Strategy to breed hot pepper for Chilli leaf curl and tospo virus resistance K. Madhavi Reddy Principal Scientist Indian Institute of Horticultural Research Bangalore-560089, India

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

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

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

Chilli leaf curl symptom variation

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 (1997-2001) 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 (2002-2008): Different isolates collected across India (Andhra Pradesh, Haryana, Rajasthan, Tamil Nadu, Uttar Pradesh and W. Bengal) were sequenced and characterized           

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 (10.1-20%): 31 Susceptible lines (20.1-50%): 53 Highly susceptible lines(>50.1%):48

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 (10.1-20%): 13 Susceptible lines (20.1-50%): 11

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)

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

Groundnut Bud Necrosis Virus (GBNV)

Capsicum Chlorosis Virus (CaCV)

Rapid tospovirus screening method – Hot Pepper

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

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

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

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

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

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