Maize seed purification and rejuvenation
Maize is a natural cross-pollination crop. In addition, the production conditions and processes are more complicated, and there are more opportunities for seed-based mechanical mixing and natural mixing. Practice has proved that in addition to conscientiously implementing safe and reliable isolation, correct seeding specifications, strict decontamination, timely and thorough decipherment, and the selection of five techniques for panicle selection, we must also do a good job in the original species breeding work. The lineage is purified and rejuvenated, and the seeds of the inbred lines on the production are regularly replaced with high-quality seeds. This is a fundamental measure to ensure the quality of hybrid seeds. The following describes the method of purification and rejuvenation of inbred lines. First, the method of isolation of ear (also known as the ear line method) This method applies to the higher purity of the inbred line. In the fall, excellent and strong, full, disease-free pests are selected from the breeding grounds. In the spring of next year, the isolated plots will be selected, each ridge will be planted and ridges shall be strictly removed after emergence. Pull out all the tassels in the mixed or suspected ear line before tasselling. The hybrid lines in the typical ear line must also be strictly eliminated. During the autumn harvest, the most typical ear lines left from the election should be selected for consistent growth and similar ear style. The typical ear is left as the seed for seed selection in the next year. From the rest of the reserved ear rows, the mixed suspect ears were eliminated and then mixed and threshed for large-scale breeding or hybrid breeding in the following year. The ear line selection process is best documented on a row-by-line basis for seedling color, tasselling period, filament color, plant height, uniformity, maturity, and pest and disease status, and is used as the basis for selection or elimination during autumn harvest. Second, the first panicle transmission purification method In order to maintain the original species of inbreds excellent species, improve the typicality of the existing inbred lines, can be used to propagate propagation method. Given that the typical inbred lines and the combining ability of different breeding units are not the same, it is better to introduce a typical ear directly from the original breeding unit as the primary species of one ear. In the first year: In the isolation and propagation area of ​​the first-pass spread, the typical ear individual seeding introduced by the breeding unit should pay attention to the miscellaneous and inferior conditions before emergence after flowering, and then select the planting bag to self-cross 5 spikes -10 spikes. After selecting one of the best heads, they will be reserved for the second year of the first-pass relay. From the remaining hundred ears, 50 to 100 typical panicles will be selected, saved by earing, and will be selected for the next year. Use kind. In the second year: Continued in the first propagation area, single seed and seedlings were self-crossed with 5 ear - 10 spikes; in ear line breeding area, 50 - 100 stays were selected in the first year Typical ears were planted at the branch level, and they were propagated and selected according to the requirements of the method of selection of the panicle line. In the autumn, one best self-crossed spikelet and 50 to 100 un-bagged typical ears are selected from the first propagation area, and the typical ear row is selected from the ear line breeding area. Ears are mixed and threshed, or they are threshed according to the ear, and they are sent to different units as the original species of inbred lines for breeding or mating. In the third year: According to the second year's practice, the first panicle propagation area, the ear line breeding area and the inbred line original breeding area were set. Grading and continuous seed selection allow the existing inbred lines to be purified quickly. China Agricultural Network Editor