Plant & Animal Genome VI Conference

W35

MAPPING GENES RESPONSIBLE FOR INBREEDING DEPRESSION IN PLUS TREE 850.55 OF Pinus radiata D. Don

1. Daniel B. Warnell School of Forest Resources, The University of Georgia, Athens, GA 30602-2152, USA
2. New Zealand Forest Research Institute Ltd., Private Bag 3020, Rotorua, New Zealand

Most coniferous species show severe inbreeding depression. Selfed individuals usually have decreased viability, reduced vigor, and more defectiveness. Segregation of markers genome-wide in selfed progenies of radiata pine plus tree 850.55 was used to investigate the genes responsible for inbreeding depression on viability. Using Expectation/Conditional Maximization (ECM) algorithm, the location, degree of dominance and selection coefficients of viability genes were estimated. Nine viability genes were discovered. One of them exhibited overdominance where selection coefficient of two homozygotes were 0.40 and 0.42, respectively. The allele SDPr (Seedling Death in Pinus radiata ) was completely lethal when homozygous. The other seven genes were sub-lethal: selection coefficients of deleterious homozygotes ranged from 0.55 to 0.79. The deleterious alleles were most likely completely recessive.