Evolution of Dioecy from Gynodioecy: Artificial Selection for Sex Allocation Patterns

从雌花异株到雌雄异株的进化：性别分配模式的人工选择

• 批准号: 9815878
• 负责人: Ann Sakai
• 金额: $ 45万
• 依托单位: University of California-Irvine
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-02-15 至 2008-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9815878&HistoricalAwards=false
• 关键词: Evolution; Dioecy; Gynodioecy; Artificial; Selection

Project Summary. Knowledge of plant reproductive systems is critical for agriculture and management of endangered species as well as for an understanding of basic evolutionary processes. Plants are usually hermaphroditic, with both male and female function in the same flowers. In many different plant groups, however, evolution has led to sexually dimorphic breeding systems including gynodioecy (females and hermaphrodites in populations) and dioecy (populations with separate male and female plants). This separation has been associated with changes in allocation of resources to male and female function. Few studies examine the genetic potential for shifts in allocation patterns to male and female function, and have taken into account known evolutionary relationships of species with various reproductive systems. The proposed study will examine the genetic potential for sex allocation shifts with artificial selection on allocation to male and female function in two closely related Hawaiian species of Schiedea (Caryophyllaceae). Given the range of allocation patterns within the genus, an artificial selection program for greater allocation to male function in hermaphrodites and to female function in females should demonstrate significant genetic potential for change. In the first experiment, additive genetic variances of sex allocation traits and their genetic covariances with other reproductive characters will be estimated. In the second experiment, artificial selection will be performed for increased biomass of stamens in hermaphrodites and increased carpel and fruit biomass in females. Both direct responses of these traits and indirect responses of correlated traits will be measured, as trait correlations may enhance or impede selection for specialization in male and female function. S. salicaria is predicted to become more male-like and therefore more similar to the sexually dimorphic S. adamantis hermaphrodites. Comparative studies have often been used to predict the course of evolution. The proposed research takes this approach forward, by determining whether evolutionary trends hypothesized on the basis of comparative studies can be produced using artificial selection.

项目摘要。植物生殖系统的知识对于农业和濒危物种的管理以及了解基本进化过程至关重要。 植物通常是雌雄同体，同一朵花同时具有雄性和雌性功能。 然而，在许多不同的植物类群中，进化导致了两性异形的育种系统，包括雌雄异株（种群中的雌性和雌雄同体）和雌雄异体（具有独立的雄性和雌性植物的种群）。 这种分离与男性和女性职能资源分配的变化有关。 很少有研究考察雄性和雌性功能分配模式转变的遗传潜力，并且考虑到物种与各种生殖系统的已知进化关系。 拟议的研究将通过人工选择对两个密切相关的夏威夷石竹属物种（石竹科）的雄性和雌性功能分配来检查性别分配变化的遗传潜力。 考虑到属内分配模式的范围，为雌雄同体中的雄性功能和雌性中的雌性功能更大分配的人工选择计划应该表现出显着的遗传变化潜力。在第一个实验中，将估计性别分配性状的加性遗传方差及其与其他生殖性状的遗传协方差。 在第二个实验中，将进行人工选择以增加雌雄同体雄蕊的生物量以及增加雌性的心皮和果实生物量。 将测量这些特征的直接反应和相关特征的间接反应，因为特征相关性可能会增强或阻碍对男性和女性功能专业化的选择。预计 S. salicaria 会变得更像雄性，因此与两性异形的 S. adamantis 雌雄同体更相似。比较研究经常被用来预测进化的过程。 拟议的研究通过确定基于比较研究假设的进化趋势是否可以通过人工选择来产生，从而推进了这种方法。