不同轮回选择方法对玉米窄基群体的改良效果

利用轮回选择进行群体改良,是玉米种质扩增与改良的有效方法,能为选育优良自交系提供基本素材,进而提高选育自交系及杂交种的效率。本研究以玉米窄基群体P4C0及其经过不同轮回选择方法改良的10个群体为材料,通过多点田间表型鉴定和配合力测定,研究不同轮回选择方法对玉米窄基群体的改良效果,利用SSR分子标记分析不同轮回选择方法对群体遗传多样性的影响。结果表明,几种轮回选择方法都能有效改良群体的主要性状及其一般配合力(GCA)。以时间计算,控制双亲混合选择(MS)对群体P4C0主要性状及其GCA改良效果优于半同胞-S2:3(HS-S2:3)轮回选择,但在株高和穗位高的改良上,HS-S2:3选择效果较好。以轮次计算,开放改良对群体P4HSC1主要性状及其GCA的改良效果优于MS,但开放改良后,群体株高和穗位高有较大幅度的增加。不同轮回选择方法对群体遗传多样性和遗传结构的影响不尽一致。P4C0经过5轮MS后,在群体改良的低代,群体遗传多样性得到了较好的保持,而多代的改良导致群体遗传多样性下降;P4C0经过1轮HS-S2:3选择后,遗传多样性比P4C0有较大幅度的下降。P4HSC1经过1轮开放改良后,遗传多样性有较大幅度的增加。P4HSC1经过3轮MS改良后,群体遗传多样性呈增大的趋势,但每轮增加的幅度均较小。     

水稻恢复系选育的轮回选择法及其应用效果研究

利用野败型细胞质雄性不育性作为遗传工具,进行水稻恢复系的轮回选择。试验证明：（1）由于构建基础群体时,加入了一定比例具有保持系性质的常规品种,以及在后续世代中,不断将经过后裔测验,证实在主要恢复基因位点上均为杂合型的中选可育株种子返回群体,给不育株授粉,因而保证了每轮次轮回选择群体内不育株比例基本稳     

轮回选择对豫综5号玉米群体产量性状配合力的改良效果

玉米群体遗传基础广泛、遗传变异丰富,是培育优良玉米自交系的源泉。玉米群体的改良研究对玉米种质资源创新、优良自交系选育具有重要的指导意义。本研究采用NC II遗传交配设计,以豫综5号5个轮次改良群体为父本,以黄早四、丹340、中综5号、齐319、掖478、Mo17为测验种配制成30个测交组合,通过一年两点的产量性状及其配合力评价试验,研究轮回选择对豫综5号群体的改良效果。结果表明,轮回选择对群体单株产量的改良是有效的,群体与各测验种间的杂交后代产量平均每轮提高3.57%。半姊妹轮回选择和相互半姊妹轮回选择在改良群体产量一般配合力方面, 均得到显著提高,呈逐轮上升的趋势;采用半姊妹轮回选择对豫综5号群体3轮的选择后,C₃群体与C₀相比,一般配合力效应值从–11.63增长到5.57,差异极显著;经1轮相互半姊妹轮回选择后,群体的一般配合力效应值从C₃的5.57增加到C₄的9.75。豫综5号改良群体与黄早四的特殊配合力得到一定的提高,逐轮朝着Reid×唐四平头杂优模式水平提高的方向稳定发展。     

陆地棉超高产轮回选择群体创建及其选择

构建陆地棉超高产轮回选择群体基础群体的亲本材料包括皖杂40的亲本I40006和I40007、湘杂棉2号的亲本I40001和I40005、中杂028的亲本中4133以及优良种质中棉所23和苏棉12。将源于长江流域的材料和源于黄河流域的材料分别互交,其后代自交后分别再在长江流域材料和黄河流域的材料内进行株与株间的选择交配,得基础群体一（Q10     

两种轮回选择方法对玉米群体主要性状的改良效果

研究了控制双亲混合选择和半同胞-S2:3(HS-S2:3)轮回选择对2个玉米基础群体P_4C_0和P_5C_0主要性状的改良效果.结果表明,对于基础群体P_4C_0,其改良群体P_4HSC_1、P_4MSC_1和P_4MSC_2的单株产量分别比P_4C_0提高21.64%,10.29%和8.70%,达显著或极显著水平;对于基础群体P_5C_0,其改良群体P_5HSC_1的单株产量比P_5C_0降低7.53%,达显著水平;改良群体P_5MSC_1和P_5MSC_2平均单株产量变化与P_5C_0相比,分别降低和提高了2.67%和3.65%,均未达到显著水平.控制双亲混合选择改良群体,其产量的显著改进伴随着株高和穗位高的显著增加;HS-S2:3轮回选择改良群体,不同基础群体,其产量和株高、穗位高的改良效果不同.两种选择方法改良群体,多数性状的表型变异系数随着选择的进行有所下降,但也有部分性状变异系数变化较小或有所增大,群体内仍保持了较丰富的遗传变异,且以控制双亲混合选择保持群体遗传多样性的效果更好.     

玉米“黄金”群体产量等性状轮回选择改良效果评价研究

利用群体改良方法,充分挖掘地方优异种质的遗传潜力是玉米种质改良与创新的一个重要途径。本研究以黄金群5个轮次改良群体为材料,通过1年2点产量比较试验,分析了混合选择和相互半姊妹轮回选择方法对黄金群产量及穗部性状的改良效果。结果表明,两种选择方法对群体产量改良是有效的,随着改良轮次的增加,黄金群的单株产量逐轮提高,平均每轮提高3.78%,其中,混合选择改良的3轮群体平均每轮提高4.27%,相互半姊妹轮回选择的改良群体提高2.07%;虽然群体产量的变异系数从15.43%下降到12.80%,但群体内仍有较丰富的变异。通过改良群体穗部性状比较发现,穗长和行粒数改良效果显著,分别提高14.71%和17.62%,说明它们的提高是群体单株产量提高的主要因素。     

Change of Expected Response to Multitrait Selection in a Synthetic Population of Perennial Ryegrass Through Recurrent Selection

The changes in genetic parameters, variances, covariances and heritabilities, caused by the Bulmer effect have been predicted for an artificial breeding population of perennial ryegrass using recursion formulae. This enabled anticipation of the decrease in the expected response to multitrait index selection, using two different sets of economic weights. This theoretical decrease in selection efficiency was found to be quite substantial; it is approximately halved after 4 cycles of individual recurrent selection with a fairly high selection intensity of 5 %. However the synthetic population is improved for 4 out of 5 agronomic traits and could theoretically reach quite a high level of performance after 5 cyles. The choice of economic weights has relatively little influence on the expected genetic progress of each trait.     

论“株系循环双向选优法”

“株系循环双向选优法”是将新品种选育与原种繁殖相结合的新方法。该方法在遵循“纯中选优”原则生产原种的同时，根据育种目标，按照“优中选优”的原则选育新品种。该方法既区别于单纯生产原种的“株系循环法”，也区别于选育新品种的纯系育种法。     

Comparative Value of Androgenetic Doubled Haploid and Conventionally Selected Spring Barley Lines

Androgenetic doubled haploid spring barley lines (DH-lines) were compared in field experiments with their pedigree-selected sister lines (PD-lines). The PD-lines resemble a selected proportion of 1 % (10^?2) or less of the original complete F₂-population. By comparison, an average of 10 DH-lines were recovered from 10,000 anthers X > 1,000 microspores, i.e. at least 10⁷ microspores per cross. The average success rate was therefore approximately 10^?6. Both PD- and DH-families showed similar levels of performance with regard to all the characters studied, although no conscious selection had been applied in deriving doubled haploid progeny. Therefore, it is concluded that the regenerated microspore-progenies may be the result of unconscious selection among the large numbers of microspores cultured.     

玉米轮回选择基础群体的评判

将６个玉米群体完全双列杂交的得到的群体及群要璋杂交种在３个地区进行试验，采用Ｇａｒｄｎｅｒ和Ｅｂｅｒｈａｒｔ的ＡＮＡＬＹＳＩＳⅡ和Ⅲ对性状进行了分析，结果表明，许白群产量ｖｊ最高，ｈｊ最低，均达显著水平，ｇｉ中等；洛孟综产量ｖｊ和ｈｊ较高，ｇｊ最高，二南２４群产量ｖｊ较高，ｈｊ较低，ｇｊ略高。这３个群综合农艺性状较好，应进行特殊配合力的轮回选择，洛孟综可用于选育自交系，ＢＳＳＳ产量ｖｊ最小，ｈｊ最     

谈茶树单株选种育种效率的提高

茶树为多年生经济作物。为了缩短育种年限,加快育种步伐,提高育种效率,主要从原始材料的采集,选繁结合,株行试验园、品比试验园和采穗母本园同步建立等几方面进行阐述,探求提高茶树育种效率的新途径。主要体会有：一是茶树原始材料的正确选择是提高单株选种工作效率和决定育种成功的关键;二是具备较全面的茶叶技术素质,有统筹全盘的工作计划;三是申报优良单株制度的建立;四是把选择、鉴定、繁育与推广紧密结合起来,实行边选择、边鉴定、边繁殖、边推广。     

Morphological evaluation of olive germplasm present in Tuscany region

Undesirable characteristic of rapeseed oil is a relatively high level of linolenic acid (18:3), which is easily oxidized leading to rancidity and a shortened shelf life of the oil. Previous attempts to reduce linolenic acid levels in rapeseed oil through breeding have been impaired by complex genetics and strong environmental sensitivity of this trait. Therefore, our objective was to develop molecular markers for low linolenic acid that could facilitate the breeding of low linolenic rapeseed. Bulked segregant analysis was employed to identify two RAPD markers associated with 18:3 in a doubled haploid population segregating for linolenic and erucic acid levels. Based on analysis of individual DH lines, the markers RM350 and RM574, representing two independent loci, accounted for a total of 39% of the genetic variability in this population. This marker RM350 alone accounted for 25% genetic variation for this trait with no evidence of recombination. Significant interlocus interaction found between the markers RM350 and RM574 suggested that epistasis was involved in the genetic control of 18:3 level in this population. Another marker designated as RM322, which was independent of the other two, was found significantly associated with the erucic acid level and oil content. RAPD markers identified in this study should be a useful tool for the early detection of low linolenic, or low or high erucic acid genotypes in rapeseed breeding programs based on doubled haploids. This revised version was published online in July 2006 with corrections to the Cover Date.     

Prediction of the Line Value of a Genotype from a Top Cross with a Single Cross Hybrid

With the assumption of biallelism it is shown that differences in line values of genotypes from a random mating population can be predicted by the differences of values in top cross progenies with a heterozygous tester. This prediction is also valid in the case of multiallelism with a constant degree of dominance for each pair of alleles and if the tester is heterozygous for the more “distant” alleles. With an arbitrary tester, the efficiency of the prediction is affected by the proportion of the loci which are heterozygous for the more distant alleles. However, with the assumptions considered on multiallelism, with partial to complete dominance, the correlation between line value and combining ability with the tester is expected to be high for a large range of the repartition ot the loci. A two tester top cross design using highly complementary lines, could also be used.     

Combination of resistances to barley yellow mosaic virus and Rhynchosporium secalis by recurrent selection with repeated haploid steps

The aim of this investigation was the incorporation of resistance to BaYMV and Rhynchosporium secalis into German winter barley varieties together with the maintenance of their high agronomic characters. The agronomic value of DH-lines after two backcrosses and three haploid steps were compared with the original parents. Lines with similar or superior results could be selected for all the agronomic features evaluated. This method of recurrent selection with repeated haploid steps can therefore lead to the development of lines useful for practical purposes.     

空间统计分析在作物育种品系选择中的效果

为了研究空间统计分析法在作物育种田间试验品系选择中的效果,采用剩余误差空间相关线性混合模型对一个具有56个品系的小麦育种随机区组设计田间试验产量资料进行了空间统计分析。运用地理统计学中的半变异函数法确定剩余误差空间协方差的函数。结果表明,试验的剩余误差存在着典型的空间相关性,利用剩余误差空间协方差结构的信息可降低品系效应估计的误差和提高品系效应差异F检验与t检验的效率。此外,空间分析法对品系效应估计受试验条件不均匀的影响小,可导致较经典方差分析法不同的品系排序和优系选择结果。     

不同保存方法对秸秆营养价值的影响

研究高粱秸、玉米秸、豆秸和甘薯藤4种秸秆在不同保存方法（露天保存、棚舍保存、青贮和氨化）下主要营养物质的变化情况。并选用2头安装有永久性瘤胃瘘管的去势本地黄牛(450±15kg)来研究不同保存方法对其DM、OM、NDF和ADF瘤胃降解率的影响。结果表明：不同保存方法对CP影响差异极显著(P<0.01)；对OM高粱秸差异极显著(P<0.01)，甘薯藤差异显著(P<0.05)；NDF差异均显著(P<0.05)；ADF差异均显著(P<0.05)，WSC差异极显著(P<0.01)；提高DM、OM、NDF和ADF降解率的方法为烘干，氨化，豆秸除外。     

利用太谷核不育小麦进行轮回选择的改良效应

由14个亲本的太谷核不育小麦不育株等量混合组成基础群体B_1,对其6个性状进行混合选择和单性状集团选择;由4个亲本的太谷核不育小麦不育株等量混合组成基础群体B_2,进行回交混合选择.结果表明,无论采取哪种方案,对单株籽粒蛋白质产量、穗粒数、百粒重和单株产量均具有较高的选择效率,三轮平均在5%以上.从单个性状的遗传进度看,集团选择效果最大;对群体的改良,以混合选择最优,其次是回交混合选择,二者均有利于群体方差的增大,而集团选择不利于群体方差的增大.就选择阶段而言,集团选择、混合选择和回交混合选择分别在第一、二、三轮选择效果最高.本文还对小麦轮回选择方法应用提出了新的看法.     

改良HS相互轮回选择法对两个玉米群体的改良

对MZZ3（改良中综3号）、MZZS4（经4轮MS1改良的中综4号群体）完成了2轮改良半同胞（HS）相互轮回选择。结果表明,两群体以籽粒产量为主要选择目标,经两轮改良HS相互轮回选择,与各测验种间的测交组合产量、杂种优势都获得了逐轮提高。测交组合产量每轮增益（△G）在285 kg/hm²（5.5%）到688 kg/hm²（13.0%）之间     

半姊妹轮回选择对玉米群体改良效果研究

用半姊妹轮回选择法完成了对中综2号三轮改良,结果表明：该法对群体产量和配合力均有显著的改良效果。经三轮选择后平均每周期获得量为7.4;一般配合力从C0的-10 081增长到C3的15.924。二者每周期的获得量与选择轮数之间均呈显著的正相关。本研究第一轮的选择用遗传基础广泛的非亲缘综合种做测验种,二、三轮的选择用自交系     

Inheritance of resistance to flax wilt (Fusarium oxysporum f.sp. lini Schlecht) in a doubled haploid population of Linum usitatissimum L.

The inheritance of resistance to fusarium wilt (Fusarium oxysporum f.sp. lini) was investigated in Linum usitatissimum as a first step towards gaining an understanding of the molecular genetics of the disease and developing a procedure for marker-assisted selection. A recombinant doubled haploid (DH) population was derived from the haploid component of polyembryonic F₂ seeds originating from a cross between a wilt resistant, twinning Linola™ Linola is a registered trademark of CSIRO line CRZY8/RA91 and the wilt susceptible Australian flax cultivar Glenelg. The segregation of resistance was studied in 143 DH lines under glasshouse and field conditions. Most of the phenotypic variation was attributable to the segregation of two independent genes with additive effects. Minor resistance genes may have also contributed by modifying the resistance response. A glasshouse screening method of DH lines proved a reliable indicator of field resistance to fusarium wilt. This revised version was published online in July 2006 with corrections to the Cover Date.