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DOUBLED HAPLOIDS IN HOT AND SWEET PEPPERS: SUCCESS AND CHALLENGES Piyush Kumar Gupta Verdenta Hybrid Seeds Pvt. Ltd., Gurgaon, Haryana 122001 ASRT 2014, Sep 9-10, 2014, Bangalore, India
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Content Outline What is a Double Haploid (DH)? How it reduces time? Why Double Haploids? Doubled haploids in Hot and Sweet Peppers ▫ Material and Methods ▫ Equipments ▫ Different stages of DH Pepper ▫ Challenges ▫ Major factors influencing DHs production ▫ Highlights Cost and Financials Doubled Haploids in Tomato
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What is a Double Haploid? A doubled haploid (DH) is a genotype formed when haploid cells undergo chromosome doubling. Haploids (n) Double Haploids (2n) Cochicine treatment
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How it reduces time? DH selection via molecular markers 100% DH AABB 6.25% homozyg ous 25% DH AABB Testing and Cultivar Release 3-4 2 1 1 2 3 4 5 6 7 8 9-10 Seasons
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Microspore and anther culture followed by colchicine helps rapid homozygosity following a cross ▫ Fast track stabilization of traits – major & minor genes. ▫ Using molecular markers helps select appropriate DH plant ▫ Inbred ready in 3rd season after F1 pollen used for DH Why Double Haploids? Cont..
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Quick development of recombinant inbred lines for mapping & genetics studies ▫ Molecular marker development, association mapping etc Proven technology in several crops- Wheat, Corn, Rice, Pepper etc Impact on Business ▫ Speed to deliver products - Prototype hybrids can be made in 3rd season itself vs 6 seasons in conventional breeding. 50% faster delivery Quick return on investment Cont..
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Asian hot peppers ▫Light Green, Bydagi, varieties/breeding lines ▫European Sweet pepper, control (Light Green blocky) Growth of anther donor plants of Hot and Sweet Peppers ▫In phytotron chamber 16-h illumination at 70 µmol m -2 s -1 with day/night temperatures of 25/20ºC day/night Key Factors ▫Late-unicellular microspores ▫Heat stress of anthers (35ºC for 8 days, dark) ▫In vitro doubling of haploid regenerants with 400 mg/l colchicine ▫Acclimatization of regenerants step by step Material and Methods
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Equipments required for DH lab Autoclave (Small & Large) Water Purifier distillation system Gyratory Shaker Refrigerator Weighing balance Magnetic Stirrer pH Meter BOD Incubator Laminar Flow (6x2x2) Microscope & Haemocytometer Media Preparator Media Pourer Dish washer Media PreparatorMedia Pourer
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Different stages of DH Pepper
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Challenges faced Recalcitrant Genotypes ▫ High genetic variability ▫ Significant genotype difference for the efficiency of DH production No reproducible protocol available Unusual regeneration ▫ Without shoot ▫ Without roots Produce 2-4 plants per 100 anthers plated
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Major factors influencing DHs production Donor plant growth condition ▫ Green House Vs Growth Chamber Temperature Moisture Light Nutrition In vitro and in vivo culture condition ▫ Pretreatment of the buds ▫ Media composition ▫ Optimal temperature and light regimes
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Highlights DH response of Recalcitrant genotype can be increased by crossing with high responsive lines Need to study genetics of response to DH. (Gene was reported for such response in Cotton) Anther donor plants in growth chambers reproduce 2 times more DH plants than Green house conditions. ▫ Reduce contamination (Thrips) ▫ Easy to target appropriate anther stage ▫ Less influence of uncontrolled environmental conditions MS Media with 2,4D (10 -7 M- 10 -8 M) shows better response than without 2,4D
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Costs & Financials 13
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Capital Investment: Facilities and Costs Assumptions: ▫ Annual volume is 2000 DH lines 10 projects and 200 DH Lines per project ▫ 2 growth chamber size 12x10 feet ▫ 1 greenhouse size 30x15 feet $ 1 = 60 Employees: 1 FTE, 1 Technician, 2 Daily paid Scaling up ▫ Double the DH plants will add only 50% cost in capital.
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Cost per DH*: INDIA can be half of that in NAFTA All pricing is based on the assumption of a 8% induction rate and a success rate of 4% Annual volume is 2000 DH lines (10 projects and 200 DH Lines per project). Scaling up: Double the DH plants will reduce per DH plant cost by 40%.
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Financial Summary Pay back period – 3.7 years IRR – 62%
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DH in Tomato
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Little progress in the tomato DH No reliable and standardized methods available so far Tomato is extremely recalcitrant in vitro developmental pathways ▫Anther culture ▫ Microspores or microsporocytes direct embryogenesis callus formation ▫Ovary culture ▫Wide hybridization using Solanum sisymbriifolium Lam. Patents ▫Tomato anther culture: US 4835339 A ▫http://www.google.com/patents/US4835339http://www.google.com/patents/US4835339 ▫Key claim 1 anthers are dissected from an inflorescence of a hybrid plant of L. esculentum (×) L. pennellii.
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Thanks for your attention
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