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Conventional high-quality late rice varieties rejuvenation method
In recent years, the cultivation of high-quality late rice varieties has expanded significantly. However, due to insufficient attention to the renewal and rejuvenation of traditional high-quality rice varieties, these varieties tend to degrade more quickly. Degraded varieties not only lose their disease resistance and yield potential but also experience a decline in grain quality. As a result, it is essential to implement timely purification and rejuvenation techniques to maintain the integrity and performance of these valuable rice types.
1. **Single Plant Selection Method**
This method involves selecting individual plants when late-season high-quality rice is nearly mature. The selection is based on the specific characteristics of the variety, such as strong growth, high yield, good disease resistance, appropriate growth duration, and no lodging. Plants with well-filled grains and typical traits are chosen as seed sources. The number of panicles selected depends on the needs of the seed field. These selected panicles are then re-examined for consistency with the variety's characteristics, and any that deviate are removed. After threshing, the seeds are stored separately and used as seeds for the next season. This approach is commonly used to restore and maintain the quality of long-cultivated high-quality rice varieties.
2. **Ear Line Purification and Rejuvenation Method**
This technique closely mimics the rejuvenation process of the original variety. When high-quality late rice matures, individual spikelets with desirable traits—such as good growth, no pests or diseases—are selected from the seed field. These spikes are dried in the sun, then threshed and carefully compared the following year. The seeds from the previous year are treated rigorously before being planted individually or in small plots. At key growth stages—seedling, tillering, heading, and maturity—plants are evaluated for typical characteristics, uniform growth, and consistent heading and maturity. Selected single ears are labeled, harvested, threshed, and stored for future use. After a second-year comparison test, the best lines are mixed and used for seed production or breeding programs.
3. **Chip Selection Method**
This method is particularly effective for maintaining the purity of high-quality rice varieties, especially newly introduced ones. It is applied in fields where the variety is already pure, with good isolation and minimal pest or disease issues. The first step is to remove impurities during the seedling stage by identifying and eliminating plants that differ significantly in plant type, height, leaf shape, or color from the standard variety. This is a critical step in preserving the variety’s purity and preventing contamination from hybrid strains. Later, additional impurities are removed based on differences in growth rate, plant structure, and other distinguishing features such as flowering time and ear structure. By systematically eliminating off-types at different growth stages, this method ensures the continued quality and stability of the variety.