| Ginkgo biloba is a relic plant belong to Ginkgoacae family with high economic and research value.Hubei is rich in ginkgo germplasm resources.Suizhou is the most principal distribution region of ancient Ginkgo trees.In order to evaluate this germplasm resources,this paper conducted researches on the growth and fruit regularity,seed traits and genetic basis of an excel ancient ginkgo tree(temporarily named as 'Da Yuanzi')located in Yumeng village,Caodian town,Sui County,with the references of a ginkgo tree in Luoyang town of Zengdu Disrict,a ginkgo tree in Huaihe town of Sui County and a ginkgo tree in the west residential zone of Huazhong Agricultural University.Main research results were as following:(1)In 2014,shooting period of this tree was in early April,female flowers blooming period was in middle April;shoots growing ended in the end of May,seeds ripened in middle September and leafs fell in middle and late November.In 2015,compared with 2014,shooting period delayed about five days,shoot growing period delayed about ten days,other phenological period was basically the same.It shooted once a year,and the growth regularity of branches length and diameter showed a "S" shape.In late April,seed fall phenomenon was observed.The growth dynamic of both longitudinal and horizontal diameters of seeds showed a "S-shape".Seeds' size stopped increasing at the end of July.Seeds' color gradually changed from green into yellow-green in middle of August,and became mature and yellow finally in the middle of September.Average seed weight of per short branch,per long branch and per cubic meters of crown was 22.79 gram,68.35 gram and 554.4 gram respectively.(2)This tree's seed nuclear type belongs to Yuanzi.Results of seed nucleus indexes comparison showed that there existed significant differences in nine of ten indexes between this ginkgo tree and two references trees.Comparison also showed that no significant differences in seed nucleus width,dry kernel percentage and fresh kernel percentage existed between the two years,but there were significant differences in other 7 seed nucleus indexes between the two years.(3)During post-ripening,individual embryos of different seeds of this tree showed different growth before November,but they had relatively less differences in length by the middle of November,and the percentage of seeds with embryos reached 76.25%.The percentage of seeds with embryos,growth of embryos and germination of the seeds under wet storage were all higher than those of the seeds under dry storage.(4)This trees' seed soluble sugar content was 2.1%;the total sugar content was 20.11%;the starch content was 63.03%;the crude protein content was 4.35%;seed soluble sugar and total sugar content of this tree were higher than those of the two reference trees.(5)For the 3 ginkgo trees,a total of 79 bands were amplified by 10 ISSR primers,in which 71 were polymorphic bands and the percentage of polymorphic bands was 89.87%.For the 71 loci detected in 'Da Yuanzi',27 loci were dominant homozygous loci,19 loci were recessive homozygous loci,and 33 loci were heterozygous loci.The average heterozygosity was 41.77%.These results indicated that the genetic basis of 'Da Yuanzi'ginkgo tree was wide.(6)In conclusion,this ginkgo tree growed well,and had full and big seeds,high nutrient contents,low percentage of seeds without embryos and wide genetic basis.Comprehensive evaluation suggested it was an excellent kernel-used germplasm with large-seed. |
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