Clonal Variation of Flowering in Pinus thunbergii Seed Orchard

해송 채종원(採種園)에서 개화특성(開花特性)의 클론 변이(變異)

This study was conducted in an attempt to quantify some traits that may be involved in the reproductive process of Pinus thunbergii. During the past 6 years (1995-2000), we surveyed flowering patterns of 60 P. thunbergii clones in a seed orchard which was established in Anmyon-do, 1979. From this survey, we estimated clonal contributions of male and female flowers and sexual asymmetry. Among 60 clones, 18 clones (30%) accounted for 0.37 (1999)~0.46 (1995) of clonal contribution in female flowers and 0.44 (1999)~0.57 (1995) of clonal contribution in male flowers. As compared with the previous reports in other pine species, more clones made contributions to reproductive process in P. thunbergii seed orchard. The relative effective population numbers for females (v♀) varied from 0.59 (1995) to 0.91 (1999) and those for males ( v♂) were between 0.56 (1995) and 0.83 (1998) at gamete level. This showed that the female gametes effectively contribute to the reproductive process more than did the male gametes. The relative effective population numbers at clonal level ($v_b$) were in the range of 0.72 (1995) and 0.93 (1999). More than 73% of the total clones showed values of 0.4~0.6 ($0.5{\pm}0.1$) in maleness index. The values averaged over all the clones were temporally variable with the range of 73% in 1996 and 100% in 2000. The degree of sexual asymmetry ($A_s$) ranged from 0.09 to 0.26. These values were relatively low when compared with those of other trees, suggesting that P. thunbergii seed orchard remains a high level of homogeneity in the number of male and female. All of the various types of effective population numbers were positively correlated with each other while they were negatively correlated with the degree of sexual asymmetry.

본 연구는 1979년에 조성된 해송 채종원에서 6년간(1995~2000년) 개화량를 조사하여 얻은 자료를 토대로 생식과정에 관계된 몇 가지 특성들을 계량화 하고자 하였다. 전체 60개 클론 중 18개 클론(30%)이 차지하는 자화의 상대적인 기여도는 0.37(1999)~0.46(1995), 웅화는 0.44(1999)~0.57(1995)로 자화보다 다소 높게 나타났으며 소수 클론에 의해 편중되는 현상이 다른 수종에 비하여 작게 나타났다. 배우체(v♀, v♂) 수준에서 상대적인 유효집단수는 각각 0.59(1995)~0.91(1999)과 0.56(1995)~0.83(1998), 접합체($v_b$) 수준에서는 0.72(1995)~0.93(1999)으로 추정되어 자성배우체가 웅성배우체보다 많게 나타났다. 웅화 개화량에 대한 평균지수는 전체 클론의 73% 이상이 0.4~0.6($0.5{\pm}0.1$)의 값을 나타내었으며, 연도간에는 73%(1996)~100%(2000)로 다양하게 나타났다. 성적 불균형도($A_s$)는 0.09~0.26으로 추정되어 다른 수종에 비해 상대적으로 낮아 높은 유전적 균일성을 나타내었다. 모든 유효집단수 간에는 정의 상관을 보였으며, 성적 불균형도는 모든 유효집단수와 부의 상관을 나타내었다.