Breeding for Resistance to Biotic

Stresses: An Introgression Pathway

in Groundnut

Sameer KhanalUniversity of Georgia

Peanut Breeding Goals, Priorities, and Constraints

Goals and Priorities: Yield Early Maturity Resistance to Biotic/Abiotic Stresses Seed Quality Traits: Improved Oil Quality and Flavor, Aspergillus

resistance Constraints: Lack of adequate allelic diversities among cultivated accessions Difficult to introgress traits of interest from diploid wild spp.

Cultivar Development

A. cardinasii (AA) A. diogoi (AA)X

AA

TXAG-6

Parents

Interspecific hybridization

3-way hybrid

Chromosome doublingSynthetic Amphidiploid

X

Florunner

AB

Interspecific hybridization

X

A. batizocoi (BB)

BC5F3

COAN1

Development of COAN and NemaTAM

NemaTAM2

BC7F3

1. Simpson and Starr 2. Simpson et al. 2003

Proposed Plan

F1

Modern CultivarAABB (2n = 4x =40)

Colchicine Double

Synthethic AllotetraploidAABB (2n = 4x =40)

Marker-Assisted Selection

A/B-GenomeWild Introgression Lines

AABB (2n = 4x =40)

A. duranensis A. batizocoi

Background for the Proposed Plan

1. More than 2,000 transcriptome-based and couple hundred genomic-based SSR markers are available

2. A large number of SNPs are identified

3. Saturated A- and B-genome diploid linkage maps are on the pipeline

4. Comparative mapping and synteny analysis with model genomes will facilitate gene tagging

5. Traits of interest will be mapped along the chromosomes

Outline of the Breeding Scheme

1. First Season: Florunner x Synthetic Amphidiploid2. Second Season: Growing F1 and Backcrossing to Florunner 3. Third Season: BC1F1 Genotyped and Backcrossed to Florunner4. Fourth – Fifth Season: Repeated Backcrosses5. Sixth Season: BC3F1 Genotyped and Selfed6. Seventh-Eighth Season: Towards introgression library (Selfed)7. Ninth-Tenth Season: Multilocational trials/Marker-trait Association8. Seed Increase of Select Lines and Varietal Release.9. Minimum of Seven Years (2 seasons per year) from Initial Crossing

to Ultimate Release of a Variety.

Thank you

Acknowledgement:

PBGG