Why do hybrid rice have to breed every year?

There have been hybrid rice can get high yields, why can not self-pollinate and reproduce as normal rice, which must be conducted every year?

The reason for this is that hybrid rice is created by two products with different genetic properties , due to different genetic characteristics between them, hybrid rice through hybridisation is created , in which the body combines Different properties of the two products: On the one hand, the different properties in the hybrid rice body will complement each other, on the other hand, the hybrid rice has a certain conflict in production, so the hybrid rice has show superiority and health.

Homosexual products have different genetic properties.

In China, for example, the undeveloped cultivated system is the temperate rice of the temperate zone, characterized by a short reproductive period, large cotton, and weak tillering. The recovery system found is the fairy rice product of the tropics of foreign countries, its characteristics are the long genital period, strong tillering, small cotton. Mixed products with different genetic characteristics, the hybrid rice obtained a longer period of reproductive than non-reproductive system, shorter recovery system.

Strong branching power, exceptionally large cotton, help the characteristics of these varieties complement each other, in addition, they also show abundant growth characteristics, fast growth rates, early branching, people Call these characteristics a heterogeneous delivery. Using this advantage can increase rice production.

But heterogeneity is only expressed in the first generation, cannot be inherited . If the seeds of the first-generation hybrid rice are retained, the second-generation mixed plants will appear fragmentary phenomena, sometimes the reproductive system will not reproduce, sometimes the reproductive system will sometimes occur. like a mixed cultivator, the population does not line up, the body is tall and short, the growth period is long, short, the branching characteristics are strong and weak, the cotton is large and small, even appears. non-reproductive rice can not be grain. Therefore, the mixed seed becomes a self-agglomeration, can only be used as food, in production has no use value.

In order to use the first generation heterogeneous advantages, only new breeds can be continually supplied to meet the needs of hybrid rice.

1. Calculation of fertilizer demand of rice plants by the technique "defect"
2. Publish a complete map of the genetic variation of rice