田间移栽及田间扩繁的方法、季节等多地多点生产性试验。结果表明:脱毒原种苗露天假植成活率稍低于温室大棚假植,但其田间移栽的成活率、恢复生长等较具优势;采用蔗渣作为保湿基质的露天假植原种苗成活率达98.5%;田间扩繁时,海南蔗区按"一年两采法"繁育,广西、云南等蔗区按"一年半两采法"繁育,其田间繁育倍数可达400倍。本研究建立的甘蔗脱毒健康种苗田间繁育技术体系为甘蔗脱毒健康种苗的繁育与应用提供理论与实践依据。     

甘蔗腋芽培养苗假植管理技术研究

甘蔗腋芽培养假植成活率较低，是目前通过组织培养的方式加速甘蔗种苗繁殖的一个“瓶颈”问题。本文在试验的基础上，分别从壮苗炼苗、一级苗假植、二级苗假植及大田移栽等环节阐述了一套行之有效的甘蔗腋芽培养苗假植管理技术操作规范。     

大花蕙兰组培苗假植炼苗及基质配方

试验测定了瓶苗等级，炼苗和不同基质对大花蕙兰组培苗假植成活率和后期生长的影响。结果表明：瓶苗健壮度、合理炼苗和不同基质与大花蕙兰假植成活率及后期生长呈正相关；M1（水苔）和M2[谷（麦）壳2＋河沙1＋珍珠岩1，体积比]是大花蕙兰组培苗假植的理想基质，移栽2个月后的成活率达95％以上，生长发育较好。综合成本、成活率、生长发育和生产管理等因素，在规模化生产条件下应大力推广使用M2作为大花蕙兰组培苗的假植基质。     

橡胶树桩种植前假植方法研究

将挖取的实生苗树桩和热研7-33-97芽接桩分别假植在砂床上和泥土床上,10 d、20 d后再种植,与当天挖取的橡胶苗树桩进行种植对比试验。结果表明：种植后30 d,在砂床上假植20 d的实生苗树桩和热研7-33-97芽接桩的出芽数、株高明显高于其他各处理。说明将挖取的橡胶苗进行假植后再种植,与当天挖苗当天种植相比,不但没有降低成活率,还可提前出芽。     

马铃薯脱毒原种生产方法及主要技术要点

试管苗在防虫网室育苗盘中假植后(以下简称假植试管苗)直接移栽大田生产原种与微型薯(原原种)种植大田生产原种进行了比较。结果表明,假植试管苗正值初雨期移栽,易成活、易管理、产量高,种薯大小一致,每平方米结薯数比微型薯繁殖生产原种好,两种途径生产出来的继代扩繁应用效果没有明显差异,而生产周期,生产成本、生产环节都优于微型薯繁殖生产原种,符合山区气候特点及经济文化发展状况。因而易于山区薯农接受,易于加速推广应用,是具有山区特色的良种繁育新方法。     

遮荫及补光对香蕉假植大苗生长及抗性的影响

研究白天遮荫及晚上补光对香蕉假植大苗培育的影响,为确定最佳育苗光照条件提供理论依据。以巴西品种香蕉组培苗为材料,采用盆栽试验,测定不同光照条件下香蕉假植大苗的假株高、假茎粗等生长指标以及叶绿素、丙二醛、保护酶活性等生理指标。结果表明：适当的遮荫有利于提高植株的抗逆性;而白天遮荫60%,晚上补光4 h,可以弥补白天遮荫导致的光照不足,使假植大苗保持较好的长势,且其叶绿素含量较全光照(CK)提高15.48%,还能显著降低香蕉假植大苗丙二醛含量,较CK处理降低22.25%,脯氨酸含量较CK提高41.80%,明显促进抗性酶POD和SOD活性增加,分别为CK的1.48及1.30倍。为本试验条件下得出较适宜香蕉大苗生长的光照条件。     

基质和炼苗方法对春石斛试管苗假植的影响

以4个品种的春石斛为材料,研究了不同的假植基质和不同的炼苗时间和方法对春石斛试管苗假植成活率和初始生长的影响。结果表明,所涉及的基质中,水苔的成活率最高,而炼苗方法以封瓶炼10 d再开瓶炼1 d最佳。     

甘蔗芽培育一、二级苗圃管理技术

针对甘蔗腑芽假植技术中存在的成活率低的问题，探索甘蔗腑芽苗假植的适宜生活条件。通过对苗床不同的土壤配方试验及采取相应的管理技术措施，摸索出一套行之有效的甘蔗芽培苗一、二级假值技术，使成活率得到大的提高，达90％以上且稳定。     

无基质高压繁殖研究

在枝条环剥部位不用生根基质的情况下，对荔枝、米兰作高压繁殖试验。结果表明，不用生根基质，仅作保湿和遮光处理，生根率可高达８５％－１００％，假植成活率可高达９２．３％－１００％，而只保湿不遮光，生根率和假植成活率都很低。     

Effectiveness of selective herbicides for the control of annual weed species in lathyrus (Lathyrus sativus L.)

Field research was conducted over a four-year period, 1987–1990, to evaluate the efficacy and selectivity of trifluralin, metribuzin, cyanazine, bentazone, imazethapyr and several formulations of MCPA in lathyrus (Lathyrus sativus L.). Lathyrus exhibited satisfactory tolerance to trifluralin applied pre-planting soil incorporated and to postemergence applications of bentazone and imazethapyr. Lathyrus tolerated both pre-planting soil-incorporated and postemergence applications of metribuzin in dry years, but was injured by this herbicide in years with adequate precipitation. Tank mixtures of metribuzin or cyanazine with sethoxydim plus surfactant markedly increased the phytotoxicity of these herbicides to lathyrus. Lathyrus was sensitive to all formulations of MCPA and phytotoxicity increased with the addition of sethoxydim plus surfactant to the spray mixture.     

Effect of pre-planting temperature and light treatments of seed tubers on potato yield and tuber size distribution

Summary From 1985 to 1987 field experiments were caried out to test the influence of different pre-planting storage treatments on yield and size distribution of potato crops. The storage treatments included 4, 8 and 12°C in the light and in the dark, for different periods before planting. Subjecting the seed tubers to light at low temperatures induced crops to produce a larger proportion of smaller sized tubers while storing seed tubers at higher temperatures in the dark led to an increase of tubers >55 mm. These observations were confirmed in five field experiments with two cultivars at two sites and in three growing seasons.     

Improving the field performance of micro-and minitubers

Summary In many seed potato producing areas, micro- and minitubers are too small for direct planting as seed tubers in the field. Such use of these propagules can, however, be feasible if the crop's growth and development can be advanced. Increasing light interception, harvest index and yield of useable progeny tubers has been proved possible with plastic mulch and pre-planting of small tubers in a greenhouse. High amounts of nitrogen (up to 180 kg ha⁻¹) or deep planting (up to 9 cm) were less effective. Using older or pre-sprouted micro- or minitubers may be beneficial, because this might increase the number of sprouts per mother tuber (and thus stems per plant) or advance the growth of sprouts or stems. However, this would require even more careful management, due to the weakness of these sprouts and stems. Micro- and minitubers should be as large as feasible when used for direct planting in the field.     

Effect of a combination of chlorine dioxide and thiophanate-methyl pre-planting seed tuber treatment on the control of black scurf of potatoes

The pre-planting seed tuber treatments of chlorine dioxide (ClO₂), thiophanate-methyl (TPM), and a combination treatment of ClO₂, followed by TPM, were evaluated for control of stem canker and black scurf (Rhizoctonia solani), and storage rots; black scurf, common scab (Streptomyces scabies), dry rot (Fusarium spp.) and silver scurf (Helminthosporium solani) on potato (Solanum tuberosum L.) cv. Kennebec. Field experiments were conducted in two consecutive years, 1999 and 2000, at the Agriculture and Agri-Food Canada Research Farm in Harrington, Prince Edward Island (PEI), Canada. The combination treatment of ClO₂ (200 μg g⁻¹) and TPM (50 g active ingredient100 kg⁻¹ of tubers) significantly (P=0.05) reduced stem canker and black scurf on progeny tubers at harvest and after storage. The low incidence of scab and dry rot in untreated controls hindered the evaluation of the efficacy of the combination treatment and also showed that conditions were not favourable for disease development during this period at Harrington. The combination treatment was not effective on silver scurf in storage. A comparison among control, ClO₂, TPM, and the combination treatment indicates that pre-planting ClO₂ treatment may have killed the majority of the black scurf sclerotia on the tuber surface and that the combination of TPM fungicide treatment following ClO₂ treatment gave protection to progeny tuber by suppressing the growth of the R. solani. A higher marketable yield was observed in the combination treatment as compared with the untreated control. Phytotoxicity was not observed in tubers treated with the combination treatment.     

Accuracy and uniformity of insecticide treatment of commercially produced plant-propagation modules

The efficiency with which insecticides were applied pre-planting to commercially produced peat blocks and loose-filled cells used to raise brassica plants was determined with 35 samples, each comprising 25 randomly selected modules, obtained from 17 producers in different areas of England in 1985. The pre-blocking incorporation of granular formulations was the most uniform treatment, doses in individual blocks varying up to threefold in all samples. In contrast, most applications of liquid formulations to the module surface were highly variable, individual doses varying more than tenfold in many samples. Only four of the block incorporations, and six of the spray treatments, achieved mean doses within 70% of manufacturers' recommended amounts and, in some spray treatments, all of the modules contained less than 50% of the specified dose. Four of the five techniques used to apply sprays were found to be capable of achieving adequate uniformity but only the purpose-built spray-race achieved uniformity that was comparable with that of the incorporation treatment. It was concluded that operator error was a major cause of inaccurate and non-uniform treatment and that improvements in calibration and operation of equipment are essential if the technique is to continue to remain available to growers.     

Impact of seed potatoes infected withPhytophthora infestans (US-1 or US-8 genotypes) on crop growth and disease risk

As the surface area with late blight symptoms of seed tubers increased, the incidence of plant emergence decreased. This relationship was more dramatic with the US-8 genotype than the US-1 genotype ofhytophthora infestans, causal agent of late blight. However, when seed tubers were inoculated with both US-1 and US-8 isolates, the plant growth responses were generally intermediate to those obtained with the two genotypes alone. More resistant cultivars (eg. Dorita, Island Sunshine, and Sebago) had greater plant emergence and less seed rot than more susceptible cultivars (eg. Green Mountain and Shepody) but the response differences between resistant and susceptible cultivars was less clear with US-8 as most cultivars had 100% seed rot. Seed handling treatments affected crop growth and disease risk; as the inoculum levels and in some cases, the pre-planting storage period increased, plant emergence decreased generally due to greater seed rot incidences. Of the one registered seed treatment fungicide and several non-registered and/or experimental fungicides tested, only two significantly improved plant emergence. During three years of study, “diseased” seed treatments generally led to seed rot except in 1996 when one plant in one experimental plot of infected seed had subsequent spread of the disease to the foliage. Furthermore, within one week, a field epidemic developed outwardly from the single infected plant due to the occurrence of favourable weather conditions. Further research opportunities are discussed relative to the impact of infected seed on crop growth and disease risk     

云南保山旅游发展问题探讨

作为西南边疆旅游地，云南保山的旅游资源有着鲜明的自然景观特色和人文优势。利用和开发这些旅游资源，将富集的资源优势转化为产业优势，经济优势，必须突出重点，示范带动，抓住机遇，开拓创新，对整体旅游发展进行正确的规划和布局，才能迎来地方旅游产业新一轮的大发展。     

Multiplex detection ofPotato virus S, Potato virus X, andPotato virus Y by non-radioactive nucleic acid spot hybridization in potato tissue culture plantlets

Potato plantlets initiated into tissue culture must be tested for numerous viruses prior to propagation for seed potato production. Ideally, one plantlet is tested for all pathogens of concern and, if found pathogen-free, this plantlet is propagated for production of seed potatoes. Commercially available ELISA kits are generally used for the pathogen tests, but the commercial kits have some limitations. For example, the protocols differ for different viruses, so multiple extractions must be completed, increasing the time and expense of testing. This is a significant problem with tissue culture plantlets, for which there is limited material available to test and an ever-increasing number of pathogens that must be tested for, including viruses in the potyvirus, carlavirus, potexvirus, luteovirus, pomovirus, tobravirus, tospovirus, alfamovirus, and tymovirus groups. We have optimized a non-radioactive nucleic acid hybridization (NASH) assay for the simultaneous detection of carlavirusPotato virus S (PVS), potexvirusPotato virus X (PVX) and potyvirusPotato virus Y (PVY) in potato tissue culture plantlets. This assay requires a single extraction from a small portion of a tissue culture plantlet for the detection of viruses from three different families.     

11个玉米自交系主要性状的配合力分析

利用一般配合力较高的玉米自交系作为杂交亲本,同时兼顾一般配合力与特殊配合力以便组配出强优势组合。组合172×137表现较好,有待进一步对其产量潜力和适应性进行多点、多年鉴定。172、K12、173、137是较理想的自交系。