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Lammas Shoot Formation in Scotch Pine

Lammas shoots are second or midseason shoots that develop precociously from buds set earlier in the season (5). These precociously developed shoots are subtended by their own bud cluster. Previous studies have indicated that laminas growth is the main cause of forking (2, 3, 6, 8). However, little evidence exists on the cause of lammas growth or the influence of site on lammas shoot formation. Some investigators have felt that a factor or factors of weather encourage lammas growth (2, 3, 6, 8). But the cause of the phenomenon is still unknown. Prior investigations have been either unable to demonstrate genetic control s that is a genetic predisposition to lammas shoot formation, or have discounted such genetic control without adequate study (6, 8). The hypothesis of a genetic variation in disposition to lammas growth has been tested in New Jersey on three Scotch pine ( Pinus sylvestris L.) plantations of 1050 individuals each representing 35 different native seed sources.


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Author(s): Richard F. West, F. Thomas Ledig

Publication: Tree Improvement and Genetics - Northeastern Forest Tree Improvement Conference - 1963