Department of Forest and Wood Science;
Stellenbosch University;
Private Bag X1;
Stellenbosch 7602;
South Africa;
Genetics Department;
Stellenbosch University;
Private Bag X1;
Stellenbosch 7602;
South Africa;
Sappi Forest Research;
P.O. Box 473;
Howick 3290;
South Africa;
Pollen; tubes; Pollen; grains; Hybridization; Reproductive; barriers; Pinus; radiata;