Intergenotypic interactions among families of loblolly pine (Pinus taeda L.).

The effects of competition on the growth of families of loblolly pine (Pinus taeda, L.) seedlings were investigated. The experimental design made it possible to evaluate the effects of crowding on growth and to determine the types and magnitudes of intergenotypic interactions among pairs of families. The results showed that intergenotypic interactions were both highly variable and pronounced in their effect on early growth. Evidence was also found for precompetition cooperating interactions occurring among seedlings surrounded by neighbors of the same family.