Breeding techniques make seed production easier

The core competitiveness of maize varieties is mainly reflected in three aspects: the first is easy seed production, that is, the seed production technology is simple and easy to operate, and the seed production yield is high, and it is easy to ensure the quality of each item; the second is field performance, high yield, stable yield, multi-resistance and wide adaptability; the third is good seed quality and good product sales. According to the overall breeding goal of "high yield, high quality, multi-resistance, wide adaptability and easy seed production", large maize varieties with strong market competitiveness and excellent comprehensive agronomic traits were bred. Among them, easy seed production is the key link to realize industrialization, so seed production must be considered in the breeding process.

Research and utilization of cross-incompatibility technique.

The yield of bred inbred line should be high, especially the yield of female inbred line must be high, which should be more than 500 kg per mu. Under the current market demand of packing and selling according to grains, not only the yield should be guaranteed, but also the grains of female parent should not be too large (1000-grain weight less than 300 grams), the number of grains per ear should be more (more than 500 grains per ear); the male parent should be slightly higher than the female parent, the male ear should have more branches, the pollen amount is large, the vitality is strong, and the pollen dispersal duration is long. Parents should be close to the flowering stage as much as possible, should not be too long sowing time at wrong time, and should not have too much light and temperature reaction, so as not to easily lead to flowering sterility; female parent should also have suitable maturity period, faster dehydration speed in later stage, easy drying, strong seed vitality; low temperature germination and strong ability to arch soil.

The parents of inbred lines bred by DH breeding technology have good uniformity, are not easy to degenerate, and can keep longer seed character. DH technology can also be used for rapid purification and optimization of hybrid degenerated parents.

Utilization of male sterile seed production technology. Using male sterile seed production technology can save the cost of artificial male selection (2 artificial per mu, at least 200 yuan), and can also improve seed quality. Mechanical emasculation can also reduce labor costs, but the imported equipment purchased at present is expensive, and it also requires large plots and flat land. At the same time, it also has high requirements for planting methods and uniformity, and it also requires multiple field emasculation operations and manual auxiliary search. In comparison, male sterility technology is more suitable for current needs. At present, C-type and S-type cytoplasmic male sterile seed production technology is mainly used in production. American Pioneer Company has developed and utilized the technology of Genic Sterile Intelligent Seed Production (SPT), and China has also begun to actively develop and utilize the technology of Genic Sterile Seed Production, and has made good progress at present.

Research and utilization of cross-incompatibility technique. Not long ago, researchers from the Institute of Genetic Development of Chinese Academy of Sciences first applied this technology to waxy corn and bred the first cross-incompatible waxy corn variety in China. This technology also has certain utilization value and potential in seed production.