Study On PMC Meiosis And Pollen Fertility Of The Sexual Progenies Using Allotetraploid Citrus Somatic Hybrid As The Pollen Parent

In this study, the meiotic behavior of pollen mother cells(PMCs) and pollen viability of 7 citrus sexual progenies acquired using allotetraploid citrus somatic hybrid as pollen parent and their corresponding parents was evaluated. Moreover, the correlation of PMC meiosis, phylliform index and RAPD marker was discussed.The main results were as follows:1. Ploidy identification indicated that there were 45 triploids, 12 diploids and1 tetraploid among the 58 sexual progenies by Flow cytometric.2. The result revealed that the meiosis of diploids were nearly normal with few meiotic abnormalities by observing meiotic behavior of citrus sexual progenies and their corresponding parents. Whereas, the chromosomal behavior of triploids meiosis was complicated and the comformations of chromosome pairing were multiplicate with 81.8ï¼…univalents and multi-valents, and there were also a series of abnormal phenomena in meiosis of its PMC such as 51.2ï¼…chromosomes orientated away from the equatorial plate at metaphaseâ… or 38.7ï¼…at metaphaseâ…¡, chromosome bridges and lagging chromosomes at anaphaseâ… or anaphaseâ…¡, chromosomes separates unequal and chromosomes separates asynchronously etc.3. The pollen fertility results of citrus sexual progenies showed that the frequency of normal tetrads and the pollen stainablity of diploids were nealy the same with the female parent. Whereas the pollen stainablity of triploids was 46.7ï¼…, lower than that of their parents, the proportion of normal tetrads and the proportion of micropollen were between their parents, the proportion of micropollen of diploids was close to the female parent and the proportion of micropollen of triploids was close to the male parent.4. The phylliform index of lamina of citrus sexual progenies and their corresponding parents were investigated. It was found that the lamina phylliform index of the diploids was simiar with one of their fusion parents, whereas triploids acquired more genetic germplasm from their parents.5. Fourteen 10-mer primers, which have the characteristics of clear bands, good polyphism and reproducibility were selected to go through RAPD test. The RAPD analysis indicated that the sexual progenies were hybrids no matter diploid or triploid, and the genetic message was from their fusion parents and their female parent, especially more from their male parent and fusion parents. And the meiosis did not show any difference on their ploidy level, no matter which parents the genetic messages were acquired from.