摘要：In this study, 60 direct seeding rice varieties with different genotypes were used as experimental materials. Through long-term submergence treatment (7 d and 14 d), the responses of different genotypes to submergence stress were compared in germination and seedling emergence, stem, leaf and root elongation, starch and other storage material consumption. The results showed that there were significant differences in submergence tolerance of different genotypes at the germination and seedling stage. Through further analysis by statistical methods such as correlation analysis, principal component analysis, weight comprehensive evaluation and cluster analysis, 60 varieties could be divided into four categories: strong submergence tolerance, medium submergence tolerance, weak submergence tolerance and submergence sensitivity, while 6, 22, 4 and 28 varieties were screened respectively. After 14 d and 4 cm deep submergence, more than 78.1% of rice seeds could germinate, and the average plant height and root length could reach more than 11.99 cm and 9.66 cm respectively. The dry matter mass, starch content and soluble sugar content per plant were significantly higher than those of other tolerant types. The average coleoptile of the sensitive type was only 3.17 cm, and the radicle had little elongation. The evaluation and variety screening of submergence tolerance of different genotypes of direct seeding rice at the seedling stage can provide a theoretical basis for further clarifying the mechanism of rice submergence tolerance, screening suitable direct seeding varieties and cultivating special varieties of direct seeding rice.
