Journal of Taiwan Agricultural Research

Author:Lit-Fu Chan, Meng-Li Wei, Chun-Tang Lu and Hsiu-Ying Lu

Abstract:

Leaf area of rice plant can be rapidly estimated by the non-destructive measurement of leaf dimensions. A coefficient of K_LÎW is required when the product of leaf length (L) and maximum width (W) are used for the measurement. Furthermore, the coefficient of K_L multiplied by leaf length alone can also be used to estimate the area of both expanded and non-expanded leaves. The objective of this study was to investigate the genotypic variation of these coefficients for estimating leaf area in rice. In the first experiment carried out in 1999, 50 japonica rice varieties (including 35 varieties bred in Taiwan and 15 collected from other origins) were used as materials. The distribution of K coefficients is normal for either Taiwanese or introduced varieties tested. However, the genotypic variation of K coefficients of Taiwanese varieties was smaller than that of introduced varieties. For Taiwanese varieties, the average K_LÎW was 0.70 ± 0.01 and K_L was 0.90 ± 0.09; while those of introduced varieties were 0.72 ± 0.03 and 0.86 ± 0.14, respectively. The genotypic variation of K_LÎW was smaller than that of K_L. A positive correlation between K coefficients and leaf shape (ratio of W/L) was observed. However, the K values were not significantly affected by leaf shape for Taiwanese varieties since the W/L ratio of all varieties was close to 0.04. An overall average K_LÎW value of 0.70 was therefore derived to predict leaf area of Taiwanese japonica rice varieties irrespective of the genotype considered. To test the prediction accuracy of this common K_LÎW, 11 randomly selected rice varieties were used as materials in a second experiment carried out in 2000. The results showed that all the difference between the estimated and measured leaf area was less than 5 per cent.

Key words:Rice, Leaf area, Genotypic variation, Distribution test, Leaf shape

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