在玉米制种生产中,弱小苗现象乃常见之事,但是,由于这类弱小苗在群体中对光能、土壤水分、养分的吸收受到抑制,表现为生长迟缓、发育不良、植株弱小,使植株个体的活力和抗逆性以及生物产量等明显降低。弱小苗与正常植株相比较,调查表明:株高降低50%以上,雄穗分枝少70%,花粉败育率达5%～10%,雌穗花丝明显减少,有的甚至不吐花丝,成穗率减少50%,穗粒数减少60%～75%,千 In the production of maize seedlings, weak seedlings phenomenon is common, but because of these weak seedlings in the population of light energy, soil moisture, nutrient absorption is inhibited, manifested as slow growth, poor growth, plant weak, so that Plant vitality and stress resistance as well as bio-yield significantly reduced. Weak seedling compared with normal plants, the survey showed that: plant height reduced by 50% or more, tassel branches less 70%, pollen abortion rate of 5% to 10%, significantly reduced the number of female filaments, and some do not spit silk, Spike rate decreased by 50%, 60% to reduce the number of grains per spike, 1000