Do you know what purity and cleanliness mean on seeds?

Summary: Do you know what purity and cleanliness on seed packaging mean?

After we buy seeds, looking carefully at the packet, we can see the purity and cleanliness of the seeds clearly marked. Now the busy autumn season is about to arrive again, and for farmer friends it is time to prepare to buy seeds once more. Perhaps everyone is still not very clear about both seed purity and cleanliness, so here Kexue Xingnong will give an introduction.

Seed purity is a statistic about the consistency of genotypes among the seeds, while seed cleanliness is a statistic for evaluating how clean the seeds are. The two are completely different concepts. Sometimes everyone may think purity also means cleanliness, but there is clearly a misunderstanding here; in seeds, the two are clearly distinguished.

The state has clear regulations on the purity requirements for seeds, which must reach 96% or above (inclusive). Many times everyone cannot grasp the concept of purity very well. To put it plainly, purity represents the consistency of crop phenotypes in the field.

Generally speaking, even if seeds are mixed, it is not easy for them to be mixed, but sometimes mixing in seeds of other varieties still has a certain impact on yield and on the quality of the crops harvested from the offspring.

To give a small example, in the past when families planted wheat, barley plants would always be found mixed in the wheat field. They were especially conspicuous in the wheat field. This is not to say barley is bad or that barley is not wheat, but allowing barley to exist and compete with the wheat in the field is also not conducive to building the population structure. It would also cause the harvested wheat to be mixed with barley, leading to a decline in quality. This is something we can see with our own eyes. However, if common wheat is mixed in, identifying purity still requires molecular methods as an aid.

The situations above are still relatively good; at least they did not cause a large yield reduction in the field. However, for hybrid seeds, once purity declines, the loss can be somewhat large. Everyone should know that at present rice still mostly uses three-line seed production, namely the male sterile line, maintainer line, and restorer line. However, it must be understood that because hybrid seeds are produced by crossing the male sterile line and the restorer line, once purity is insufficient, that is, when the male sterile line produces a trace amount of pollen due to weather factors, self-pollination and seed setting will occur. In this situation, if farmers buy such seeds with insufficient purity, a large number of sterile plants will appear in the field and cause yield reduction, resulting in agricultural economic losses.

As for seeds with purity of 96% or 98%, there is essentially not much difference, and the performance in farmland is actually very difficult to distinguish, because the difference itself is very small. Therefore, buying seeds with higher purity will make the growth uniformity in the field more consistent.

This is Kexue Xingnong, taking you to learn together.