Study On Plant Lodging Resistance Of Mianhui725 Series Rice Varieties

Using check variety ?you 838 in national uniform trials of china as a control, four high yield hybrid rice varieties derived from Mianhui 725, including ?you 725,Gangyou 725, Jinyou 725 and Yixiang 725, which were used to research plant lodging resistance and its relationship with stalk physical characteristics, plant stalk microsurgical anatomical structure and chemical composition, chlorophyll content and change law of flag leaf,variation regularity of photosynthetic parameters of flag leaf,dry matter accumulation and transport characteristics of plant in different growth stages,then correlation analysis were taken. The experiment results showed as follows:1. The plant height of a series of rice varieties derived from mianhui725 increased mainly in the upper internode and ear length, the basal internode length had no significant difference compared with the control variety. Stalk bending moment increased and the basal internode breaking resistance was obviously improved, the increase of the latter is greater than the former, ensure mianhui725 series varieties lodging index was significantly lower than the control variety ?you 838. Through the regression equation of stalk basal internode characters and breaking resistance, the main reason of mianhui725 series varieties with large bending force is thickening the stalk basal internode. The basal internode diameter, thickness and cross sectional area were significantly increased compared with the control variety, and there was no significant difference between the basal internode length and control variety.2. The varieties vascular bundles area, vascular phloem area and vascular xylem area of different internode of mianhui725 series were significantly higher than control variety ?you 838, the stalk epidermis and mechanical tissue arranged regular and closely, the position of small bundles is on the outside. That show that mianhui725 series rice varieties with excellent vascular system, effectively improved the stalk material transportation system, further improve the lodging resistance of rice plants; the cellulose content of mianhui725 series rice is lower than control variety ?you 838, but the advantage of high internode cellulose content significantly. Mianhui725 series ricevarieties stalks lignin content is generally higher than that of the control varieties and the lignin content of element N2, N3 and N4 stalk internode had little difference. Ash content increased can significantly improve the amount of material storage of mianhui725 series rice varieties culm internodes, but different varieties increased effect varied with varieties.3. Leaves chlorophyll content of mianhui725 series hybrid rice varieties was decreased in the process of senescence. Before 13 days after heading, there is little difference between chlorophyll content of control varieties ?you 838 and mianhui725 series rice varieties, then the chlorophyll content of control varieties had a sharp decline and reach minimum values in 19 days after heading, which significantly lower than mianhui725 series rice varieties; The net photosynthetic rate of the tested rice varieties was in a downward trend, the trend of stomatal conductance and intercellular CO2 concentration are close to transpiration rate. Comparing with the control variety ?you838, the net photosynthetic rate decreased slowly when after heading 16 days to 19days(period of the strongest leaf photosynthesis) of mianhui725 series rice varieties,with higher intercellular CO2 concentration to meet the supply of CO2 play a certain role in maintain a high photosynthetic capacity. The above shows that photosynthesis of mianhui725 series rice varieties after heading and during flag leaf senescence is more stable, the higher photosynthetic activity and longer photosynthetic function duration could still be ensured after the heading for a longer period of time.4. The yield of mianhui725 series rice varieties were significantly higher than?you 838, the average increased yield was 8.15%.Because of vegetative organs accumulated the dry matter quickly, effectively and largely, plant had excellent characters of large dry matter accumulation. In order to ensure panicle(sink capacity) to accumulate dry matter,higher levels of output rate and conversion rate prompted dry matter of plant stalk, leaf and leaf sheath began to transport to grains.These results show that dry matter accumulation and transfer system of mianhui725 series rice varieties were better than?you 838, and have advantages of more powerful yield storage capacity and higher biomass.