Study On The Differences Of The Lodging Resistance In Culm Morphology&Physiology Between Rice Hybrids With Higher Biomass

Abstract:This paper focused on the relationship between culm morphological and physiological traits and lodging resistance with three typical representative super hybrid rice(Zhunliangyou527、Y1and Liangyoul128) and two rice hybrids with higher biomass combinations(6303S/R292and guangzhan63S//R527/0293), based on this study, further experiment of the differences in the content of plant endogenous hormones GA1and IAA and nitrogen application rate,chemical regulation on lodging resistance and yield in rice hybrids with higher biomass was conducted. The main results were as follows:1. The bending moment of the basal internodes in rice hybrids with higher biomass increased due to its heavier panicle and higher plant, but the breaking resistance was also obviously increased and it resulted in that the lodging index had no change comparing with medium panicle type of rice. The reason for the breaking resistance increase in culm morphology and physiology were:The increase of the plant height originated from the sixth internode other than from the first and the second internode. Rice hybrids with higher biomass had greatly increased the diameter, wall thickness and dry weight of basal stems, the content of total Silicon and Potassium, coarse fiber in culm and leaf sheath.2. Positive effect existed between the content of plant endogenous hormones GA1and IAA and the first internode, the correlation was found between the first internode and the content of endogenous hormones IAA was significant (r=0.764**).3. As the nitrogen application rate increased form0kg/hm2to180kg/hm2, the lodging resistance force of rice hybrids with higher biomass decreased but their lodging index increased gradually. Rice hybrids with higher biomass had increased the plant height, diameter, wall thickness and dry weight of basal stems, and plant height, dry weight of basal stems were significantly increased in7.39%-14.36%,35.04%-57.53%. But descended the content of total Silicon and Potassium, coarse fiber in culm and leaf sheath. Rice yield was extremely significantly increased19.62%-27.12%.4. The treatment by spraying Prohexadione calcium (Lifengling) decreased significantly the content of plant endogenous hormones GA1and IAA, and the content of GA1and IAA reduced29.78%、23.80%; shortened the first, the second and the third basal internodes and thickened their stems and increased weight of basal stems and the content of total Silicon and Potassium, coarse fiber in culm and leaf sheath to some extent. Resulting in the lodging resistance force of basal stem internodes significantly was increased and lodging index was decreased. It was also found that, compared with the control, had not negative effects on grain yield.