Breeding for disease resistance in

BREEDINGFOR DISEASE RESISTANCE IN
PEARL MILLET
1
Speaker : Gade Abhijit Anant Course No. : PBG-901
Degree : M.Sc. (Agri.) PBG Date : 31-3-2010
Major Advisor : Dr. K. K. Patel Time : 3:00 pm

I. Introduction
II. What is disease resistance ?
III. Downy mildew
 Screening techniques
 Resistance sources
 Genetics
IV. Ergot
 Genetics
V. Smut
 Genetics
VI. Rust
 Genetics
VII. Breeding methods
VIII. Emerging technologies
IX. Conclusion
X. Future thrust
CONTENT
2

 Botanical name:- Pennisetum glaucum (L)
 Family:- Poaceae
 Sub Family:- Panicoideae
 Genus:- Pennisetum
 Origin:- Sahel zone of West Africa
 Chromosome no.:- 2n=14,
 Common Names:- Bajra, Bulrush millet, Spiked millet, Cat tail millet.
 Distribution:- Semi-arid, arid regions of Africa, South America,
Southern Asia (Mainly India).
 Summer pearl millet is popular in Gujarat State (2.35 t/ha. yield)
 Uses:- Pearl millet is a dual purpose drought resistant crop useful for,
Human consumption - Leavened or Unleavened bread, Porridge, snacks,
unfermented beverage, beer and distilled drinks.
Animal Feed - Fodder, Hay, poultry feed.
Production of starch for industrial purpose.
3
INTRODUCTION

2007-08 2008-09 2009-10
Area (’000 hec.)
India 9507.9 9571.3 8734
Gujarat 937 921 703.3
Production (’000 tonns.)
India 8423.7 9970.1 8890
Gujarat 1019 1307 961.3
Productivity (Kg/ hectares)
India 886 1042 1018
Gujarat 1088 1419 1370
Table 1 : Area and production of pearl millet in India and Gujarat
Anonymous (2009) 4

DOWNY MILDEW
Sclerospora graminicola
Loss: 20- 40%
SMUT
Tolyposporium penicillariae
Loss: 5- 20%
ERGOT
Claviceps fusiformis
Loss: 5- 10%
RUST
Puccinia graminae
Loss: >15%
FUNGAL DISEASES
LOSSES DUE TO FUNGAL DISEASES
5

What is Disease Resistance ?
6

 THE DEVELOPMENT OF FUNGAL DISEASES OCCURS IN FOUR STAGES –
1. Contact
2. Infection
3. Establishment
4. Development
1. Contact represents the loading of a pathogen on the host tissue.
2. Infection is the process by which the pathogen gains entry into host tissue.
3. In establishment phase, the pathogen proliferates and spreads within host
tissue, but the symptoms of disease do not become visible during this stage.
4. Development phase, is characterized by the development of characteristic
symptoms of disease and generally associated with multiplication of the
pathogen.
‘‘Disease resistance in host involves a restriction on the establishment and development
(multiplication) phase of pathogen. ’’
7

 Escape:
Certain varieties of crop plants which undergo development and
maturation, may complete their life cycle before maximal infection
occurs.
 Tolerance:
Inherent or acquired capacity to endure disease and to give
satisfactory returns.
 Resistance:
Resistance is relative term and measured by using susceptible
cultivars of the same species as checks, which denotes less disease
development in the genotype than that in the susceptible variety.
 Immune:
Means 100% freedom from infection. Pathogen can not
establish parasitic relationship with the host even under most favorable
condition.
MECHANISM OF RESISTANCE
8

A conceptual gene-for-gene interaction between host & pathogen leading to
Resistant (R) & Susceptible (S) reaction.
THE HOST PATHOGEN INTERACTION FOLLOWING GENE
FOR GENE CONCEPT
India Thakur et al. (2008) 9

(i) Vertical (Specific ) resistance
Specific resistance of host to the particular race of a pathogen
governed by mono or oligogenes.
(ii) Horizontal (General) resistance
The resistance of a host to most of the prevailing races of pathogen is
called horizontal resistance (non-specific resistance or minor gene resistance)
and governed by polygenes, and rarely by oligogenes.
TYPES OF RESISTANCE
10
1. To prevent yield losses
2. Cost effective
3. Easily adoptable
4. Eco-friendly control of disease
WHY RESISTANCE BREEDING?

 Causal Organism:- Sclerospora graminicola
 Class:- Oomycetes
 Order:- Peronosporales
 Family:- Peronosporaceae
 Disease firstly reported by Butler (1907) in India and then by
Kulkarni (1913).
 In India, downy mildew epidemics caused substantial yield losses
in F1 hybrids during 1970-76, 1983-1984 and again in 1987-1988.
 First epidemics occurred in 1971.
 Yield reducing potential is directly proportional to disease severity.
 Yield reduces upto 60-70%.
 Primary infection caused by (soil-borne, sexual) Oospores.
 Secondary infection caused by (air-borne, asexual) Sporangia.
 Disease is seed transmitted in the form of seed-carried oospores.
DOWNY MILDEW
12

I. Seedling stage:
 Infected plants tiller excessively
 Dwarfing and shortening of internodes
 Foliage become pale and chlorotic
 Broad chlorotic streaks extended from base to tip of leaf observed
 Downy fungal growth can be visible on lower surface of leaf and in sever case it may appear on
upper surface
 Chlorotic yellow streaks turn brown and leaf becomes shredded lengthwise
II. Green ear head stage:
 When the pathogen infects the host systemically, ear head become malformed
 Entire ear head is transformed into leafy structure the floral parts glumes, palea, stamens and
pistil converted into leafy structure.
 Leafy structure become brown and dry up without grain formation, in some cases partial grain
filling observed.
 Favourable conditions:-
 High humidity < 90%
 Presence of water on the leaves
 Low atmospheric temperatures 150 _ 250 C.
SYMPTOMS
14

 ICRISAT has developed highly effective field and greenhouse screening
techniques that can easily differentiate between resistant and susceptible
progenies.
I. Field screening technique
 Both sporangia and oospores are used as sources of inoculum.
 Involves sowing of susceptible infector genotypes, test materials and a
range of indicators and controls, in oospore-infected plots, and scoring
for disease incidence.
 Infector rows are mixtures of two or more susceptible genotypes, which
are sown at regular intervals several weeks before planting the test
materials.
 From emergence to the 1-2 leaf stage, these infector rows are spray-
inoculated with sporangial suspension during evening.
 Material to be screened are sown in between rows after the infector
rows have 50-60% downy mildew incidence.
 Known susceptible and resistant controls are sown with the test
materials at regular intervals to show the level of disease pressure and its
distribution in nursery.
SCREENING TECHNIQUES
15

II. Greenhouse and laboratory screening technique
 Potted seedling are inoculated at the coleoptile to 1-leaf-stage either
by putting a drop of sporangial suspension (1 x 106 sporangia/ml) at the
tip of each seedling or spray inoculated using a hand sprayer.
 Inoculation is done in an inoculation chamber maintained at 200 C and
> 95% relative humidity with a variable sporangial suspension and pots
are incubated overnight in this chamber.
 Pots are then kept on green house benches at 25-300 C temperatures.
 Seedlings are evaluated for downy mildew incidence two weeks after
inoculation.
16
ICRISAT, Patancheru. Hash et al. (1996)

RESISTANCE SOURCES
SOURCES OF RESISTANCE
17

Sr.
No.
Entry Downy mildew incidence (%) Pooled
mean
1991/92 1992/93 1993/94 1994/95 1995/96
1 J 2002 0.0 0.0 0.0 1.6 2.0 0.7
2 ICMH 451 4.3 3. 3.5 13.4 5.8 6.2
3 ICMP 451 22.2 27.8 42.9 31.0 36.5 32.1
4 Pusa 23 1.8 0.0 0.0 0.0 1.7 0.7
5 HC 4 2.3 6.3 5.6 4.2 3.4 4.4
6 HHB 50 0.0 0.0 0.0 0.0 0.0 0.0
7 HHB 60 1.7 0.0 0.0 2.7 0.0 0.9
8 HHB 67 0.0 0.0 0.0 2.8 0.0 0.6
9 HHB 68 0.0 0.0 0.0 0.0 0.0 0.0
10 81 A 0.0 2.0 2.4 0.0 1.9 1.3
11 81 B 0.0 2.0 0.0 0.0 1.9 0.8
12 841 A 0.0 0.0 0.0 0.0 0.0 0.0
13 841 B 0.0 0.0 3.4 0.0 3.2 1.3
14 5054A 23.1 22.7 3.1 8.4 5.0 12.5
15 5054B 31.2 5.2 16.5 17.2 15.0 17.0
16 ICMA 88004 0.0 0.0 0.0 0.0 0.0 0.0
17 ICMB 88004 2.1 11.4 2.1 5.2 0.0 1.9
18 H 77/833-2 4.0 0.0 6.3 2.6 19.2 6.4
19 H 90/ 4-5 0.0 0.0 0.0 2.3 0.0 0.5
20 NHB 3 (control) 88.6 86.2 88.3 90.7 92.4 89.2
S. E. ±8.80 ±8.20 ±13.33 ±13.70 ±9.05 ±10.62
LSD (p = 0.05) 18.88 28.50 28.59 29.39 19.41 24.95
Table 2: Downy mildew reactions of pearl millet hybrids and varieties, male sterile lines, their maintainers,
and restorers against downy mildew during 1991-96.
Hisar Rathi and Panwar (1997)
18

Sr.
No.
Land Race Downy mildew
Incidence (%) Reaction
1 Ardi-Beniya Ka Bas 3.1 HR
2 Dhodsar local (Sunda ram) 4.5 HR
3 Desi Bajri-Chomu 4.3 HR
4 Desi Bajri-Osian 6.4 R
5 Chadi local 7.0 R
6 Bikaneri Bajri-Raisar 9.4 R
7 Bikaneri Desi-Jodhasar 10.0 R
8 Jakharana (Ex-situ) 8.5 R
9 Ardi-Dungarsi Ka Bas 5.3 R
10 Mandeta local 6.8 R
11 Dhodsar local (original) 6.7 R
12 Desi-Karnoo 19.2 S
13 Chadi (NB) 13.6 S
14 Chadi local (Ex-situ) 12.8 S
15 Desi-Panchu 12.4 S
16 Desan Bajri (SPS) 14.9 S
17 Desan Bajri-Panchu 11.7 S
18 Sulkanya local (Ex-situ) 12.0 S
19 Desan Bajri 23.2 S
20 Desi-Birsalu 37.6 HS
21 Desi-Biraniya 36.7 HS
22 7042S (susceptible check) 94.5 HS
SEm± 2.098 –
CD (0.05) 6.172 –
Table 3: Evaluation of local landraces of Rajasthan for downy mildew resistance
Rajasthan Sharma et al. (2007)
Highly Resistant = 0-5% Incidence,
Resistance = > 5-10% Incidence,
Susceptible = > 10-15% Incidence,
Highly Susceptible = > 25% Incidence.
HR = Highly Resistant
R = Resistance
S = Susceptible
HS = Highly Susceptible
19

Identity
Downy mildew incidence (%)2
Greenhouse Field
Sg 409 Sg 212 Soft-dough
ICMA 88006 79 50 23
ICMB 88006 62 45 15
ICMA 92444 79 88 11
ICMB 92444 93 90 10
ICMA 92777 2 0 3
ICMB 92777 1 0 3
ICMA 92888 99 97 13
ICMB 92888 95 98 16
ICMA 93111 99 29 13
ICMB 93111 99 39 26
ICMA 93333 74 41 6
ICMB 93333 62 47 7
Controls
81A 93 76 30
81B 92 96 31
841A 88 65 3
841B 62 63 4
7042S 99 97 100
Mean 75 60 18
SE(m)± 3.5 2.1 3.2
LSD (P <0.05) 10.0 5.7 9.1
Table 4: Downy mildew1 incidence of eight A/B lines evaluated under field and greenhouse
conditions at ICRISAT during rainy season, 2005.
1. Downy mildew pathotype Sg 409 from Patancheru and Sg 212 from Durgapura.
2. Mean of five replications based on total and diseased plants both in field and greenhouse.
Patancheru Rao et al. (2006) 20

Table 5: Downy mildew reaction and segregation ratios in F2 and BC generations from the pearl millet
cross DMSP 23 × DMRP 292 in the greenhouse during 1996–97 at ICRISAT Asia Center,
Patancheru.
Generation
Number of plantsa
Resistant Susceptible X2 Ratio P value
DMSP 23 × DMRP 292 F1 77 0 … …
DMSP 23 × DMRP 292 F2 202 63 3:1 0.95-0.50
DMSP 23 × (DMSP 23 × DMRP 292) BC1 211 195 1:1 0.50-0.20
DMRP 292 × (DMSP 23 × DMRP 292) BC2 230 0 … …
DMSP 23 2 240 … …
DMRP 292 185 0 … …
a. Pooled data from all tests.
Patancheru Singh and Talukdar (1998)
22

Crosses m d h i j l
114-1-R x CN-74-1 11.17** -1.90 -14.51** -17.40** -1.32 24.18**
114-1-R x CN-74-5 12.43** -0.86 -16.99** -18.44** 0.23 10.89*
114-1-R x SDN 347-1 5.67** -0.67 -0.64** -5.62** -0.14 8.26*
114-1-R x ECT-77 6.00** -1.92* -0.50 -1.17 -2.40 18.46**
7042 x CN 74-1 14.11** -11.94** 16.39** 35.40** 29.44** -35.63**
7042 x CN-74-5 24.37** -34.99** -0.53 17.14** -16.09** -3.67
7042 x SDN 347-1 11.82** -26.98** -28.64** 50.92** -0.52 -60.28**
7042 x ECT-77 13.07** -41.06** 52.64** 72.87** -27.71* -107.01**
Table 6: Estimates of gene effects for S. graminicola in different crosses of pearl millet.
*, ** Significant at 5% and 1% level, respectively;
D = Duplicate epistasis, C = Complementary epistasis.
Rahuri Shinde et al. (1984)
23

DM Resistance Breeding
DM Screening
Hybridization / Selection
Resistance / Virulence
monitoring
B - R -line x DMR line
F1 / F2 / F3 ----- / BC Progenies
F5 / F6 / BC5 / 7 Progenies
Advanced A -/ B- / R- lines
Initial hybrids
Advanced hybrids
Released / commercial hybrids
PMDMVN
Resistance stability / Donor
Virulence diversity
On – farm DM survey
 Disease reaction of hybrids
 Isolates collection and
Characterization
 Identification of new virulent
pathotypes
Greenhouse
Single / Multiple
pathotype
DM Field nursery
Location – specific
pathotype
FIGURE: PROPOSED PROTOCOL FOR DOWNY MILDEW (DM) RESISTANCE BREEDING IN PEARL MILLET
24

 Causal Organism:- Claviceps fusiformis loveless
 Class:- Ascomycetes
 Order:- Hypocreales
 Family:- Hypocreceae
 Ergot was first reported on pearl millet in India by Thomas et al. (1945).
 The causal fungus of ergot of pearl millet was first described by Loveless (1967).
 First report of this disease in epiphytotic form was reported in 1956 from
Maharashtra by Bhide and Hegde (1957), and Shinde and Binde (1958).
 Disease reduces grain yield up to 58.4 – 70.5%.
 It adversely affected grain quality by mixture with the toxic alkaloids
contaminating sclerotia of pathogen.
 Ergot contains poisonous alkaloids like ergosterol, ergotoxin, ergotomine,
ergosterine, ergocalvin. They cause vomiting, paralysis, gangrene or even death.
This toxins also reduces seed germination.
 Longer protogyny periods usually result in higher disease incidence.
 Primary infection caused due to Ascospores.
 Secondary infection caused due to conidia produced in honey dew like
substance.
ERGOT
26

 Disease appears only at flowering stage
 Exudation of small droplets of light pinkish or brownish sticky fluid (honeydew) from
the infected spikelets
 Under sever infection, many such spikelets exude plenty of honeydew, which trickle
long the ear head
 Honeydew attracts the insects which helps in secondary spread of disease in the field
 The infected ovaries darken with age and small grayish dark brown sclerotia are
formed
 The sclerotia contain the alkaloid ergotoxin, which causes nervous breakdown in
human being and animals
 High rainfall and high humidity during flowering
 Presence of collateral host increase the disease development
 Cool weather
SYMPTOMS
28

 ICRISAT Center has developed an effective screening techniques that involves:
Bagging panicles at the boot-leaf stage with glassine selfing bags to allow
stigma emergence in a pollen-protected environment;
Inoculating panicles, 3-4 days later by briefly opening the bags and spraying the
panicles at the full protogyny stage (> 75% fresh stigmas) with an aqueous
conidial suspension (1 x 106 conidia ml-1 ) produced from honey dew of infected
panicles; providing high humidity (>80% RH) with overhead sprinklers twice a
day for 30 min each at 10 am and 5 pm on rain-free days;
Removing bags two weeks later and scoring ergot severity using a standard key.
29

RESISTANCE SOURCES
30

Sr.
No.
Parent Origin Ergot
resistance
score
Height
(cm)
Days to
50%
flowering
Ear
length
(cm)
Tiller
number/half
meter
Yield
g/half
meter
 Stock resistant to ergot
A. Exotic
1 IP 517 Mali R (1.5) 175 54 29 11.5 182
2 IP 1956 Nigeria R (1.0) 173 53 35 10.5 133
3 IP 1959 Nigeria R (1.5) 171 52 31 9.5 171
4 IP 326 Senegal R (2.0) 198 51 36 7.0 107
5 IP 855 USA R (1.5) 237 54 28 9.5 182
B. Indian
1 IP 1251 Andhra R (2.0) 177 51 28 11.0 155
2 IP 1833 Gujarat R (1.5) 155 49 29 12.0 217
3 IP 1847 Gujarat R (2.0) 183 50 26 10.5 186
4 IP 1902 Gujarat R (1.0) 197 50 24 8.0 163
5 IP 1581 Kashmir R (1.0) 180 53 27 11.0 111
Table 7: Some characteristics of the ergot resistance lines used in breeding for ergot resistance.
R – Resistance
New Delhi, ICAR Marthy (1977)
31

Entry
Mean ergot severity (%)2 at location3
SMR ABD JMN ICR LHD NDL MYS
ICMPE 13-6-27 3 1 2 2 3 3 1
ICMPE 13-6-30 1 1 2 2 4 2 4
ICMPE 134-6-25 1 1 1 1 2 1 1
ICMPE 134-6-34 1 1 1 1 2 1 1
ICMPES 1 1 1 1 1 2 1 2
ICMPES 2 1 2 1 1 1 2 5
ICMPES 23 1 2 1 2 2 2 3
ICMPES 27 1 1 1 1 1 1 1
ICMPES 28 1 5 1 3 1 6 8
ICMPES 32 1 15 2 4 2 1 8
Susceptible Control 86 79 44 93 65 49 54
Table 8: Performance of some selected ergot- resistant lines in the international pearl millet ergot
nursery (IPMEN) at one location in West Africa and six locations in India over 2-4 yrs (1981-84)
1. ICMPE = ICRISAT millet pathology ergot resistant line. ICMPES = ICMPE sib-bulk.
2. Of 20-40 inoculated head in two replications.
3. Locations:
SMR = Samaru (2 years’ data) ABD = Aurangabad (3 years’ data)
ICR = ICRISAT Center (3-4 years’ data) LDH = Ludhiana (3-4 years’ data)
NDL = New Delhi (3-4 years’ data) MYS = Mysore (3 years’ data)
Patancheru Thakur and Chahal (1987) 32

Table 9: Mean grain yield and disease reactions of five selected ergot - resistant populations (ICMPES)
Entry Ergot severity (%)2 Yield (Kg ha-1)1
ICMPES 8 1 2210
ICMPES 28 0 2170
ICMPES 29 0 2050
ICMPES 32 1 1970
ICMPES 9 1 1940
WC-C75 (control) 45 1942
S.E. 229
Mean 1730
C.V. (%) 23
1. Mean of seven locations: ICRISAT Center high fertility, ICRISAT Center low-fertility, ICRISAT Center
ergot nursery, Aurangabad, Pune, Bhavanisagar (all rainy season 1984), and ICRISAT Center, post
rainy season 1984. Plot size 6m2.
2. Based on open-head inoculation in ICRISAT Center ergot nursery, rainy season, 1984.
Patancheru, ICRISAT Thakur and Chahal (1987)
33

Mean ergot
severity (%)
Percentageb of lines in each classes at
F2 F3 F4 F5 F6
< 1 0 0 0 4 31
1-10 0 0 63 36 59
11-20 0 7 21 24 5
21-30 0 16 16 4 0
31-40 33 36 0 13 3
41-50 33 10 0 2 0
> 50 0 32 0 16 2
Total lines
screened
3 31 19 45 64
Table 10: Seven ergot severity classes in five generations of pearl millet from a crossa
between J 2238 and J 2210-2
a. One of two crosses having the greatest resistance at F6.
b. Rounded off to whole numbers.
c. Three populations screened but only two scored.
Patancheru Thakur et al. (1982)
35

SMUT
 Causal Organism:- Tolyposporium penicillariae
 Class:- Basidiomycetes
 Order:- Ustilaginales
 Family:- Ustilaginaceae
 The disease has been reported from Pakistan, India, and the United States,
and from many countries in Africa. The earliest reports of this disease are
from Senegal by Chevalier (1931) and India by Ajrekar and Likhite (1933).
 Smut is a panicle disease (it attacks the flowering head of the pearl millet).
 Primary infection caused due to sporidia from spore balls in the soil from
previously infected crop residue and surface contaminated seeds used for
sowing.
 Secondary infection caused due to air-borne sporidia (Teliospores).
 The hybrid cultivars having long protogyny and poor fertility restoration
usually result in disease incidence.
 Early pollination reduces the infection by pathogen.
 Disease is seed transmitted.
37

 Disease becomes apparent at the time of grain setting
 Pathogen infects few florets and transforms them into black spore
containing smut spores
 The infected sori larger and greater than normal healthy grains and they
are bright green to dirty black in colour
 when the sori are ruptured, it releases millions of black smut spore balls
 High relative humidity (>80 %)
 Successive cropping with bajra
 Cool temperature
SYMPTOMS
39

 An effective screening technique for smut resistance in pearl millet involves:
 Inoculation of panicles by injecting aqueous suspension of sporidia
(1 x 106/ml) into the ‘boot’.
 Covering the inoculated panicles with parchment paper selfing bags.
 Providing high humidity (> 80% RH) by using an overhead sprinkler,
normally twice a day, 30 min each at 10 am and 5 pm, on rain-free days.
 Removing bags 15-20 days after inoculation and scoring panicles for smut
severity using a standard smut severity assessment key.
40

RESISTANCE SOURCES
41

Entry1
Mean smut severity (%)2 at
Hisar ICRISAT
Center
Jamnagar Bambey
SSC FS 252-S-4 0 0 1 1
ICI 7517-S-1 1 1 1 1
EBS 46-1-2-S-2 1 1 1 1
EB 112-1-S-1-1 1 0 0 1
NEP 588-5690-S-84 1 1 1 1
P 489-S-3 1 0 1 4
ICMPS 100-5-1 0 0 0 1
ICMPS 200-5-5-5 1 0 0 -3
ICMPS 700-1-5-4 1 0 0 -
ICMPS 900-3-1 1 0 0 1
ICMPS 1300-2-1-2 1 0 0 -
ICMPS 1400-1-6-2 1 0 0 -
ICMPS 1500-7-3-2 0 0 0 -
Susceptible Control 38 76 30 37
Table 11: Performance of some selected smut- resistance lines in the International Pearl Millet Smut
Nursery (IPMSN) during 1978-84.
1. SSC = Super Serere, Uganda; ICI = ICRISAT inbred; EB = Ex Bornu, Nigeria; NEP = Lebanon;
P = Mali; ICMPS = ICRISAT Millet Pathology Smut resistant lines.
2. Based on 20-40 inoculated heads in two replications.
3. Entries not tested.
Patancheru Thakur and Chahal (1987) 42

Entry
Smut severity (%) Mean
1991/92 1992/93 1993/94 1994/95 1995/96
J 2002 30 13 35 35 33 29.3
ICMH 451 23 35 50 22 30 32.0
ICMP 451 10 15 18 13 15 14.4
Pusa 23 13 23 23 55 30 29.0
BK 560 18 47 25 25 15 26.0
WC- C75 18 25 50 35 23 30.3
HC 4 30 17 28 15 25 23.0
HHB 50 27 35 40 22 20 28.6
HHB 60 38 45 32 38 18 34.3
HHB 67 15 10 35 37 33 26.0
HHB 68 15 15 17 15 10 14.3
81 A 53 55 30 33 55 45.3
81 B 33 40 25 18 30 29.3
841 A 25 35 53 35 30 35.6
841 B 15 18 35 23 30 24.3
843A 15 30 40 25 18 25.7
843B 10 13 25 10 13 14.3
5054A 33 20 47 20 27 29.3
5054B 33 27 33 25 15 26.6
ICMA 88004 18 27 38 38 25 29.3
ICMB 88004 30 18 37 25 35 28.9
H 77/833-2 13 23 20 20 25 20.3
H 90/4-5 13 18 25 22 35 22.7
S. E. ±7.10 ±6.70 ±5.40 ±7.89 ±5.29 ±6.48
LSD (p = 0.05) 15.34 14.50 11.70 15.43 11.42 13.69
Table 12: Comparative performance of pearl millet varieties/ hybrids, male sterile lines, their maintainers, and restorer line
against smut disease under artificial inoculation in the field from 1991/92 to 1995/96 at Hisar, Haryana, India.
Haryana Panwar and Rathi (1997)
43

Identity Smut severity (%)1
ICMA 88006 30
ICMB 88006 27
ICMA 92444 0
ICMB 92444 0
ICMA 92777 0
ICMB 92777 0
ICMA 92888 0
ICMB 92888 0
ICMA 93111 35
ICMB 93111 40
ICMA 93333 40
ICMB 93333 33
Controls
81A 89
81B 94
841A 84
841B 68
7042S 97
Mean 37
SE(m)± 2.2
LSD (P <0.05) 6.2
Table 13 : Smut severity of eight A/B lines evaluated at ICRISAT during rainy
season, 2005.
1. Mean of five replications, 10 plants per replication under artificial inoculation in field.
Patancheru Rao et al. (2006)
44

Source
d.f.
Grain yield Smut severity
Normal
sowing
Late
sowing
Normal
sowing
Late
sowing
Replications 2 14.0 15.3 32.6 263.3
Hybrids 69 139.0** 186.4** 376.6** 638.3**
Lines
(Sterile and fertile cytoplasm)
9 273.2** 328.3** 690.7** 1092.2**
Sterile cytoplasm 4 219.0** 146.1** 779.8** 1563.9**
Fertile cytoplasm 4 348.5** 592.3** 773.2** 887.9**
Sterile vs fertile cytoplasm 1 188.9** 0.5 4.4 23.0
Testers (Fertile cytoplasm) 6 88.7** 27.2** 1069.9** 2286.6**
Line x testers 54 122.2** 180.5** 247.3** 379.6**
Error 138 5.5 5.8 14.0 17.2
General predictability ratio 0.3 0.2 0.5 0.5
Table 14: Mean square obtained from line x tester analysis of variance for grain yield and smut
severity in pearl millet grown in two environments.
** Significant at 1% level.
Hisar Om Prakash et al. (1988)
46

Sr.
No.
Parent Grain yield/plants Smut severity
Normal sowing Late sowing Normal sowing Late sowing
1 Lines (Females)
111A -3.24** -3.92** -3.38 -0.86
111B -5.89** -7.01** -1.08 5.05**
81A 0.76 0.22 3.19 4.95**
81B -3.61** -3.16** -3.50 -0.58
841A 0.36 0.87 4.62 2.29*
841B 1.54** 3.84** 6.14 2.15*
5141A 4.55** 3.27** 5.14 5.28**
5141B -1.09* 0.41 5.74 6.85**
10A 3.77** 0.99 -3.95 -15.41**
10B 4.39** 6.22** -7.95 -9.72**
2 Testers (males)
SR/ICMPS-101-1 1.12** 0.74 -1.39* -2.70**
SR/ICMPS-904-3 2.04** -0.09 -2.11** -0.22
SR/ICMPS-1600-3 -0.65 -0.23 -3.14** -10.11**
77/181-4-4-3-1-5 -2.22** -0.16 13.08** 14.08**
77/245-7-1-1-5 -2.21** -1.73** -0.31 2.61**
H 90/4-5 1.02* 0.14 -1.12 6.41**
H 833-2 0.88 1.34** -5.02** 10.06**
3 SE Lines (gi - gj’) 0.72 0.74 1.16 1.28
4 SE Testers (gj – gj’) 0.61 0.62 0.97 1.07
Table 15: Estimates of general combining ability for grain yield and smut severity in pearl millet
*’** Significant at 5% and 1% respectively.
Hisar Om Prakash et al. (1988)
47

RUST
 Causal Organism: - Puccinia substriatia var. penicillariae.
: - Puccinia substriatia var. indica.
 Class:- Teliomycetes
 Order:- Uredinales
 Family:- Pucciniaceae
 First reported by Zimmerman in 1904 on pearl millet at Amani, East Africa. Later on
the same rust was observed from several parts of India by Butler (1918) on pearl
millet.
 Pearl millet rust is heteroecious i.e. required two distinct and unrelated host to
complete its life cycle.
 Alternate host required for pathogen are,
- Brinjal, Solanum melongena L.(Egg - plant)
- Solanum spp.
- Wild type weed sp. (Euphorbia pulcherimma)
 Eggplant provides primary inoculum for rust of pearl millet.
 Rust is a foliar disease. Occurrence of the disease during the seedling stage can result
in substantial losses in grain and fodder yield and quality.
 When rust appears late in the season grain yield may not be affected, but the disease
causes a severe reduction of digestible dry matter yield of forage.
49

 United States
 Asia: India, Sri Lanka, Pakistan
 Africa: Chad, Congo, Ethiopia, Ghana, Guinea, Ivory Coast, Kenya, Malawi,
Mozambique, Nigeria, Senegal, Sierra Leone, South Africa, Sudan,
Tanzania, Uganda, Zambia and Zimbabwe.
 Niger
 Infection of the aecial host has been reported in Brazil, India, and
 It has also been reported in Georgia, USA
GEOGRAPHICAL DISTRIBUTION
50
ICRISAT, Patancheru. Singh and King (1991)

 Symptoms first appear on the lower older leaves .
 Small, reddish brown to reddish orange, round to elliptical uredinia
develop mainly on foliage.
 In infection sites developing late in the season, uredinia are replaced by
telia, which are black, elliptical, and sub- epidermal.
 As severity of infection increases, leaf tissue will wilt and become
necrotic from the leaf apex to base.
 Symptoms can occur on upper and lower surfaces of the leaves, but are
common on the upper surface.
 Highly susceptible cultivars develop large pustules densely grouped on
leaf blades and on sheaths.
 Cooler temperature
 High humidity
SYMPTOMS
51

 Screening against rust has been based largely on testing material at locations
where rust occurs in severe form every year if sowing is done at the
appropriate time. Known field inoculation procedures have been carried out at
ICRISAT Center:
 Urediniospores from earlier-sown infector rows;
 Spraying urediniospores on 25-40 day old crops; and
 Spreading of uredinia-bearing leaves among 25-30 day old test plants.
 Spraying urediniospores twice, at 25 and 35 days after sowing.
However, both field and greenhouse screening procedures are used at
the Coastal Plain Experiment Station in Tifton, Georgia.
52

RESISTANCE SOURCES
53

Genotype
Rust intensity (scale 1-5)
2000 2001
ICMV 97775 3.0 2.0
ICMV 97776 4.0 3.0
ICMV 97774 4.0 3.0
ICMV 97772 3.0 3.0
ICMV 96776 4.0 3.0
ICMV 96492 4.0 3.0
ICMV 96495 4.0 4.0
ICMV 96472 3.0 2.0
ICMV 96883 3.0 2.0
ICMV 96843 5.0 3.0
ICMV 96793 4.0 2.0
EEBS 6 4.0 3.0
ICRC II 4.0 3.0
GB 8715 3.0 3.0
ICMV 96491 3.0 3.0
81A 3.0 3.0
ICRC 2 4.0 4.0
ICMP 451 3.0 3.0
WC C75 5.0 4.0
S E m± 0.35 0.28
C.D. (0.05) NS NS
CV% 16.73 14.64
Table 16: Evaluation of pearl millet genotypes for rust resistance.
Bijapur Jahagirdar et al. (2005) 54

Lines Pedigree
Rust severity
in field screen (%)1
Rust severity
in greenhouse
screen (%)1
Lower
leaves
Top four
leaves
ICMB 96222 [{26B x (81B x SRL 50-1)}-1-1-2 x 852B]-69-1-1 10 3 2
ICMR 01007 Selected from a single selfed BC4F2 plant derived
from backcrossing of donor parent ICMP 451-P6
with a pure line selection from H 77/833-2
5 0 49
ICMR 06999 MRC S1-4-1-3-B-B-B-B 3 0 HSR2
ICMP 451-P8 Downy mildew resistant restorer selection from
ICMP 451 (LCSN 72-1-2-1-1)
10 0 HSR
ICMP 451-P6 Downy mildew resistant restorer selection from
ICMP 451 (LCSN 72-1-2-1-1)
10 0 HSR
K-08-18395 MRC HS-130-2-2-1-B-B-1-B-B-B 0 0 33
K-08-18399 MRC S1-155-4-3-B-B-B-B-1-B-B 3 0 57
K-08-18400 MRC S1-191-2-1-5-B-B-B-B-B 5 0 36
ICMP 83506
(Resistant check)
(B 282x S10B-38)-3-1-3-2 – – 34
ICML 11
(Resistant check)
IP 2696-1-4 – – HSR
ICMB 89111
(Susceptible check)
{843B x (GNS x SS-48-40-4)-1-9-8}-30-B-B-1 58 21 51
Trial SE(m)± 4.9 6.1 3.18
Trial LSD (P <0.05) 13.6 17.1 9.23
Table 17: Rust severity in the selected B- and R-lines of pearl millet.
1. Mean of two replications based on the modified Cobb scale.
Resistant = 1–10% severity; moderately resistant = 11–20% severity;
Susceptible = 21–30% severity; Highly susceptible = >30% severity.
2. HSR = Hypersensitive response (chlorotic specks without rust pustules).
Patancheru Sharma et al. (2009)
55

Cross Generation
No. of plants
X2 P value
Segregation
resistant Susceptible R : S
PT 3832 x ICMPES 11
F2 335 100 0.938 0.50 - 0.25 3 : 1
BC1 98 90 1.42 0.25 - 0.10 1 : 1
PT 3832 x ICMPES 15
F2 211 58 1.69 0.25 - 0.10 3 : 1
BC1 98 93 2.40 0.25 - 0.10 1 : 1
PT 3832 x 81B
F2 133 31 3.25 0.10 - 0.05 3 : 1
BC1 98 80 1.82 0.25 - 0.10 1 : 1
PT 3832 x 732B
F2 236 82 0.43 0.75 - 0.50 3 : 1
BC1 94 76 1.90 0.25 - 0.50 1 : 1
ICMPES 11 x PT 3832
F2 292 108 0.85 0.75 - 0.25 3 : 1
BC1 149 142 0.16 0.25 - 0.50 1 : 1
81B x PT 3832
F2 120 148 1.15 0.50 - 0.25 3 : 1
BC1 160 152 0.20 0.75 - 0.50 1 : 1
ICMPES 15 x PT 3832
F2 315 117 1.00 0.50 - 0.25 3 : 1
BC1 91 73 1.98 0.25 - 0.10 1 : 1
732B x PT 3832
F2 216 87 2.24 0.25 - 0.10 3 : 1
BC1 86 69 1.86 0.25 - 0.10 1 : 1
Table 18: Segregation for rust resistance in F2 and BC1 generation of pearl millet
Tamil Nadu Ramamoorthi (1995)
57

Parents F1behaviour
(Reaction)
F2generation
Total
Ratio X2
value
S R R S R : S
PA 11B x 7042-1-4-4 R 186 59 245 3 : 1 0.110
PA 11B x 700481-27-5-2 R 260 62 322 13 : 3 0.054
PA 11B x IP 8695-4 R 130 39 169 3 : 1 0.333
PG - 12 x 7042-1-4-4 R 298 96 394 3 : 1 0.084
PG-12 x 700481-27-5-4 R 235 52 287 13 : 3 0.075
PG-12 x IP 8695-4 R 220 65 285 3 : 1 0.730
PG- 41 x 7042-1-4-4 R 175 53 228 3 : 1 0.393
PG - 41 x 700481-27-5-2 R 260 58 318 13 : 3 0.054
PG - 41 x IP 8695-4 R 183 59 242 3 : 1 0.115
Table 19: Reaction of parents, F1 and F2 segregation of pearl millet stocks (susceptible x resistant) to
P. substriata var. indica.
Ludhiana Pannu et al. (1996)
58

BREEDING METHODS
Conventional breeding Methods
1. Selection
2. Back-cross method
3. Pedigree selection
4. Recurrent selection
5. Mutation breeding
Non-conventional breeding methods
1. Marker-assisted selection
2. Genetic transformation
59

PEARL MILLET DOWNY MILDEW RESISTANCE QTL
India and UK Hash and Witcombe (2005)
61
 Colored block indicate approximate genomic
positions of downy mildew resistance QTLs.
 Color of block indicates the parental line that
contributed resistance mapping that position
in pearl millet genome.

PEARL MILLET MAPPING POPULATION CONTRIBUTING MORE RESISTANT ALLELE
India and UK Hash and Witcombe (2005)
62
Sources of pearl millet downy mildew population (and year of collection) used in
greenhouse disease screens of pearl millet mapping populations used to detect QTLs for
host plant resistance to Sclerospora graminicola.

63
TRANSGENIC PEARL MILLET
1. Two-week-old plants after challenging with Sclerospora graminicola.
1T2 - Resistant transgenics showing healthy, normal growth.
UC - Susceptible plants of untransformed control with stunted growth.
SC - Plants of susceptible check with stunted growth.
2. 1T2 transgenics bearing selfed spikes grown in the glasshouse.
3. Plasmid Constructs used for genetic transformation.
3
Hyderabad Latha et al. (2006)

Table 20: Fungal bioassays on T2 progenies and segregation for downy mildew resistance
Susceptible controls/T2
transgenic lines
Total no. of
seedlings inoculated
No. of
resistant
seedlings
No. of
susceptible
seedlings
Untransformed control
(ICMP 451) 27 0 27
Susceptible check (7042S)
30 0 30
1T2 1 31 30 1
1T2 6 37 35 2
1T2 9 27 26 1
1T2 10 28 28 0
1T2 12 26 25 1
1T2 13 32 26 6
1T2 15 30 28 2
χ2 values for 1 df = 3.841 at 5% P - level.
Resistant, no disease symptoms. Susceptible, chlorotic streak and stunted growth
Hyderabad Latha et al. (2006)
64

Fig. Dendrogram based on AFLP polymorphisms in 19 pathogen isolates of Sg of pearl millet.
DETECTION OF GENETIC VARIABILITY IN (Sclerospora graminicola) BY AFLP
India Singru et al. (2002)
65

 A1 cytoplasm is not associated with susceptibility or resistance. Nuclear
genes alone were responsible for the observed resistance or susceptibility.
 Effective screening techniques (both field and greenhouse) are developed
which can easily differentiate between resistance and susceptible progenies.
 Newer sources resistance are obtained from transgenic developments.
 Resistance to downy mildew is governed by one gene with complete
dominant.
 Resistance to ergot is recessive and polygenically controlled.
 Smut severity and grain yield are controlled by both additive and non-
additive gene effects.
 Resistance to rust is dominant trait with monogenic control.
 QTLs information for downy mildew resistance in pearl millet allows
breeders, to incorporate and pyramid resistance gene into cultivars.
 Use of AFLP to detect genetic variation is particularly important in selecting
mildew isolates to screen breeding material for identification of rust
resistance millet and monitoring changes in S. graminicola in relation to
changes in host for effective disease management.
66
CONCLUSION

 Newer sources of resistance (stable, complete, recovery resistance)
needs to be identified and used in an effective disease resistance
breeding program.
 Effective breeding methods which break the negative correlation
between disease resistance and yield.
 Need to study details of host and pathogen interaction.
 Studies on genetics and resistance mechanisms should receive more
attention to better understand the genetic diversity and stability in
the available resistance sources.
 Tissue culture can be used to generate highly resistant somaclones for
diseases.
 Identification of genetic markers for avirulence in pathogen.
 Identification of disease resistance gene/ QTLs against specific
pathotypes.
 Marker assisted selections along with conventional breeding methods
can be used for disease resistance breeding.
67
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