| Six wheat cultivars mainly planted in Henan province were used in thefield experiment to evaluate the stem morphological and mechanical properties andtheir relationship with lodging resistance. The regulatory effect of planting density onstem lodging resistance of wheat was tested, and the key management measures forimprovement of lodging resistance of stem and high yield of winter wheat werediscussed. The main results were as follows:1. The morphological characteristics and mechanical strength of stem basalinternode were closely related with lodging resistance of wheat varieties. Comparedwith the lodging varieties (Zhengmai004,Yanzhan4110and Yunong416), the plantheight, gravity center height, basal internodes length and percentage of basalinternod（e1+2）length in the total stem length of the lodging resisted varieties (Aikang58, Zhoumai22and Yunong202) significantly reduced, while the stem diameter, wallthickness, Culm mechanical strength and lodging resistant index significantlyincreased. Correlation analysis showed that there was very significantly negativecorrelation between culm lodging resistant index and the plant height, gravity centerheight and the2nd basal internode length, while there was very significantly positivecorrelation between the stem diameter and wall thickness of the2nd basal internode.It showed that varieties with high lodging resistance had coarser stem, thicker walland higher mechanical strength.2. The anatomical structure and physiological component had close relationshipwith the lodging resistance of wheat stem. The research showed that the lodgingresisted wheat varieties (Aikang58, Zhoumai22and Yunong202) had relativelyfewer small vascular bundles, more and thicker mechanical tissue cell layers, highersoluble sugar content and lower nitrogen content. Correlation analysis showed that thelodging resistance index had very remarkably positive correlation with the amount and thickness of the mechanical tissue cell layers as well as the content of solublesugar, and had very remarkably negative correlation with the amount of smallvascular bundles, while had no clear correlation with the amount of big vascularbundles. Small-amount of small vascular bundles, high-developed mechanical tissues,high-content soluble sugar and low-content N, all which could be used as importantindicators to breed lodging resisted wheat varieties.3. Planting density significantly influenced the features of wheat. With theincrease of planting density, the height of the wheat, the basal internodes length andthe percentage of basal internode（1+2）length in the total stem length increased, whilethe stem diameter, the wall thickness, the mechanical strength and lodging resistanceof the2nd basal stem decreased. It showed that in practice, the main reasons for theculm lodging varieties were that the length of the basal internodes extended and themechanical strength decreased. As the planting density increased, in the basalinternode of Yumai49-198and Zhengmai9694, the numbers of big and smallvascular bundles reduced; also the amount of mechanical tissue cell layers andthickness decreased; meanwhile the soluble sugar and nitrogen content lowered, all ofwhich led to the lowering of culm mechanical strength and lodging resistant index.From the results we concluded that, the stem quality and lodging resistance couldbe improved by using cultivars with relatively lower gravity center of height, shortbasal internode, and thicker stem with high-developed mechanical strength, and byproper cultivation measures such as improving the quality of the soil, sowing inproper time and rate, irrigating and fertilizing reasonably, improving the efficiency ofchemical control, preventing the insect disease and so on, reasonable communitystructure could be established. Therefore high-yield and high-efficiency wheat wouldbe realized. |
