《植物育种学》课程教学资源（PPT课件讲稿，英文版）CHAPTER 9 DISTANT CROSS BREEDING

BAP下R ANTCROSSBREEDING Niu Yingz 先应译 Dept, of Plant Breeding and Seed-Engineering

CHAPTER 9 DISTANT CROSS BREEDING 远缘杂交育种 BY Niu Yingze （牛应泽） Dept. of Plant Breeding and Seed Engineering

8 1 Concept and Roles of Distant Cross 远缘杂交的过概念和作用 1. The Concept of Distant Cross p 159 Distant Cross Between Species Distant cross- Distant hybridization -Wide cross Sub-distant Cross: Between Subspecies · Near cross Between varieties

1. The Concept of Distant Cross p. 159 • Distant Cross ： Between Species Distant cross – Distant hybridization – Wide cross • Sub-distant Cross: Between Subspecies • Near Cross: Between Varieties §1 Concept and Roles of Distant Cross 远缘杂交的过概念和作用

2. Roles of distant cross (1) Creation of new crop types: e.g Triticale (2) Creation of new male sterile types: Backcrossing 3 Transfer of pest and stress resistance: Late blast resistance in wild potato (4)Improvement of crop quality: High strength Fiber breeding in cotton Ⅴ c content in Tomato

2. Roles of Distant Cross (1) Creation of new crop types: e.g Triticale (2) Creation of new male sterile types: Backcrossing (3) Transfer of pest and stress resistance: Late blast resistance in wild potato (4) Improvement of crop quality: High strength Fiber breeding in cotton Vc content in Tomato

(5)Induction of Haploidy e.g Barley h. bulbosum induces haploids in barley and wheat (6)Use for studies of evolution of Crops e.g 2n wheat-4n wheat- 6n wheat B campestris x B oleracea ---B napis (⑦) Use for heterosis In cotton:陆地棉×海岛棉—杂种F1 In vegetables: Use of vegetative heterosis Nucleus- cytoplasmic Hybrids/Fixed heterosis

(5) Induction of Haploidy e.g Barley H. bulbosum induces haploids in barley and wheat (6) Use for studies of evolution of Crops e.g 2n wheat – 4n wheat – 6n wheat B. campestris x B. oleracea --- B. napis (7) Use for Heterosis In cotton: 陆地棉 × 海岛棉——杂种F1 In vegetables: Use of vegetative heterosis Nucleus – cytoplasmic Hybrids/Fixed heterosis

s2 Difficulties and Solutions in Distant Cross Breeding 远缘杂交的困难与克服方法 Three big difficulties: a Cross incompatibility Hybrid death and sterility Wide segregation of offspring

§2 Difficulties and Solutions in Distant Cross Breeding 远缘杂交的困难与克服方法 Three big difficulties: ▪ Cross incompatibility ▪ Hybrid death and sterility ▪ Wide segregation of offspring

1. Cross Incompatibility in Distant Cross (1) Cross incompatibility(noncrossability) Pollens not germinate pollen tubes not penetrate into the stigma Pollen tubes not reach the embryo sac Degradation of pollen nucleus in the sac The Couses Structures of floral organ: Stigma lengths Physiological disharmony: Enzymes; PH; Osmosis Genetic disharmony: Chromosome number; chrom?' Lengths; Crossability genes: eg.kr1,kr2 in wheat“ China spring

1. Cross Incompatibility in Distant Cross (1) Cross incompatibility (noncrossability) Pollens not germinate pollen tubes not penetrate into the stigma Pollen tubes not reach the embryo sac Degradation of pollen nucleus in the sac … (2) The Couses Structures of floral organ: Stigma lengths Physiological disharmony: Enzymes; PH; Osmosis Genetic disharmony: Chromosome number; Chrom’ Lengths; Crossability genes: e.g. kr1, kr2 in wheat “China spring

2. Solutions to Cross incompatiblity (1) Chromosome doubling of the parents (2)Appropriate combination of the parents (3)Intermediator plant (4)Special methods for pollination Mixed pollens Repeated pollination Advanced or delayed pollination Irradiation treatment of pollens

2. Solutions to Cross incompatiblity (1) Chromosome doubling of the parents (2) Appropriate combination of the parents (3) Internediator plant (4) Special methods for pollination: Mixed pollens Repeated pollination Advanced or delayed pollination Irradiation treatment of pollens

2. Solutions to Death and sterility of Distant Hybrids 远缘杂种天亡和不育的克服方法 1. Death and sterility in the distant hybrids (1)Death and sterility of hybrids Death of young embryo(abnormal zygote development: imperfect embryos; imperfect seed,.) Sterility of adult hybrid(male, female sterile)

2. Solutions to Death and Sterility of Distant Hybrids 远缘杂种夭亡和不育的克服方法 1. Death and Sterility in the Distant Hybrids (1)Death and Sterility of Hybrids • Death of young embryo (abnormal zygote development: imperfect embryos; imperfect seed, …) • Sterility of adult hybrid (male, female sterile)

(2) Causes Imbalance in interaction of nucleus and cytoplasm Imbalance in chromosomes(Chrom'number) Imbalance in genes(Alien dna degradation)

(2) Causes • Imbalance in interaction of nucleus and cytoplasm • Imbalance in chromosomes (Chrom’ number) • Imbalance in genes (Alien DNA degradation)

2. Solutions to the death and sterility of Distant Hybrids (Embryo Culture (2) Chromosome Doubling 3)Backcross: to the cultivated parent (4) Better careful cultivation (5)Elongation of growing period (6) Grafting

2. Solutions to the death and Sterility of Distant Hybrids (1)Embryo Culture (2) Chromosome Doubling (3) Backcross: to the cultivated parent (4) Better careful cultivation (5) Elongation of growing period (6) Grafting