Conditional differentiation between haploids and diploids has been proposed to drive the evolutionary stability of isomorphic biphasic life cycles. The cost of producing and maintaining genetic information has been posed as a possible driver of this conditional differentiation. Under this hypothesis, haploids benefit over diploids in resource‐limited environments by halving the costs of producing and maintaining DNA. Spared resources can be allocated to enhance survival, growth or fertility. Here we test in the field whether indeed haploids have higher growth rates than diploids. Individuals of the red seaweed Agarophyton chilense, were mapped and followed during 2 years with 4‐month census intervals across different stands within the Valdivia River estuary, Chile. As hypothesized, haploids grew larger and faster than diploids, but this was sex‐dependent. Haploid (gametophyte) females grew twice as large and 15% faster than diploids (tetrasporophytes), whereas haploid males only grew as large and as fast as the maximum obtained by diploids in summer. However, haploid males maintained their maximum sizes and growth rates constant year‐round, while diploids were smaller and had lower growth rates during the winter. In conclusion, our results confirm the conditional differentiation in size and growth between haploids and diploids but also identified important differences between males and females. Besides understanding life cycle evolution, the dynamics of A. chilense frond growth reported informs algal farmers regarding production optimization and should help in determining best planting and harvesting strategies.

中文翻译：

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长期原位监测同构单倍体-二倍体红海藻Agarophyton chilense的叶前生长差异

已经提出了单倍体和二倍体之间的条件分化，以驱动同构双相生命周期的进化稳定性。生产和维护遗传信息的成本被认为是这种条件分化的可能驱动因素。在这种假设下，在资源有限的环境中，单倍体比二倍体受益，因为它将生产和维护DNA的成本降低了一半。可以分配备用资源以提高生存，增长或生育能力。在这里，我们在现场测试单倍体是否确实比二倍体具有更高的生长速率。红藻Agarophyton chilense的个体在智利瓦尔迪维亚河河口的不同林地进行了为期2个月的普查，并进行了为期2个月的普查。如假设的那样，单倍体比二倍体长得更大，更快，但这是性别依赖性的。单倍体（配子体）雌性的体长比二倍体（四倍体植物体）大两倍，快15％，而单倍体雄性的体长和快于夏季二倍体所获得的最大值。但是，单倍体雄性全年保持最大大小和增长率不变，而二倍体较小，并且在冬季生长速率较低。总之，我们的结果证实了单倍体和二倍体之间大小和生长的条件差异，但也确定了男性和女性之间的重要差异。除了了解生命周期的演变之外，A. chilense叶的生长报告了藻类养殖者有关生产优化的信息，应该有助于确定最佳的种植和收获策略。