EMPLOYING HPR IN THE CONTROL OF COWPEA APHIDS AND STRIGA GESNERIOIDES IN NORTHERN GHANA

Transcription

1 EMPLOYING HPR IN THE CONTROL OF COWPEA APHIDS AND STRIGA GESNERIOIDES IN NORTHERN GHANA GLORIA TETTEH KUBI 1 ; FRANCIS KUSI 2 ; AARON ASARE 3 ; MARY BOTCHEY 1 1 DEPT. OF CONS. BIO & ENTOMOLOGY, UNIVERSITY OF CAPE COAST, GHANA; 2 CSIR,SARI-GHANA; 3 DEPT. OF MOLECULAR BIO & BIOTECH, UCC Feed the Future Innovation Lab for Collaborative Research on Grain Legumes glory193@gmail.com

2 Introduction Background Objectives Materials and methods Plant materials Preliminary works Screening methods Breeding scheme Results so far Way forward Acknowledgements Presentation Outline

3 Introduction Aphids Striga Ecological Nitrogen fixation Economic Income, food security Social Improved living standards Ecological? Economic? Social?

4 Expensive Ecologically unsafe Harmful to humans Resistant plant varieties Common among commercial growers; Boosts crop yield (Jackai et al., 1985; Kyamanywa, 1996); Peasant farmers??? Reduced production cost Food security Poverty alleviation Environmetally friendly Cost effective

5 Background to Study Studies by A. T. Asare (UCC) identified some Striga resistant cowpea genotypes Based on field performance and their response to aphids pressure, 7 promising genotypes were selected for further screening for aphid resistance Identify other potential sources of aphid resistance Improve the field resistance of those found to be susceptible

6 Objectives To improve Striga gesnerioides resistant genotypes by introgressing the aphid-resistant gene from SARC using MABC Determine the mode of inheritance and allelism of the UCC source of aphid resistance Check for polymorphism between the UCC resistant lines and Apagbaala using known SSR markers

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8 Plant Materials 7 Striga resistant genotypes UC96-11, UC96-32, UC96-241, UC96-460, UC96-471, UC & UC Aphids resistant donor/check SARC Aphids susceptible check Apagbaala

9 Methodology Phenotyping Seeds were planted in pots in an insectary 3-4 days after emergence, each seedling was inoculated with 5 four days old aphids (Kusi et al., 2010) Population build up was allowed until susceptible check died (8-15 days) Seedlings were then grouped as resistant or susceptible Genotyping DNA samples from each plant was taken using the FTA plant card PCR were run with the SSR markers CP171/172, SSR1 and C42-2B CP171/172- aphids res. SSR1 & C42-2B- Striga res.

10 Phenotyping SUSCEPTIBLE CHECK Vs. RESISTANT CHECK Apagbaala SARC

11 Phenotyping SUSCEPTIBLE PARENT Vs. RESISTANT PARENT UC UC96-241

12 Genotyping 176bp Res chk Aphids screening Res parent Sus parent Sus chk CP171/172 Sus chk Striga screening Res parent SSR1 Res parent Sus chk C42-2B

13 Based on preliminary results, four genotypes were finally selected UC96-11 & 471; Aphids sus. UC & 513; Aphids res. Crosses Methodology SARC x Sus; improve field resistance through backcross SARC x Res; determine genetic relatedness Apagbaala x Res; mode of inheritance

14 Susceptible (r) x Resistant (R) Crossed F 1 x r Select heteros BC 1 F 1 x r Select homos BC 4 F 1 Selfed BC 4 F 2 Screen for aphids & Striga res

15 All F 1 s obtained were genotyped to identify successful crosses Res. par Heterozygous F 1 s Sus. par Gel plate of successful F 1 cross between 471(r) & SARC (R)

16 Methodology At each BC, pots were infested with Striga seeds before planting and each seedling with aphids The seedlings were genotyped with CP171/172 and SSR1 to eliminate susceptible lines (Marker Directed Phenotyping) The recurrent parent at each BC was allowed to self and used in subsequent BC

17 Results so far New sources of aphids resistance has been identified in UCC lines Polymorphism between the lines using SSR markers have also been established Crossing to determine the allelism and mode of inheritance are far advanced Introgression of SARC source of aphid resistance to improve the UCC susceptible lines is in progress

18 The Way Forward Genotyping of the BC 1 population to select heteros. for next BC generation Screening of the population developed from the UCC resistant lines for mode of inheritance and allelism Finally, lines combining aphid and Striga resistance will be developed and establish the mode of inheritance and/or the allelism of the UCC resistant lines

19 Acknowledgements

20 MERCI