水稻穗著粒密度之研究I.穗著粒密度類型之分類、預測模式之建立及其相關性狀之探討

Abstract

Using 34 rice cultivars/lines as materials, the principal component analysis was performed to elucidate the relationships between the panicle density parameters and its 10 related characters. Results showed that the first principal component (Z1) was mainly concerned with the length factor, the primary branch factor and the total number of spikelets per pancile; The second principal component (Z2) was largely due to the pancile weight, the primary branch factor and the total number of spikelets per panicle; The third principal component (Z3) was mainly associated with the length of rachis, the number of primary branches, the number of secondary branches and the ratio of the total number of spikelets of secondary branches and the total number of spikelets per panicle; while, the fourth principal component (Z4) was mainly performed by the pancile length, the number of primary branches and the average number of spikelets per primary branch. The relationships between the four principal components and panicle density parameters, evaluated by two different methods K (Number of spikelets/Total length of rachis and primary branches in cm) and L (Number of spikelets/10cm panicle length), were established by stepwise regression analysis method, A total eight equations were obtained, respectively. Among them, four for panicle density parameter K and two for panicle density parameter L, their coefficients of multiple determination were very high (＞0.84). Equations, K2 (=0.918Z1-0.215Z3, R^2=0.888) and L3 (0.808Z1+0.374Z2-0358Z4, R^2=0.920), estimated by the use of the least principal components, respectively, were selected as the best models for predicting the panicle density rice. Moreover, from the relationships between panicle density parameters and its related characters, it was found that the higher panicle weight, average number of spikelets of primary branches, secondary branch factor and the total number of spikelets per panicle. the higher their pancile density. While, the panicle length, length of rachis and the sum of the length of primary branches were down lower as their pancile density toward high. From the scatter diagram for the related characters of panicle density, 34 cultivars/lines, belonging to seven groups, could be classified into four different panicle density types: very low, low, middle and high panicle density type.