Evaluation And Analysis Of The Combining Ability And Heterosis Among Goldqueen Landrace And 7 Improved Populations In Maize

It is necessary for breeder to broad the germplasm base of maizebreeding. Knowledge of the breeding potential of maize collection and new heterotic patterns can contribute to a widening of the genetic base. The objectives of this study were to (1) evaluate the breeding potential of eight improved maize populations in differential levels, and (2) provide further information to clarity the relationships among them. Two field experiments were conducted in this study. One China landraces (Goldqueen) and seven populations (YuzongS, 525, Huangmo49, Ernan24, Lancaster, BSSS, and ZiT36) were crossed in a diallel mating system. The parents and 28 hybrids were evaluated in two environments for grain yields and the other main agronomic traits. The other field experiment was testcross between Goldqueen and 15 inlines that are often used in maize breeding programs in China.Results showed that the grain yields, combining ability and the main agronomic traits o f t he e ight m aize p opulations w ere s ignificant. It was d ifferent for h eterotic relations among eight materials. The best materials were populations, YuzongS, Huangmo49, ZiT36 and Goldqueen. Two potential heteroic patterns, YuzongS X ZJT36, Goldqueen X Tropical germplasm, were also put forward. Corresponding measure of improvement were put forward according to the defects of pattern.The characters of YuzongS, Huangmo49, ZiT36 and Goldqueen were: (1) Among 8 populations, YuzongS origined from the American maize germplasm had the best comprehensive traits, especially in grain yields, kernel production per plant and weight of 1000 kernel. The plant height, ear height and days to harvest were also signficient and its ear length, ear diameter and kernel rows were average. YuzongS' yield GCA was in the seat of the mumber 2. The hybrid YuzongS XZiT36 showed better high-parent heterosis value. (2) Huangmo49 containing subtropical germplasm had the best mean grain yields along with GCA. The GCA of its traits, ear diameter, kernel rows, weights of 1000 kernel and kernel production per plant had better than the other populations, especially in the GCA of weight of 1000 kernel. But higher ear height was its mainful shortcoming. The population of Huangmo49 had better heterosis with the populations, Goldqueen Landrace and Lancaster. (3) The excellent landrace, Goldqueen, its mean grain yields and GCA of grain yields were in the middle rank among 8 populations. All of its traits, good kernel rows lower plant height and ear height were its excellent characters. The excellent heterotic pattern was Goldqueen x tropical, subtropical germplasms. .The further measures of improving its GCA was also summerized.The second experiment showed that Goldqueen Landrace can be used in maize breeding program in China. Its combining ability with the lines representing main corn germplasms in China was tropical germplasm, Tangsansipingtou, Reid, Lancaster and Liudahonggu.