Study On Head Smut Resistance Of Semi-exotic Populations Using CIMMYT Maize Resource

The head smut is a main corn disease in the world. It significantly affect on production losses so cultivating resistant varieties have became a major work .According to the shortage of resistant germplasm, introduction and application of exotic germplasm is a key way to solve the straitness of genetic background of head smut resistant in corn breeding in China. The resistances of improved inbreds selected from semi-exotic germplasm by CIMMYT and inbreds in Heilongjiang were identified by the method of artificial inoculation under field conditions. It would give a reference for introducing and utilizing CIMMYT germplasm. The main results were summarized as follows:(1) The highest incidence rate population was Pob101, and the lowest incidence rate population was Pob46.The incidence from Pob46, Pob45, Pob69, Pob70 to Pob101 was gradually higher and resistance was lower.(2) The incidence rate of combinations between Pob70 and test varieties were higher than others, and the incidence rate of combinations between Pob45 population and test varieties were lower than others. The incidence rate of combinations is gradually lower from Pob70, Pob69, Pob46 and Pob45.(3) The numbers of improved inbred line of middle resistance and above accounted for more than a half and the high resistance accounted for 35.9%, so it would enhance head smut resistance to introduce CIMMYT germplasm in Heilongjiang province.(4) The resistances of K10 and 444 improved inbreds from semi-exotic high resistance CIMMYT germplasm Pob46 would significantly enhance, so the head smut resistances of Tangsipingtou and other susceptible germplasm would improved by introducing Pob46.(5) The head smut resistance of susceptible Pob101 was bad, and crossed with He344 were poor .So Pob101 is not used to improve head smut resistance in Heilongjiang province.