杂交晚稻穗粒结构观察分析

对多个两系和三系杂交晚稻新组合的穗总粒、一次枝梗、二次枝梗、结实率和空秕率等穗粒性状进行了观察分析，指出了穗粒主要性状差异主要来源于组合本身，一次枝梗性状较稳定，二次枝梗受营养和环境条件影响较明显。从而为新组合的选育及高产栽培提供了依据。     

苹果短枝型品种矮化早果机制研究──营养特性

比较了在同一立地条件下生长年龄、砧木完全一致的苹果短枝型品种和普通型品种的营养特性。结果表明：（１）短枝型品种地上部的Ｎ素营养、碳素营养明显高于普通型品种，地下部根系的营养含量相反；（２）短枝型品种耐肥性较高；（３）两类品种对铵态氮和硝态氮肥的田间反应存在差异。     

杂交水稻及其花粉植株后代某些生理生化特性比较研究

杂交水稻(Oryza sative)汕优桂34F_1的三个花培品系89 AH-97,89 AH-167和88AHW-16叶绿素含量在分蘖盛期明显低于亲本汕优桂34F_1,在孕穗期则差异不大。但三个花培品系的净光合强度在分蘖盛期与汕优桂34F_1无明显差异,在孕穗期则显著地高于汕优桂34F_1。各品系的乙醇酸氧化酶活性均无明显差别。同时,三个花培品系的硝酸还原酶活性和核酸量均极显著高于汕优桂34F_1,其可溶性蛋白质含量在分蘖盛期和孕穗期亦均显著地高于汕优桂34F_1。经4℃低温处理后,三个花培品系脯氨酸含量增加率极显著地低于汕优桂34F_1,其超氧物歧化酶(SOD)活性下降率则极显著地高于汕优桂34F_1。而三个花培品系的酯酶和SOD等同工酶谱无质的差别,只有某些酶带的活性与汕优桂34F_1有不同程度的差异。以上结果表明,通过花药(粉)培养所得植株后代可相对地将杂交水稻亲本某些优良性状“稳定”下来。     

家蚕血液酯酶同功酶的研究

采用不连续聚丙烯酰胺凝胶电泳法.测定了24个家蚕品种及杂交种从三龄到后蛹不同发育时期的血液酯酶同功酶酶谱.结果表明:家蚕血液中存在着丰富的酯酶同功酶酶带类型,整个试验可观察到22条酶带,根据其迁移率及染色特点可分为A、B、C、D、E五大染色区.在不同发育阶段中共有13条酶带经常显现,后蛹期主要同功酶酶带活性降低,但非主带A-1区酶带却清楚地显示出来.在幼虫阶段,酶带的数目及活性防着食下量的增多而增人.并观察到A-2-b带与B-2带的表现最为突出,推测A-2-b带可能是家蚕血液部酶同功酶的基本酶带.进一步分析表明,A-2-b带活性与大多数经济性状间呈高度的正相关性.     

不同品种大豆抗旱性能比较研究

多年生产实践表明,在众多影响内蒙古大豆生产发展的因素中,干旱是极为重要的障碍因子,大豆品种的抗旱性也成为大豆高产的重要性状。本试验着眼于内蒙古大豆旱作生产实际,选用21个大豆品种(系),对开花结荚期不同品种大豆的叶绿素含量、保护酶活性、相对含水量及质膜透性等与抗旱性有关的生理生化指标进行了测试,并利用抗旱隶属函数法对供试大豆品种的抗旱性能进行分析,判断抗旱性强弱,为大豆生产提供理论指导和技术支持。结果表明:供试品种根据抗旱性能可分为4类,强抗旱品种为半野生大豆、秣食豆、吉育39号及晋豆15,抗旱类型为吉育30、吉育70、九农20、兴抗线1号、兴00-5091、吉育55、吉育35、吉育47、王中王和吉育56,中抗旱类型的品种有抗线4号、CK125、开育10号和吉育62号,弱抗旱品种有吉育38、中作962及中作引1号。     

Variation of Phyllosphere Microflora of Different Rice Varieties in Sri Lanka and its Relationship to Leaf Anatomical and Physiological Characters

Anatomical and physiological characters of the leaf surface and its physico‐chemical environment substantially influence the density and diversity of phyllosphere‐inhabiting microorganisms, which may include natural antagonists of important pathogens. The objective of this investigation was to quantify the phyllosphere (i.e. leaf surface) microbial population in a range of rice varieties grown in Sri Lanka and to identify the leaf anatomical and physiological characters that determine the density and diversity of phyllosphere microbes. Fifteen rice varieties including both traditional and new high‐yielding varieties were used in a planthouse experiment and a field experiment in two consecutive seasons to quantify the phyllosphere microbial population and measure leaf characters that may influence it. There were highly significant intervarietal variations in the density and diversity of epiphytic bacterial, fungal and total microbial populations under both planthouse and field conditions. However, there was no difference between traditional and new, high‐yielding varieties in their capacity to harbour epiphytic microbes in the phyllosphere. Total microbial density (TMD) under both conditions showed positive correlations with leaf hair density, stomatal density and transpiration rate. Under planthouse conditions, TMD was also positively correlated with leaf hair length and negatively correlated with leaf temperature. These correlations can be explained in terms of providing favourable microsites on the phylloplane for epiphytic microbial growth.     

距离分析方法在小麦亲本选配中的应用研究

作者对距离分析方法在小麦亲本选配中的应用问题做了系统研究,本文是这一研究的总结报告。结果表明:1.遗传距离与杂种优势的关系受试验材料的影响。从聚类结果来看,在小麦育种中选择类间亲本进行杂交要优于类内亲本间的杂交。2.就性状选用方法而言,广义遗传力法要优于常规法和权重法。3.距离分析所反映的遗传差异不同于亲缘差     

丰抗号小麦的选育和若干性状选择的探讨

本文对抗锈、越冬、抗倒伏、熟期和籽粒灌浆等性状的选择进行了探讨.研究结果表明:①正确选配亲本对选育优良品种具有重要的意义.洛夫林10号对锈病和白粉病的抗性突出,且遗传传递力强,在灌浆和落黄等特性的传递方面表现也好.有芒红7号不仅越冬性好,遗传传递力强,而且是一个配合力较强的早熟亲本.它和特晚熟的洛夫林10号杂交后,通过各世代连续“中中选早”选出了中早熟的丰抗7号.可见,二者都是我国北部冬麦区不可多得的好亲本.②两个高杆品种杂交后,选育出了比较矮的后代——丰抗2、5号(株高80—85厘米).此试验表明,在矮化育种中可取材广泛些,除着重应用矮杆基因种质外,还可以选用一些综合性状好的中杆或高杆品种.     

A plant ideotype for Bromus inermis Leyss. in Western Canada

Summary This study relates the yield of two harvests of Bromus inermis Leyss. to tiller type and morphology. Tillers were classified as being nonelongated, elongated and headed. At four times during the growing season, observations were made of tiller density; individual tiller weight; leaf number, area and weight; stem length, area and weight; leaf to stem ratio; specific leaf weight; head area and weight.Results showed that there was a pattern of tiller control over yield which was different for each of the two harvests. Stem characters contribute more to yield than leaves. Growth, early in the season, had a prominent effect on yield of the first harvest and also influenced the second harvest. Height at the time of each harvest was highly predictive of yield of the respective harvests. A morphological ideotype for bromegrass harvested twice in a season was described.     

Yield and Agronomic Characters of Tropical Maize (Zea mays L.) Cultivars under Different Irrigation Regimes

Drought spells are unpredictable under tropical conditions and can occur at every growth stage of the maize plants. Little is known about the reactions of tropical maize cultivars to water shortage. A set of Thai cultivars was examined in the field during the dry season. Three stress situations were imposed: prolonged stress throughout the growing season, pre- and post-anthesis stress. Pre-anthesis water stress delayed flowering and especially the data of silking. Thus, the anthesis-silking interval was wider. Prolonged water stress decreased grain yield mainly due to a low number of kernels and/or thousand kernel weight (TKW). Post-anthesis stress mainly reduced TKW grain set per ear. Relief from pre-anthesis stress increased grain yield by a grater number of kernels and higher TKW as compared to prolonged stress. Genotypic differences were high for the anthesis-silking interval following pre-anthesis stress. Low yielding, early but generally drought-stable cultivars existed as well as cultivars which were generally high yielding even under water stress because of a good residual yield. Some cultivars were resistant to pre-anthesis stress but not to post-anthesis stress and vice versa. It can be concluded that ample genotypic variability exists for adaptation to varying situations of pre-and post-anthesis stress within tropical maize cultivars.