Rice Genomics and Genetics 2025, Vol.16, No.4, 180-198 http://cropscipublisher.com/index.php/rgg 193 no rice false smut has occurred. The main drawback of both is that their resistance to rice planthoppers is average: "Xiushui 1717" needs to pay attention to preventing planthoppers, and "Jiahe 567" is highly susceptible to brown planthoppers, and their large-scale occurrence should be strictly prevented. This also reminds that when promoting these two varieties, green integrated prevention and control of planthoppers should be kept up. In terms of rice quality, "Xiushui 1717" rice quality reaches high-quality grade 3, with short and round rice grains, good transparency, and moderate soft and glutinous taste, which is a typical southern japonica rice flavor. It is reported that "Xiushui 1717" has won awards in the national japonica rice taste quality evaluation. "Jiahe 567" rice quality also reaches the national standard high-quality grade 3, with medium-long grain shape, low chalkiness, and good taste quality. In the 2022 Zhejiang Province late japonica rice regional trial, "Jiahe 567" taste score reached 74 points, ranking at the top. Therefore, the two varieties have both high yield and better quality, and are competitive in the market. In terms of promotion adaptability, "Xiushui 1717", as a continuous late japonica rice, is suitable for one-season late rice planting in Zhejiang and adjacent areas. Its growth period is moderate, suitable for connection with medium rice or wheat stubble. "Jiahe 567" is early maturing, resistant to high temperature and certain drought during the panicle neck filling period, suitable for single-season late rice in the plains of Zhejiang, and can also be used in double-season late rice seed production. It is worth mentioning that "Jiahe 567" has integrated the bloodline of multiple excellent strains of Jiaxing Academy of Agricultural Sciences during the breeding process, and has good adaptability. In the 2020-2021 regional trial in Zhejiang Province, 8 out of 10 pilot sites increased production, with an increase rate of 80%, and stable performance. In the 2021 production trial, all pilot sites increased production. These data show that Jiahe 567 has excellent performance under different ecological conditions and is considered to be a high-yield and stable variety that can be promoted throughout the province (Ding et al. 2023). Although "Xiushui 1717" does not have the outstanding yield increase rate of "Jiahe 567", it is stable and has outstanding stress resistance. It is also a variety that has performed well in multiple demonstration sites in the Yangtze River Delta. At the Shanghai Yangtze River Delta Japonica Rice New Variety Exhibition, "Xiushui 1717" was also rated as a "potential variety", further proving its comprehensive strength. By comparison, "Xiushui 1717" and "Jiahe 567" represent two directions of conventional late rice breeding: the former emphasizes plant robustness, good resistance, and strong stable yield; the latter pursues the limit of yield and excellent quality. The two complement each other and can serve regional grain production together. In terms of promotion, it is recommended to match them according to the planting system: "Jiahe 567" can be given priority in fields that need to be sown early and have extremely high yield requirements; "Xiushui 1717" can be selected in fields with general production conditions and hope for stable and reliable yield. The successful application of the two varieties has broken the stereotype that "conventional rice yield is not as good as hybrid rice" and reflects the great potential of modern conventional rice breeding. With the selection and breeding of more new lines, conventional rice is expected to further approach or even surpass the yield level of hybrid rice while maintaining high quality, which is of positive significance to ensuring food security and meeting consumers' demand for high-quality rice. 6.3 Correlation between varietal traits, management strategies, and yield outcomes Through the above analysis of typical varieties, it can be seen that the high yield of new rice varieties is the result of the interaction between the variety's own genetic characteristics and cultivation management. From the perspective of varieties, the key traits that determine yield include panicle-grain structure, plant height and stalk strength, fruit set rate and thousand-grain weight. Among them, the number of panicles and the fruit set rate jointly determine the number of grains per panicle, which is directly related to the yield; plant height and stalk strength affect lodging resistance, which in turn determines whether the effective panicles can be fully utilized; thousand-grain weight is related to the fullness of the grains, but there is little difference between the varieties in this study. Each new variety achieves the high-yield goal through different combinations of traits: hybrid rice relies on large panicles and many grains (such as "Yongyou 33" with 300+ grains per panicle) and a high fruit set rate, while conventional rice relies on a large number of panicles (such as "Jiahe 567" with 200 000 effective panicles/mu) and a high fruit set rate to achieve high yield.
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