Genotypic differences for induction of bracting in cauliflower with 2-chloroethylphosphonic acid (ethephon)

Summary Bracting (i.e. bracts of the inflorescence growing through the surface of the curd) is a serious problem in commercial growing of cauliflower. Enhancement of bracts was most effective when ethephon was applied to plants that had just initiated a curd. When ethephon was applied 7 to 10 days later the effect diminished again. Ethephon effects were small when the chemical was applied after only a few curds had been initiated. Bracting increased continuously over the range (0 to 960 mg l^-1) of applied concentrations. There was an interaction with temperature during the early curd growth. Higher temperatures increased the effectiveness of ethephon.After an ethephon application significant differences between cultivars were observed in the extent of bracting. For screening cultivar differences in resistance against bracting, an ethephon application (240 mg l^-1) when nearly all plants had initiated a curd, was best.The experiments were carried out when the author was employed at the Research Station for Arable Farming and Production of Field Vegetables (PAGV) in Lelystad, The Netherlands.     

海藻酸和磷酸二氢钾对烟草花期和烟叶品质的影响差异

为探讨高海拔烟区在植烟期易发生冷害、导致烟草早花的问题,采用抗冷剂海藻酸和磷酸二氢钾处理烟苗,对烟草的现蕾时间、烟叶品质和产量进行了研究。结果表明：喷施海藻酸可延迟现蕾期约8天;磷酸二氢钾最多延迟现蕾期5天。喷施海藻酸和磷酸二氢钾对烤烟致香成分的总量影响不大。但在产量方面,海藻酸处理获得了2100 kg/hm2的最优产量,比对照增产16.67%;中上等烟比率占97.80%,高于对照3.7个百分点。     

蓖麻雌性单株不同时期高空压接研究

通过对6个蓖麻宿生雌性单株材料在3月18日、4月19日和5月17日三个时期的高空压接,研究出雌性材料品种之间高空压接成活率无显著差异,而压接时期4月19日与其它两个时期有极显著差异,表明云南昆明地区在露地栽培条件下高空压接的主导因子为压接时期,最适宜的压接时期为4月中下旬。     

The induction by mutation of all-year-round flowering in Streptocarpus

Summary A mutant form of Streptocarpus cv. Constant Nymph has been induced by X-irradiation, which shows a drastic change in its flowering habit. whereas the original form flowers under long-day conditions the mutant flowers under both long- and short-day conditions. The relative performance of these two genotypes in defined growth-room conditions and under natural short-days in the glasshouse is described, as well as the response of the plants to certain growth hormones.     

利用WGCNA进行玉米花期基因共表达模块鉴定

权重基因共表达网络分析(weighted gene co-expression network analysis, WGCNA)是系统生物学的一种研究方法,在挖掘生物学数据与特定性状之间的生物学关系方面具有十分重要的作用。本研究利用玉米(Zea mays L.)自交系B73的14份不同发育阶段的转录组数据,筛选掉低表达丰度的基因,最终得到了22,426个高表达的基因用于创建基因表达矩阵;利用不同组织作为性状,创建表型矩阵。然后利用R软件中的WGCNA包建立了共表达网络,共得到20个模块。本研究将与组织相关性高于0.65的模块定义为组织特异性模块,最终鉴定到14个组织特异性模块。利用在线网站Agrigo对组织特异性模块中的基因进行GO (gene ontology)富集分析,发现14个模块中均可以得到富集种类。开花作为玉米生育周期中的一个重要生理过程,不仅代表着植物从营养生长到生殖生长的转变,也关系到产量、株高和抗逆性等农艺性状。本研究发现8个组织特异性模块中的基因可以富集到与开花调控的代谢通路。此外,有17个已经报道过的开花时间调控基因存在于共表达模块中,并且主要分布在Blue模块和Darkmagenta模块,因此本研究重点关注了这2个模块内部的基因调控网络。本研究通过计算不同组织中的基因表达丰度,并联合权重基因共表达网络分析的方法,鉴定到了具有生物学意义的共表达基因模块,挖掘到了数个开花相关的模块,有助于揭示玉米开花调控的遗传机制。     

叶面施用氨基酸对菜心产量和品质的影响

通过盆栽试验研究了叶面喷施氨基酸对菜心产量和品质的影响。结果表明喷施200 mg/kg甘氨酸和丙氨酸均能提高菜心产量;喷施氨基酸能够显著提高可溶性糖含量,以200 mg/kg甘氨酸效果最佳;施用氨基酸对菜心叶片叶绿素无明显影响,维生素C含量有所降低;喷施甘氨酸能显著降低菜心硝酸盐和草酸含量,最高降低幅度分别为85.03%和70.19%,而喷施丙氨酸硝酸盐含量降低幅度较小,草酸含量显著增加;同时,喷施氨基酸均能够显著提高硝酸还原酶(NR)和谷氨酸脱氢酶(GDH)活性,而且甘氨酸处理效果优于丙氨酸。说明喷施氨基酸,尤其是喷施甘氨酸有利于提高菜心产量,改善品质。     

Influence of recurrent selection for flowering on flowering and yields in kura clover

Summary These investigations were conducted to determine the effectiveness of first- and second-season selection programs for increasing forage and seed yield in kura clover (Trifolium ambiguum Bieb.).Rhizo kura clover, the base population, was grown as spaced plants in two programs for six generations of selection for flowering in the seedling and second seasons. Remnant seed for each generation of selection was used to establish spaced plant and broadcast evaluation trials.The first-season selection program was effective in increasing flowering not only in the first season, but for two subsequent seasons. The second-season selection for flowering had little or no effect. However, vigor, forage and seed yields were not increased by either program, and the first-season program progressively reduced vigor and forage yields as generations of selection increased. The cause of this is unknown but may be associated with inbreeding depression or detrimental physiological effects of first-season flowering. Reselection to eliminate possible inbreeding effects is being conducted to further examine the possibility of increasing seedling and aftermath vigor in kura clover.     

Growth Promotion of Wheat Seedlings by Streptomyces atroolivaceus

Treating grains and roots of wheat seedlings with supernatants of different aged cultures of Streptomyces atroolivaceus stimulated plant growth. The treatment resulted in increased shoot elongation, shoot fresh and dry weights, and root fresh and dry weights but suppressed the depth of the root system. The supernatants resulted in increased shoot DNA but not root DNA. Shoot and root contents of RNA and protein were also enhanced. Effects probably caused by activity of plant growth regulators.     

龙眼雌花数和坐果率与温度及降雨量的关系

为了解龙眼雌花开放数量和雌花坐果率与温度及降雨量的关系,应用调查研究和数理统计方法对石硖龙眼开花前后的温度、降雨量与雌花开放数及雌花坐果率的关系进行了分析。分析结果表明：开花前30d的气温对正处于雌蕊形成期的小花原基分化具有影响,日均温21.0℃时雌花开放数最多;当开花前30d、50d的降雨量依次＜41.8mm和＜57.5mm时,降雨量增加可提高雌花开放数,降雨量过大雌花开放数减少;开花当日和开花后1-15d的气温影响雌花坐果率,开花当日日均温越高,坐果率越低,日均低温<20.2℃时,随温度升高,雌花坐果率提高,开花后1-15d日均温和日均低温越高,坐果率越低,日均高温<30.7℃时,温度升高雌花坐果率提高;在开花坐果和第一次生理落果期,降雨量增多雌花坐果率下降。     

Accelerated flowering of strawberry seedlings

For shortening the life-cycle of strawberry plants a combination of seed- and plant treatment was applied to seeds and resulting seedlings of the varieties Climax, Jucunda and Deutsch Evern.Of the seed treatments applied, a cold treatment of 16 days at 3–5°C produced a very bad germination. A treatment with H₂SO₄ 96% gave a more rapid germination and a considerably higher percentage of germination.Seedlings with three trifoliate leaves cannot be induced to flower by short-day treatment. For an effective short-day treatment of Deutsch Evern at least five and with Climax and Jucunda at least seven trifoliate leaves should be formed prior to short-day treatment. The freshly harvested seed from seedlings forced to rapid flowering has normal germination power.Through a combination of sulfuric acid treatment of the seed and a short-day treatment of the seedlings as soon as the latter have become sensitive, the life-cycle can be shortened from 18–24 months to 8–9 months.

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Publikatie 175     

Propagation and flowering of cauliflower

Summary Production of seed from selected plants in the shortest possible time is an important factor in the improvement of cauliflower. A requirement of the propagation technique is that it should not diminish plant growth. A modification in technique, previously reported, which included a portion of the curd in decapitation of the selected plants made it possible to obtain flowering in approximately 65 days after moving the plants to the greenhouse.     

A model describing the flowering of single plants, and the heritability of flowering traits of Dimorphotheca pluvialis

In the development of new crops such as Dimorphoteca pluvialis (L.) Moench, improvement of flowering synchronisation is an important breeding objective. The flowering of single plants of Dimorphotheca pluvialis could be described by a logistic curve obtained by the regression of cumulative number of open flowers on time. The curve is characterised by three parameters, corresponding with the total number of flowers produced by the plant, the rate of flowering development and the day at which peak bloom is reached. From these parameters two other characteristics were derived, i.e., onset of flowering and duration of flowering. The use of the flowering model for selection for improved flowering synchronisation is discussed. Heritabilities of flowering traits were estimated using parent-offspring regression and variance components analyses. Onset of flowering and date of peak bloom showed high (>0.69), and total number of flowers moderate to high (0.30–0.90) heritability values, indicating that for these traits considerable progress may be expected from mass selection, particularly in the early selection generations. Duration of flowering showed low to moderate values (0.25–0.45), and methods other than mass selection (e.g. family selection) should be considered. Determination of phenotypic and genetic correlations revealed only an additive genetic correlation between date of peak bloom and duration of flowering (r _A = 0.80 and 0.69 for 1993 and 1994, respectively), suggesting the possibility of indirect selection for curtailed duration of flowering by means of selection against late date of peak bloom. Duration of flowering, total number of flowers and onset of flowering were not correlated. This revised version was published online in August 2006 with corrections to the Cover Date.     

Modelling flowering of plants using time-to-event methods

Climate and environmental factors are known to influence the propensity of plants to flower. In order to capture the time dynamics in the underlying biological processes, this paper proposes to use a grouped-data survival analysis methodology. We formulate a semi-parametric model for the hazard rate of flowering, which allows all available climatic and environmental data to be included. Estimation can be carried using a generalized linear model approach. In addition, the model can be validated by means of recently developed residual-based model-checking procedures similar to what is available for ordinary regression models. The main finding is that the model proposed captures the major trends and is a first step in the direction of a model-based quantification of some climatic and environmental factors that influence the flowering of plants.     

超声对橡木陈酿白兰地促溶工艺的优化

为了优化橡木中单宁类物质的溶出工艺,以50％Vol新蒸馏白兰地为试验原料,采用超声波非热力加工技术,通过单因素试验研究了超声时间、超声功率、橡木添加量、浸泡时间对白兰地中色度、总酚、单宁、pH值、总酸、总酯、感官评价的影响,结合Box-Behnken响应面法优化超声促溶橡木中单宁物质的溶出工艺.结果表明,超声促溶的最佳工艺条件为:超声时间11 min,超声功率180 W,橡木添加量1.20 g/100 mL,浸泡时间20 d,该条件下单宁含量为1319.42 mg/L.     

Early determination of genotypes for apple scab resistance by forced flowering of test cross progenies

Summary Apple selections with different major genes for resistance to apple scab (Venturia inaequalis) derived from Malus floribunda and M. pumila were crossed with each other. The progenies were screened as young seedlings for their reaction to V. inaequalis race 1. A gene for resistance from M. pumila, causing stellate necrotic (SN) lesions, was epistatic to a second gene for resistance from M. floribunda, causing irregular chlorotic (Chl) lesions. Although in most cases SN, Chl and susceptible phenotypes were clearly distinct, occasionally reactions were difficult to characterize or varied from one inoculation to another. Selected seedlings showing resistant or susceptible reactions were forced to flower in 16–20 months in the greenhouse and test crossed with susceptible cultivars. Test cross seedlings were screened for scab reaction. The presence of both genes for resistance in a resistant plant was indicated by presence of both Chl and SN resistant phenotypes in the test cross progeny. Chi-square analysis of four large progenies produced a good fit to the expected ratio. The use of the forced flowering technique to determine scab resistance genotypes in 28 months demonstrated its value in breeding apples with multiple disease resistance.     

Induction of male flowering in gynoecious cucumbers (Cucumis sativus L.) by silver ions

Summary Silvernitrate (AgNO₃) and silverthiosulphate (Ag(S₂O₃)₂ ^3-) effectively induced male flowering in many nodes of 7 gynoecious cucumber genotypes in 3 glasshouse trials. A single spraying of the plants in the first true leaf stage with 3 mM Ag⁺ as Ag(S₂O₃)₂ ^3- or AgNO₃ (500 ppm) yielded many more staminate flowers than GA-3 (1500 ppm) and almost as many as 3 consecutive sprayings of GA-4/7 (50 ppm).Male flowering started about 3 weeks after treatment and lasted for a period of up to 4 weeks thereafter. Plants treated with silver ions did not elongate and grew normally; effective concentrations of AgNO₃ proved phytotoxic only in poor growing conditions, while Ag(S₂O₃)₂ ^3- never gave deleterious side-effects. Even very strongly female lines can be induced to male flowering with silver ions, thus increasing the feasibility of large scale seed production of gynoecious × gynoecious cucumber hybrids.     

发展套作大豆促进四川大豆产业发展

以四川省旱地农业发展新模式"麦/玉/豆"为例,分析了四川发展套作大豆的必要性与可行性;阐述了套作大豆经济效益高、生态效益好、社会效益突出、技术优势明显等优势;揭示了套作大豆发展中存在对大豆产业认识不足、重视不够,产量低、配套品种和技术有待完善,大豆加工技术落后、产业化程度低等问题,并提出相应的科学建议。     

Identification of population-specific QTLs for flowering in soybean

Flowering is an important stage in plant development and crucial for adaptation of plant species to different environments. Two soybean mapping populations were used to identify quantitative trait loci (QTLs) for days to flowering (DF) and days to maturity (DM) by genotyping simple sequence repeat (SSR) markers. Single-factor analysis of variance detected association of phenotypic data with SSR markers in each population. DF QTLs were identified on four chromosomes (chrs.); two QTLs located on chrs. 2 and 13 with Satt041 and Satt206 in the Jinpumkong 2 × SS2-2 population and other two DF QTLs were detected on chrs. 6 and 19 with Satt100 and Satt373 in the Iksannamulkong × SS2-2 population. The major QTLs associated with Satt100 explained 30.3% of maximum phenotypic variation. Especially, all DF QTLs included QTLs for DM, except Satt206 on chr. 13. Moreover, two additional DM QTLs were mapped on chrs. 10 and 11 with Satt243 and Satt359, respectively. DF QTL on chr. 2 with Satt041 was the newly identified QTL only in the Jinpumkong 2 × SS2-2 population and explained 10.3% of the phenotypic variation. The single locus of Satt100 on chr. 6 and Satt373 on chr. 19 were located on soybean genomic regions of the known flowering gene loci E1 and E3, respectively. These population-specific QTLs (Satt100 and Satt373) are the major QTLs for flowering time, putatively, they may be related to maturity QTLs with large effect. Additionally, these QTLs are valuable for marker-assisted approaches and could be widely adopted by soybean breeders.