COMPARISON OF FIELD GROWTH AMONG LOBLOLLY-PINE SEEDLINGS AND 3 PLANT TYPES PRODUCED INVITRO

To study differences in field performance between tissue culture plantlets and seedlings of loblolly pine, two field plantings containing four plant types (seedlings, excised embryos, rooted hypocotyls, and tissue culture plantlets) were established. After 3.5 growing seasons, the plantlets were 80% the height of the seedlings and appeared more mature than seedlings for other characteristics. Despite their smaller initial planting size, by 1.5 years, the two additional plant types performed as well as the seedlings in every respect. Comparisons suggest that the cause of differences between plantlets and seedlings lies with the adverse affect of producing shoots by tissue culture techniques rather than with the tissue culture environment or rooting procedures