均值变点及分叉比确定最佳汇流阈值的对比

DEM为水文分析提供了更加多样化的研究分析途径。研究以ASTER GDEM为数据源,利用均值变点和水道分叉比综合对比分析不同区域的水文特征和流域地貌特征,对比不同区域在最佳阈值提取的河网差异及彼此间流域河道分叉比的特征。试验结果表明:清溪河样区和杏子河样区的最佳汇流阈值分别为1500和1300,其所对应的河网密度分别为0.63和0.68;不同的流域内取相同的汇流阈值时河道的分叉能力相同或相近,但河道的数目上有较大的区别。这两者的结合可以在今后的地形分析中提供必要的理论依据。     

水稻早世代稳定特性的遗传研究

422、429、430、942、950、966是由多倍体(四倍体或三倍体)与二倍体杂交得来的早世代稳定水稻品系,利用上述早稳型水稻与普通二倍体水稻杂交,以研究水稻早世代稳定特性在杂交后代的遗传。通过田间观察和分子标记的检测F2,结果发现在大量的杂交组合后代中,只有429×9311杂交组合后代仍具有早世代稳定特性,即早世代稳定特性在该杂交组合中遗传了下来,而其它杂交组合中,早世代稳定特性未能遗传下来,推测早世代稳定特性的遗传可能和杂交双亲均有关。     

大豆不同亲本组合对早世代群体蛋白质含量的影响

结合大豆育种实际工作,配制低蛋白×低蛋白、低蛋白×高蛋白两种不同类型的大豆杂交组合,对各组合F1代及F2代单株蛋白质、油分含量进行测定分析。结果表明:大豆杂交亲本蛋白质含量对早世代群体蛋白质含量特征有显著的影响,亲本蛋白质含量与早世代群体蛋白质含量表现为正相关,在各杂交组合早世代群体中蛋白质与油分含量均表现为极显著的负相关。根据蛋白质含量具有较高遗传力的特点,预期杂交亲本蛋白质含量性状可以自早世代材料保持到高世代材料而形成稳定品系。     

不同世代玉米自交系配合力规律及杂种优势表现研究

研究不同世代玉米自交系配合力变化规律及杂种优势表现,确定最佳配合力测定时期,可以为玉米早代选择和缩短育种进程提供理论参考。将2个群体早中晚3个不同世代18个选系（每个世代3个选系）和4个测验种（每个群体2个测验种）,按NCII试验设计组配36个杂交组合,对各世代抽丝期、株高、收获时籽粒含水量及产量配合力变化规律和杂种优势表现进行研究。结果表明：随着世代的增加,不同世代配合力间变幅逐渐减小,趋于稳定,S1～S3世代是自交系严重分离,S3～S5自交系从分离走向稳定,S3是配合力测定的最佳时期,应该结合自交系自身表现进行选系,进一步增加选系的准确性。S3与S5世代间超标优势呈极显著正相关,说明在育种过程中可以通过S3世代组合的杂种优势预测S5世代组合的杂种优势。     

早代稳定水稻的遗传特点与应用前景

早代稳定现象首先在水稻杂交育种过程中发现并报道,论述了早代稳定水稻的来源、分析方法、遗传特点、所取得的成就、应用前景及今后应注意的问题.     

水稻早世代稳定株系的农艺性状分析

育种实践表明，水稻品种间和亚种间杂交后代农艺性状发生疯狂分离，纯合个体的出现一般需经7~10代，5~8年^[1,2]。采用花培^[3,4]和远缘杂交染色体消除技术^[5,6]虽已应用于缩短作物育种时间，但仍耗时耗力。在作物如小麦、大麦、花生、水稻 ^[8~13]等育种实践中，偶尔会遇到杂种F2不分离的现象。吴先军等^[11]提出了水稻早世代稳定现象的概念，即水稻杂交后代F3以前出现农艺性状整齐一致、以后世代不分离的遗传现象。由于水稻早世代稳定现象在育种中具有巨大的应用潜力，对其遗传机制和育种应用进行深入而系统的研究具有重大的理论探讨价值和现实意义。     

水稻早世代稳定特异性的研究

利用9个具有早世代稳定遗传特性的水稻品系和7个栽培稻作为主体亲本杂交配组，在130个组合F2群体963个株系中，发现28个组合中出现73个稳定株系。遗传分析表明水稻早世代稳定既不是质量性状遗传也不是数量性状遗传，是按株群分离的遗传方式，出现稳定株系的组合F1群体发生了分离，F2群体中既有性状不分离的稳定株系又有孟德尔     

小麦花培品质育种各世代的品质参数分析

通过对冬小麦花培1代至花培5代的品质测试,研究了花培品质育种的品质测试的世代程序和有效性。结果表明,品质性状在花培早代已趋于稳定,高分子量谷蛋白亚基组成从H1起就稳定遗传,115对H1与H2材料和62对H2与H3材料的籽粒蛋白质含量、硬度和沉降值具有高度相关性,且籽粒蛋白质含量和SDS沉降值H2与H3世代间差异不显著。对中选的京单00-594的H4和H5世代进一步品质测定结果表明,通过花培早代选出的优质材料是可靠的,其优质性状能稳定遗传。研究提出了花培品质育种各世代品质测试的程序,证明了花药培养结合早代品质测试,是一条快速、有效的小麦品质育种途径。     

转Bt+Sck双价基因棉花的遗传稳定性研究

外源基因在转基因植物中遗传和表达的稳定性,直接关系到转基因材料的应用前景。本研究以转Bt+Sck双价基因棉花纯合株系312-5T2、332-2T2的T0,T1,T2和T3及T4连续世代为材料,Southern杂交进一步证明外源基因已经整合到棉花的基因组,并稳定地遗传给后代;RT-PCR以及抗虫性测定表明,外源抗虫基因在各个转基因世代稳定的表达,为该材料的育种应用打下了基础。     

辐射与杂交结合提高冬小麦辐射育种效果的探讨

γ射线辐照优良的杂交组合是提高诱变效率的基础;杂种比品种具有较高的辐射的敏感性;辐照杂种早期世代可以提高诱变效率,辐照杂交当代,使辐射世代与杂交世代同步,有利于各世代的选育,育种效果最好;辐照杂种后代的性状分离稳定进程与杂种杂合程度有关。研究表明,辐射与杂交结合是提高辐射育种效果的有效途径之一。     

小豆杂交F2世代结荚高度遗传变异及选择策略

选用不同结荚高度的5个小豆亲本材料进行杂交,研究4个杂交组合F2世代结荚高度性状的遗传变异。结果表明：各组合结荚高度在该世代均有较丰富的变异;含有高结荚亲本的3个组合F2世代,结荚高度均出现个别超高亲材料,遗传力为62.48%~74.49%,可以在早世代进行较严格的选择。从遗传进度值看,3个组合F2世代群体,都具有将结荚高度提高5cm以上的选择空间。相关性研究表明,小豆结荚高度性状表现在不同种植环境条件下,具有较好的相对稳定性;杂交后代结荚高度可在播种后9d~18d通过第一节高度进行间接鉴定。文章讨论了播种技术环节和施肥对小豆结荚高度的影响。     

Fixation of hybrid vigor in rice: opportunities and challenges

Rice, one of most important crops, is emerging not only as a model plant for molecular biological studies in cereal crops, but also as a model system for hybrid breeding methodologies, which include three-line system, two-line system and one-line system, corresponding to inter-varietal heterosis, inter-subspecific heterosis and heterosis of distant hybridization based on enhancing heterosis level, respectively. The developmental goal and direction of rice breeding are to simplify procedure of hybrid breeding and to enhance heterosis level. One-line breeding is not only to use distance cross for enhancing heterosis but also to lock hybrid vigor and to produce permanent hybrid. Rice of early generation stability, sporophytic apomictic rice or gametophytic apomictic rice might be used as a genetic tool for one-line breeding, and also represent three main methods and three development stages in one-line breeding.     

甘薯远缘杂交强优势组合同工酶分析

本试验探索了甘薯过氧化物酶、酯酶、淀粉酶同工酶电泳的最佳条件,利用这3种同工酶对本课题组保存的优势组合甘薯野生材料Y-6和栽培品种冀21-2及其由其杂交选育出的系列品种(品系)冀98、冀99、冀79、冀71、冀52进行深人的分析,结果显示:优势组合Y-6与21-2的杂交后代中出现了杂种优势的特征酶谱类型--杂种型、偏亲本型等等,各材料生产上的实际表现证实了同工酶分析的可靠性;表明:远缘组合Y-6与冀21-2属于强优势组合,并且同工酶分析技术可以用于筛选鉴定甘薯优势组合及其杂交后代早期辅助选择,加快育种进程.     

Feasibility of selection for traits associated with cold tolerance in rice under rapid generation advance method

Summary Variability of the hybrid population can be preserved through generations during the process of rapid generation advance (RGA). Effective selection can be done in an early generation for those traits having high heritability value like growth duration and plant height. But selection is not advantageous for traits having low heritability. Thus, selection for panicle exsertion, cold tolerance at seedling stage and panicle length would not be wise during the early generations. However, in the low temperature areas growth duration and plant height are two important factors which determine varietal suitability. As selection of these two characters are possible through RGA, it should be a standard parctice during RGA to eliminate the plants with long growth duration and select plants with optimum plant height.     

小麦几种品质性状与产量性状早代选择效果的研究

以三个冬小麦单交组合为试验材料,采用遗传力、遗传进度和杂种后代品质性状表现在年份间的稳定性等分析方法,对小麦几种品质性状与产量性状早代选择的效果进行了研究.结果表明,沉淀值、容重的遗传力较高,蛋白质含量和单株蛋白质产量的遗传力较低.沉淀值、蛋白质产量在各杂种早代的相对预期遗传进度均在20%以上.不同的品质性状受环境的影响较大,但所表现出的稳定性不同.     

利用种子醇溶蛋白选育玉米姊妹系和姊妹种的研究

不同分离世代产生的姊妹系配制的早晚代姊妹种在农艺性状、产量和种子蛋白图谱上存在很大的差别。大多数早代姊妹种种子蛋白谱带具有双亲的互补带，并表现出较强的优势，晚代姊妹种的种子蛋白图谱基本上与亲本相同，优势不及早代姊妹种明显。     

Selection for seed set capacity uncorrelated with flower heteromorphism in Primula vulgaris Hudson

Within-line pollinations were used when measuring the seed set of plants from seven early generation inbred lines of Primula vulgaris. One high seed setting plant and one low seed setting one were selected from each line and the seed set was evaluated on the offspring from selfings and within-line pollinations of these plants. Regression of offspring on parents for seed set was studied. The slope was estimated to be 0.17 ± 0.08, equivalent to an estimated heritability of around 34%. No significant differences in the slope of regression between the two reproduction methods (selfings or within-line pollinations) were detected. The realized improvement through one cycle of selection of high seed setting single plants in this early generation inbred material of P. vulgaris was 23.7%. Analysis of the seed set of within-line pollinated clones from late generation inbred lines of P. vulgaris revealed that only limited within-line variation remained after removal of the effects of the heteromorphic incompatibility system. It was concluded that selection of high seed setting single plants during early generations of inbreeding is efficient for improvement of seed set in future inbred lines of P. vulgaris to be used for hybrid seed production.     

Utilizing Arachis cardenasii as a source of Cercospora leafspot resistance for peanut improvement

Summary Advanced generation 40-chromosome hybrids between A. hypogaea (2n=4x=40) and a wild diploid species. A. cardenasii were evaluated for early leafspot, Cercospora arachidicola resistance and agronomic potential. The objective of this investigation was to determine if early leafspot resistance derived from a wild species could be incorporated into the A. hypogaea genome. Interspecific hybrid selections were made and then compared in the field and greenhouse to susceptible cultivars and to A. hypogaea lines which are reported to be resistant to early leafspot. Significantly higher levels of resistance were found in five hybrid selections than in cultivated lines based on numbers of lesions per leaf. In a greenhouse study, several hybrid selections also had greatly reduced sporulation from lesions as compared to A. hypogaea. Several mechanisms of resistance are believed to be present. Although hybrid selections had small seeds and low yields as compared to A. hypogaea, a new and valuable source of early leafspot resistance derived from the species A. cardenasii is present.Paper no. 8814 of the journal series of the North Carolina Agricultural Research Service, Raleigh, NC 27695. This research was partially funded by AID-Peanut CRSP grant DAN-4048-G-SS-2065-00.     

小麦品种抗旱性鉴定指标遗传规律研究

依据Griffing方法I配制种植不同类型的复合双列杂交组合,在人工模拟干旱棚和田间自然干旱条件下,分别设水、旱2种水分条件。在不同生育时期测定株高、株穗数、株粒重、穗粒数、黄叶片数、SOD、POD、MDA等农艺、生理生化性状,研究不同组合类型对杂交后代的遗传力影响及其与抗旱性的关系及遗传规律。结果表明,可采用抗旱指数(DRI)作为评价小麦品种抗旱性强弱的指标。旱地株粒重、旱地穗下节长、旱地黄叶片、籽粒饱满度、落黄、旱地成穗数、旱地株高等7个质量性状和数量性状与抗旱性关系密切且遗传力较强,可作为高产种质杂种后代的早期抗旱性鉴定指标。SOD活性和MDA含量由于广义遗传力和狭义遗传力均较高,可以在杂种后代早期世代进行选择,OA能力和POD活性广义遗传力较高但狭义遗传力低,适宜在杂种后代的晚期世代进行选择。