Plant Breeding Chapter 3 Genetic and Cytogenetic Structure

Plant Breeding Chapter 3 Genetic and Cytogenetic Structure of Plants 植物的遗传和细胞遗传体系

Genetic and Cytogenetic Structure of Plant Contents 主要内容 Sexual Reproduction 有性生殖 Genetic Materials 遗传物质 Cell Division: Mitosis and Meiosis 细胞分裂：有丝分裂与减数分裂 Gamete Produciton 配子形成 Mendelian Inheritance 孟德尔遗传 Polyploidy 多倍性 Changes in Chromosome Number 染色体数目的变化 Cytoplasmic (Non-mendelian) Inheritance 细胞质（非孟德尔遗传）遗传

Genetic and Cytogenetic Structure of Plant 1 Sexual Reproduction 有性生殖 ① Gametophytic and sporophytic generation of plant 植物的配子体世代和孢子体世代 A. Gametophytic generation: meiosis, sex cells have precisely half the genetic makeup of the parent 配子体世代：减数分裂，产生遗传组成正好为母细胞一 半的雌雄性细胞 B. Sporophytic generation: mitosis, daughter cell has exactly the same genetic makeup as the parent cell 孢子体世代：有丝分裂，子细胞有与母细胞相同的遗传 组成 ② Asexual, or vegetative reproduction: an alternative form of sexual reproduction 无性或营养生殖是有性生殖的替代方式

Genetic and Cytogenetic Structure of Plant

Genetic and Cytogenetic Structure of Plant 2 Genetic Materials 遗传物质 ① Genetic materials of plant consist of DNA, RNA and protein 植物的遗传物质包括三个基本成分：DNA、RNA和蛋白质 A. DNA: Double helix, semiconservative replication DNA：双螺旋、半保留复制 B. RNA: The genetic information of DNA can be transferred to m. RNA by transcription RNA：DNA的遗传信息经转录作用传递给m. RNA C. Protein: Assembled according to the information of m. RNA in ribosome using 20 amino acids taken by t. RNA 蛋白质：根据m. RNA的遗传信息、由t. RNA携带的二十种 氨基酸在核糖体上进行组装

Genetic and Cytogenetic Structure of Plant

Genetic and Cytogenetic Structure of Plant 3 Cell Division: Mitosis and Meiosis 细胞分裂：有丝分裂与减数分裂 ① Mitosis 有丝分裂 A. Prophase: the chromosomes condense into short, thick threads and can be distinguished individually 前期：染色体收缩成短粗线状，可以 区分单个染色体 B. Metaphase: the centromere of each chromosome becomes positioned along the equatorial plane 中期：每个染色体的着丝粒都沿赤道 板排列

Genetic and Cytogenetic Structure of Plant C. Anaphase: centromere divides, allowing the two chromatids to be pulled to each pole by the spindle fiber 后期：着丝粒分开，两个染色单体 分别由纺锤丝牵引移向两极 D. Telophase: the daughter chromosomes at each pole gradually uncoil and revert to chromatin 末期：两极的子染色体分别展开并 转变为染色质

Genetic and Cytogenetic Structure of Plant ② Meiosis 减数分裂 A. Prophase I: five stage — leptotene, zygotene, pachytene, diplotene and diakinesis — have been recognized 前期I：可分为 5个时期：细线 期、偶线期、粗线期、双线期、 终变期 a. Leptotene: each chromosome resembles a thin thread 细线期：每个染色体都像 一条细线

Genetic and Cytogenetic Structure of Plant b. Zygotene: maternal and paternal chromosomes pairs or synapse to form bivalents 偶线期：来自双亲的染色体配 对或联会形成二价体 c. Pachytene: chromosomes contracted to thick strands, the bivalents are designated tetrads 粗线期：染色体收缩成粗线， 此时的二价体称为四分体

Genetic and Cytogenetic Structure of Plant d. Diplotene: the paired chromosomes double to form chromatids and the chiasmas occur 双线期：配对的染色体形成染色 单体，并且交叉结出现 e. Diakinesis: the chromosomes more contracted, and the bivalents form ringlike structures 终变期：染色体进一步收缩，二 价体形成环状结构

Genetic and Cytogenetic Structure of Plant B. Metaphase I: the nucleolus has disappeared, and the tetrads are oriented at the central region of the cell 中期I：细胞核消失，四分体定位到细 胞中央 C. Anaphase I: the centromeres of the two paired chromosomes separate, but each centromere of a chromosome remain undivided 后期I：成对染色体的着丝粒分离，但 每个染色体的着丝粒并不分离

Genetic and Cytogenetic Structure of Plant D. Telophase I: the cell plate arises and divides the cell into two daughter cell, each with half the chromosome number 末期I：细胞板出现，将细胞分为两个子细胞，每个子细 胞的染色体数目为母细胞的一半 E. The meiosis processes of stages of prophase II, metaphase II, anaphase II and telophase II are similar to the corresponding stages of mitosis 减数分裂的前期II、中期II、后期II和末期II过程类似于 有丝分裂的相应阶段

Genetic and Cytogenetic Structure of Plant

Genetic and Cytogenetic Structure of Plant

Genetic and Cytogenetic Structure of Plant 4 Gamete Production 配子形成 A. Microsporogenesis: male gamete production (pollen) B. 小孢子发生：雄配子形成（花粉） Megasporogenesis: female gamete production (eggs) 大孢子发生：雌配子形成（卵）

Genetic and Cytogenetic Structure of Plant

Genetic and Cytogenetic Structure of Plant C. Xenia: influence of pollen genes on the endosperm 花粉直感：花粉基因对胚乳的影响 在 3 n胚乳的性状上由于精核的影响而直接表现父本的某些 性状，这种现象称为花粉直感

Genetic and Cytogenetic Structure of Plant 5 Mendelian Inheritance 孟德尔遗传 ① Independent Assortment: each trait segregated independently 独立分配：每个性状独立地分离 ② Linked Genes: genes located on the same chromosome may be linked and inherited as a unit 连锁基因：同一条染色体上的基因可能连锁在一起而作 为一个单元共同传递

Genetic and Cytogenetic Structure of Plant ③ Crossing over: its frequency depending on the distance between two gene loci 交换：其频率根据基因间距离的不同而不同 ④ Chromosome Mapping: determining the position of genes on a chromosome according the frequency of crossing over 染色体作图：根据交换频率确定基因在染色体上的 位置

Genetic and Cytogenetic Structure of Plant

Genetic and Cytogenetic Structure of Plant ⑤ Changes in chromosome structure: broken ends of chromosomes are not rejoined as expected 染色体结构的变化：断裂后的染色体末端不能像原来 那样连接 A: normal 正常 B: duplication 重复 C: deficiency 缺失 D: translocation 易位 E: inversion 倒位

Genetic and Cytogenetic Structure of Plant ⑥ Gene Interaction: Mendel segregation ratios (9: 3: 3: 1) were modified when two genes control the same trait 基因互作：当两个基因控制同一个性状时，分离比例分 偏离孟德尔遗传 A. Complementary gene action: both genes must be dominant (9: 7) 互补作用：两个基因必须同时为显性 B. Additive gene action: both genes affect a character in the dominant state (9: 6: 1) 加性作用：两个基因均在显性状态时影响性状

Genetic and Cytogenetic Structure of Plant C. D. E. Duplicate gene action: both genes have similar expression (15: 1) 重复作用：两个基因有相似的作用 Epistasis gene action: a gene is masked by another dominant or recessive gene (12: 3: 1 or 9: 3: 4) 上位作用：一个基因的作用被另一个显/隐性基因掩盖 Inhibiting gene action: a gene is inhibited by another irrelative dominant gene (13: 3) 抑制作用：一个基因的作用被另一个无关的显性基因 抑制

Genetic and Cytogenetic Structure of Plant ⑦ Heterosis: vigor increase in F 1 progeny 杂种优势：F 1代的生长势优于双亲 A. Dominance theory: favorable dominant genes accumulate in F 1 显性理论：有益显性基因在F 1中积累 B. Overdominance theory: heterozygous genotype is superior to the homozygous genotype 超显性理论：杂合基因型优于纯合基因型 C. Epistasis theory: nonallelic genes interaction 上位性理论：非等位基因间的互作 ⑧ Gene changes (mutations): occurring during the production of gametes or in the formation of somatic cells 基因变化（突变）：在配子产生或体细胞形成过程中发生

Genetic and Cytogenetic Structure of Plant ⑨ Changing Chromosome Number 染色体数目的变化 A. Doubling Chromosome Number: the replicated chromosomes do not segregate during cell division (colchicine) 染色体数目加倍：加倍的染色体在细胞分裂时不分离 B. Halving the Number of Chromosome Sets: anther or pollen culture and ovary culture, (haploid) 染色体数目减半：花药或花粉和子房培养（单倍体）

Genetic and Cytogenetic Structure of Plant 6 Polyploidy 多倍性 ① Concepts 概念 A. Genome: An entire set of chromosomes (n) 基因组：一套完整的染色体（n） B. Autoploids: have three or more copies of the same genome 同源多倍体：具有三个或多个相同的基因组 C. Alloploids: have three or more different genomes 异源多倍体：具有三个或多个不同的基因组

Genetic and Cytogenetic Structure of Plant ② Effect of Polyploidy on Phenotype 多倍性对表型的影响 A. Autopolyploid: bigger, lusher, more vigorous and thicker leaves and larger flowers 同源多倍体：更大、多汁、旺盛；叶片更厚、花更大 B. Allopolyploid: partially sterility, diploidization 异源多倍体：部分不育，二倍体化

Genetic and Cytogenetic Structure of Plant

Genetic and Cytogenetic Structure of Plant ③ Autopolyploidy 同源多倍性 A. Gene Segregation in Autotetraploids 同源四倍体的基因分离情况 Genotype Gametic Frequency 配子频率 基因型 AA Aa aa AAAA (quadplex)（四式） AAAa (triplex) （三式） AAaa (duplex) （双式） Aaaa (simplex) （单式） aaaa (nulliplex) （零式） 1 1/2 1/6 0 0 0 1/2 4/6 1/2 0 0 0 1/6 1/2 1

Genetic and Cytogenetic Structure of Plant B. Phenotypic Segregation after Crossing 杂交后的表型分离情况 Parents 亲本 Progeny 后代 AAAA×AAAA 1: 0 AAaa×aaaa 5: 1 AAAa×AAAa 1: 0 Aaaa×Aaaa 3: 1 AAaa×AAaa 35: 1 Aaaa×aaaa 1: 1 AAaa×Aaaa 11: 1 aaaa×aaaa 0: 1

Genetic and Cytogenetic Structure of Plant C. Gametes Produced by Double Reduction 双减数分裂产生的配子

Genetic and Cytogenetic Structure of Plant 7 Changes in Chromosome Number 染色体数目的变化 ① Euploids: having an exact multiple of the haploid number 整倍体：具有单倍体的整数倍 ② Aneuploids: having a chromosome number other than an exact multiple 非整倍体：染色体数目不是单倍体的整数倍 A. Monosomic (2 n-1) 单体 B. Double monosomic (2 n-1 -1) 双单体 C. Nullisomic (2 n-2) 缺体 D. Trisomic (2 n+1) 三体 E. Double trisomic (2 n+1+1) 双三体 F. Tetrasomic (2 n+2) 四体

Genetic and Cytogenetic Structure of Plant 8 Cytoplasmic (Non-mendelian) Inheritance 细胞质（非孟德尔）遗传 ① Cytoplasmic inheritance: controlled by cytoplasmic factors, nonchromosomal, non-Mendelian, or maternal inheritance 细胞质遗传：由细胞质因子控制，非染色体、非孟 德尔、母系遗传 ② Cytoplasmic male sterility (CMS): controlled by mitochondria or chloroplast 细胞质雄性不育（CMS）：由线粒体或叶绿体控制

Genetic and Cytogenetic Structure of Plant Exercise 思考题 • How many types there about genes interaction? 基因互作有哪些类型？ • What is the difference between meiosis and mitosis? 有丝分裂和减数分裂的区别有哪些？ • What is the autoploids and alloploids? 什么是同源多倍体与异源多倍体？