Studies On Combining Ability And Heterosis Between Temperate And Tropical Maize Populations

The narrower genetic background is the first constraint restricting the maize (Zea Mays L) breeding efforts in China. The approach to solve this Problem is to enhance and improve the germplasm,based on heterotic groups and patterns. Genetic diversity research has been conducted for inbred lines, but not yet for ovps, populations and synthetics with genetic background. Design with NCII method. The 20 populations were evaluated based on GCA and SCA effects. The main results are summarized as follows:1. The evaluation for the 20 populations measurement crossed comprehensive performance. The results shows that tropical and temperate populations that the measurement intersection combination basic to adapted our countries climatic environment conditions. The ideal material for germplasm amplification, modified and innovative in China. But the plant and ear height,using in temperate need dorcas considering. According to the yield characters and other mainly agronomic comprehensive manifestations. Hyperthermia hybridization advantage manifestations excellent, utilization potential more large.2. The actual data indicated that the hybridized combination of total combining effect and actual manifestations basic anastomosis, at the same time total combining ability effect can better reflection combination practical yield level high also manifestations well, conversely differential. When selection and breeding in maize bybridization breed, sould selection the populations or self-intersection lines of the parents general combining ability both higher, while must considered its special combining ability that should selection the total combining ability high. Through this method can selection have strongly advantage hybridized combination. So combining ability total effect can reflection the real level of the hybridized combination.3. According to the results of production,heterosis,general combining ability and special combining ability of the 84 crosses, the 4 tropical maize lines have higher heterosis with represent lines of Chinese heterosis groups. According to the results of cluster for effect total combining ability will tropical and subtropical population choice of 1 and choice of 6 was clustered into Reid group, choice of 4 with Lancaster main lines relationship more nearly should was clustered into Lancaster group. The choice 2 and 340 with CA339 more nealy was clustered into same group. The populations of Chen 18,choice of 5 and choice of 3 and so on can't into populations, can be regarded new heterosis group.