Study On Intergeneric Distant Hybridization Between Prunus And Armeniaca And New Germplasm Creation

Prunus and Armeniaca are abundant in germplasm resources in stone fruits. Newgermplam will be created if by using excellent cultivars (maturing early, good quality) indistant hybridization as parents between plum and apricot, thus can enrich the geneticdiversity, and also occupy germplasm for further breeding program and related studies. Aimedat the arising problems such as the cross-incompatibility and hybrid's sterility during distanthybridization of fruit trees, effects of different treatments on cross-compatibility of distanthybridization in stone fruits were studied based on the former studies, then physiological andbiochemical changes during hybridization between plum and apricot were primarily discussed,and rescue and culture system of hybrids' embryos were also conducted, further the geneticvariation and principle between the hybrids and their parents were analyzed and methods ofidentification of hybrids were established. Some hybrids were transplanted into the fieldsuccessfully. The plum-apricot germplasm resources in nature were analyzed by RAPDmarkers. The main results were as followings:(1) The effects of different treatments on cross-compatibility showed that the settingpercentage in balloon stage was obviously higher than that in early blooming stage; Thedifferences of fruit set between positive and reverse crosses were significant; Female parentaffected cross compatibility more remarkably than male parent in distant hybridization. Thecross incompatibility were easily overcome by using the cultivars with high level ofself-compatibility and high open-pollinated setting percentage as female parent, and thesetting percentage could be increased by using the cultivars(lines) with high pollen vigor andpollen germination as male parent;The appropriate electrostatic field, He-Ne laser andcompound treatment with 60Co γ-ray and He-Ne laser could improve the pollen germinationrate in vitro effectively, the fruit set percentage was higher than control; while 60 Co γ-raytreatment reduced the pollen germination rate in vitro, and the fruit set percentage obtained bydistant hybridization was lower than control. The results of the treatments on maternal ovaryor stigma indicated that plant growth regulators (GA and β-NAA) and NaCl solution can'timprove cross-compatibility among stone fruits.(2) The physiological and biochemical changes during intergeneric hybridizationbetween plum and apricot were discussed, and the results showed that SOD activities of crosscombinations were increased in the former period and then decreased in the latter withfluctuant change, and differences were also observed in different combinations and the peaksof SOD activity of control appeared earlier than those of the treated. The POD activities hadfluctuant changed either, while the POD activities of the hybrid cross combinations werehigher than control and the peaks of the treated appeared also earlier than that of control. The 3李,杏属间远缘杂交及种质创新的研究content of soluble protein in Plum × apricot combination increased slowly, while that of thereverse combination decreased in a great range and then increased slowly. The content ofMDA in distant hybridization combinations increased with the pollination period prolonged,while the control was still in a stable level during the pollination period. These changes werecorrelated with the cross incompatibility and recognition barriers between pollen and stigmaduring hybridization.(3) The interaction of distant pollen and stigma showed that the incompatibility andrejection responses had occurred between each other in a certain extent, and were stronger onstigma than inside of style. The pollen grain could not germinate after 6h of pollination, andlittle germinated but could not enter the style after 12h. Little pollen tube began to germinateand grow b...