Some Botanical Characteristics of Green Foxtail (Setaria Viridis) and Harvesting Experiments on the Grass
Lu, Tracey L. -D., Antiquity
Green foxtail (Setaria viridis) is an annual grass widely distributed over the Old World, including China, where evidence of the earliest foxtail millet domestication to date has been discovered in the Cishan assemblage, Hebei province, dated to approximately 7900-7500 BP (Institute of Archaeology CASS 1991). Isozymic analysis and interspecific cross between S. viridis and S. italica (domesticated foxtail millet) demonstrated that S. viridis is the progenitor of domesticated foxtail millet (Gao & Chen 1988; Li et al. 1945). Yet little is known about the process of millet domestication, and even less about either the botanical characteristics of S. viridis or its cultural significance regarding human domestication.
An investigation of S. viridis involving both plant observation and harvesting experiments was carried out in the lower valley of the Yellow River, from early July to early August in 1996. One objective was to identify the growing schedule of S. viridis, especially relating to ripening and seed shattering. Another was to test the outcome of various harvesting methods, thus providing data for analysing the possible impact of harvesting selection as a crucial part of domestication.
Observation used stands of S. viridis found within a radius of about 2 sq. km from a field station at the edge of a small town, Qufu, in the lower valley of the Yellow River. For the purpose of recording the growing schedule, 30 plants were randomly selected and numbered. Each plant was then observed and recorded every day in the morning from 8 a.m. onwards. Meanwhile, plants that were not numbered were also under observation in order to broaden the sample, although the record of the unnumbered plants was less detailed.
According to Chinese botanical documents, S. viridis is an annual grass which can be found from northeast to southwest China, and its tolerance to drought, heat and poor soil is remarkable (Nanking University 1965). This record is further confirmed by the 1996 observation. S. viridis is found in various habitats in Qufu: on road-sides, in dry sandy deposits, in courtyards [ILLUSTRATION FOR FIGURE 1 OMITTED], even in the middle of highways where the grass has to endure not only hot and dry conditions, but also heavy pollution. In these various mini-environments green foxtail seems to grow well, showing its strong adaptability.
On the other hand, it was noted that dense stands of S. viridis were seldom found with other grasses, especially where other grasses were dense. The major cause of this distribution pattern could be the manner of seed-dispersal of S. viridis. Although S. viridis has longer awns than its domesticated counterpart, the awns are not attached to its seeds, but remain on the spike after all the seeds have shattered [ILLUSTRATION FOR FIGURE 2 OMITTED]. It seems that this grass disperses its seeds mainly by dropping them to the ground, although animals are likely to be another seed-dispersal agent. It was observed once that a dog was eating leaves of S. viridis. According to local villagers, dogs do so when they feel unwell. Consequently dogs might have carried and delivered the seeds. But the distribution of S. viridis stands in Qufu seems to suggest that the distance of seed dispersal is quite limited, usually close to where the parent plants stood.
As an annual plant S. viridis generally germinates in spring, according to Chinese botanical records (Nanking University 1965). But during the observation it was noticed that germination also took place in summer, particularly after rain. The time-span from germination to flowering for those plants germinated later in the year was quite short: within 20 to 25 days after the germination, some of the plants began to flower. based upon the mean value of the observed life cycle of this wild grass (see below, TABLE 1), these late-germinating plants could have begun to ripen within another 30 days, and shed their seeds soon after. …