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31.
Asparagus is especially suitable for polyploidy breeding. The aim is to develop clone-based hybrid varieties, in particular male 4 × varieties. For this purpose, genetically divergent diploid idiotypes * * Idiotye (according to Reiger et al. 1976) is the sum of total hereditary determinants of an organism, consisting of its genotype (all determinants localized in the chromosomes) and its plasmotype (all determinants localized extra-chromosomally).
) are subjected to mitotic or meiotic polyploidization. In developing hybrid partners, special attention is paid to resistance in addition to yield and quality characters. Early diagnoses are applied in selection so as to shorten breeding times. Somaclonal variations may occur relatively often on in vitro propagation; these need to be eliminated. Triplex and quadruplex type males are suitable for paternal hybrid partners. Strong inbreeding depressions need to be avoided in their production.  相似文献   
32.
The soil‐plant transfer factors for Cs and Sr were analyzed in relationship to soil properties, crops, and varieties of crops. Two crops and two varieties of each crop: lettuce (Lactuca sativa L.), cv. Salad Bowl Green and cv. Lobjoits Green Cos, and radish (Raphanus sativus L.), cv. French Breakfast 3 and cv. Scarlet Globe, were grown on five different soils amended with Cs and Sr to give concentrations of 1 mg kg–1 and 50 mg kg–1 of each element. Soil‐plant transfer coefficients ranged between 0.12–19.10 (Cs) and 1.48–146.10 (Sr) for lettuce and 0.09–13.24 (Cs) and 2.99–93.00 (Sr) for radish. Uptake of Cs and Sr by plants depended on both plant and soil properties. There were significant (P ≤ 0.05) differences between soil‐plant transfer factors for each plant type at the two soil concentrations. At each soil concentration about 60 % of the variance in the uptake of the Cs and Sr was due to soil properties. For a given concentration of Cs or Sr in soil, the most important factor effecting soil‐plant transfer of these elements was the soil properties rather than the crops or varieties of crops. Therefore, for the varieties considered here, soil‐plant transfer of Cs and Sr would be best regulated through the management of soil properties. At each concentration of Cs and Sr, the main soil properties effecting the uptake of Cs and Sr by lettuce and radish were the concentrations of K and Ca, pH and CEC. Together with the concentrations of contaminants in soils, they explained about 80 % of total data variance, and were the best predictors for soil‐plant transfer. The different varieties of lettuce and radish gave different responses in soil‐plant transfer of Cs and Sr in different soil conditions, i.e. genotype x environment interaction caused about 30 % of the variability in the uptake of Cs and Sr by plants. This means that a plant variety with a low soil‐plant transfer of Cs and Sr in one soil could have an increased soil‐plant transfer factor in other soils. The broad implications of this work are that in contaminated agricultural lands still used for plant growing, contaminant‐excluding crop varieties may not be a reliable method for decreasing contaminant transfer to foodstuffs. Modification of soil properties would be a more reliable technique. This is particularly relevant to agricultural soils in the former USSR still affected by fallout from the Chernobyl disaster.  相似文献   
33.
黄增艳  周永元 《安徽农业科学》2007,35(15):4473-4474
以常绿品种布克荚蒾(Viburnum x burkwoodii)为试材,进行了嫩枝扦插研究。结果表明:布克荚蒾属于愈伤组织生根类型;用100mg/kg IBA1、00 mg/kg NAA均能促进插穗生根,以IBA效果最好;自制混合试剂对生根率有显著抑制作用;分析100 mg/kg IBA在不同时间处理后对插穗的生根率、不定根长、不定根数的作用,发现以21 h处理最佳。  相似文献   
34.
对由车用6110直喷式柴油机改造的单缸柴油机的排放特性进行了试验研究。结果表明,在大负荷和高速小负荷工况下,微粒的排放量较大;中等转速中等负荷工况下,NOx的排放量较大。  相似文献   
35.
关于南京市红叶石楠种类及应用调查研究   总被引:2,自引:0,他引:2  
本文针对南京市主要公园、城市主次干道中分带、校园、居住区等处范围内,结合整个石楠属植物的调查,对石楠属植物的种类、生长状况、园林中的应用范围及在各市园林绿地中的应用形式等方面进行调查,并且结合具体应用实例,进行分析,以期为以后红叶石楠的应用提供有意义的借鉴作用。  相似文献   
36.
Standing ability is a major component of combining ability and yield stability in dried peas. In performance trials during 1986–1988 commercial varieties and new breeding lines were evaluated for standing ability at one location. Standing ability was measured by visual scores, crop height and standardized crop height (crop height in percent of plant length) at several observation dates during the generative phase. Visual scoring proved to be the most suitable method for the measurement of standing ability as far as time requirement and precision are concerned.
Considerable differences between years and varieties were found for both the course of lodging during the generative phase and the standing ability shortly before harvest. Several, at least three or four measurements of standing ability should be done during the generative phase. Also highly significant variety x year interactions were observed. Heritability values estimated for different parameters of standing ability were medium to high as compared to plant length and maturity date (high) or grain yield (low).
In general, standing ability of the semi-leafless varieties proved to be much better than standing ability of the conventional ones. However, the semi-leafless plant type was not always associated with an improved standing ability.
Problems relating to the methods of measurement of standing ability, its phenotypic expression and variability are discussed.  相似文献   
37.
Zusammenfassung Die im Wachstum begriffene australische Erdbeerindustrie ist geprägt durch optimale Klimabedingungen und einfachen Zugang zu den Ressourcen, hohe Intensivierung und — wie in Kalifornien — hohe Erträge über 30 t/ha. Der Markt ist fast autark, Im- und Exporte frischer Erdbeeren spielen keine Rolle. Mit einem derzeitigen Produktionsvolumen von 40.000 t/Jahr auf ca. 1.300 ha wird eine Ausweitung auf 71.000 t bis zum Jahre 2008 angestrebt. Dies entspricht — bei ca. 20 Mio. Einwohnern Australiens — einer Steigerung des Erdbeerkonsums von 2,0 kg auf ca. 2,7 kg/Kopf und Jahr im Jahr 2008. Der gegenwärtige Erdbeerkonsum in Deutschland liegt bereits bei ca. 2,7 kg/Kopf und Jahr, wobei die Erdbeerimporte von ca. 120.000 t die Eigenproduktion von ca. 100.000 t auf 10.420 ha Anbaufläche — im Gegensatz zu Australien — übersteigen. Die drei australischen Hauptanbaugebiete konzentrieren sich auf Queensland im Nordosten, Perth im Westen und Victoria im Südosten Australiens. Der überwiegend einjährige Anbau erfolgt mit 45.000–66.000 Grünpflanzen/ha als Einzel- oder Doppelreihe in Dammkultur und Mulchfolie mit integriertem Fertigationsschlauch. Nach telefonischem Verkauf erfolgt die Lieferung im Kühl-LKW direkt an die Supermärkte oft weit entfernter Großstädte. Als tagneutrale Erdbeersorten dominieren mit 90% amerikanische Sorten wie Selva, Camarosa und Camino Real aus Kalifornien sowie Sweet Charlie und Festival aus Florida. Interessante Neuzüchtungen aus dem Jahre 2003 sind Rubygem, Sugarbaby, Brighteyes und Harmony aus Queensland als Kurztagssorten. Zusammen mit tagneutralen Sorten aus dem südlichen Züchtungsprogramm in Victoria stieg ihr Marktanteil in den letzten drei Jahren von 8% auf 10%. Primäre Zuchtziele des nördlichen Züchtungsprogramms in Queensland sind Kurztagssorten mit frühem Reifebeginn und hohem Ertrag über 1,2 kg/Pflanze. Das südliche Züchtungsprogramm um Victoria zielt dagegen sowohl auf Kurztagssorten als auch Tagneutralität sowie eine zusätzlich lange Ernteperiode über mindestens 10 Wochen. Während die Zuchtziele der äußeren Fruchtqualität wie Fruchtgröße, Fruchtfestigkeit und Glanz mit denen Deutschlands übereinstimmen, unterscheiden sich die der inneren Fruchtqualität wie süßer Geschmack bei gleichzeitiger Säurearmut und hoher Fruchtfleischfestigkeit.  相似文献   
38.
We characterised cultured canine mammary gland adenocarcinoma cells by exhaustive step protein expression analysis to identify factors associated with tumour progression or metastasis of canine mammary gland tumour. Cultured adenocarcinoma cells derived from a total of 3 primary and 3 metastatic lesions from 3 dogs (CHMp/m, CIPp/m and CNMp/m, where CHM, CIP, and CNM indicate the 3 animals) were used in this study. The expression of 24 proteins reported to be related to tumourigenesis or malignancy of human breast cancers were examined by Western blot analysis using 24 antibodies. The expression of sialyl Lewis X [sLe(x)] was only observed in CHMm cells, which were derived from pleural effusion. This expression was further confirmed by immunohistochemistry. The levels of some factors, such as 14-3-3sigma, cyclinD1 and Rb, differed among cells or between the primary and metastatic cells in the pair. Though the difference in their expression was not consistent within the cells from primary and metastatic origin, this characterisation should provide useful information for further molecular analysis of these cultured cells. Since some of the factors, such as sLe(x), 14-3-3sigma, cyclinD1 and Rb, showed different levels of expression in the pair, these cultured cells might be meaningful tools for clarification of distant metastasis in canine mammary gland tumours.  相似文献   
39.
40.
从一个特殊的角度描述3x 1问题,引入了部分新的概念,建立了3x 1问题的等价命题,得到了关于3x 1问题特别是数列{fk(x)|k∈Z }的一部分性质.  相似文献   
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