水稻籽粒游离氨基酸含量及其产量的种子和母体遗传效应分析

本文利用朱军等提出的禾谷类作物种子数量性状平均数遗传模型,探讨了水稻籽粒游离氨基酸含量及其产量的遗传效应．结果表明：籽粒游离氨基酸含量、游离氨基酸产量除受控于种子直接加性效应外,还受母体植株加性效应和显性效应的作用,且母体效应比种子直接加性效应更重要,其中尤以母体显性效应最重要．2个性状种子直接遗传率和母体遗传率均达显著或极显著水平,狭义遗传率均较高,基因累加选择的同时不能忽视杂种优势利用．游离氨基酸含量与游离氨基酸产量细胞质效应、母体显性效应间存在极显著相关性．     

籼稻糙米厚度的发育遗传研究

应用包括３套遗传体系基因效应的数量性状发育遗传模型,分析了１２个籼稻亲本在４个不同稻米发育时期的糙米厚性状。结果表明,三倍体胚乳、二倍体母体植株基因的加性和显性效应以及细胞质效应均可以明显影响各个稻米发育时期的糙米厚度,其中灌浆始期以二倍体母体植株效应为主,灌浆中后期以三倍体胚乳效应为主,成熟期则以细胞质效应为主。在４个不同发育时期中,控制糙米厚的基因加性效应和显性效应交替为主。胚乳显性方差和母体     

甘蔗生物量育种的ADGE遗传分析

对甘蔗11个亲本品种及不完全双列杂交(NCdesignⅡ)遗传设计的30个组合的F1代实生苗生物量进行加性-显型-随机环境效应模型(ADGE)分析。结果表明:甘蔗的生物量性状遗传主要是由基因的加性、显性及加性×环境互作效应共同决定的,但基因的加性效应作用较大;甘蔗杂交亲本对其后代表型的遗传作用主要为母本的遗传效应影响;甘蔗生物量性状都具有较高的广义遗传率(h2B)和狭义遗传率(h2N),且h2B>h2N,说明了对甘蔗生物量性状在选育种早期阶段的选择效果好;通过对亲本的加性基因随机效应分析的综合,较优良的甘蔗亲本有粤糖72/426、粤糖79/177、粤糖85/177、ROC24和ROC25;根据杂交组合显性随机效应分析,认为粤糖72/426×ROC16、粤糖79/177×ROC24、粤糖79/177×ROC23及粤糖80/101×ROC22是较优良的高生物量甘蔗杂交组合,可以应用于甘蔗的高生物量育种。     

云南香型软米水稻资源农艺性状遗传效应研究

选取5份云南地方香型软米水稻种质资源和6份自育香型软米保持系按5×6不完全双列杂交设计(NCⅡ)配制成30个组合,采用加性-显性-上位性遗传模型,分析云南香型软米11个农艺性状的遗传效应。结果表明,云南香型软米多数农艺性状的遗传主要受加×加上位性效应、加性×环境效应、显性×环境效应的影响,还存在不同程度的加性效应和显性效应,单株产量受基因加性效应、显性效应、加×加上位性效应、加性×环境效应、显性×环境效应的影响;株高、有效穗的遗传率以普通狭义遗传率为主,其他性状的普通狭义遗传率和互作狭义遗传率均达极显著水平;产量构成性状之间存在不同类型和不同程度的遗传相关,多数性状之间以加×加上位性、加性×环境和显性×环境互作效应显著。     

高等植物胚胎的发育生物学研究——Ⅰ.水稻、小麦胚胎发育的生长模式

本文结合稻胚的发育模式描述了水稻开花后1至30天期间胚分化发育过程,并指出了胚分化早期胚柄部分与珠被等组织的密切关系。对水稻开花后6～30天及小麦开花后8～27天期间胚鲜重、干重、体积和细胞数的发育模式进行了测定。在此基础上计算了平均每个细胞鲜重和体积的变化,以及麦胚细胞鲜重、干重和体积的变化。此外还测定了水稻胚长度,胚乳鲜重和体积的变化。结果表明;稻胚体积、鲜重在开花后6～11天,干重在6～13天期间呈指数增长,小麦胚鲜重、干重和体积变化在开花后8～15天期间指数增长趋势亦明显,稻胚每个细胞的平均鲜重和体积在开花后7天以前较小,9天以后明显增大;小麦胚每个细胞的平均鲜重、干重、和体积在开花后10天以前较小,12天以后则明显增大。稻胚在开花后1～30天期间长度变化呈S形曲线。     

辣椒植株性状Hayman双列杂交分析

用辣椒（Capsicam annuum L．）6个亲本,按（1／2）n（n-1）双列杂交法配制15个杂交组合,用Hayman双列杂交分析法估算了5个植株性状的遗传参数。Wr对Wr的回归分析结果表明,侧枝数、株高、株幅、主茎高和首花节位的遗传都符合加性-显性模型。Wr＋Vr与Yr间相关分析表明,侧枝数、株高、株幅、主茎高呈负相关,说明含有更多显性基因的亲本具有较小的Wr＋Vr值;首花节位呈正相关,且达到极显著水平,说明含有更多显性基因的亲本具有较大的Wr＋Vr值。遗传参数估算表明侧枝数、株幅、主茎高和首花节位性状的遗传以加性效应为主,加性效应比显性效应更加重要。株高的遗传中加性效应和显性效应都很重要。     

烤烟主要农艺性状对产量的遗传贡献率分析

为了研究烤烟主要农艺性状对产量的贡献,以14个品种（系）及其配制的41个杂交组合为材料,利用估算条件方差分量和预测条件遗传效应值的统计方法对多点实验数据进行了分析。结果表明,株高对产量的加性遗传方差贡献率最高,腰叶长对产量的显性遗传方差贡献率最高,各农艺性状对产量的加性X环境互作遗传方差、显性X环境互作遗传方差的贡献率均较小。对产量加性效应贡献最大的农艺性状因不同亲本而异,表明各亲本具有其独特的遗传和发育特性。多数杂交组合产量的显性效应主要受腰叶长影响,因此腰叶长可作为间接选择组合产量显性效应的指标。     

二棱大麦熟期性状的遗传研究

以甘木二条等7个二棱大麦品种进行不完全双列杂交,对其亲本、F1和F2的抽穗期,灌浆期和成熟期三个性状以1992和1995年（播种年份）的两年资料,采用加性-显性-上位性（ADAA）模型进行遗传分析．遗传方差分量的比率估算表明,三个性状都存在上位性作用．除灌浆期外,其余二性状还受显性和加性效应的作用,并以加性为主．显性效应和加性效应与环境的互作均达显著水平,基因效应的预测值表明采用P3（黔浙1号）和P4（浙农大3号）较易获得早熟后代．     

晒晾烟重要农艺性状遗传分析

以8个优良的晒晾烟品种(系)为亲本,配置完全双列杂交,进而利用基于混合线性模型的统计学方法,对晾晒烟株高、叶数、节距、腰叶长、腰叶宽以及茎围6个主要农艺性状进行遗传分析。结果表明,在多数农艺性状遗传中加性效应和显性效应都起重要作用,但所占比例有所不同,腰叶长和叶数主要受加性效应影响,而株高、节距、腰叶宽和茎围性状显性效应起主要作用;6种重要农艺性状狭义遗传率由高到低分别为:腰叶长>叶数>株高>节距>腰叶宽>茎围,其中,腰叶长和叶数狭义遗传率较高,分别为0.35和0.33,适合进行早代选择。另外,估算了供试材料的遗传效应值,并对各亲本及组合的育种利用价值进行了评价。本研究为晒晾烟重要农艺性状遗传改良提供了一定的理论依据。     

水稻对受体植物化感作用的遗传生态学研究

选用化感作用潜力差异较大的 5个水稻品种 (系 ) ,按不完全双列杂交设计 (4× 5 )配制成一套包括亲本、F1两个世代的遗传材料 ,在不同环境条件下 ,测定其不同叶龄时期对受体植物莴苣幼苗茎长的抑制作用 .采用包括基因型与环境互作的数量性状加性 显性发育遗传模型 ,分析了水稻化感作用的动态遗传及与环境互作效应 .结果表明 ,水稻叶龄在 7叶期对莴苣茎长的化感作用受加性效应的影响 ,在 3叶期和 6叶期由显性效应控制 ,在 5叶期和 8叶期加性和显性效应均有作用 ,以显性效应为主 ,呈现间断表达的遗传特点 .普通狭义遗传率在 5叶期、7叶期和 8叶期达显著水平 ,随叶龄增大趋于下降 .水稻化感作用受基因型与环境互作效应的影响较大 ,应注意控制水稻生长发育的环境 ,以达到最佳利用水稻化感作用潜力的目的 .     

Developmental Genetic Analysis of Brown Rice Weight Under Different Environmental Conditions in indica Rice

Analysis of genetic main effects and genotype×environment (GE) interaction effects for brown rice weight (BRW) at four different filling stages in indica rice ( Oryza sativa L.) was conducted for two-year experimental data by using developmental genetic models and corresponding statistical approaches for quantitative traits of seeds in cereal crops. It was indicated that the genetic main effects and their GE interaction effects of triploid endosperm, cytoplasmic and diploid maternal plant genes were important for BRW at different filling stages of rice, especially for endosperm or maternal additive main effects and their additive interaction effects. Because of the higher additive effects and additive interaction effects for BRW at different filling stages, the better improving effects for this trait could be expected by selection in rice breeding. The results of conditional genetic variance components showed that the new expression of quantitative genes in endosperm and maternal plant for BRW was mostly found at all different filling stages of rice. The gene expression, however, was most active at the early filling stages especially for the first (1-7 d) and the second filling stages (8-14 d after flowering). The phenomena that some genes were spasmodically expressible among filling stages of rice were detected for some genetic effects especially for net cytoplasmic main effects or its interaction effects and net dominance main effects. Predicted genetic effects at different filling stages of rice showed that some parents such as V20 and Zuo 5 were better than others for improving the BRW.     

玉米籽粒性状的遗传效应分析

采用二倍体胚和三倍体胚乳种子遗传模型及其分析方法,以5个玉米自交系及其配制的F1,F2,BC1,BC2世代为材料,研究5个玉米种子性状的胚直接效应、胚乳直接效应、母体效应和细胞质效应。分析结果表明,除粒宽外,各性状的遗传同时由细胞质效应和胚、胚乳、母体基因效应所控制,百粒重主要受胚乳和母体效应的影响,粒长的遗传以母体效应为主,粒宽和粒厚以胚乳效应为主。各部位籽粒百粒重的胚乳直接加性效应与母体加性效应的协方差达到显著或极显著水平,其余性状的胚、胚乳直接效应与母体效应间的协方差均不显著,通过母体植株的遗传表现可以对这些性状进行有效的选择。S22 是改良百粒重的优良亲本。 Abstract：The embryo,endosperm and cytoplasm effects of seven seed traits were studied by genetic model for diploid embryo and triploid endosperm plant seeds using five inbreds and their F1, F2, BC1 and BC2 generations. The estimates of genetic variance components indicated that the inheritance of all other kernel traits was controlled by the four effects except kernel width. The 100?kernel weight was mainly controlled by endosperm and maternal effects , and kernel length was controlled by the maternal effects,while endosperm conrrolled kernel width and kernel thickness. Except the significant or highly significant covariances between the endosperm direct additive and maternal additive effects for 100－kernel weight,all other traits between the embryo or endosperm direct effect and the maternal were not significant. So,maize inbreds could be developed by direct selection based on maternal plants for these traits. S22 was the best inbred of the improvement for kernel weight in this study.     

A Genome-Wide Association Analysis Reveals Epistatic Cancellation of Additive Genetic Variance for Root Length in Arabidopsis thaliana

Efforts to identify loci underlying complex traits generally assume that most genetic variance is additive. Here, we examined the genetics of Arabidopsis thaliana root length and found that the genomic narrow-sense heritability for this trait in the examined population was statistically zero. The low amount of additive genetic variance that could be captured by the genome-wide genotypes likely explains why no associations to root length could be found using standard additive-model-based genome-wide association (GWA) approaches. However, as the broad-sense heritability for root length was significantly larger, and primarily due to epistasis, we also performed an epistatic GWA analysis to map loci contributing to the epistatic genetic variance. Four interacting pairs of loci were revealed, involving seven chromosomal loci that passed a standard multiple-testing corrected significance threshold. The genotype-phenotype maps for these pairs revealed epistasis that cancelled out the additive genetic variance, explaining why these loci were not detected in the additive GWA analysis. Small population sizes, such as in our experiment, increase the risk of identifying false epistatic interactions due to testing for associations with very large numbers of multi-marker genotypes in few phenotyped individuals. Therefore, we estimated the false-positive risk using a new statistical approach that suggested half of the associated pairs to be true positive associations. Our experimental evaluation of candidate genes within the seven associated loci suggests that this estimate is conservative; we identified functional candidate genes that affected root development in four loci that were part of three of the pairs. The statistical epistatic analyses were thus indispensable for confirming known, and identifying new, candidate genes for root length in this population of wild-collected A. thaliana accessions. We also illustrate how epistatic cancellation of the additive genetic variance explains the insignificant narrow-sense and significant broad-sense heritability by using a combination of careful statistical epistatic analyses and functional genetic experiments.     

花椰菜主要经济性状的配合力及遗传效应研究

采用Griffing 6×6完全双列杂交设计,对长江流域内秋冬栽培的6个主要花椰菜（Brassica oleraceaLinn.var.botrytis Linn.）资源的自交系育种材料的球高、球径、单球重、成熟期、毛花率和内叶盖球度等6个花球主要经济性状进行一般配合力（GCA）和特殊配合力（SCA）分析,并对花椰菜的各个性状进行了遗传相关性分析。结果表明：花椰菜的6个经济性状同时受加性和非加性效应控制。其中成熟期、毛花率、球高和内叶盖球度性状的一般配合力大于特殊配合力,受加性基因效应影响大;而球径、单球重等性状间一般配合力小于特殊配合力,在相当程度上受非加性基因控制。花椰菜各性状的狭义遗传力由大到小依次为：成熟期、毛花率、内叶盖球度、球高、球径和单球重。花椰菜的球高与单球重、球径与单球重、球高与成熟期、单球重与内叶盖球度、成熟期与内叶盖球度等5个成对性状应该同时选择;而球高与毛花率、球高与内叶盖球度、球径与成熟期、球径与毛花率、单球重与毛花率、成熟期与毛花率、毛花率与内叶盖球度等7个成对性状的选择可以独立进行,彼此间不会相互影响,可实现同一组合或品种具备多种优质性状。在6个自交系中,P2和P5是理想亲本;P4是配制耐寒组合的亲本材料;亲本P6应用价值最低。组合中表现最好的为P2×P4,各性状的特殊配合力均较优。     

Timing of gene expression from different genetic systems in shaping leucine and isoleucine contents of rapeseed (Brassica napus L.) meal

Experiments were conducted on rapeseed (Brassica napus L.) using a diallel design with nine parents: Youcai 601, Double 20-4, Huashuang 3, Gaoyou 605, Zhongyou 821, Eyouchangjia, Zhong R-888, Tower and Zheshuang 72. The seed developmental process was divided into five stages, namely initial (days 1-15 after flowering), early (days 16-22 after flowering), middle (days 23-29), late (days 30-36), and maturing (days 37-43) developmental stages. The variation of dynamic genetic effects for leucine and isoleucine contents of rapeseed meal was analysed at five developmental stages, across different environments using the genetic models with time-dependent measures. The results from unconditional and conditional analyses indicated that the expression of diploid embryo, cytoplasmic and diploid maternal plant genes were important for leucine and isoleucine contents at different developmental stages of rapeseed, particularly at the initial and early developmental stages. Among different genetic systems, nutrition quality traits were mainly controlled by the accumulative or net maternal main effects and their GE interaction effects, except at maturity when the net diploid embryo effects were larger. The expression of genes was affected by the environmental conditions on 15, 22, 29 or 36 days after flowering, but was more stable at mature stage. For the isoleucine content the narrow-sense heritabilities on 15, 22, 29, 36, and 43 days after flowering were 43.0, 65.7, 60.1, 65.5 and 78.2%, respectively, while for the leucine content the corresponding narrow-sense heritabilities were relatively smaller. The interaction heritabilities were more important than the general heritabilities at the first three developmental times. The improvement for isoleucine content could be achieved by selection based on the higher narrow-sense heritabilities. Various genetic systems exhibited genetic correlations among the developmental times or leucine and isoleucine contents. A simultaneous improvement of leucine and isoleucine contents seems possible because of the significant positive genetic correlation components from different genetic systems at different developmental times.     

Genetic parameters for agronomic characteristics. II. Intermediate and advanced stages in a true potato seed breeding population

The aim of this research was to determine the genetic variation available in some important characteristics for true potato seed breeding in intermediate and advanced stages of a breeding population developed by the Centro Internacional de la Papa. A factorial mating design was used to calculate variance components and heritability at both selection stages. Four males were crossed with four females within each set (4 for intermediate stage and 5 for advanced stage) and their resulting offspring tested across two contrasting locations. Tuber yield and set were the only common characteristics recorded in both selection stages. In the intermediate stage early development characteristics (seed germination plus root and internode length) were also measured. In the advanced breeding material, vine earliness and other reproductive traits (days to flowering, flowering intensity, style length and pollen production) were scored. The heritability for tuber yield (0.35) and tuber set (0.32) in the advanced selection stage was higher than in the intermediate stage (0.26 and 0.13 respectively), which suggest that recombination through more cycles of recurrent selection brought untapped variation for both characteristics in this breeding material. Significant additive genetic variation, and thereby high heritability, was observed for internode length (0.52) in the intermediate selection stage, and for days to flowering (0.53) in the advance stage. Progress through selection may be expected for both characteristics. The heritability for pollen production was intermediate (0.23), while it was low (i.e.< 0.10) for the other characteristics recorded in both populations.     

花生重组近交系(RIL)根部性状的遗传分析

利用花生R IL群体,分析了主根长、侧根数、根基粗(1 cm和3 cm处)、根体积、主根鲜重、干重、侧根鲜重和干重、主侧根瘤数等11个花生根部性状的遗传力,估算基因对数及性状间的相互关系,根据偏度系数(g1)和峰度系数(g2)的估算控制性状基因互作情况。结果表明:在11个研究性状中,有6个性状在2个亲本间差异显著或极显著。但不论性状在亲本间的差异显著与否,在R IL群体中基因型间的性状差异均表现为连续变异和明显的超亲分离。同时主根粗(1 cm)和主根长的变异系数较小,分别为11.27%和11.218%。11个花生根部性状都是受多基因控制的数量性状,如影响侧根根瘤数、侧根鲜重和侧根干重的基因均在10对左右;而其它性状的基因估计在5~7对左右,尤其是控制侧根数的基因最少为5对左右。而在R IL群体中,除侧根干重的遗传力最高,达0.569,其次是侧根根瘤和侧根数分别达0.545和0.542外,其它性状的遗传力均较低。同时控制主根长和主根粗(1 cm)的基因间存在重叠作用;而控制侧根根瘤、侧根鲜重和侧根干重基因间存在互作,表现为互补作用;控制其它性状的基因间互补或重叠作用不明显或者不存在。主根干重和侧根干重与根体积、主根粗(1 cm)和主根粗(3 cm)显著相关,根体积与主根粗(3 cm)极显著相关,主根鲜重和侧根鲜重与根体积的相关表现不一致。     

Genetic parameters in a rubber tree population: heritabilities,genotype-by-environment interactions and multi-trait correlations

Rubber tree breeding programs are mainly driven by selection of individuals with high yield and quality of rubber. Data from 51 open-pollinated progenies tested on six sites in Brazil were analyzed over several traits to estimate the following: genetic parameters such as narrow-sense heritability and additive genetic variance in single- and multi-site analyses, type B correlations to determine the relevance of genotype-by-environment interactions and its effects on alternative selection strategies, additive genetic repeatability correlation for rubber yield based on three consecutive yearly measurements, and type A correlations to evaluate trait-to-trait genetic associations for all measured traits. Average rubber yield (RYm) showed an estimated narrow-sense heritability of 0.31, with an estimated type B correlation of 0.84, indicating low levels of genotype-by-environment interaction. The trait survival and number of latex vessel rings (RG) showed larger genotype-by-environment interaction and the lowest heritabilites. High to moderate type B correlation was found for most traits, with a value of 0.85 between diameter (or girth) and RYm; therefore, it is possible to achieve interesting rubber yield genetic gains (over 3 years of measurements) from indirect selection based on diameter at age 2.     

小麦种子活力性状的遗传变异和相关研究

本研究利用12个普通小麦品种对10个种子活力性状的遗传变异和相关研究,表明除正常幼苗百分率外,其余种子活力性状在品种间均存在显著的差异。种子贮藏物质转换效率、电导率两个性状问及与其它性状均无显著的遗传相关,因此对他们的选择不会影响到其它性状。通径分析表明幼苗干重主要取决于种子贮藏物质转换效率、种子贮藏物质利用速率;发芽指数主要由平均发芽时间决定。电导率、发芽势、幼苗于重、种子干重、发芽指数、种子贮藏物质消耗比率6个性状表现中到高的遗传力、遗传变异系数和相对遗传进展,指明通过遗传育种手段改良这些性状是可能的。     

EVOLUTIONARY PREDICTABILITY IN NATURAL POPULATIONS: DO MATING SYSTEM AND NONADDITIVE GENETIC VARIANCE INTERACT TO AFFECT HERITABILITIES IN PLANTAGO LANCEOLATA?

Quantitative genetics has been an immensely powerful tool in manipulating the phenotypes of domesticated plants and animals. Much of the predictive power of quantitative genetics depends on the breeder's control over the context in which phenotype and mating are being expressed. In the natural world, these contexts are often difficult to describe, let alone control. We are left, therefore, with a poor understanding of the limits of quantitative genetics in natural populations. One of the crucial contextual elements for assessing breeding value is the genetic background in which an individual's genes are being assessed. When interacting genes are polymorphic within a population, the degree of mating among relatives can influence the correlations among mates and the predictions of a response to selection. Population structure can strongly influence the degree to which dominance and epistasis influences additive genetic variance and heritability. The extent of inbreeding can also influence heritabilities through its effect on the environmental component of phenotypic variance. The applicability of standard quantitative genetic breeding designs to the measurement of heritabilities in natural populations therefore depends in part on: (1) the mating system of the population; and (2) the importance of gene interactions in determining phenotypic variation. We tested for an effect of mating structure on the partitioning of phenotypic variance and heritability by comparing two breeding designs in a common environment. Both breeding designs used 139 pollen parents taken from mapped locations in a population of Plantago lanceolata L., and crossed to 280 seed parents from the same population. One design was random-mating, the second was biased toward near-neighbor matings to an extent determined by field measure of pollen-mediated gene flow distances. The offspring were grown randomly mixed in a common garden. Nine traits were measured: central corm diameter, number of leaves, area of the most recently fully expanded leaf, density of hairs (cm^-2) on the leaves, dry weight per unit leaf area, photosynthetic capacity, transpiration rates, water use efficiency, and reproductive dry weight. Heritabilities and variance components from the two designs were compared using randomization tests. None of the variance components or the heritabilities differed significantly between breeding designs at the 0.05 level. The test could distinguish differences between the heritabilities measured in the two breeding designs as small as 0.11, on average. Thus, for the degree of inbreeding normally exhibited in P. lanceolata there is insufficient gene interaction present within populations to influence the partitioning of variance between additive and nonadditive components or to influence heritability estimates to a meaningful extent. We suggest that for Plantago other sources of variation in heritability estimates, such as maternal effects and genotype × environment interactions, are more important influences than the interaction between inbreeding and gene interactions, and standard heritability estimate based on random breeding is as accurate as one taking the natural mating structure into account.