Construction Of Genetic Maps And QTL Mapping For Growth Period Related Traits In Maize

Maize (Zea mays L.) is an important crop which could use as food, forage and energy inthe world. It plays an important role in agricultural production, social life, national economyand easing the energy crisis. As is one of the important traits of maize production, growthperiod is a significant part of the objectives of maize breeding. Days to tasseling(DTT), daysto pollen-shedding(DTP), days to silking(DTS) and anthesis-silking interval(ASI) are themost important period of growth. In addition, the traits of leaf number and spikedifferentiation are also closely related with the growth period. Thus, the study of theinheritance of these traits is significant to improve the stability and adaptability of maize yield,to make male and female flowers synchronized in maize breeding process, to increase theyield of seed production. In this study, we used SSR markers to construct the genetic linkagemap and carry out the QTL analyses of traits which related to growth period, and cleared theirprecise positions and effects in chromosomes. The main results were as follows:(1) A mapping population of355families of recombinant inbred lines (F9) of maizederived from the cross between80007and80044was used to develop a genetic linkage mapwhich including219SSR markers by the technology of the SSR molecular marker. The totallength of this genetic map is2133.5cM, and the average interval distance is9.7cM. Thenumber of markers on different linkage groups varies from17to29and their average numberis22markers.(2) The simple correlation analysis of four traits which related to growth period showsthat the DTT, DTP, DTS have significant positive correlation between each other; ASI hassignificant negative correlation with DTT or DTP.(3) QTL mapping of maize traits relating to growth period of DTT, DTP, DTS and ASIwere analyzed by the inclusive composite interval mapping method (ICIM). The analysisshows that a total of60QTL for maize traits relating to growth period were detected,including20QTL of DTT,15QTL of DTS,20QTL of DTP and5QTL of ASI. There are11QTL which detected in different growing environments in these QTL, and they are stable QTL because they might not be affected by environments significantly. There are7QTLs’rate of contributions of phenotypic variation is high, and the ratio is higher than10%. Theresults show that, QTL of maize traits relating to growth period are clustered together on thechromosomes, and QTL with higher contributions controlled multiple traits at the same time.The results also indicate that bin3.04-3.05, bin3.09, bin7.03and bin9.02-9.03, clusters ofQTL of maize traits relating to growth period on the chromosomes, have some major siteswhich have important functions on maize traits relating to growth period.(4) A total of eight QTL for maize traits relating to leaf number and tassel spike traitswere detected. Cultivated in Ledong, six QTL of leaf number which are located onchromosome2、3、7、9and10. Cultivated in Tai’an, two QTL of tassel spike traits which arelocated on chromosome3.