Auswirkungen der Züchtung bei Winterweizen in einem landwirtschaftlichen System mit geringer Betriebsmittelzufuhr von außen

Impact of Wheat Breeding in an Agricultural Low External Input System
Low external input systems, e.g. ecological agriculture, are able to solve problems concerning environmental pollution, diminishing ressources, and overproduction. Since growing conditions of winter wheat are very different in ecological agriculture as compared to conventional systems, the impact of genetic improvement of winter wheat in low external input systems is not well known. Investigations were carried out in two years at two ecologically managed farms using 24 genotypes of winter wheat of different periods of release (about 1900 to 1983). The results can be summarized as follows:
1. The tendency towards higher yields among modern varieties as compared to older cultivars in ecological agriculture was highly significant.
2. The rate of yield improvement was smaller under low external input as compared to conventional conditions results. Yield improvement was greatest in recent decades.
3. In ecological agriculture higher yields among modern varieties resulted from an increased harvest index along with an unchanged biomass production, improved resistance properties, and higher ear weight. Reduced plant height probably has negative effects.
4. Baking quality was improved clearly by wheat breeding.
5. Further genetic improvement of winter wheat yields in low external input systems may result from increased biomass production along with a constant or enhanced harvest index, improved resistance properties, increased plant height, and pronounciation of ear weight.     

不同类型玉米笋产量因素及采笋期的分析

通过对不同类型玉米（甜玉米、普通玉米、糯玉米）笋产量因素比较分析表明，３种不同类型玉米均可做玉米笋罐头加工原料；对不同类型玉米笋性状的偏相关分析表明，笋长与笋粗均呈极显著负相关，笋长与笋重、笋粗与笋重均呈极显著正相关；根据笋长与青苞长、青苞粗、花丝长间的偏相关分析表明，一般不同类型玉米笋长与青苞长、笋长与花丝长间均呈显著正相关，因此不同类型玉米笋采收系数分别为１∶０．３５～０．４５（青苞长与笋长比值）、１∶０．９５～１．８９（花丝长与笋长比值）。     

汾西县坝地防洪能力分析和防洪保收经验调查

坝地土肥水足,适宜于发展高产优质高效农业。晋西水土流失严重的汾西县打坝淤地历史悠久,经过多年配套建设,目前共有坝地3344hm~2,农业人均0.03hm~2。统计资料表明:坝地仅占全县耕地面积的9.26％～10.04％,而粮食产量却占总产量的27.2％～51.7％;坝地平均每公顷淤积泥沙26595m~3,全县坝地共拦泥8527万m~3,折合11511万t,相当于治理前年均向黄河输沙量593.6万t的19倍。坝地防洪保收在很大程度上取决于降雨的时间分布及雨量大小,其允许淹水深度依坝地作物株高而定。经典型小流域分析,汾西坝地具有较高防洪保收能力。其主要经验是,合理布设坝系工程,修建坝地排洪渠和加强管护。     

Kresse (Lepidium sativum L.) als Bioindikator zur Beurteilung der pflanzenphysiologischen Verträglichkeit von Flüssigmist

Uptake and distribution of nitrogen in old and new German summer wheats
Five old German summer wheat varieties, bred in the first third of this century, were compared with five new varieties in an outdoor pot trial. The modern genotypes had taken up slightly more N, both at anthesis and at maturity. At anthesis, N percentage in all organs was considerably higher for modern cultivars. This resulted mainly from a dilution effect caused by superior dry masses of old varieties. Modern genotypes accumulated more N in the upper leaves and ears. As compared with the old varieties, less N was found in the stems of the new cultivars. At maturity, N concentration in vegetative organs was simular for both groups of varieties. N percentage of grains was higher for old cultivars. However, the new genotypes achieved higher N yields. This resulted in part from the slightly higher assimilation of N. Moreover, new genotypes were superior in N translocation which was reflected by higher nitrogen harvest indexes. The postfloral loss of N from the vegetative tissue depended on the organ and the age of the varieties.     

木材物理力学性质的综合分析(Ⅰ)——主成分分析

本文利用主成分分析方法,对中国主要树种木材的物理力学性能进行了综合分析。结果表明,木材物理力学性能的第1主成分为强度指标,第2主成分为干缩指标,这两个主成分的累计贡献率为84.3％。另外,按第1、2主成分的样本排序图,可将所研究的木材分为WL 11—WL 56十七个等级,从每个等级的编号就可了解到某种木材的强度及干缩性能。     

微纳米气泡技术的研究进展及其在果蔬采后的应用

微纳米气泡（micro-nano-bubbles，MNBs）技术具有比表面积大、气体溶解能力强、表面带有Zeta 电位等特性，在环境治理、清洗、生物医学及农业等领域具有较强研究意义和应用前景。微纳米气泡技术与臭氧（O₃）、二氧化碳（CO₂）、1- 甲基环丙烯（1-MCP）等气体结合可用于果蔬采后非化学洗涤与保鲜，其中臭氧微纳米气泡、二氧化碳微纳米气泡处理通过减少有害微生物数量达到保鲜目的，1-MCP 微纳米气泡通过抑制乙烯生成延长果蔬保鲜期。本文综述了微纳米气泡技术的研究进展及其在果蔬采后的应用，以期为后续推广应用提供理论依据。     

Reduced Tillering Spring Wheats for Heavy Textured Soils in a Semi-arid Mediterranean Environment

Low tillering lines of spring wheat ( Triticum aestivum L.), were evaluated for their ability to conform to a high yielding ideotype in a dryland environment with spring drought. The ideotype was based on a concept of saving water as a result of reduced canopy development before anthesis; this should improve moisture supply for grain filling, thus reducing the effect of drought.
Five genotypes were compared under two nitrogen (N) levels, and at similar plant densities, at a site in the drier wheatbelt area of southwestern Australia. The genotypes formed three tillering groups based on the maximum number of culms produced: a free tillering group (G1), which included the standard cultivar Gamenya , with 4.3 culms per plant, an intermediate tillering group (G2) with 3.2 culms per plant, and a low ullenng group (G3) with 2.4 culms per plant.
Leaf area indices (LAI) were strongly affected by N but this was not reflected in total water use and biological yield. However, water was prematurely depleted before anthesis as a result of rapid early leaf development in response to N, and this reduced grain yield. Reduced tillering produced no significant increase in gram yield over the controls; fewer tillers per plant failed to suppress LAI development and water-use before anthesis because of a compensating increase in LAI; this resulted from a greater leaf size in the reduced tillering lines. Hence the low tillering lines did not fully conform to the requirements of the ideotype.
The development of low tillering lines is seen as a significant advance towards the ideotype; with yields comparable to commercial cultivars grown in the region, their performance indicates a potential for substantially higher yields if compensating increases in leaf development can be suppressed.     

玉米收获机械化技术现状与发展趋势

玉米是中国种植面积第二大的粮食作物,在国民经济发展中具有举足轻重的地位。现阶段玉米种植机械化技术已趋于成熟,实现玉米收获机械化具有十分重要的意义。     

不同采收期对黔产地稔中多糖含量的影响

为了摸索地稔药材的适宜采收期,采用苯酚-硫酸比色法测定了贵州惠水产地稔中的多糖含量。结果表明,不同采收期地稔中的多糖含量差异较大,其中,5月(开花期)和9月(果熟期)采地稔药材中的多糖含量较高,分别为3.24%和3.10%,1月最低,为1.10%,但由于9月地稔药材的产量较高,因此,以9月作为地稔药材的最佳采收时期。     

小麦杂种F_3代茎秆机械强度的选择效应分析

以山农3068/济麦4072、山农3068/济麦20两个组合的F3、F4群体为试材,研究了高、中、低三类茎秆机械强度类群的选择效应。结果表明:F3代高机械强度类群的直接选择在F4代获得了较高的相对遗传进度;不同类群的茎秆机械强度的选择对其他抗倒性状的影响不同,其中高机械强度类群的选择能有效降低抗倒指数,从而提高抗倒性;不同机械强度类群的选择都提高了千粒重,但减少了穗粒数,对穗数的影响较小,总体上利于单株产量的提高。