“鳥梨”實生後裔株高與枝幹生育特性之關係

Relationship between Plant Height and Shoot Characters of “Bird” Pear (Pyrus sp.) Seedling

將卓蘭、大湖及三灣三地區之鳥梨實生後裔之主要植株跗伏與株高進行相關與迴歸分析，以瞭解其與株高間之相關性。三年內所有性狀與株高之相關係數均達極顯著水準，除了樹皮／幹徑之比值為負相關外，其餘性狀，包含節數、節間長、幹徑、幹徑截面積、分枝數、枝刺數等，與均呈正相關。第一年之結果以幹徑與株高的相關係數最高，在卓蘭與大湖系中，其次依序為節數｀幹徑截面積及節間長度，在三灣系則為幹徑、截面積、節間長及節數。第二年卓蘭系以幹徑與株高之相關係數最高，其次為節數、幹徑截面積及節間長度，大湖與三灣系以節數與株高間之相關係數最高，其次為幹徑。第三年三地區均以株高與節數的相關係數最高，次高者為株高與幹徑，其他性狀相關係數之高低在系統間雖略有變動，但以節間長度及幹截面積較高。株高與分枝數及株高母枝刺數之相關係數高低，則與該系統之枝刺數與分枝數的多寡有關·即分枝數與枝刺數較多的族群，兩者與株高之正相關性優於較少者。

The relationship between shoot characters and plant height of three groups of'bird'pear seedling, which were collected from Chuo-lan, Da-hu and San-wan, were analyzed by regression and correlation method. The results reveales that most of the characters had very high significant positive correlation with the plant height except for the bark thickness/the trunk diameter. The results of the first year obtained evidence to show that the regression of plant height and trunk diameter(D) had the highest correlation coefficient(r) value; in Chuo­Ian and·Da-hu groups, followed by number of node(N), trunk cross section area(TCSA) and internode length(IL), while in San-wan group the order were TCSA, IL and N. The results of second year in Chuo-Ian group was the same as the first year, but in San-wan and Da-hu groups, N and D exchange there position. In the third year, the highest correlation with plant height was found to be with the N and followed by D. The number of thorns and branches indicated large difference amng the three groups, hence these characters sould be considered as essential variables to be correlated with the plant height, especially in the groups -which had a lot of thorns and branches.