Abstract:

【Objective】Lodging is one of the constraints to the integrated production target of high yield, good quality, high efficiency, ecology and security for rice. This study investigated the lodging resistance of super rice under different planting methods. It could provide a theoretical basis for rational use of planting methods and realization of “ten word” integrated target.【Method】By using two super rice cultivars Huaidao 9 and Ⅲyou 98 as materials and setting three planting methods of precision artificial transplanting with dry nursery middle and strong seedling (ATR), mechanical transplanting with small seedling (MTR) and direct seeding (DSR) in the rice-wheat cropping system in the lower Yangtze River, with lodging index as an indicator to measure culm lodging resistance, in the twenty-fifth days after full heading, the lodging resistance of the first basal internode (N1), second basal internode (N2), third basal internode (N3), fourth basal internode (N4) and main physical characteristics were studied. Furthermore, the correlation analysis between the lodging index, breaking resistance and main culm physical characteristics were studied.【Result】The culm lodging resistance of rice planted with different planting methods was significantly different. The lodging index of ATR was the lowest and culm lodging resistance was the best, while DSR was the highest and culm lodging resistance was the worst. The main reason for difference in the lodging index among different planting methods was the size of the breaking resistance. The breaking resistance of the 1st, 2nd, 3rd, 4th internode and plant height, gravity center height, culm diameter, culm wall thickness, dry weight of culm, dry weight of leaf sheath, dry weight of unit internode, length and fresh weight from basal internode to top, bending moment had
significant or very significant positive correlation, while with the ratio of gravity center height to plant height and internodes length showed a significant or very significant negative correlation. Compared to MTR and DSR, the main reasons for the breaking resistance increased and lodging index reduced of basal internodes of ATR were: The increase of the plant height was due to the increased internodes numbers, the increased length of panicle and 1st and 2nd top internode. However, the length of the 2-3 internodes in the basal stem which was apt to lodge was shorter than that of MTR and DSR. The culm diameter and wall thickness of every basal internodes were obviously increased, and dry weight of culm and sheath were larger, and the dry weight of unit internode was significantly increased, so the stem plumpness status of ATR was better. 【Conclusion】The optimal combination of some main culm physical characteristics of rice was different under different planting methods. The direct reasons for breaking resistance increased and lodging index reduced of ATR were short and thick basal internodes, large wall thickness and good culm plumpness status.

Key words: cultivation method, super rice, lodging resistance, lodging index, culm physical characteristics