Abstract:

Aims: Understanding of phenotypic plasticity and local adaptation in marginal populations is fundamental for predicting how plants will respond to climate change. Common wild rice Oryza rufipogon is an endangered but agriculturally important rice species, which has its northernmost range in China. Climate warming is the main environmental stress that the northern populations of O. rufipogon have to face in the global climate change scenario. However, relatively little attention has been paid to the phenotypic plasticity and local adaptation of O. rufipogon. Here we test the northern and central populations of O. rufipogon for variations in plant fitness traits under the exposure of different temperatures.

Methods: Focusing on the northern population of O. rufipogon, with the center populations (middle and southern populations) as the controls, we established experimental populations at three common gardens along a latitudinal-gradient. According to the method of space-for-time substitution, three common gardens were set up in the northernmost boundary, relatively northern and southern areas of the range of O. rufipogon in China (i.e., high, middle and low latitude) to model the phenotypic performance of common wild rice populations under a future climate change scenario.

Results: The examined populations of O. rufipogon displayed strong phenotypic plasticity, and the levels of phenotypic plasticity varied between populations. The northern population had higher plant height, seed number, and overwintering survival rate at native common garden, suggesting the population’s adaption to relatively low temperature environment. This population could normally set seeds and complete life cycle regardless of whether it was planted northward or southward, demonstrating that it could survive under the future temperature changes. The middle and southern populations did not survive the winter in Shanghai common garden, implying that the low-latitude populations might be more vulnerable to extreme cold climate events.

Conclusion: These results indicate that O. rufipogon has adaptive differentiation between populations and strong phenotypic plasticity, by which both the northern and central populations can respond to climate warming.

Key words: Oryza rufipogon, phenotypic plasticity, local adaptation, climate change