ABSTRACT

Cajuput (Melaleuca cajuputi subsp. cajuputi) is cultivated widely in Indonesia for its medicinal foliar essential oil. Breeding programs of cajuput have established seed orchards for the provision of improved seed to support the establishment of large areas of plantations. Information on pollen dispersal and genetic structure in such seed orchards is important for enhancing the genetic quality of seed produced from these seed orchards. We analysed eight microsatellite loci in 160 established trees and 240 offspring of ten selected mother trees in a cajuput seed orchard in Yogyakarta, Indonesia. We investigated the genetic structure and inheritance, pollen dispersal patterns and rates of pollen contamination. The parent trees showed high genetic diversity (H_O = 0.480, H_E = 0.755), but approximately 5% of alleles were not inherited by the offspring. Pollen dispersal in the cajuput seed orchard was panmictic, with an average pollen donor number (N_ep) of 17 and an average pollen dispersal distance of 43 m. However, 11.6% of genotypes contained a mismatch, indicating pollen contamination from nearby unselected cajuput trees. Stimulating synchronous flowering in the orchard and providing suitable habitat for pollinating insects may help to optimise outcrossing and random pollination within the seed orchard and thereby to fully capture genetic diversity and reduce pollen contamination.

摘要

Cajuput ( Melaleuca cajuputi subsp. cajuputi ) 因其药用叶面精油而在印度尼西亚广泛种植。cajuput 育种计划建立了种子园，以提供改良的种子，以支持大面积种植园的建立。有关此类种子园中花粉传播和遗传结构的信息对于提高这些种子园生产的种子的遗传质量很重要。我们分析了印度尼西亚日惹 cajuput 种子园中 160 棵已建树和 10 棵选定母树的 240 个后代中的 8 个微卫星位点。我们调查了遗传结构和遗传、花粉传播模式和花粉污染率。亲本树表现出较高的遗传多样性（H _O = 0.480, _HE  = 0.755)，但大约 5% 的等位基因不是由后代遗传的。cajuput 种子园中的花粉传播是混乱的，平均花粉供体数 (N _ep ) 为 17，平均花粉传播距离为 43 m。然而，11.6% 的基因型包含不匹配，表明来自附近未选择的 cajuput 树的花粉污染。刺激果园同步开花并为授粉昆虫提供合适的栖息地可能有助于优化种子园内的异交和随机授粉，从而充分捕捉遗传多样性并减少花粉污染。