The Analysis Of Taxonomic Status And Application Value As Pollen Donor Of Some Androecious Genotypes Native To China

Some androecious genotypes of Diospyros spp. were found in Dabie mountain area in Hubei province in the mid-1990s by proficients in Huazhong Agricutural University. They were characteristic for blooming staminate flowers only, which different from other Diospyros spp. that generally opening only female flowers or outcrossing monoecious. But there are some issues need be explored. Such as whether they were Diospyros kaki or a new species of Diospyros, and what about the relationship with the PCNA native to China (C-PCNA) in a same distribution, moreover, how about the application value as a pollen donor and in PCNA breeding. In this study, chloroplast DNA (cpDNA) sequences and nuclear SSR (nSSR) molecular markers were applied to analyze the relationship of these androecious genotypes. At the same time, the pollen biological characteristics of the androecious genotypes were observed. The separation of RO2(a molecular marker linked with the natural deastringency character in persimmon) in F1had also been discussed. The main results were as follows:1. Eighteen Diospyros spp. materials were used in cpDNA sequences analysis, including7androecious genotypes and7Diospyros spp. matK, psbA-trnH, trnL-trnF and trnL intron of cpDNA were amplified and sequenced. The results showed that all sequences of7androecious genotypes were the same with D. kaki Thunb. and D. kaki var. silvestris Mak. but different with other five species. Phylogenetic trees constructed by NJ, ML and MP methods all exhibited that7Diospyros spp. were distinguished with each other and the androecious genotypes were clustered with D. kaki Thunb.. So the androecious genotypes should be D. kaki Thunb., but not a new species of Diospyros.2. Twenty six SSR primers were used to explore the kinship between the androecious genotypes and other persimmon native to China or Japan. The results showed that the ’Male strain No.1’,’Male strain No.2’,’Male strain No.3’,’Male strain No.8’ and ’Male strain No.9’ were clustered with ’Luotian-tianshi’, while ’Male strain No.11’ clustered with four Chinese PCA types (C-PCA), but ’Male strain No.10’ clustered with Japanese PCNA types (J-PCNA).The results may reflect their respective origions, but the exact genetic relationship needed to be further explored.3. Pollen biological characteristics analysis showed that pollen number of the androecious genotypes was relatively higher. Moreover, pollen germinability in vitro of the androecious genotypes was stable in two years and almost equal with ’Zenjimaru’, but higher than other varieties. Germination of pollen on stigma observations showed well pollen-stigma compatibility between the androecious genotypes and ’90-3-99’(C-PCNA) or ’Maekawa Jiro’(J-PCNA). Then, the androecious genotypes may be used as pollen donors.4. SCAR-PCR (based on a molecular marker as RO2that linked with the natural deastringency characteristic of C-PCNA) analysis showed that ’Male strain No.l’,’Male strain No.2’,’Male strain No.3’,’Male strain No.8’ and ’Male strain No.10’ owned the characteristic bands, suggesting that those androecious genotypes might own the natural deastringency traits similar with C-PCNA, so that they may be the parents in PCNA breeding. But ’Male strain No.9’ and ’Male strain No.11’ did not own the characteristic bands, suggesting that their genetic background may be different.5.6hybridized combination had been done, like ’Mopanshi’×’Male strain No.1’,’Luotian-tianshi’×Male strain No.1,’Mopanshi’×Male strain No.2,’Luotian-tianshi’×Male strain No.8,’Gongcheng-shuishi’×Male strain No.8and ’Youhou’×Male strain No.8. A total of650female flowers were tested and396fruits were harvested. Fruit setting rate was among29%-85%. Moreover,921embryos were obtained by embryo rescue technique. SCAR-PCR analysis for the offsprings of ’Mopanshi’×Male strain No.1,’Luotian-tianshi’×Male strain No.1,’Mopanshi’×Male strain No.2,’Luotian-tianshi’×Male strain No.8and ’Gongcheng-shuishi’×Male strain No.8showed that the separation ratio of with or without RO2was34:37,78:16,34:34,42:15,41:35, in line with the expected separation ratio as1:1and1:3, suggesting that the tested androecious genotypes may own the CPCNA gene (controlling the natural deastringency traits).In summary, the androecious genotypes belong to Diospyros kaki Thunb., and a part of them were closed with ’Luotian-tianshi’. And some of them might own the dominant natural deastringency traits. Moreover, they may meet the requirement as pollen donor. Therefore, they may have the potentiality to be the pollination varieties in PCNA breeding and parents in genetic improvement.