种植密度对不同耐密夏玉米品种茎秆性状与抗倒伏能力的影响
利用暴雨大风后玉米倒伏情况，分析了增密过程中不同夏玉米群体植株形态与茎秆力学变异规律。结果显示，大风后随密度增加根倒率和茎折率显著增加；登海618的根倒率和茎折率显著低于浚单20。随着密度增加，玉米株高和穗位高增加，基部3-7节间均表现为节间伸长、变细，茎粗系数、穿刺强度、抗折力、压碎强度显著降低，两品种表现一致。相关分析表明，根倒率和茎折率与节间长度、株高、穗位高和穗位系数正相关，与茎粗、茎粗系数和茎秆力学三参数负相关。站秆率与倒伏率均与基部第3节间性状的相关性达到显著水平。与浚单20相比，登海618具有较低的节间长度、株高、穗位高、穗位系数和较高的茎粗、茎粗系数、茎秆力学，抗倒性能较强。
英文摘要:
In order to discuss the impact of increasing density on different density-resistant summer maize varieties (Denghai 618 and Xundan 20), using maize lodge after rainstorm and strong wind, this study analyzed the plant morphology, variation rule of stalks mechanics when the planting density was increased from lowing level (67500/hm2) to middle level (90000/hm2) and higher level (112500/hm2). The research result show that：after rainstorm and strong wind, the root lodging ratio and stalk break ratio were increased with the increasing of plant density; the root lodging ratio and stalk break ratio of Denghai 618 were significant lower than that of Xundan20. With the increasing of planting density of the two maize varieties, maize plant height the ear height were increased, basal internodes of 3-7th were longer and leaner, and stem diameter coefficients, the three stalks mechanics parameters (rind penetration strength, breaking-resistant strength and stalk crushing strength) were declined significantly. The correlation analysis result show that root lodging ratio and stalk break ratio were positive correlated to basal 3-7th internodes length, plant height, eat height and ear height coefficients, but negative correlated to internodes diameter, stem diameter coefficients and the three stalks mechanics parameters. The relation between 3rd internodes parameters and root lodging ratio and stalk break ratio ware reached significant level. Compared to Xundan20, the 3-7th internodes length, plant height, ear height and ear height coefficients of Denghai 618 were lower, and the internodes diameter, stem diameter coefficients and three stalks mechanics parameters were higher.
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