Studies On Genotypic Difference Of Effect Of Potassium Fertilizer And Irrigation Mode On The Growth, Development And Yield Formation In Rice (Oryza Sativa L.)

In recent years, with the increase in rice yield, the lack of K in rice is much more serious , and this problem is becoming one of the most important factors which limit rice production. Although applying K fertilizer can solve this problem, the increase in cost of production and the limitation of the resource of K in China and the world make it unfeasible, since the exhaustion of this resource will be a severe obstacle to agricultural sustainable development. In addition, there are significant differences in K nutrition of rice between different genotypes. Whiles the production of some varieties increase as the application of K fertilization is carried out, that of others are stable or decrease. So the study and utilization of the rice genotypic difference in K nutrition to enhance the efficiency of K nutrition and improve adaptability to low K could be considered as an effective approach of solving the problem of lack of K in rice. Drought is another important factor effecting crop yield and one important measure towards increasing food production is enhancing the drought resistance in crops and adopting a water saving irrigation to increase efficiency of water utilization.Therefore, the research of the impact of K nutrition and irrigation mode on development and the formation of yield and the physiological and morphological characteristics of rice will be the important theory foundation and practical instruction to screen rice genotypes of low K tolerance and drought resistance. It will help us to solve the problem of potassium deficit and water shortage while increasing the yield of rice.Six rice genotypes popularly applied in production (two Indica hybrid composition:Liangyoupei 9 (G1) and Xieyou 9308 (G2); four Japonica rice varieties: Bing 0001 (G3), Bing0004 (G4), Bing 9904 (G5) and Huayu No.l (G6)) were used in this study. The impact and thedifference of genotype of K nutrition on rice development and the formation of yield andmorphological character and nutrient absorption were studied in different irrigation mode(including lowland and upland). The main results are summarized as follows:1.There are significant genotypic difference and effect on yield of rice under different K level andirrigation mode. K fertilizer helps to increase yield of rice, but the effect of yield increase isdifferent with different rice genotype. The effect of upland on rice yield is different with K leveland rice genotypes. From the result of this study: G1 is more adaptable to upland; G2 and G4are sensitive to K. fertilizer and upland, G3 is sensitive to K fertilizer and upland; G5 is notadaptable to upland and is sensitive to K fertilizer and lowland; G6 is tolerant to low K leveland adaptable to upland.2.There are different effects on the yield components under different K level and irrigation mode. K fertilization can increase the effective panicle number of genotypes which are sensitive to Kfertilizer, and the effect has more significance under lowland. The upland will significantly increase the effective panicle number of unit area of upland-tolerant genotypes and reduce thai of the genotypes which are not resistance to dry conditions, but there is a tendency of the effect of upland reduced by application of K fertilizer. There is significant effect of K level and irrigation mode on grain number per panicle of rice and there are significant differences among different genotypes. The effect of K fertilizer on grain number per panicle is contrary to the effective panicle number of unit area. The effect of K application and upland is the same on the effective panicle number and grain number per panicle of all genotypes on upland except Gl; The ripened grain rate (RGR) of Gl and G4 will greatly increase when K fertilizer is applied. The effect of K fertilizer on the other genotypes is different under different irrigation mode. Upland can significantly increase RGR of Gl and it also can significantly increase RGR of G2 without the application of K fertilizer, and RGR of G6 isn't significant with application of K fertilizer, but it will significant reduce the RGR of the rest genotypes. The upland will reduce the 1000 grain weight of all genotype, K fertilizer can increase 1000 grain weight of all the genotype and the effect is more remarkable on upland c3. K fertilizer can significantly increase the harvest index of rice, upland can significantly decrease the harvest index of rice; The effect of increase the harvest index of rice under K. level is better on upland than lowland. The response of harvest index of rice to K fertilizer and upland is that, G6 is the least sensitive, followed by G5, and G4 is very sensitive.4.K fertilizer can significantly increase plant height of rice. The most sensitive rice genotype in plant height response to K fertilizer is G3, followed by G2 and G5; The other rice genotypes are not sensitive. Upland decrease the plant height of rice; The most sensitive rice genotype of plant height response to upland is G4, followed by G2, and the other rice genotypes are not sensitiveo5.The effects of K fertilizer on basic internode length of rice are as follows: no significant effect for G3; the basic internode length of Gl and G5 can be significantly increase; the basic intemode length of G2 and G4 can be significantly decreased; The basic internode length of G6 is increased or decreased depending on the irrigation mode. The K fertilizer can significantly increase the diameter of the basis culm of G3. Application K fertilizer can significantly increase the diameter of the culm basis of Gl under upland condition and significantly increase the diameter of the culm basis of G4 under lowland condition. The effects of irrigation mode on the basic internode length of rice are as follows: upland did not affect basic internode length of G3 and G5; The upland without application of K. fertilizer significantly decreases the basic internode length of G2, G4 and G6, but it did not affect the basic internode length when K fertilizer was applied; The basic internode length of Gl will be significantly decreased when K...