Maize Genomics and Genetics 2025, Vol.16, No.3, 149-166 http://cropscipublisher.com/index.php/mgg 163 and management timing, thus limiting the large-scale continuous demonstration planting of new varieties. Late temperature recovery affects the appropriate sowing period. Spring sowing of fresh corn requires that the soil temperature at a depth of 5 cm is stable above 12 ℃. However, in some years, the spring warming is late, and the time for the open-field soil temperature to reach the standard is delayed. In order to seize the early spring planting window, the experiment adopted measures such as seedling transplanting and arch shed insulation, sowing and seedling raising in early March and transplanting in early April. However, for large-scale promotion, not all planting entities have the conditions for facility seedling raising. If the temperature rises slowly and sowing is forced to be postponed to late April or even May, the growth period of corn will be postponed to the hot and rainy summer. Not only will the flowering and pollination period be easily impacted by high temperature and drought, but the maturity and harvest period may also encounter the risk of autumn rain or early frost. The delay in the sowing period caused the planting time of different farmers' fields to be uneven, and the growth in the field was not synchronized, making it difficult to implement unified field management measures in time, reducing the uniformity and persuasiveness of the overall acceptance of the demonstration field (Guo et al., 2022). Labor shortage leads to inadequate management. The high-quality and high-yield cultivation of fresh corn requires high timeliness of field management. From seedling transplanting, seedling selection and seedling supplementation to topdressing irrigation, insect prevention and disease prevention, each link requires sufficient labor input. However, at present, there is a general shortage of labor in rural areas, and the contradiction of seasonal labor is prominent. There have been many cases of shortage of manpower during the trial demonstration. For example, corn needs to be top-dressed and soiled in batches during the jointing stage and the large bell mouth stage, but due to limited labor, some demonstration fields failed to complete these operations at the same time in the best period and had to postpone them, affecting the consistency of plant growth. For example, pests such as corn borers require timely and unified prevention and control at the early stage of larvae. When there is insufficient labor, it is difficult to apply pesticides to large areas of fields in a timely manner, resulting in the leakage of pests in individual fields. The lack of labor also limits the promotion of seedling transplanting, an efficient cultivation method. Some farmers give up seedling cultivation and switch to direct seeding because they have no help, which leads to further delays in the sowing period or uneven emergence of seedlings. It can be seen that the labor bottleneck makes it difficult to implement standardized and synchronized field management, weakening the actual effect of demonstration and promotion. Delayed field preparation affects continuous planting. Carrying out continuous demonstration planting requires that each field in the experimental base can be vacated, prepared and sown in time. However, in reality, the harvest of the previous crop and the progress of field preparation in different fields are often inconsistent. Some plots of land were harvested late in the previous season (such as winter wheat, green manure, etc.), missing the appropriate sowing period for early spring corn; some plots were unable to complete land preparation and sowing as planned due to excessively wet soil or untimely deployment of tillage machinery. In this demonstration and promotion, some farmers' plots failed to catch up with the unified sowing rhythm due to delays in the previous crop cleaning, and had to switch to other crops, affecting the integrity of the demonstration area. Continuous operation requires coordination among farmers in the region, but coordination is difficult in the early stages of promotion: some farmers hesitate and miss the best sowing window; some participate but are not well prepared, resulting in problems such as improper sowing depth or missing basal fertilizer, and late management is not standardized. These inconsistencies in timing make it difficult for the demonstration plot to achieve the ideal effect of simultaneous harvesting of ears, and field management cannot be fully standardized, which is not conducive to the centralized display of new varieties and supporting technical effects. 7 Concluding Remarks This study systematically evaluated the biological and agronomic traits of new varieties of fresh corn introduced in Linhai City, and screened out a number of varieties with excellent comprehensive performance. These new varieties have the common characteristics of uniform emergence, early maturity and high yield, resistance to lodging and stress, and excellent quality, and have adapted well to the ecological conditions of Linhai City. In the early growth period, the emergence rate and seedling rate of each variety were at a high level, and the seedlings grew robustly, laying the foundation for the final yield.
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