Abstract: Under field condition,effects of shading on stalk mechanical and rind penetration strength were investigated using three maize cultivars differing in lodging resistant ability,i.e.JK519,CS1 and ZD958.The results showed that JK519 with a large spike under thinned planting density was sensitive to shade stress,its plant height and ear height were decreased significantly,and LAI(leaf area index) was also declined.With lower internodes diameter and shorter internodes length at basal stem,the ratio of dry weight to length of internodes was reduced in shading condition.The rind penetration strength of JK519 was decreased by 36.4% and 66.0% under a shading intensity of 30% and 60%,respectively;and field lodging seriously.However,with a shading intensity of 30%,CS1(a compact and tolerant to high density type) was declined slightly in the ear height,LAI and internodes diameter,and its rind penetration strength was only decreased by 5.9%.The rind penetration strength was decreased obviously by 60 % shading intensity,lodging heavily.Meanwhile,the finally maize yield,the number of harvest ear and grain per ear,and weight of 1 000 kernels of three maize cultivars were decreased significantly with increasing shading intensity.The 30% shading intensity should be definite as an appraise and selection condition of the mechanical strength of maize high yield and lodging resistance.

Key words: Maize (Zey mays L．), Shading, Stalk, Rind penetration strength, Yield

CLC Number: 

• S513．01