Studies On Genetic Principles Of Wheat Traits Relevant To Nitrogen And Phosphorus Efficiency

Using model â…¡ of Griffng Diallel Cross Method 2, eight wheat genotypes with different uitilization efficiency of nitrogen and phosphorus were selected to study genetic principles of wheat traits relevant to nitrogen and phosphorus efficiency. All seeds were divided into two parts: one part were planted in normal environment with fertilizer, the other were planted in starving environment without fertilizer. In maturity, total nitrogen and phosphorus concentration of grain, leaf and stem were determined .NUE and PUE were also calculated and then utilization efficiency of nitrogen and phosphorus was calculated. At the same time, the correlation between total nitrogen and phosphorus concentration of different organs and some important agronomy traits was studied. During data analysis, interaction of combining ability with environment and genetic model were analased by methods brought forward by D.singh and Heman's diallel cross analysis. Some genetic parameters were also estimated.Of all the effects of 8 traits, additive effect is smaller, but environmental effect or non-additive effect or interacton between non-additive effect and environment is the major effect, which makes these traits easy to be affected by environment, their very low H2N(%) and not suited to be selected in earlier generation. Stability of some traits for GCA is lower(under 50%), such as phosphorus concentration of leaf and stem, and PUE. But stability of other traits for GCA is much higher, which is above 60%. Stability for SCA, only that of nitrogen concentration of grain is much higher, that of other traits is lower. Except phosphorus concentration of leaf and PUE, stability of other traits for SCA is lower than their stability for GCA.The results showed that inheritance of nitrogen concentration of grain fit additive-dominance model in normal environment, but fit additive-dominance- epistasis model in stress; the inheritance of nitrogen concentration of leaf had epistasis without dominance in normal environment, but fit additive model in stress; the inheritance of NUE had epistasis without dominance, but fit additive- dominance-epistasis model in stress; the inheritance of PUE fit additive -dominance- epistasis model in two environments. These results showed that genetic control of some traits under two conditions were different, which may result from effect of environmental conditions on gene expression.Analysis of correlation showed the correlation coefficient of nitrogen and phosphorus concentration of leaf in normal environment, nitrogen concentration of leaf in normal and stressful environment, nitrogen concentration of leaf in normal environment and phosphorus concentration of leaf in stress, phosphorus concentration of leaf in normal environment and nitrogen concentration of leaf in stress, phosphorus concentration of leaf in normal environment and in stress, nitrogen and phosphorus concentration of leaf in stress are significant, that of others are not significant.At last, major problems in current genetic research of plant nutrition, parent evaluation of traits relevant to nitrogen and phosphorus efficiency, the principles of selecting parents for crossing and their offspring selection, stability and estimation of combining ability of combining ability, and so on, were discussed.