Rice Genomics and Genetics 2025, Vol.16, No.4, 180-198 http://cropscipublisher.com/index.php/rgg 187 resistance of new varieties through semi-dwarf breeding and other means. Most new varieties remain upright during maturity and show good lodging resistance. For example, "Xiushui 1717" is a medium-dwarf variety with thick stems. It did not lodge under the continuous rainy conditions of the typhoon in northern Zhejiang in 2021. "Jiahe 567" is less than 1 meter tall, with short and tough internodes at the base. It did not lodge during the typhoon season in northern Zhejiang in 2021, indicating that it has strong lodging resistance. Although the hybrid rice "Yongyou 33" is relatively tall, its stems are elastic and its root system is well-developed. It did not lodge in this demonstration field, effectively supporting large panicles and heavy loads. Some new varieties such as "Jiafengyou 121" also show good lodging resistance. Relatively speaking, some varieties have insufficient lodging resistance. For example, the stems of "Zhejingyou 4" softened and lodged in the later stage of maturity, and it was judged to be unsuitable for local promotion; "Zhehangyou 220" had poor lodging resistance in the later stage due to its too compact plant type and high height. In general, conventional late japonica rice varieties generally have good lodging resistance due to their short plants; the lodging resistance of indica-japonica hybrid rice varieties varies from variety to variety and requires specific analysis. The application of semi-dwarf genes in breeding has enabled many new varieties to have a higher lodging resistance foundation (Teng et al., 2021). However, cultivation measures are also important. For example, mechanized cultivation methods have a significant impact on the lodging resistance of rice plants. A study compared the stem characteristics of varieties under different cultivation methods and found that pot seedling machine transplanting can shorten the internodes at the base of rice, thicken the stem wall, and increase the dry weight, thereby significantly improving the stem's bending resistance and bending moment resistance and reducing the lodging index. The matrix seedling machine transplanting method used in this demonstration belongs to this category, which helps new varieties to fully exert their lodging resistance potential. On the other hand, the fertilizer tolerance of new varieties (i.e., the response to high nitrogen fertilizer input) varies significantly among different varieties. Varieties with good fertilizer tolerance will not grow vigorously even if they are fertilized too much, and are not prone to lodging in the later stage; while varieties with poor fertilizer tolerance will easily lead to excessive vegetative growth and loose stem tissue once excessive nitrogen fertilizer is applied, resulting in lodging or late maturity. "Yongyou 33" requires control of late fertilization in management because if there is too much nitrogen fertilizer in the late tillering stage, it will increase the risk of rice planthopper damage and reduce lodging resistance. "Xiuyou No. 6" has dark leaves and is less tolerant to fertilizer. If fertilizer is applied too heavily, the stems will grow too long and easily fall over. Therefore, measures such as "reducing weight, early sowing, and sparse planting" should be taken to enhance lodging resistance for this type of variety (Xing et al., 2017). In contrast, "Jiafengyou 121" has better lodging resistance, does not react excessively to fertilizer, and can still maintain upright under fertilization conditions, showing good fertilizer tolerance. "Jiahe 567" has medium to weak fertilizer tolerance. When nitrogen fertilizer is too heavy, the field maturity phase is poor in the later stage, and it is also easily damaged by borers and leaf rollers. Therefore, it is required to sow and control fertilizer appropriately early in cultivation to prevent lodging due to greed. New varieties are generally better than old varieties in lodging resistance and fertilizer tolerance, but high-yield varieties require more meticulous management to avoid the hidden danger of lodging caused by their high biological yield. By selecting and breeding semi-dwarf and thick-stem varieties combined with scientific fertilization, high yield and lodging resistance can be achieved in synergy (Wang et al., 2022). The practice of this demonstration base has proved that under the conditions of reasonable control of fertilization level and supporting mechanized cultivation, none of the new varieties suffered serious lodging, which provides confidence for subsequent large-scale promotion. 4.3 Senescence and consistency of grain filling The aging rate of functional leaves in the late growth period of rice and the consistency of grain filling will directly affect the yield and quality. Varieties with strong tolerance to late premature senescence have a longer photosynthetic time during the grain filling period, which is conducive to full grain filling. If the variety has "premature senescence", that is, the leaves turn yellow too early, it may lead to insufficient filling stamina, unfull grains or even an increase in barren grains. This demonstration comparison found that different new varieties have obvious differences in leaf color change speed and filling synchronization during maturity. The overall
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