Abstract: The newly released super high-yielding hybrid rice combinations, Yueza 122, Fengyou 428, Peiza 67, and the super high-yielding conventional cultivars, Guangchao 3 and Shengtai 1, were grown in both early and late seasons. The morphological characters of each population were investigated at the heading stage, and the data were analyzed by using ANOVY and other statistic methods. The plant ideal morphological characters at the heading stage were established as follows: 1) for the early-season cropping, 90–105 cm plant height; 11–12 tillers per plant; 35–40 cm length and 2.1–2.2 cm width of flag leaf; 46–50 cm length and 1.8–2.1 cm width of the second leaf from the top (L2); 59–64 cm length and 1.4–1.9 cm width of the third leaf from the top (L3); 7°–14°, 18° and 20°–33° for the ideal leaf angles of the flag leaf, L2 and L3, respectively; 2) for the late-season cropping, 90–100 cm plant height; 9–15 tillers per plant; 30–41 cm length and 1.8–2.0 cm width of flag leaf; 53–61 cm length and 1.3–1.8 cm width of L2; 52–58 cm length and 1.2–1.5 cm width of L3; 9°–19°, 15°–37° and 16°–49° for the ideal leaf angles of the flag leaf, L2 and L3, respectively. The main physiological characteristics of these varieties were also analyzed.

Key words: super high-yielding, morphology, ideotype, heading stage, South China, double cropping rice