Identification of rice seeds
Although some seed morphological characteristics can be used successfully for seed identification, it is very difficult even for taxonomists to apply them correctly and there are species whose seeds are difficult to identify by morphology only. This explains why the wrong seeds were occasionally distributed to users. Here, we show that 17% of seeds were mislabeled, a figure high enough to deserve serious consideration. Although no algorithm has improved the assignment of specimens to species (Spouge & Mariño-Ramírez, 2012), our findings suggest that phylogenetic methods offer the most reliable but also the least sensitive approach in this respect. At species level, samples in a monophyletic clade with a reasonable bootstrap support belong to the same species.

Acknowledgement

We thank Wenpan Dong for guidance on chloroplast genome assembly. This study was partly supported by the Strategic Priority Research Program of the Chinese Academy of Sciences, Grant No. XDA 19050303 & XDA 23080204, and the Fundamental Research Funds for the Central Public-Service Research Institute [2018JB001].
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