Screening And Genotypes Identification Of Low Potassium Tolerant Rice

Our country cultivated land area is expanding every year, rice producing areas in southern China appeared potassium deficiency or severe potassium deficiency in soil has reached more than50%of the cultivated land. Potassium has become one of the major factors limiting high yield and quality of rice. China is a potassium resource-poor country, which need to import large quantities of potash, but the prices is rising, rely heavily on imports of potash to solve our problems is not a feasible way. Thus, screening for low potassium tolerant rice genotypes which can adapt to the environment of low potassium, is an important way to solve potassium deficiency problem. In this research, we have screened490kinds of hybrid offspring parent materials and732kinds of Nipponbare/9311offspring for low potassium tolerant, and the low potassium tolerant varieties strongest and weakest of potassium absorption related genes are test. The purpose is to provide theoretical and technical support for the breeding of potassium-resistant rice in the south of our country, and promote grain production safety while reducing the cost of food production and reduce the adverse impact of agricultural production on environment. The main results are as follows:1. Law of effect on the rice growth in different K+concentrations Through hydroponics, the rice cultivate in8different concertrations of low potassium nutriend solution and complete nutrient solution to five-leaf stage. When K+concentration in the0-2mg/L condition, all rice materials growth are severely hampered, short, thin; when the K+concentration increased to3mg/L, its morphological indicators improved significantly among different varieties biggest difference; along with K+concentration further increase gradually the plants grow better, the growth differences of low potassium tolerant rice under conditions of complete nutrition rapidly becomes smaller; when the K+concentration up to20mg/L, the growth trend to improve plant growth slows.2. Comparison of low potassium tolerant ability of rice and screening of level1low potassium tolerant rice varietiesIn low potassium (3mg/L) nutrient solution and complete nutrient solution (40mg/L) conditions to five-leaf stage of growth period appropriate screening, the roots of the plant above ground is relatively dry weight, combined with the relative plant height, root length, fresh weight and potassium deficiency symptoms, etc. On the1222kinds of different rice were resistant to potassium capability classification,(level1is the most resistant to a low potassium, level4is low potassium sensitive). From Nipponbare/9311hybrids were screened four kinds of level1low potassium tolerant material, elect5varieties of level1of low potassium tolerant materials from hybrid rice parent material,239 varieties of level2of low potassium tolerant materials,507varieties of level3of low potassium tolerant materials,467varieties of level1of low potassium tolerant materials.3. Comparison of potassium content of different low potassium tolerant rice in leavesUnder conditions of low potassium, as different rice have different capabilities of potassium absorption and utilization, the potassium content in leaves is significant different. The ability of different genotypes of absorption and utilization of potassium are different. The low potassium tolerant genotypes are higher than low potassium intolerant genotypes in potassium content of leaves.4. Analysis of potassium-related genes in low potassium tolerant rice.With primers designed by11genes associated with potassium absorption to filter out24kinds of low potassium tolerant and intolerant genotypes by PCR, In all the material could be detected the target band of C2、 OsHKT4-eGFP and OsTPK-A, but not corresponding relationships with the ability of rice resistant to low potassium. The target band of OsKAT3、OsSKOR1、Pa2.1、OsKAT2、OsAKT4、AtKAT1、AtAKT1and OsHAK1are not detect in materials.8kinds of tolerance and intolerance low potassium material are testing by RT-PCR, C2、 OsHKT4-eGFP、OsTPK-A and OsKAT3were expressed in all materials. In four different genotypes, the expression of genes are different, but still not correlated with the ability of rice resistant to low potassium, the remaining genes not detected target band. The products of RT-PCR of OsKAT3by the4kinds of materials were sequenced. We found16differences in base site, compared with OsKAT3gene sequences of Nipponbare, the least different sites between low postassium tolerant genotype and Nipponbare, the more different sites between low postassium intolerant genotype and Nipponbare. These differences in base sites probably related to the ability of rice resistant to low potassium, which needs further study and verification.