Ch.9 Breeding by interspecific or intergeneric hybridization

1. interspecific or intergeneric hybridization

2. Cross incompatibility

3. Breeding Methodology

1. Interspecific or intergeneric hybridization(종속간 교잡 )

(1) Definition (Chang TT & Vaughan DA. 1991. Conservation and potentials of rice genetic resources. In Biotechnology in Agric. & Forestry 14 (Rice), Bajaj YPS ed. Springer-Verlagpubl. pp. 531-552)

General term Definition Classification category

Hybridization Within a taxonomic speciesIntraspecific hybridization

Wide hybridization Between species having the same genome Interspecific hybridization

Distant hybridizationBetween species having different genomes, or unknown genome in the same genus

Intersectional hybridization

Remote hybridization

Between species of different genera within the same family

Intergeneric hybridization

Between species of different families or kingdoms

Interfamily or interkingdomhybridization

(2) Various uses of wild species <1>- Introgression breeding : resistance, quality, yield, ...- The induction of haploids through pseudogamy in potato, alfalfa, cotton. popular, and via

chromosome elimination in barley and wheat (Nitzsche W & Wenzel G, 1977. Haploids in Plant breeding, Verlag Paul Parey publ. 101p.)

- The (re)synthesis of allopolyploid crops, e.g., in Brassicaceae and Gramineae.- The induction of cytoplasmic male sterility, e.g., in wheat, rice, potato, tobacco, sunflower,

Brassica crops

(3) Choice of wild species- close to cultivated species : to overcome cross cross-incompatibility and/or sterility problems- diploids preferred : in order to easily eliminate undesirable traits of wild species

(4) ExamplesA. Amphidiploids

- Triticum

- Brassica Brassica campestris 배추

(AA, 2n=2x=20)B. napocampestris(AAAACC)

B. napus 유채 B. juncea 갓(AACC, 2n=4x=38) (AABB, 2n=4x=36)

B. napo-oleracea(AACCCC)

B. oleracea B.carinata B. nigra(CC, 2n=2x=18) (BBCC, 2n=2x=34) (B, 2n=2x=16)

양배추 Abyssinian mustard 흑갓

- Brassica Brassica campestris 배추

(AA, 2n=2x=20)B. napocampestris(AAAACC)

B. napus 유채 B. juncea 갓(AACC, 2n=4x=38) (AABB, 2n=4x=36)

B. napo-oleracea(AACCCC)

B. oleracea B.carinata B. nigra(CC, 2n=2x=18) (BBCC, 2n=2x=34) (B, 2n=2x=16)

양배추 Abyssinian mustard 흑갓

(amphidiploid, allohexaploid) Triticum aestivum

AABB DD

AABBDD

AA BB

X

X

Triticum turgidum Triticum tauschii

Triticum monoccum Agropyron?1립계

1립계2립계

- Triticasecale : AABBDDRR, AABBRR

AABBDDTriticum aestivum Secale cereale

RRX

ABDR

AABBDDRR

Chromosome doubling

2n=56

AABBDD

T. turgidum

RRX

ABR

AABBRR

Chromosome doubling

2n=42

wheat(42) rye(14)Triticale(56)

Somatic metaphasechromosome complement andkaryotype of B. campestris ssp.pekinensis (2n = 20), upperleft; R. sativus (2n = 18), upperright; and 9Brassicoraphanus(2n = 4x = 38), bottom.(Plant Biotechnol Rep (2012) 6:107)

배무채(Baemoochae)cabbage x radish

Morphology of roots of four mutant lines (a), of representative plant of the wild line and a mutant (b), ovules maturedand degenerated in the wild and a mutant, line code 551 (c) in ‘Baemoochae’ * microspore culture mutants

B. Interspecific/intergeneric hybridization grouped by genome and chromosome number

i) Same genome, same chromosome numberN. alta (n=9)<A> x N. sanderae (n=9) <A>N. tomentosa (n=12) <T> x N. tomentosiformis (n=12) <T>T. aestivum (n=21) <ABD> x T. spelta (n=21) <ABD>O. sativa (n=12) <A> x O. nivara (n=12) <A>

ii) Partially same genome, different chromosome number N. rustica (n=24) <PU> x N. paniculata (n=12) <P>T. aestivum (n=21) <ABD> x T. monocum (n=7) <A>T. dicoccum (n=14) <AB> x T. spelta (n=21) <ABD>

iii) different genome, same chromosome numberO. sativa (n=12) <A> x O. punctata (n=12) <B>

iv) different genome, different chromosome number N. suaveolens (n=16) <Su> x N. glutinosa (n=12) <Gu>T. aestivum (n=21) <ABD> x Secale cereale (n=7) <R>O. sativa (n=12) <A> x O. grandiglumis (n=24) <CCDD>

Success rate in Interspecific/intergeneric crossing

- I > ii > iii > iv - 2~3 genomes x 1 genome

(♀) (♂)- chromosome number

higher (♀) x lower (♂)- Self compatible x S. incompatible

(♀) (♂)

2. Cross incompatibility

Williams EG. 1987. Interspecific hybridization in pasture legumes. PBR 5. pp.237-305

incompatibility : a mechanism that "prevents or disturbs the functioning of the pollen-pistil relationship --- a precise and specific reaction to the negative effects of inbreeding active inhibition

incongruity : the incompleteness of the relationship as a byproduct of evolutionary divergence passive rejection

(1) Pre-fertilization barriers --- similar mechanism to self-incompatibility- Arrest of pollen tube growth, - Lack of fertilization

* Heslop-Harrison. 1982. Pollen-stigma interaction and cross-incompatibility in thegrasses. Science 215: 1358-1364

* Evans.1962. Euphytica 11: 164-176, 256-262: Trifolium에서 relationship between cross-compatibility and grafting compatibility

--- related to anatomical similarity among species

(2) Post-fertilization barriersA. Chromosome elimination <1>

H. vulgare x H. bulbosumT. aestivum x H. bulbosumH. vulgare x H. marinumWheat x sorghum

" x maize : chromosome-eliminatedB. Hybrid embryo breakdown

- delayed cell division in embryo (Roupakias,1986. Euphytica. 35:175-183): Vicia fava x V.narbonensis F1 embryo는 2 weeks after crossing 200 cells

parental embryo는 “ “ 2000-5000 cells- breakdown of embryo --- possibly due to endosperm abnormalities

* Abbo et al. 1991. Bot. Gaz. 152(3): 316-320 water and nutrient supply to hybrid embryo were blocked in Medicago의 interspecific crossing aborted

* Rabakoarihanta 외 1979. TAG 54: 55-59Williams 외 1980. Bot.Gaz.141: 252-257

- failure of the endosperm ( followed by starvation of the hybrid embryo)reason: ' endosperm genome의 genetic unbalance

' marternal tissue와 zygote의 genetic composition의부조화* EBN(endosperm balance number) hypothesis --- Solanum, Trifolium(클로버), Avena 등. Parrott

& Smith. 1985. Evidence for the existence of endosperm balance number ~ ~Can. J. Genet. & Cytol. 28: 581-586. : Each species has an effective endosperm ploidy level(termed EBN) that determines its crossing behavior. For a cross to be successful, the endosperm must have a ratio of two EBNs from the female parent to one EBN from the male parent. 즉 same EBN successful development of endosperm in hybrid seeds

(3) Genetics for interspecific incompatibility

○ Nettancourt. 1977. Incompatibility in angiosperms

* Incongruity hypothesis

○ Lange 외. 1976. Euphytica 25: 609-620* dominant alleles in wheat-rye crosses: Kr1, Kr2 --> crossability genes ' additive effect

' Kr1의 effect --- bigger

wheat(T.aestivum)Hope(Kr1Kr1Kr2Kr2) x rye

↓X (no zygote)

Chinese spring x rye(kr1kr1kr2kr2) ↓

OC.S./Hope 5B (chr. substut. line) x rye (Kr1Kr1kr2kr2) ↓

poor crossability* Kr1은 located on 5B

Hope에서 5B가 eliminated된 plant Kr2Kr2 alone x rye intermediate

crossability( 5A? -- not confirmed)

○ Kr1 on 5BL, Kr2 on 5AL, Kr3 on 5D and Kr4 on 1A, with Kr1 having the largest effect on crossability (http://www.jic.ac.uk/staff/graham-moore/index.htm)

* Chr. 5B contains Ph1 locus.○ Manickavelu et al 2009. Plant Syst. Evol. 278: 125-131

- CS (kr1kr2) x Mara 5B (Kr1 kr2) 의 progeny RILs 들을 crossed with rye to know the effect of Kr1

- cDNA-AFLP 방법으로 identified candidate genes for Kr1

○ Alfares et al. 2009 Genetics 183: 469–481. Fine Mapping and Marker Development for the crossability gene SKr on chromosome 5BS of hexaploid wheat.- There was a SKr on chromosome 5BS, besides Kr1 on 5BL - Fine-mapped and Identified candidate gene for SKr

○ Laurie and Bennett (1987) TAG 73: 403-409- The effect of the crossability loci Krl and Kr2 on fertilization frequency in hexaploid

wheat x maize crosses- Highbury = Kr1 Kr2 CS (5B) = Kr1 kr2 CS = kr1 kr2

==> - Even Highbury was compatible with maize- No significant difference between CS(5B) and CS. Why??

===> The effect of Kr1 and Kr2 may differ along species.

(4) Methods for overcoming interspecific incompatibility

* Khush & Brar. 1992.

a. Application of growth substances : Auxins, GA3b. In vitro fertilization or stump pollination

stigmatic pollinationstyler “ placental “ intra-ovarian “ : injection of pollen soln directly into ovarystump pollination : on intact plants without ovary culture, particularly when style length

of two species are different--- Solanum, Nicotiana 등c. Irradiation of flower buds --- X-ray

: removal of interspecific incompatibility by means of induced mutationsd. Use of mentor pollen

irradiation freezing and thawing on mentor pollen + incompatible pollenmethanol treatment --- effective in Populas, Sesamum

* incompatibility within style tissue was maintained.

e. Treatment of stigma or pollen with organic solvents: n-hexane, ethyl acetate 등, treatment on stigma before pollination or

pollination after pollen washing with chemicals--- Populas 등

f. Somatic hybridization

g. Use of immunosuppressors: breakdown of immune system

--- injection treatment of amino-n-caproic acid(EACA), salicylic acid, acriflavin, etcduring megasporogenesis effective in crosses of wheat x barley, maize x sorghum

h. Bridge crossN. rependa (RR)N. sylvestris (SS)N. tabacum (TT)

compatible: RR x SS, SS x TTincompatible : RR x TT

i. Embryo culturej. Backcrossk. Others

* bud pollination* crossing at low temp. condition

( 20℃ in rice interspecific cross)* crossing after chromosome doubling

Rice Genetics II p.149 Fig.1

* genotypic variation in success rate <2: p.69 Tab.12>

3. Breeding Methodology

(1) Introgression

Chu. 1982. Anther culture of rice and its significance in distant hybridization. In Rice Tissue Culture Planning Conf., IRRI: 47-53

(2) Chromosome substitution or addition

(3) Amphidiploid: AABBDDRR, AABBRR 등(4) Others -- haploid breeding, CMS