Effects Of Population Light Transmission On Stalk Strength And Lodging-resistance Of Maize

For solving lodging problem, this program investigted stalk mechanical and high density-tolerance mechanism of several different types of maize under different densities and shading. The main results were as follow:1.With increasing planting density and the severity of shade, the lodging of every cultivars has occurred to varying degrees. The difference between cultivars were significant. When planting density increased to above 8.25×10⁴plant hm^-2,the large area loding of ZD808 has occurred with lodging rate 77.1%,but the low lodging rate of the lodging resistant type CS1 was 3.7%.The response to light conditionos of varieties is different. The lodging rate of JK519 and ZD808 increased by 76.3% and 56.2%,but CS1 was only 16.7% under 30% shading degree compared with control.2.The changes of diameter and length of stem were not significant from silking to dough stage. With increasing planting density, the light transmission of era layer and half of under ear layer significantly decreased and the changes of diameter and length of stem were significantly,the ratio of dry weight to length of internodes was reduced significantly. The significance exist between culvitars. The change of stem internode length and diameter of resistant varieties were not significant with the density increaseing, and the thin planting variations in the high density conditions prone to lodging.3.The rind penetration strength and stalk crushing strength is closely related with the lodging of corn. Correlation analysis showed that highly significant negtive correlations existed among lodging rate, stalk rind penetration and crushing strength. The stalk rind penetration and crushing strength of CS1 were significantly higher than ZD808 under high planting density,it can be used as a measure of corn stem lodging resistance quantitative indicators.4.In the high density conditions, light transmission rate of population was significantly reduced. The content of compounds in the stem decreased, Light transmission rate of ear, ear of 1/2 were closely correlated with compounds content in stem. Soluble sugar content of stalk in maize was significantly correlated with stalk rind penetration and crushing strength in the silking stage, less relevant in the dough stage. The content of stem cellulose and lignin in the stem had significantly or highly significantly correlation with stalk of strength at all stage. Correlation analysis showed that the semicellulose content in the stem had no effect on stem strength.It can be drawn that the stem soluble sugar content play an important role for stem strength,the content of stem cell wall material of structural composition of stem cellulose and lignin had a decisive effect on stem strength in the whole growth period.5.Light transmission rate of ear,ear of 1/2 and base has very significant positive correlation with internode diameter, On the contrary,has significant negative correlation with lodging rate and the correlation coefficient becomes smaller, this change was consistent with the correlation coefficient betwenn light transmission rate of ear,ear of 1/2 and base and puncture strength .CS1-resistant varieties of compact density and the shading in the high density conditions, the puncture strength and crushing strength were significantly higher than that of Sparse large panicle ZD808; field lodging rate lower; each species occurs in lodging tasseling silking , when the density increased to 82,500 / hm² time, ZD808 is a major area lodging, lodging rate was 77.1%, while the CS1 on the density of reaction is not sensitive,with population density increasesing, barren stem percentage and lodging was small.6.This experiment showed that the yield of different type of maize under natural conditions has a little difference but significant.Shading treatment showed that the yield of maize were singnificantly decreased,and with increasing shade,the yield decreased significantly. Meanwhile, The corn harvest spikes,single grain number and grain weight were significantly decreased with the shading increase. Density of each species under different yield differences have reached a significant level.In summary, the shading and density experiment, more systematic study of the light distribution Maize stem agronomic traits of corn, mechanical properties and chemical composition of compared density tolerance of maizevarieties in different light Response to the weakening effect, the theory provides a basis for corn lodging.