MALE STERILITY, TYPES & USES IN HYBRID SEED

PRODUCTION

PRESENTED BY-HIRDAYESH ANURAGI

ADM. NO. 2015A29DPhD GENETICS & PLANT BREEDING

CCS HAU HISAR, HARYANA

PRESENTED TO-Dr. M. S. PUNIA

PROFESSORGENETICS & PLANT BREEDING

CCS HAU HISAR, HARYANA

Course: Heterosis Breeding (GP-507)

Male sterility Manifestation of Male sterility History of Male sterility Need of Male sterility Detection of Male sterility Creation of Male sterility Classification of Male sterility Cytoplasmic Male sterility (CMS) Genetic Male sterility (GMS) Cytoplasmic genetic Male sterility (CGMS) Transgenic Male sterility Chemical hybridizing agents (CHAs) Applications of Male sterility in Hybrid seed production

Contents

Male Sterility

Male sterility is characterized by nonfunctional pollen grains, while female gametes function normally.

Inability to produce or to release viable or functional pollen as a result of failure of formation or development of functional stamens, microspores or gametes.

Main reason is mutation.

Sterile SterileFertile Fertile

Manifestations of Male Sterility

Absence or malformation of male organs.

Failure to develop normal microsporogenous tissue- anther

Abnormal microsporogenesis (deformed or inviable pollen)

Abnormal pollen maturation

Non dehiscent anthers but viable pollen, sporophytic control

Barriers other than incompatibility preventing pollen from

reaching ovule

History of Male Sterility

J.K. Koelreuter (1763) observed anther abortion within species

& species hybrids.

Genic male sterility has been reported in cabbage (Rundfeldt

1960), cauliflower (Nieuwhof 1961)

Male sterility systems have been also developed through

genetic engineering (Williams et al. 1997) and protoplast fusion

(Pelletier et al. 1995)

Male sterility were artificially induced through mutagenesis

(Kaul 1988)

Manual emasculation

Use of male sterility

Use of self-incompatibility alleles

Use of male gametocides

Use of genetically engineered “pollen killer”

genetic system

Several forms of pollination control

Why Male Sterility ???

Reduced the cost of hybrid seed production.

Production of large scale of F1 seeds.

Avoids enormous manual work of emasculation

and pollination.

Speed up the hybridization programme.

Commercial exploitation of hybrid vigour.

Creation of Male Sterility

Spontaneous mutations

Interspecific hybridization

Mutation induction (EtBr)

Genetic Engineering

Chemically induced male sterility (CHAs)

Detection of Male Sterility system

Whether a particular sterile genotype belongs to which MS

system can be detected by its progeny performance on crossing

with a few normal genotypes.

Trend-I- All progenies in all the rows may be sterile- CMS

Trend-II- Some rows may consist all fertile

Some rows sterile and fertile in 1:1 ratio- GMS

Trend-III- Some rows fertile. Some rows sterile and some

rows sterile and fertile in 1:1 ratio - CGMS

Classification of Male SterilityKaul (1988) Classified Male Sterility in three major groups

1. Phenotypic Male Sterility (Morphological) Structural or Staminal Male Sterility Pollen Male Sterility Functional Male Sterility

2. Genotypic Male Sterility Genetic Male Sterility (GMS)

Environmental Sensitive (EGMS)a) Thermo sensitive genetic male sterility (TGMS)b) Photoperiod sensitive genetic male sterility (PGMS)

Environmental non-sensitive Cytoplasmic Male Sterility (CMS) Cytoplasmic Genetic Male Sterility (CGMS) Transgenic Male Sterility (TMS)

3. Chemically Induced Male Sterility (CHA)

Pollen sterility: in which male sterile individuals differ from normal only in the absence or extreme scarcity of functional pollen grains (the most common and the only one that has played a major role in plant breeding).

Structural or staminal male sterility: in which male flowers or stamen are malformed and non functional or completely absent.

Functional male sterility: in which perfectly good and viable pollen is trapped in indehiscent anther and thus prevented from functioning

Phenotypic Male Sterility

Cytoplasmic Male Sterility (CMS)

Determined by the cytoplasm (mitochondrial or chloroplast genes).

Result of mutation in mitochondrial genome (mtDNA)- Mitochondrial dysfunction.

Progenies would always be male sterile since the cytoplasm comes primarily from female gamete only.

Nuclear genotype of male sterile line is almost identical to that of the recurrent pollinator strain.

Male fertile line (maintainer line or B line) is used to maintain the male sterile line (A line).

CMS is not influenced by environmental factors (temperature) so is stable.

CMS can used in hybrid seed production of certain ornamental species or in species where a vegetative part is of economic value.

But not for crop plants where seed is the economic part because the hybrid progeny would be male sterile.

This type of male sterility found in onion, fodder jowar, cabbage etc.

Utilization of CMS in Plant Breeding

Use of CMS lines

Transfer of CMS to new strains (Diversification)

Genetic Male Sterility (GMS)

Also called as nuclear male sterility.

Mostly governed by single recessive gene (ms) but dominant gene governing male sterility (safflower).

Origin: Spontaneous mutation or artificial mutations (Gamma rays, EMS) are common.

‘ms’ alleles may affect staminal initiation, stamen or anther sac development, PMC formation, meiosis, pollen formation, maturation and dehiscence.

S.No. Mutagens Crops1 Colchicine Jowar2 Ethidium Bromide Groundnut, Maize, wheat3 Acetone Barley

Types of GMS

Environment insensitive GMS: ms gene expression is much less affected by the environment.

Environment sensitive GMS: ms gene expression occurs within a specified range of temperature and /or photoperiod regimes (Rice, Tomato, Wheat etc.).

1. TGMS: sterility is at particular temperature e.g. In rice TGMS line (Pei- Ai645) at 23.30C (China). TGMS at high temperature is due to failure of pairing of two

chromosomes at metaphase was evident. This abnormality led to abnormal meiosis, abnormal or sterile pollens. Anthers were shriveled and non-dehiscence-Male sterile. However, these lines produced normal fertile pollen at low temp. Sensitive period : PMC formation to Meiosis

2. PGMS: Governed by 2 recessive genes. Sterility is obtained in long day conditions while in short days, normal fertile plant. Rice:- Sterile under Long day conditions (13 hr. 45 min + Temp. 23-

290 C) but fertile under short day conditions. Sensitive period: Differentiation of secondary rachis branches to

PMC formation

Inheritance & Maintenance Of male sterile line

Nuclear male sterility and hybrid seed production

msms Msms

P1P2

X

Msms

Male fertile

Male sterile Male fertile

msms

Male sterile

MsMs

Male fertile

X

F1 Msms

Male fertile

Cytoplasmic Genetic Male Sterility (CGMS)

CGMS is also known as nucleoplasmic male sterility.

Case of CMS, where a nuclear gene (R) for restoring fertility in

male sterile line is known.

R (restorer gene) is generally dominant can be transferred from

related strains or species.

This system is known in cotton, maize, jowar, bajra, sunflower,

cotton, rice and wheat etc.

Hybrid seed production using CGMS system

rr S RR F

Rr S rr F

rr S Rr S

rr S Rr S

rr S RR S

rr S Rr S

♂♀

♂♀

Strain A Strain B

×

×

♀ × rr F ♂

rr F ♂×

6-7 Back crosses

×RR S

1 2 1: :

CMS Restorer

Male fertile Non restorer (Strain-C)

Male fertile

× Male fertile Male sterile Discarded

Discarded

DiscardedMale sterile

Male sterile

DiscardedMale sterile ×

Self pollinatedMale fertile

Male sterile Self pollinated

Male fertile(Strain-C)

Male fertile(Strain-C) ♀

Male fertile

Restorer line R is crossed to Male sterile A

Male fertile F1 is crossed to Strain C in which R gene is to be transferred

Male fertility progeny is back crossed to strain C

× Male fertility progeny is back crossed to strain C

Male fertile progeny is self pollinated

Male fertile progeny is self pollinated. Individual plant progenies grown in next generation and non segregating progenies are selected

Transfer of Restorer gene ‘R’ to non restorer strain

Inbred A (Cytoplasmic Male Sterile)

Inbred B (Non restorer male fertile)

Inbred C (Cytoplasmic Male Sterile)

Inbred D (Non restorer male fertile)

♂

♂

♀

♀

rr S

rr f

rr S

RR S

Single Cross –I A×B

(Male Sterile)

Single Cross-II C×D

(Male Fertile)

rr S

Rr S

♀

♂

Double Cross (A×B) × (C×D)

rr S

Rr S

50%

50%

Production of Double cross maize hybrids using CGMS

(1:1 Segregation for Male Fertility & Sterility)

Sources of CMS & Restorer genes in some Crops

Crop species Cytoplasm Restorer Genes

Rice

CMS-CW O. spontanea

CMS-bo O. Sativa boroII (single dominant)

CMS-WA O. Spontanea (WA, four genes)

CMS-W18 O. rufipogon

Wheat (T.aestivum) T. timopheevi Rf1 and rf2

A. caudata -

T. Durum Aegilops ovata -

Maize

CMS-C Rf4

CMS-S Rf3

CMS-T Rf1 and Rf2

Crop species Cytoplasm Restorer Genes

TobacoN. Debneyi -

N. Megalosiphon -

N. bigelovii -

CottonG. Anomalum -

G. Arboreaum -

G. harknesii -

Sunflower PET-1 (H. petalaris) 2 polymorphic genes (Rf1, Rf2)

Jowar Milo or A1 Msc from kafir race

Bajra Tift-23A -

S.No. Crop Hybrid Variety Seed Production

1. Maize Ganga 101, Ganga 1, Deccan, Ranjit,

Trishulatha, DHM-107, DHM-109

CMS

2. Sorgum CSH1 CMS

3. Bajra HB1 CMS

4. Sunflower BSH1 CMS

5. Rapeseed PGSH51 CMS

6. Red Gram ICPH-8 GMS

7. Rice PRH1 CMS

Male Sterility based Hybrids in Important Crops

Recombinant DNA techniques for disturbing any or number of

developmental steps required for the production of functional

pollen within the microspore or for the development of any

somatic tissues supporting the microspores.

Transgenes for male sterility are dominant to fertility.

Also to develop effective fertility restoration system for hybrid

seed production.

Example: Barnase/Barstar system

Transgenic Male Sterility

Undesirable effects of the cytoplasm

Unsatisfactory fertility restoration

Unsatisfactory pollination

Spontaneous reversion

Modifying genes

Contribution of cytoplasm by male gamete

Environmental effects

Non availability of a suitable restorer line

Limitations of Cytoplasmic-Genetic Male Sterility

Barnase is extracellular RNase; barstar is inhibitor of barnase

(Bacillus amyloliquefaciens)

Plants with TA29 promoter-Barnase construct are male sterile

Those with TA29-Barstar are not affected by the transgene barnase.

Barstar is dominant over the Barnase

Fuse the barnase and barstar genes to TA29 promoter–TA29 is a plant

gene that has tapetum specific expression.

Cross male sterile (barnase) with male fertile (barstar) to get hybrid

seed, which now has both barnase and barstar expressed in tapetum

and, hence, is fully fertile

Barnase/Barstar system

Hybrid seed production using Barnase/Barstar system

CHA is a chemical that induces artificial, non-genetic male

sterility in plants so that they can be effectively used as female

parent in hybrid seed production.

Also called as Male gametocides, male sterilants, selective male

sterilants, pollen suppressants, pollenocide, androcide etc.

The first report was given by Moore and Naylor (1950), they

induced male sterility in Maize using maleic hydrazide (MH).

Chemical Induced Male Sterility

Properties of an Ideal CHA

Must be highly male or female selective.

Should be easily applicable and economic in use.

Time of application should be flexible.

Must not be mutagenic.

Must not be carried over in F1 seeds.

Must consistently produce >95% male sterility.

Must cause minimum reduction in seed set.

Should not affect out crossing.

Should not be hazardous to the environment.

S.No. CHAs Critical stage Crop species

1. Zink Methyl ArsenateSodium Methyl Arsenate

5 days before heading Rice

2. Ethephon/ Ethrel Depends on crop Barley , oat, bajra, rice

3. Mendok Depends on crop Cotton, sugarbeet

4. Gibberellic acid 1-3 days before meiosis Maize, Barley, Wheat, Rice, Sunflower

5. Maleic Hydrazide Early microsporogenesis Maize, wheat, cotton, onion

Some important CHAs

Hybrid Seed Production based on CHAs

Proper environmental conditions (Rain, Sunshine, temp, RH etc.)

Synchronisation of flowering of Male & Female parents.

Effective chemical emasculation and cross pollination

CHA at precise stage and with recommended dose

GA3 spray to promote stigma exertion.

Supplementary pollination to maximise seed set

Avoid CHA spray on pollinator row.

Conditions required:-

Advantages of CHAs

Any line can be used as female parent.

Choice of parents is flexible.

Rapid method of developing male sterile line.

No need of maintaining A,B&R lines.

Hybrid seed production is based on only 2 line system.

Maintenance of parental line is possible by self pollination.

CHA based F2 hybrids are fully fertile as compared to few sterile

hybrids in case of CMS or GMS.

Limitations of CHAs

Expression and duration of CHA is stage specific.

Sensitive to environmental conditions.

Incomplete male sterility produce selfed seeds.

Many CHAs are toxic to plants and animals.

Possess carryover residual effects in F1 seeds.

Interfere with cell division.

Affect human health.

Genotype, dose application stage specific.

Male sterility a primary tool to avoid emasculation in hybridization.

Hybrid production requires a female plant in which no viable

pollens are borne. Inefficient emasculation may produce some self

fertile progenies.

GMS is being exploited (Eg.USA-Castor, India-Arhar).

CMS/ CGMS are routinely used in Hybrid seed production in corn,

sorghum, sunflower and sugarbeet, ornamental plants.

Saves lot of time, money and labour.

Significance of male Sterility in Plant Breeding

Existence and maintenance of A, B & R Lines is laborious and difficult.

If exotic lines are not suitable to our conditions, the native/adaptive lines have to be converted into MS lines.

Adequate cross pollination should be there between A and R lines for good seed set.

Synchronization of flowering should be there between A & R lines.

Fertility restoration should be complete otherwise the F1 seed will be sterile Isolation is needed for maintenance of parental lines and for producing hybrid seed.

Limitations in using Male Sterile line

Applications of

Male Sterility in

Hybrid Seed Production

Male sterility system in Rice hybrid seed production

Male sterility: a condition in which the pollen grain is unviable or cannot germinate and fertilize normally to set seeds.

Male Sterility Systems (genetic and non-genetic):Cytoplasmic genetic male sterility (CMS)

Male sterility is controlled by the interaction of a genetic factor (S) present in the cytoplasm and nuclear gene (s).

Environment-sensitive genic male sterility (EGMS)Male sterility system is controlled by nuclear gene expression, which is influenced by environmental factors such as temperature (TGMS), daylength (PGMS), or both (TPGMS).

Chemically induced male sterilityMale sterility is induced by some chemicals (gametocides)

 

 

Two Commercial MS Systems for Hybrid Rice

SOURCE NURSERY Elite lines from different sources

TGMS Line Breeding To evaluate parents and make testcross B & R line Breeding Program

Pollinator line Breeding ProgamBreeder Seeds TESTCROSS NURSERY

To identify TGMS & P lines Hybrid Seed Production for OYTCore Seeds Premarily heterosis evaluation, 2 rows w/ parent Isolation Bags or hand-crossing

Foundation Seed RETESTCROSS NURSERY (OYT)Re-evaluate F1 hybrids Hybrid Seed Production for PYT

Certified Seeds Stage 1, 1 rep, 3 rows Isloated Net or bags

TGMS Line Release Preliminary Yield Trial (PYT)Stage 2, 1 rep, plot Hybrid Seed Production for AYT & NYT

Isolation BlockAdvanced Yield Trial (AYT)

Stage 3, 3 reps, plot

Hybrid Pilot Seed ProductionNational Yield Trial Isolation Block

Stage 4, 3-4 reps, muti-location, 2-years

Hybrid and R line ReleaseOn-Farm Trial (Strip Trial)

Flowchart of 2-Line Hybrid Rice Evaluation and Seed Production

TGMS and two-line hybrid

Based on the discovery of P(T)GMS mutant

Male sterility controlled by 1 or 2 pairs of recessive gene(s) Fertile

S-lineMultiplication

Critical Fertility Point

Critical Sterility Point

Reproductive Upper Limit

Reproductive Lower Limit

SterileF1 Seed

Production

Partial Sterility

Model of Sterility / Fertility Expression for TGMS Rice

Temperature

low

high

Advantage & Disadvantage of 2-line hybrid rice system

AdvantagesSimplified procedure of hybrid seed production Multiple and diverse germplasm available as parents

Any line could be bred as female97% (2-line) vs 5% (3-line) of germplasm as male

Increased chance of developing desirable & heterotic hybridsMultiple cytoplasm courses as female parents

DisadvantagesEnvironmental effect on sterility could cause seed purity

problem

Requirements for 3 Lines in CMS System

A-lineStable SterilityWell developed floral traits for outcrossingEasily, wide-spectum, & strongly to be restored

B-lineWell developed floral traits with large pollen loadGood combining ability

R-lineStrong restore abilityGood combining abilityTaller than A-lineLarge pollen load, normal flowering traits and timing

Elite CMS line SOURCE NURSERY Elite lines from different sources

To evaluate parents and make testcross B & R line Breeding Program

P line Breeding Progam

CMS BACKCROSS NURSERY TESTCROSS NURSERYBC2- BC4, CMS Evaluation To identify B, R & P lines R & P Line

Backcross CMS pairs (BC1)Premarily heterosis evaluation, 2 rows w/ parent Hybrid Seed Production for OYT

Isolation Bags or hand-crossingAxB Paircross RETESTCROSS NURSERY (OYT)Breeder Seeds Re-evaluate F1 hybrids

Stage 1, 1 rep, 3 rows Hybrid Seed Production for PYTIsloated Net or bags

AxB Increase Preliminary Yield Trial (PYT)Core Seeds Stage 2, 1 rep, plot

Hybrid Seed Production for AYT & NYTAxB Seed Production Advanced Yield Trial (AYT) Isolation Block

Foundation Seeds Stage 3, 3 reps, plot

AxB Seed Production National Yield Trial Hybrid Pilot Seed ProductionCertified Seeds Stage 4, 3-4 reps, muti-location, 2-years Isolation Block

A & B Line Release On-Farm Trial (Strip Trial) Hybrid and R line Release

Flowchart of 3-Line Hybrid Rice Evaluation and Seed Production

Advantage & Disadvantage of 3-line hybrid rice system

Advantages

Stable male sterility.

Disadvantages

Limit germplasm source (CMS, Restorer)

Dominant CMS cytoplasm in large area (WA)

One more step for parental seed production

Time consuming of CMS breeding

Male sterility system in Maize hybrid seed production

Different ways of inducing male sterility in maize

I. Manual/mechanical emasculation (detasselling)

II. Genic male sterility

III. Cytoplasmic genetic male sterility

IV. Gametocides

1. Genetic Male sterility

Male sterility determined by single recessive gene

40 loci involved have been identified (ms1 to ms52)

ms5 –cloned

Problem : impossible to maintain male sterile inbred

detasselling required

2. Cytoplasmic Male sterility

1. CMS-T (Texas) (Rogers and Edwardson, 1952)

Highly stable under all environmental conditions

Characterized by failure of anther exertion and pollen abortion

Susceptible to race T of the southern corn leaf blight - (Cochliobolus

heterostrophus = Bipolaris maydis)

Widespread use of T-cytoplasm for hybrid corn production led to

epidemic in 1970 with the widespread rise of Race T.

Toxin produced by C. heterostrophus = T-toxin.

Fertility restoration is sporophytic Rf1 (chr. 3) & Rf2 (chr.9) are responsible for fertility restoration

2. CMS-C (Charrua) (Beckett, 1971) Mutations in three genes viz atp6, atp 9 and cosII- confer CMS

phenotype Fertility restoration is Sporophytic Rf4, Rf5, Rf6 are responsible for fertility restoration

3. CMS-S (USDA) (Jones,1957) Sterility associated with orf355-orf77 chimeric mt gene Fertility restoration is Gametophytic Rf3 (chr. 2) are responsible for fertility restoration Plasmid like element S1 & S2

T-urf13 gene in T cytoplasm maize Mitochondrial gene T-urf13 is a unique chimeric sequence Effect of URF13 protein- Degeneration of the tapetum during microsporogenesis Disruption of pollen development leading to male cell abortion

Reversion to fertility

The reversion of CMS strain to male fertility is based on genetic change

Reversion can be spontaneous or mutagen induced

S-cytoplasm revert rather frequently to male fertility (than T & C). Maize-CMS Restoration of fertility system:

different classes of pollen grains are produced, but not all of them are viable

A X B(frfr) (frfr) ms mf

AB(frfr)ms

X C (FrFr) mf

ABC(Frfr)

mf

Triple Cross Hybrid C X D(frfr) (FrFr) ms mf

CD(Frfr)

mf

A X B(frfr) (frfr) ms mf

AB(frfr)ms

X

ABCD1

(Frfr)mf

1(frfr)ms

:::

Double Cross Hybrid

Types of Hybrids

Single cross hybrid (A×B)

Double cross hybrid (A×B)×(C×D)

Three way cross Hybrid (A×B)×C

Top cross (C×OPV)

Hybrid blends

Inter-population hybrids

Chance hybrids

Male sterility system in Bajra hybrid seed production

Hybrid seed production using CGMS Depends on the cytoplasm that produce male sterility and gene that

restores the fertility.

Steps: Multiplication of CMS (A) line Multiplication of Maintainer (B) line and Restorer (R) line Production of Hybrid seed (A×R)

Maintenace of A & B lines: Grow A line and its corresponding B line together in an isolated

plots. Isolation distance for A×B production fields is at least 1000m. A ratio of 1A:1B row is maintained. Pollens produced by the B line fertilize the male sterile plant (A)

and seeds produced thus Give rise to A line again.

Maintenance of R line: Pearl millet R line could be either an inbred line or an Open

pollinated variety which can be multiplied as variety.

Seeds of R lines are produced by multiplying seeds in isolated

plots having distance 1000m.

Any plant in the R line plot appearing different from true R

type should be uprooted or rogued out before anthesis.

Purity of the parental seed is very important because it affects

the quality of the hybrid seeds that is generated.

Scheme of hybrid seed production in pearl millet

Layout of hybrid seed production plot

Identification of potential hybrid parents (A,B and R lines)

Potential male and female parents for hybrid seed production are identified by crossing male fertile parent (Inbreds, variety, germplasm, breeding stocks in advanced generations) to a male sterile line (A line) and observing their corresponding hybrids in small plots of an observation nursery.

A few plants of each cross are subjected to the bagging test i.e. covering the few panicles with the paper bags before anthesis and observing the seed set under the bag after few weeks.

CGMS

A1 Tift 23 A (Most of the world hybrids contains A1 Blood), Burton,1958

A2, A3 Not stable cytoplasmA4 Derived from P. glacum subspecies monodii

Does not have effective restorerUsed in forage hybrid production

Male sterility system in Brassica hybrid seed production

Cytoplasmic male-sterile

Stamen (anther and filament) and pollen grains are affected It is divided into:

a. Autoplasmic Arisen within a species as a result of spontaneous

mutational changes in the cytoplasm, most likely in the mitochondrial genomeb. Alloplasmic

Arisen from intergeneric, interpecific or occasionallyintraspecific crosses and where the male sterility can be interpreted as being due to incompatibility or poor co-

operationbetween nuclear genome of one species and the organellar

genome. Another CMS can be a result of interspecific protoplast fusion

Raphanus or ogu system Polima or pol system Shiga-Thompson or nap system Diplotaxis muralis or mur system Tournefortii (tour) system Moricandia arvensis or mori system Chinese juncea or jun system

17 systems are available, only difference is the use of male sterile cytoplasmic sources differs for each system

Nap system– B.napuus cross b/w winter & spring var. pol system – B.napus var polima mur system--Diplotaxis muralis x B.campestris cv Yukina tour system– B.juncea collections

Various CMS systems

Ogu system:-

First discovered in Japanese radish (Raphanus sativus) by Ogura, 1968

B.napus genome was transferred into the back round of R.sativus (mst) through intergeneric crosses followed by back crossing with B.napus.

CMS seedling under low temperature showed chlorosis , because chloroplast of R.sativus is sensitive to cold, it is governed by cp-DNA , but mst is governed by mt DNA.

Protoplast fusion of R.sativus with B.napus carried out to have normal green plants with ogu CMS characterisitics

This system now has been used for developing alloplasmic male sterile line in B.juncea and B.campestris.

Genetic Male Sterility GMS is governed by two genes either recessive or dominant

genes(Kaul,1988)

One more dominant gene is associated with development of male sterility in B.napus type by means of transgenic male sterility

Chemical Male sterility

Enthrel – Brassica juncea

Zinc methy arsenate- B.napus

GA- B.oleracea var capitata

B.napaus

F1 interspecific cross

xRhapanus sativus

F1 Sterile

G-Rs

C-Rs

G-Bn

N-Bn

1/2G-Rs1/2G-Bn

C-Rs

mftmst

Doubling by colchince Fertile amphidiploid

1/2G-Rs1/2G-Bn

C-Rsmst

Development of Male sterile B. napus from R. sativus

1/2G-Rs1/2G-Bn

C-Rs

x G-Bn

N-Bn

G-Bn

C-Rs

B.napus

mst

BC3

Male sterile B.napus

mft

Development of Alloplasmic Male sterile Brassica campestris

xN-Bc

B.campestris

F1 interspecific cross

xG-Bn

S-Rs

G-Bct

N-Bc

1/2G-Bn1/2G-Bc

S-Rs

mftmst

G-BC

S-Rs

BC4

G-Bc G-Bc

Male sterile B.napus

Presently genetic male sterility (GMS), cytoplasmic male sterility

(CMS) and thermo sensitive genetic male sterility (TGMS) lines are

available in India.

Development of agronomically superior genetic male-sterile lines in

safflower in India have resulted in the development and release of

spiny safflower hybrids DSH-129 and MKH-11 in 1997 and NARI-

H-15 in 2005, the first non-spiny hybrid safflower NARI-NH-1 in

2001.

Male sterility system in Safflower hybrid seed production

Genetic Male sterility (GMS)

Complete male sterility ms1-ms5 = male sterility in sunflower recessive gene

Two types of g-mst

Type 1-gmst-Bloomington type Type 2-gmst-Modern type

Cultivated Sunflower variety Karlik-68(Dwarf 68)- two recessive genes msi1,msi2 (Stable and complete male sterile)

Partial male sterility –p mst

Male sterility system in Sunflower hybrid seed production

CGMS

H.petiolaris × H.annuus Repeated backcross of H.annuus results in cms1 which is extensively used mst in hybrid seed production of sunflower all over the world

H.giganteus× H.annuus Cms3( S cytoplasm source)

H.annuus subspp lenticularis × H.annuus CV commander

Indiana 1

Genetic Male Sterility (GMS): Reported in upland, Egyptian and arboreum cottons. In tetraploid cotton, male sterility is governed by both

recessive and dominant genes. However, male sterility governed by recessive genes is used in

practical plant breeding

All three types of male sterility occurs (g mst,c mst,gc mst) in cotton

Sixteen different genes in tetraploid cottons (13 in G. hirsutum and 3 in G. barbadense) and two in G. arboreum have been identified for genetic male sterility.

Sterility is conditioned by dominant alleles at five loci viz, MS4, MS7, MS10, MS11 and MS12 by recessive allele at other loci viz. msl, ms2, ms3, ms13, ms14 (Dong A), ms15 (Lang A) and ms16 (81 A).

Male sterility system in Cotton hybrid seed production

G. hirsutum line Gregg (MS 399) from USA is the basic source of GMS possessing ms5 ms6 gene for male sterility.

Genetic Male Sterility

CMS System

In case of CMS, the originally discovered CMS sources involving G. arboreum and G. anomalum cytoplasmic systems having interaction with ms3 locus were not found effective or stable under different environments.

The only stable and dependable CMS source under varied environment was developed through the utilization of G. harknessii. The complete genome of G.hirsutum was transferred into the G. harknessii cytoplasm.

A single dominant gene ‘Rf’ from G.harknessii is essential for fertility restoration.

Fertility enhancer factor 'E' for this CMS restorer system was obtained from a G.barbadense stock.

The harknessii system is reported to contribute to good agronomic properties and attraction to honey bees.

Sources of Male sterility in Cotton

Source of ms cytoplasm Nuclear genomeG. anomalum, G. arboreum, G. harknessii

G. hirsutum

G. anomalum, G. arboreum Heat sensitive , less stableG. harknessii × G. hirsutum Stable cms all over the environment New sources of CMSG. aridum Skovt. × G. hirsutum (D4)G. trilobum × G. hirsutum CMS 8 (D-8)G. sturtianum × G. hirsutum CMS-C1 New sources of CGMSG. anomalum x G. thurberi Cg-mst

Mutation G. arboreum, the first spontaneous male sterility mutant was identified

in variety DS-5

Chemical based male sterility FW 450(Sodium B-Dichloro-iso-butyrate) MH-30 (Maleic hydrazide) Ethidium bromide

Male sterility based hybrid Production GMS system. CPH2 (Suguna), First hybrid based on GMS released at

CICR, RS, Coimbatore G. harknessii based cms with fertility restoration gene sources were

used in developing the hybrid CAHH 468 (PKV Hy-3).

Cytoplasm Nuclear genome ReferenceS.acaule (4X) S.tuberosum Lamm,1953S.chacoense(4X) S.tuberosum Rammanna and Hersmen(1974)

S.phureja(2x) S.tuberosum Magoon et al.,1958b

S.stoloniferum(4x) S.tuberosum Ross (1961)

S.Verrucosum(2X) S.tuberosum Abdalla (1970)

Inter-specific Hybridization

Male sterility system in Potato hybrid seed production

FW 450(Sodium B-Dichloro-iso-butyrate) MH-30 (Maleic hydrazide) Ethidium bromide

Chemical mutagens

Development of Male sterility

Genome transfer S cytoplasm is in the genome of fr genes

Unreduced Gamete ProductionS.tuberosum (2x) × S.tuberosum (4x)

Protoplast Fusion S cytoplasm is retained

Di haploid

S.tuberosum (4x) × S.phureja (4x)

(2x) (2x) F1 (4x)

Anther culture

DiHaploid (2x)