Rice Genomics and Genetics 2025, Vol.16, No.4, 180-198 http://cropscipublisher.com/index.php/rgg 181 al., 2024). For example, the water-saving and drought-resistant rice series such as "Hanyou 73" have been promoted in more than 10 million mu of land nationwide and won the National Science and Technology Progress Award, reflecting the advantages of new varieties in efficient resource utilization and stress resistance. This study sorted out the types and distribution of newindica-japonica hybrid rice and conventional late japonica rice varieties displayed in the demonstration base in Dahao Village, Jiashan, and classified and introduced the characteristics of the main participating varieties; starting from plant morphology and growth and development indicators, the growth traits and yield performance of the new varieties were analyzed, including plant height, tillering and ear formation, panicle-grain structure, fruit set rate, 1 000-grain weight and other indicators; the physiological resistance and adversity adaptability of the new varieties were evaluated, such as disease and insect pest resistance, lodging resistance, fertilizer tolerance, and aging status at maturity; the ecological cultivation techniques used in the demonstration base were summarized, including the matrix seedling raising machine transplanting mode, controlled-release fertilizer "one base and one topdressing" fertilization and green prevention and control measures, and their effects on the production benefits of new varieties; on this basis, typical representative varieties were selected for case analysis, the comprehensive performance of different types of varieties was compared, and the relationship between variety traits and cultivation management and yield was explored. This study aims to clarify the unique growth and stress resistance advantages of the new variety and its interactive effects with supporting cultivation measures, provide a scientific basis for the selection and large-scale promotion of excellent rice varieties in the region in the future, summarize the successful experience of the demonstration base in Dahao Village, Jiashan, in order to promote the establishment of a regional agricultural green yield-increasing technology system. 2 Classification and Distribution of New Rice Varieties 2.1 Types of varieties: indica-japonica hybrids and conventional late japonica rice The Dahao Village Demonstration Base in Jiashan concentrated on displaying two types of new late rice varieties, indica-japonica hybrid rice and conventional late japonica rice. Among them, indica-japonica hybrid rice is a hybrid advantage variety selected through hybridization between indica and japonica subspecies, with the characteristics of high yield potential and wide adaptability (Zhou et al., 2020). For example, the "Yongyou" series of indica-japonica hybrid rice is composed of indica sterile lines and japonica restorer lines, which fully exerts the hybrid advantages between subspecies and shows high and stable yield in the Yangtze River Delta region. "Yongyou 33" is one of the representative varieties. Conventional late japonica rice refers to late rice varieties among japonica rice varieties that have not been hybridized and bred by conventional breeding methods. They usually have shorter rice plants, a late maturity period, better rice quality and resistance, and occupy an important position in the late rice production in the lower reaches of the Yangtze River. For example, the "Xiushui" and "Jiahe" series are representative varieties of conventional late japonica rice in Jiangsu and Zhejiang. Among the 19 new varieties displayed in this demonstration base, there are 9 indica-japonica hybrid rice and 10 conventional late japonica rice. By classifying and displaying hybrid rice and conventional rice varieties, it is helpful to intuitively compare the differences in growth performance and adaptability between the two types of varieties, and provide a basis for the promotion of different types of varieties. 2.2 Demonstration area and spatial arrangement The demonstration base adopts a layout mode combining "centralized display, small area trial + large-scale demonstration". In the display stage, each new variety is planted in a small area of about 1 mu, and the total display area of 19 new varieties is about 20 mu. Each display area is arranged in the same field, and the cultivation management is unified to fairly compare the trait differences and yield performance between varieties. Based on the display and screening, the base carried out large-scale demonstrations of 5 new varieties with excellent performance, including 2 indica-japonica hybrid rice (91.78 mu of "Yongyou 33" and 10 mu of "Jiangliangyou 7901"), and 3 conventional japonica rice (7.51 mu of "Xiushui 1717", 14.83 mu of "Jiahe 567", and 8.65 mu of "Xiushui 1813"), with a total demonstration area of about 133 mu. These demonstration plots are located in the core area of the base, which is convenient for mechanized operation and field observation (Figure 1).
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