CASE-STUDIES ON HIGH YIELDS OF PADDY RICE IN JIANGSU PROVINCE, CHINA .2. ANALYSIS OF CHARACTERS RELATED TO LODGING

To clarify lodging resistance of high yield examples, characters relat ed to lodging of Shan You 63 (F1 hybrid rice) with 965 gm-2 of a brown rice weight were analyzed. There were various factors for early lodgi ng regarding external morphological characters. The lodging index (a d istance between fulcra in 5 cm) at the 4th internode from the top (N4) at maturity was more than 200. High yield of Shan You 63 was obtained under quite dangerous conditions as regards lodging. The reason for i ncrease in the lodging index at N4 was low breaking resistance. This p henomenon could be explained by a high rate of translocation of non-st ructural carbohydrate (NSC) and total nitorogen (N) from the culm and leaf to ear, and an extreme decrease in dry weight per unit length of the portion lower than N4 at maturity. To consistently obtain a yield exceeding 965 gm-2 in Shan You 63, it is necessary to develop cultivat ion techniques to store more NSC, N and dry matter in the culm and lea f sheath and car.