Inheritance Pattern Of Maize Fructification Habits And Its Utilization In Maize Breeding Efforts

Maize (Zea Mays L.) is one of the most important cereals over the world. Maize production has been increasing as diversified utilization in feedstuff, starch, energy and medicine industry, as well as foodstuff. There is still a big challenge to meet the increasing demands for maize in the future, and it is still very hard and critical to improve yield potential of maize.The phenomenon of ear barren tip composed from aborted kernels and florets without fecundation at the tip of ear is an important factor causing yield losses.The length of ear barren tip was mostly adopted to characterize this phenomenon, which mainly focused on the development of aborted kernels, the influencing factors, and the reasons caused ear barren tip, etc. Very few papers were found studying genetic backgrounds and inheritance patterns of ear barren tip in maize. Two concepts, definite fructification type (abbr. DF type) and indefinite fructification type (abbr. IDF type) were adopted to characterize maize germplasm in this paper. The effects of ear barren tip on yield performance were analyzed based on the data of national and provincial variety evaluation trials. DF and IDF type materials were selected to study the features of their silk emergence, the inheritance patterns of fructification habit and the relevant molecular markers. Also, the application of the inheritance pattern of fructification habit in maize breeding was discussed in the dissertation. Main results of this research were summarized as follows:1. Apparent differences of the phenomenon of ear barren tip were found among genotypes. Two levels of understanding on this phenomenon were definitely revealed. The first one was the presence or absence of ear barren tip. The ear barren tip phenotype was speculated possibly to be determined by ear fructification habit. Maize varieties were classified into DF and IDF type mainly according to the ear barren tip is presence or absence, based on the conditions of kernel development, following the concepts used in crops such as sesame, cotton and soybean, etc. The other one was the length of ear barren tip which was easily affected by biotic or abiotic stresses.2. Ear barren tip was an important character relevant to yield performance. It was found that the character of ear barren tip was independent of yield potential, but related to the yield stabilization significantly. The DF type varieties had a more stable yield performance than the IDF ones.3. The silk emergence of DF type varieties was more uniform and rapidly comparing with that of IDF ones. This character might be related to the yield stabilization of the varieties...