How can breeding technology make seed production simpler?
The core competitiveness of a corn variety is mainly reflected in 3 aspects. The first is ease of seed production, that is, the seed production technology is simple and easy to operate, and the seed production yield is high, making it easy to ensure all quality parameters; the second is field performance, with high yield, stable yield, multiple resistance, and wide adaptability; the third is good grain commercial quality and good product marketability. According to the overall breeding goal of "high yield, high quality, multiple resistance, wide adaptability, and ease of seed production," large corn varieties are bred that meet production needs, have strong market competitiveness, and have excellent comprehensive agronomic traits. Among these, ease of seed production is the key link in achieving industrialization, therefore, the issue of seed production must be considered in the breeding process.
Research and utilization of cross-incompatibility technology.
The selected inbred lines themselves must have high yield, especially the female parent inbred line must have high yield, and should be above 500 kg per mu. Under the current market demand for sales packaged by seed count, not only must yield be guaranteed, but also attention should be paid to the fact that the female parent's grains should not be too large (1000-grain weight below 300 g), and the number of grains per ear should be high (above 500 grains per ear); the male parent should be slightly taller than the female parent, with many tassel branches, a large amount of pollen, strong vigor, and a long duration of pollen shedding. The flowering periods of the male and female parents should be as close as possible, the staggered sowing time should not be too long, and there should not be excessive photoperiod and temperature responses, so as to avoid easily causing flowering period mismatch; the female parent should also have a suitable maturity period, relatively fast dehydration in the later stage, easy drying, and strong seed vigor; strong ability to germinate and emerge under low temperature.
The parental inbred lines bred using doubled haploid (DH) breeding technology have good uniformity and consistency, are not prone to mixing and degeneration, and can maintain their varietal characteristics for a longer time. Using DH technology, parents that have already become mixed and degenerated can also be quickly purified and optimized.
Utilization of male sterility seed production technology. Using male sterility seed production technology can save the cost of manual detasseling (2 labor days per mu, at least more than 200 yuan), and can also improve seed quality. Mechanical detasseling can also reduce labor costs, but currently the imported equipment purchased is expensive, and also requires large plots and flat land, while also having relatively high requirements for planting methods and uniformity, and also requires multiple field detasseling operations as well as manual assistance in searching. Comparatively speaking, male sterility technology is more suitable for current needs. At present, what is mainly used in production is C-type and S-type cytoplasmic male sterility seed production technology. The American company Pioneer has already developed and utilized nuclear male sterility intelligent seed production (SPT) technology, and China has also begun to actively carry out the research, development, and utilization of nuclear male sterility seed production technology, and good progress has been made at present.
Research and utilization of cross-incompatibility technology. Not long ago, researchers at the Institute of Genetics and Developmental Biology of the Chinese Academy of Sciences first applied this technology to waxy corn and bred China's first cross-incompatible waxy corn variety. This technology also has certain utilization value and potential in seed production.