苦楝种源果核及种子性状地理变异的研究

Geographic variation in traits of fruit stones and seeds of Melia azedarach

为了更准确地掌握苦楝的地理变异及其规律,对17个省份的70个苦楝种源的果核和种子的18个性状进行了观测和分析。结果表明:苦楝不同种源间在果核和种子表型性状上存在显著差异,大多数性状的重复力大于85%,其中种子百粒重、果核宽的种源重复力较高,达到98%以上;其次是果核百粒重、种子大小性状;而棱粒比、果核果形系数b的重复力较小,分别为74.56%、49.14%。部分性状的种源变异存在明显的地理趋势:由东向西,果核的宽度和质量、种子宽度、果核皮厚度、果核单果棱数均有增大的趋势;由南向北,果核长度、种子宽度、种子质量、果核单果棱数和果核皮系数均有增大的趋势,种子趋于粗短的椭圆形;海拔由低到高,果核和种子宽度、果核质量、果核皮厚度、果核单果棱数呈增大趋势,果核趋于圆形,种子趋于粗短的椭圆形。根据苦楝果实的18个性状指标的聚类分析,可将70个种源划分为8类,种源类群间性状差异也显著。

In order to more accurately know the geographical variation characteristics of Melia azedarach, 18 traits of fruit stones and seeds from 70 provenances （ 17 provinces of China） were analyzed. The results showed that phenotype traits of fruit stones and seeds were significantly different among the provenances. The repeatability of most of the traits exceeded 85% , where the repeatability of 100-seed weight and fruit stone width was more than 98% , followed by 100-fruit-stone weight and seed sizes, and the repeatability of ridge-grain ratio and coefficient b of fruit stone was lower, only 74.56% and 49.14% , respectively. The provenance variation in some traits showed obviously geographical trends. From the east to west distribution, fruit stone width and weight, seed width, thickness of fruit stone coat and ridge of each fruit stone increased. Meanwhile, from the south to north distribution, fruit stone length, seed width, seed weight, ridge of each fruit stone and fruit stone coat ratio increased as well, and the seed shape was to be short oval. From low to high altitude, the width of fruit stone and seed, fruit stone weight, thickness of fruit stone coat, fruit stone ridge increased, fruit stone longitudinally tended to be round shape and seed to be stubby and oval. Using the cluster analysis of 18 traits of M. azedarach, 70 provenances can be divided into 8 types. The geographical pattern and characteristics showed significant different among provenance groups.