Crossability Of The Different Ploidy Involving Maize,Zea Perennis And Their Hybrids

To search the crossability and find out the crossing barrier between different ploidy in intraspecific and interspecific hybridization of Maize and Zea perennis, different ploidy corns, Zea Perennis and their hybrids were used in this study. The main results were as follows:1. Pollen fertility of Maize, autotetraploid(398), Zea perennis, allotriploid(MP30), allotetraploid(413), hererologous pentaploid(MPM50) and allohexaploid(MP60) were98.88%,19.95%,88.64%,92.25%,91.53%,41.63%and75.61%respectively.2. When Maize was hybrided with autotetraploid,the pollen tube behavior in the pistil was nomal, but the main reason of the hybrid sterility was that hybrid couldn’t develop the emvryo and the endosperm degenerated. When Maize was hybrided with hererologous pentaploid, a very small amount of pollen tubes entered the ovary and the main reason of the hybrid sterility was that hybrid couldn’t develop the emvryo and the endosperm degenerated. When Maize was hybrided with allohexaploid, the pollen tubes couldn’t enter the ovary and this caused0.00%of hybrid setting percentage directly.3. When autotetraploid was hybrided with Maize,the pollen tube behavior in the pistil was nomal,but the main reason of the hybrid sterility was that the endosperm of hybrid degenerated completely in the late stage. When autotetraploid was hybrided with hererologous pentaploid, a very small amount of pollen tubes entered the ovary, but after completing double fertilization, embro and endosperm could develop normally. When Maize was hybrided with allohexaploid, the pollen tubes couldn’t enter the ovary and this caused0.00%of hybrid setting percentage directly.4. When hererologous pentaploid was hybrided with Maize, the pollen tube behavior in the pistil was nomal, but the main reason of the hybrid sterility was that hybrid couldn’t develop the emvryo and the endosperm degenerated. When hererologous pentaploid was hybrided with autotetraploid, the pollen tube behavior in the pistil was nomal and the development of the embro and endosperm were nomal.5. When allohexaploid was hybrided with Maize, a very small amount of pollen tubes entered the ovary and this caused3.33%of hybrid setting percentage directly. When allohexaploid was hybrided with autotetraploid, the pollen tube behavior in the pistil was nomal and the development of the embro and endosperm were nomal.6, When Maize was hybrided with autotetraploid, Maize was hybrided with Zea perennis, Maize was hybrided with allotetraploid, Maize was hybrided with hererologous pentaploid, Maize was hybrided with allotetraploid, Maize was hybrided with allohexaploid, autotetraploid was hybrided with Maize, autotetraploid was hybrided with hererologous pentaploid, autotetraploid was hybrided with allohexaploid, hererologous pentaploid was hybrided with Maize, hererologous pentaploid was hybrided with autotetraploid, allohexaploid was hybrided with Maize, allohexaploid was hybrided with autotetraploid, the setting percentage of maize selfing were75.89%,19.12%,20.14%,22.9%,21.99%,0.94%,24.44%,19.6%,0.00%,2.00%,45.90%,3.33%43.33%respectively. 7. Using "Endosperm balance number hypothesis" forecast the crossing results between different ploidy of Maize, Zea perennis and their hybrids.The forecast results were that the EBN ratio were2:1and the endosperm developed nomally in these cross combinations that maize selfing, Maize was hybrided with Zea perennis, autotetraploid was hybrided with hererologous pentaploid, autotetraploid was hybrided with allohexaploid, hererologous pentaploid was hybrided with autotetraploid, allohexaploid was hybrided with autotetraploid. But the EBN ratio were not2:1and the endomsperm developed abnomally in other cross combinations. In this study,the crossing results of all twelve cross combinations tallyed with forecast results. So "Endosperm balance number hypothesis" coubld be used in crossing results forecast between different ploidy involving Maize and Zea perennis.8. Comprehensive analysis showed that when the female was low ploidy, the pollen tubes behavior barrier was stonger when the polidy of male was higher,but the reciprocal cross could weaken the pollen tubes behavior barrier obviously.