3. Wild-rice seeds found in an oldest rice remain

To check whether or not wild rice had been domesticated in Taifu area of east China several thousand years ago, we examined 25 spikelets excavated from Hemudu archaeological remain (ca. 5,000 BC) under a scanning electronic microscope at Zhejiang Agricultural University.

About half of the 25 seeds observed were awnless, and were judged to be of cultivated rice. Other half had traces of awns, suggesting their probability of being wild rice. Spikelets of cultivated and wild rices differ in the presence or absence of well-developed bristles on the surface of awns, and in their length and density (Fig. 1). Of awned spikelets excavated, four had bristles as long and dense as those of the common wild rice. One spikelet, whose bristle length was not measurable due to heavy breakage, showed dense bristles like that of the common wild rice.

Fig. 1. Relationship between length and density of bristles on awn surface in wild and cultivated rices and in Hemudu wild-type seeds.

Some of the 25 spikelets had a fragment of panicle rachis at their base points, suggesting that they were removed from panicles upon harvest (Fig. 2). Several spikelets including the three awned ones lacked the fragment and showed traces of natural shedding at maturity (Fig. 2).

These data suggest that in the Hemudu findings, seeds of domesticated and wild rices and of intermediate wild-cultivated ones were mixed together. Hemudu site is known to be one of the oldest remains of rice cultivation in the world. lt may be inferred that the Hemudu people handled rice domestication, and that the Taifu area is a homeland of cultivated rice.