Effects of Inbreeding on the Male and Female Functions of Plants

斯蒂芬森9806691近交衰退是指近交后代(自花授粉或近亲授粉产生的后代)相对于异交后代适合度降低。一个令人印象深刻的理论机构预测，近亲繁殖衰退是植物花卉特征(花的大小、形状、颜色、气味等)和交配模式进化的主要力量。在过去的一个世纪里，许多研究表明，近亲繁殖会降低植物的相对存活率以及种子的相对数量和质量。然而，大多数研究忽略了近亲交配对植物雄性(花粉)功能的影响，尽管大多数植物是两性的(既产生花粉又产生种子)。此外，我们对近亲交配抑郁的程度如何随着不断增长的(环境)条件变化知之甚少。最后，关于近亲繁殖抑郁症的遗传基础，仍有很多争论。因此，我们将执行一系列项目，旨在1)通过男性和女性的功能来量化和比较近亲繁殖抑制对生存和生殖的影响，2)检查近亲繁殖抑制与环境压力之间的关系，3)确定近亲繁殖与健康之间的关系，以及4)确定近亲交配抑制对男性功能的直接原因。从本提案中的项目中获得的数据将导致对近亲繁殖对植物雄性功能的影响的第一次全面研究；它们将产生关于近亲繁殖衰退的遗传基础的可测试的预测(以及测试这些预测所需的种子)；它们将使我们能够更好地预测不同环境条件下花卉性状的进化方向；它们将使我们能够批判性地评估围绕植物交配模式进化的理论。从实践的角度来看，我们的发现将对农业(例如，杂交种子行业使用近交系植物作为其育种计划的主要组成部分)、保护生物学(例如，保护目前仅存在于少数高度近亲繁殖的种群中的濒危植物)和林业(在这些领域，花粉选择是至关重要的，因为传统的植物育种技术由于树木的长时间繁殖而失败)将产生重要的影响。

Stephenson 9806691 Inbreeding depression is the reduction in fitness of inbred progeny (progeny resulting from self-pollinations or pollinations by close relatives) relative to outcrossed progeny. An impressive body of theory predicts that inbreeding depression is a major force in the evolution of floral traits (size, shape, color, odor, etc. of flowers) and mating patterns in plants. Over the past century many studies have shown that inbreeding reduces relative survivorship and the relative number and quality of the seeds produced by plants. However, most studies have ignored the effects of inbreeding on the male (pollen) function of plants despite the fact that most plants are hermaphrodites (produce both pollen and seeds). Moreover, we know little about how the magnitude of inbreeding depression changes with growing (environmental) conditions. Finally, there remains much debate concerning the genetic basis of inbreeding depression. Consequently, we will perform a series of projects designed 1) to quantify and compare the magnitude of inbreeding depression on survivorship and reproduction through both the male and female functions, 2) to examine the relationship between inbreeding depression and environmental stress, 3) to determine the relationship between inbreeding and fitness across four levels of inbreeding, and 4) to determine the proximate cause of inbreeding depression on the male function. The data obtained from the projects in this proposal will result in the first comprehensive study of the effects of inbreeding on the male function of plants; they will generate testable predictions (and the seeds necessary to test these predictions) concerning the genetic basis of inbreeding depression; they will allow us to better predict the direction in which floral traits will evolve under different environmental conditions; and they will allow us to critically evaluate the theory surrounding the evolution of plant mating patterns. From a practical perspective, our findings will have important ramifications for agriculture (e.g., the hybrid seed industry uses inbred lines of plants as the major component in their breeding programs), conservation biology (e.g., the preservation of endangered plants that now exist only in small, highly inbred populations), and forestry (where pollen selection is of utmost importance because traditional plant breeding techniques fail due to the long generation time of trees).