2019 Volume 88 Issue 1 Pages 18-26
Resistance against wind-caused cane-top breakage is one of the important characteristics in sugarcane breeding in Japan, and it has been evaluated based on the breakage incidence in the field. However, a more reliable evaluation method is required because many unpredictable factors affect the breakage incidence. We previously found that the bending moment at breaking of the growth ring located about 50–60 cm below the highest dewlap showed a correlation with the breakage incidence in the field, suggesting it could be one of the candidate indexes for the resistance. In the present study, to verify the applicability of the bending moment at breakage as the index, we assessed its seasonal variation and varietal differences. The bending moment at breaking, section modulus and bending stress of 8 sugarcane clones were measured 3 times during the active growth stage. Measured bending moment at the breaking of each clone showed positive correlations between each measurement, and relative order among the clones was maintained. Result of the measurement of the section modulus and the bending stress indicated that the factor that mainly contributed to the high bending moment at breakage varied with the clone. In conclusion, the bending moment at breaking could be measured in a reproducible fashion, indicating that it was one of the useful indexes to evaluate the resistance against wind-caused cane-top breakage.
