1. Strategy to breed hot pepper for
Chilli leaf curl and tospo virus resistance
K. Madhavi Reddy
Principal Scientist
Indian Institute of Horticultural Research Bangalore , India

2. Introduction
Chilli (Capsicum annuum L.) introduced in to India by the Portuguese during 16th Century – is endowed with excellent biodiversity
The total area under chilli cultivation in India is 1.0 mHa with annual dry chilli production of 1.2 mMT
India is the largest producer & exporter of chillies contributing 25% of the world production & 25% of the total chilli global exports
Andhra Pradesh is accounting 50% of the production in the Country
Major production constraints – viruses, fungi & sucking pests

3. Factors driving the emergence of begomo and tospoviruses in peppers
Changes in the agricultural practices - Large scale monoculture, Continuous cropping
Increase in the population and/or distribution of insect vectors – mainly due to climate change
Evolution of biotypes due to pesticide resistance
Genetic variability in the virus due frequent mixed infections and recombination
Long distance transport of plant material

4. Major emerging threat in India: Chilli leaf curl disease
Upward leaf curl with reduced leaf size
          

5. Chilli leaf curl symptom variation

6. CLCD incidence 40-95%; yield loss up to 100% has been reported
Chilli Leaf Curl Disease in India
CLCD incidence 40-95%; yield loss up to 100% has been reported
Murda Complex
Thrips
Mites
Viruses
Chilli Leaf curl virus initially reported in 1954 and subsequently LCV resistant varieties were developed in 1970’s
SAVERNET project at IIHR ( )
Out of 14 Pepper lines evaluated, three lines PTY4, PTY5 and PTY6 were found susceptible to tomato leaf curl virus under screen house conditions
GTZ AVRDC Project at IIHR ( ): Different isolates collected across India (Andhra Pradesh, Haryana, Rajasthan, Tamil Nadu, Uttar Pradesh and W. Bengal) were sequenced and characterized
          

7. Screening of Pepper lines against local isolate of Chilli leaf curl virus, Thoranguchi, Trichy, TN
Total lines Screened:148
Highly resistant lines(0-10%):16
Resistant lines ( %): 31
Susceptible lines ( %): 53
Highly susceptible lines(>50.1%):48

8. Screening of Pepper lines against local isolate of Chilli leaf curl virus, Murthal, Haryana
Total lines Screened:34
Highly resistant lines(0-10%):10
Resistant lines ( %): 13
Susceptible lines ( %): 11

9. Major begomoviruses associated with chilli leaf curl disease in Indian subcontinent
Monopartite
Chilli leaf curl virus (ChLCV)
Chilli leaf curl India virus (ChLCIV)
Chilli leaf curl Vellanad virus (ChLCVeV)
Chilli leaf curl Multan virus (ChLCMV)
Chilli leaf curl Pakisthan virus (ChLCPkV)
Chilli leaf curl Salem virus (ChLCSV)
Pepper leaf curl Bangladesh virus (PepLCBV)
Radish leaf curl virus (RLCV)
Tomato leaf curl Joydebpur virus (ToLCJV)
Tomato leaf curl Karnataka virus (ToLCKV)
Bipartite
i) Tomato leaf curl New Delhi virus (ToLCNDV)

10. Tospoviruses: Another major emerging
production constraint in chilli production
Currently Tospovirus is emerging as serious problem in chilli production in India causing yield loss up to 100%
GBNV and CaCV are major tospoviruses affecting chilli
Natural transmission by thrips and survives in infected plants, weed hosts and insect vectors

11. Groundnut Bud Necrosis Virus (GBNV)

12. Capsicum Chlorosis Virus (CaCV)

13. Rapid tospovirus screening method – Hot Pepper

14. Strategies to overcome emerging threats
Source of resistance to viruses/ vectors
Breeding for virus/ vector resistance
3. Markers to accelerate breeding program

15. Resistance to viruses
1. Reliable & effective selection method under controlled conditions
2. Hot spot evaluation in recurrent virus occurring region
3. Confirmation of resistance by ELISA and/or PCR/nucleic acid probes
4. Virus specific screening against predominant viruses
5. Introgression of host resistance genes – prebreeding
6. Haploidization

16. Resistance to vectors
Antixenosis – morphological (trichome density, cuticle thickness) or chemical factors (Tocopherols, Terpene, Sterols) resulting low preference
Antibiosis – ↑ insect mortality, ↑ developmental period, ↓ reproduction
Tolerance – ability to produce marketable yield in spite of insect attack

17. MAS: to accelerate breeding program
Solanaceous genome Synteny - Validation of Ty gene linked markers
Identification of R genes linked to virus resistance
Genome-wide search for virus resistance genes
QTL analysis to identify metabolites potentially related to thrips/ whitefly resistance

18. Way forward
Chilli leaf curl disease and Tospovirus are fast spreading with increase in incidence
Due to presence of mono and bipartite begomoviruses, a broad spectrum resistance is required
Identification of begomovirus species specific resistance and gene pyramiding for durable solution
Identification of stable source of tospovirus resistance
Team effort will win against the begomo and tospovirus threats in pepper

19. "….when the cause of disease is discovered, consider that the cure is discovered"
Cicero
Thank you