MATING SYSTEM VARIATION IN HYBRIDIZING IRISES - EFFECTS OF PHENOLOGY AND FLORAL DENSITIES ON FAMILY OUTCROSSING RATES
MATING SYSTEM VARIATION IN HYBRIDIZING IRISES - EFFECTS OF PHENOLOGY AND FLORAL DENSITIES ON FAMILY OUTCROSSING RATES
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DOI：
10.1038/hdy.1994.12
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发表时间：
1994-01-01
期刊：
影响因子：
3.8
通讯作者：
BENNETT, BD
中科院分区：
文献类型：
--
作者：
CRUZAN, MB;HAMRICK, JL;BENNETT, BD
在两个杂交种的虹膜异交的频率估计人口和个人的水果。花物候和花的局部密度对异交率的影响进行了研究，并评估了在不同花粉环境下杂交种子形成的潜力。所研究的种群在植物的空间分布和遗传结构水平上存在差异; fulva种群由许多低密度斑块组成，并出现了一定的遗传分化，而I hexagona种群由一个随机分布的基因型的单一高密度实验区。这两个物种的种群异交率估计值相对较高（0.67-0.90）。家庭异交率的分布往往是双峰的两个物种与个别水果要么有大部分的种子受精异交捐助者或几乎完全自交。异交结实的频率随异交植株上开花数的增加而增加，随异交植株上同一茎上开花数的增加而减少。六边形在重症fulva相反的趋势是明显的;当更多的花在其他茎上开放时，异交减少，而当更多的花在同一茎上开放时，异交增加。异交频率的意外反应。富尔瓦病可能是较高水平的营养繁殖和遗传结构以及花粉载体行为的结果。在低花密度条件下观察到的花粉优势性差异和较高的自交率。六角形可能有助于观察到的杂交种子形成的模式。家系异交率的分析为研究交配系统的变异和进化提供了重要的信息。
The frequency of outcrossing in two hybridizing species of Iris was estimated for populations and for individual fruits. Effects of floral phenology and the local densities of flowers on outcrossing rates were examined and the potential for hybrid seed formation under different pollen environments was assessed. The populations examined differed with respect to the spatial distribution of plants and the level of genetic structure; the I. fulva population consisted of a number of low density patches and appeared to have some genetic differentiation whereas the I hexagona population consisted of a single high-density experimental plot of randomly distributed genotypes. Population outcrossing rate estimates were relatively high (0.67-0.90) for both species. The distribution of family outcrossing rates tended to be bimodal for both species with individual fruits either having the majority of seeds fertilized by outcrossed donors or being almost entirely selfed. The frequency of outcrossed fruits increased with the number of flowers open at other plants and decreased when more flowers were open on the same stem in I. hexagona. In I. fulva the opposite trends were apparent; outcrossing decreased when more flowers were open on other stems and increased when more flowers were open on the same stem. The unexpected responses of outcrossing frequency in I. fulva may have been a consequence of higher levels of vegetative reproduction and genetic structure and the behaviour of pollen vectors. Differences in pollen prepotency and the higher selfing rates observed at low floral densities in I. hexagona may have contributed to the observed patterns of hybrid seed formation. The analyses of family outcrossing rates provide important information on factors responsible for mating system variation and evolution.