Research On Megaspore, Microspore Development And Exogenous Pollen Pollination Effect Of Pinyi Tiancha (Malus Hupehensis Rehd.)

China is most resource-rich countries for Malus. Different area and cultivated varieties requirement of different root stocks.The root stock have an impact on fruit quality, fruit yield, growth, disease resistance, adaptability and so on. Therefore, it is a great production significance that bred to adapt to the requirements of the root stock. It is very time consuming and low efficiency in improving characters of the apple root stock use conventional hybridization breeding method. But the reproductive characteristics of apomixis can be fixed hybrid advantage of reducing the required time for breeding.This study used Pingyi Tiancha(Malus hupehensis Rehd.) as the female parent and Malus'Red Splender'pollen as the male parent. Malus'Red Splender'dominant characteristic is red leaves. We are Pollinate in different periods of Pingyi Tiancha with Malus'Red Splender'pollen. The rate of apomixis in Pingyi Tiancha though emasculation, bagging and artificial pollination combination statistics. We observed the whole process of embryo sac, male gametophyte development, Pingyi Tiancha stigma pollen germination after artificial pollination, fruit traits, seedlings ploidy and so on by paraffin sections, microscopic observation, and flow cytometry techno fogy. The main results are shown as follows:1. Pingyi Tiancha is a typical ovary anatropous which sac is no gametocytes type of apomixis. Pingyi Tiancha meiosis can be a handful of sexual sac and occurs sexual reproduction. Most of the sexual embryo sac is abortion in blossom period. Eventually, the asexual embryo sac development of apomixis replaces sexual embryo sac. In the transmission electron microscope observation showed that when the internal structure of abortion when cells have been destroyed.2. We observed the Pingyi Tiancha microspore development found that the microspores were surrounded by callose wall in tetrad period. Thus impact on the further development of tetrad and resulting microspores in tetrad abortion. Artificial pollination of calls after Malus stigma germination observation show that pollen germination is slow and low germination rate. Further observation found that only a small number of pollen tube growth can lower end of the style.3. Used flow cytometry instrument for the offspring of different treatments during the pbidy determination. We get several types of hybrid seedlings, such as the diploid, triploid, tetraploid, five-ploidy and non integer ploidy. The result is Pingyi Tiancha has sexual reproduction and reproductive process is more complicated. We can be inferred through the determination of ploidy Pingyi Tiancha the types of the female gametophyte is haploid, diploid and triploid. we still need to further test to verify the offspring of triploid is produced through sexual reproduction or apomixes by SSR markers.