J Plant Ecol ›› 2020, Vol. 13 ›› Issue (1): 36-41.DOI: 10.1093/jpe/rtz054

• Research Articles • Previous Articles     Next Articles

Genetic diversity and offspring fitness in the red and white fruit color morphs of the wild strawberry Fragaria pentaphylla

Lu-Xi Chen1, Su-Ting Xu1,2, Wei-Hang Ding1, Jun-Min Li1,* and Peter Alpert3   

  1. 1Zhejiang Provincial Key Laboratory of Plant Evolutionary Ecology and Conservation, Taizhou University, Taizhou 318000, China, 2School of Life Science, Shanghai Normal University, Shanghai 200234, China, 3Biology Department, University of Massachusetts, Amherst, MA 01003, USA
  • Received:2019-05-21 Revised:2019-11-28 Accepted:2019-12-05 Online:2019-12-07 Published:2020-02-01

Abstract:

Aims

Fruit color polymorphisms are widespread in plants, but what maintains them is largely unclear. One hypothesis is that some morphs are preferred by dispersers while others have higher pre- or postdispersal fitness. This leads to the prediction that fruit color morphs will differ in pre- or postdispersal fitness.

Methods

We compared genetic and clonal diversity, mating system, morphological traits that might be associated with resistance to freezing, and germination, survival and seed production of progeny of the red and white fruit morphs in a population of a diploid, wild strawberry, Fragaria pentaphylla, from south-central China.

Important Findings

The red morph was much more abundant than the white but did not show higher genetic diversity as measured by observed and effective numbers of alleles, Shannon information index, or expected or observed heterozygosities. AMOVA showed that most of the genetic variation in the population was within rather than between morphs. Morphs did not differ in mating system parameters, and no significant biparental inbreeding was found in either morph. Gene flow between two morphs was high (Nm = 6.89). Seeds of the red morph germinated about 2 days earlier and had a 40% higher rate of germination than those of the white morph, but survival of seedlings and seed production by surviving offspring did not differ between morphs. The whole postdispersal fitness of the red morph was about two times higher than that of the white morph. Red morphs had hairier petioles but not more surface wax on leaves. Overall, results showed partial evidence for difference in pre- and postdispersal fitness between fruit color morphs in F. pentaphylla. Differences in fitness independent of dispersal may thus partially account for fruit color polymorphism in all cases.

Key words: Fragaria pentaphylla, fruit color polymorphism, genetic diversity, mating system, south-central China

摘要:
果实颜色的多态性在植物界普遍存在,但是其维持机制尚不清楚。一些假说认为扩散者会偏好一些果色形态,但也有其它假说认为不同的果色形态具有各异的前扩散或后扩散适合度。我们比较分析了中国中南部野生二倍体五叶草莓(Fragaria pentaphylla)红白果型种群的遗传多样性、克隆多样性、交配系统、与抗冻性有关的形态特征以及子代的萌发、存活和种子产量等特征。五叶草莓红果型远远多于白果型,但基于观察到的有效等位基因数、香农信息指数、预期或观察到的杂合度数量等指标,红果型并未表现出更高的遗传多样性。分子方差分析(AMOVA)表明,大多数种群的遗传变异存在于红白果型内,而不是在红白果型间。红白果型的交配系统参数没有差异,且红白果型均未发现存在显著的双亲近交。红白果型间的基因流很高(Nm=6.89)。与白果型相比,红果型的种子的种子萌发约早2天,萌发率高出40%,但红白果型间的幼苗存活率和子代的种子产量没有差异。红果型总的扩散后适合度是白果型的2倍左右。红果型叶柄毛较多,但叶表面蜡质不多。综上所述,研究结果部分证据表明不同颜色形态的五叶草莓果实在扩散前后的适合度存在差异。因此,与扩散无关的适合度的差异部分解释了所有情况下果实颜色的多态性。

关键词: 五叶草莓, 果实颜色多态性, 遗传多样性, 交配系统, 中国中南部