阴湿环境对玉米杂交种生长发育特性的影响

Effects of shade-humid environment on the growth characteristics of different maize(Zea mays) hybrids

比较了在人工遮光增湿环境和自然环境下18个玉米杂交种生长发育特性的差异，研究了阴湿环境对玉米杂交种生长发育特性的影响．结果表明：遮光增湿环境使空气湿度比自然环境增加15．0％～16．4％，土壤湿度增加27．0％～78．4％，光照强度降低72．9％～77．9％，光量子减少72．8％～79．6％，差异均达显著或极显著水平，但不影响环境温度．阴湿环境导致玉米植株第7叶宽、有效功能叶数、成株叶片数、雄穗分枝数、茎粗、株高、穗位高、穗长、穗粗、穗行数、行粒数、百粒重和单株粒重13个性状表现为负向变异（表型值变小），其中单株粒重降幅达72．3％，株高降幅7．1％，其余性状降幅介于14．8％～53．8％之间；第7叶长、第7叶长宽比、散粉至抽丝间隔天数（ASI）、小斑病指数和纹枯病指数等5个性状表现为正向变异（表型值增大），分别增大39．8％、80．5％、114．3％、73．0％和54．8％．用ASI、雄穗分枝数、成株叶片数、株高、单株粒重、小斑病指数和纹枯病指数7个性状计算出的综合耐阴湿系数作为玉米杂交种耐阴湿鉴定的指标，具有一定的可靠性，且简便易行．运用该指标可将18个杂交种划分为耐阴湿性强、耐阴湿性中等和耐阴湿性弱3类．

The growth traits of 18 maize hybrids were studied in natural and artificial simulation shade-humid environments. Significant differences were observed between the natural and shade- humid environments, and the air relative humidity in the shade-humid environment increased 15.0% -16.4% , the soil moisture increased 27.0% -78.4%, the illumination intensity decreased 72.9%-77.9% , and the quantum decreased 72.8% -79.6%. Shade did not affect the ambient temperature. The 7th leaf width, effective functional leaves, plant total leaves, tassel branch num- ber, stem diameter, plant height, ear height, ear length, ear diameter, rows per ear, kernels per row, 100-grain mass and grain yield per plant under the shade-humid environment showed negative variations （reduction in phenotypic values）, with the grain yield per plant and plant height being reduced by 72.3 % and 7.1% respectively, and the declining changes of the remaining traits rang- ing from 14. 8% -53.8%. However, the 7th leaf length, 7th leaf length-width ratio, anthesis to sil- king （ASI） duration, southern leaf blight （SLB） index and sheath blight index showed positive variations （increase in phenotypic values） , with increases by 39.8% , 80.5% , 114.3% , 73.0% and 54.8%, respectively. The comprehensive shade-humid-tolerant coefficient calculated from the seven traits of ASI, tassel branches, plant total leaves, plant height, individual grain yield, south- ern leaf blight and sheath blight index could be easily and reliably used to evaluate the shade- humid-tolerant ability of the maize hybrids. According to this coefficient, the 18 hybrids could be classified into three categories, strongly-resistant, moderately-resistant and weakly-resistant to the shade-humid environment.