Abstract:

Objective: In this study, we comprehensively measured for the first time the embryo-free rate (EFR) and the main components of embryonic and embryo-free seeds of Ginkgo biloba clones, screened out high embryo-free germplasm resources of G. biloba clones, and conducted in-depth research on the causes and mechanisms of embryo-free phenomenon, in order to provide reference for further development and utilization of G. biloba industrial resources. Method: The seeds of 47 ginkgo clones were randomly collected from the female plants in the sole national Ginkgo Elite Variety Base in Pizhou City, Jiangsu Province. After sampling, the seed coat was peeled off one by one to observe the presence or absence of seed embryos, to investigate the embryo-free phenomenon, and to calculate the EFR. According to relevant national and industry standards, those ginkgo seeds were distinguished between embryo-free seeds and embryonic seeds. And their main nutrients were measured. Result: The EFR of the 47 ginkgo clones ranged from 17.16% to 100%, with an average of 59.74% and a median of 59.02%. There were significant differences in EFR among the clones determined by ANOVA. The fruit shape index (FSI) of these ginkgo clones ranged from 1.19 to 1.81, with a significant correlation coefficient of -0.285 between the FSI and the EFR. Twelve ginkgo clones were selected to differentiate the variety groups, and it was found that the fat, soluble sugar, starch, soluble protein, total amino acids, total flavonoids and terpene lactones of embryo-free seeds were not significantly different from those of embryonic seeds; while the contents of ginkgotoxin, Ca and Fe were significantly lower than those of embryonic seeds. The EFR was also strongly correlated with starch and terpene lactone content, with correlation coefficients of 0.698 and ?0.599 respectively. Conclusion: The scientific understanding of the processing and use of ginkgo seeds has been deepened from the perspective of the presence or absence of embryonicity. The embryonic relationship of the main clones of G. biloba is discovered, and excellent ginkgo germplasm resources with an EFR of over 90% or 100% are found. We have distinguished between embryo-free and embryonic seeds of those clones, and found differences in their main nutritional components, minerals, and main secondary metabolites, as well as their correlations. This study confirms that the EFR of G. biloba was highly significantly positively correlated with its starch content and negatively correlated with its terpene lactone content, providing more accurate scientific and technological support for the development of G. biloba seed industry.

Key words: ginkgo clones, embryo-free seeds, fruit shape index, main components