Research On The Identification Of Sugar Beet Variety Fertility By Molecular Marker Technology And Morphology

Sugar Beet is a typical sugar crop that is widely grown in China and around the world.Due to the lack of sugar beet germplasm resources in China,in order to select the resources we need from the excellent sugar beet varieties abroad,to understand the cytoplasmic and nuclear fertility genotypes of the existing sugar beet registered varieties,and to quickly identify the fertility of sugar beet varieties,we can screen resources from foreign excellent sugar beet varieties for our use in the future and cultivate sugar beet varieties more efficiently.In this study,a pair of Owen-type male sterile lines and maintainer lines of sugar beet were used as control group.The developed specific TR1 primers acting on the number of variable tandem repeat(variable number of tandem repeats,VNTR)loci in sugar beet mitochondria were used to identify sterile cytoplasm(S)and normal cytoplasm(N)in sugar beet.The molecular markers s17 associated with Rf1 locus and molecular marker o7 associated with Rf2 locus were amplified,and the fertility composition was analyzed combined with field pollen fertility investigation.The results showed that most of the tested materials were homozygous S-type cytoplasm,and only 3 varieties had heterozygous cytoplasmic fertility cultivated independently in China,indicating that some sugar beet varieties cultivated independently in China had mixed cytoplasmic fertility,and the results of molecular markers associated with Rf1 and Rf2 locus showed heterozygosity of different nuclear fertility patterns.Among the tested materials,39 were sterile varieties,accounting for 36%.Most of the sugar beet varieties whose pollen is sterile are sugar beet varieties cultivated by foreign breeding companies,and the male parents of these varieties use polyembryonic maintainer lines.The fertility composition of 109 sugar beet varieties was complicated.When the band amplified by s17 primer was 1.8kbp,the result of restriction endonuclease analysis showed that when the heterozygous type was 4/5,the fertility of the variety had both sterile and normal.No matter which type of bands were amplified by o7,the varieties were fertile when the 4/5 and 5/5 patterns were covered,no matter which type of bands were amplified by o7.There was no significant difference between the amplification results of o7 molecular markers and pollen fertility among different varieties.Rf2 site does not play a role in fertility restoration or plays a small role.According to the data of this experiment,we speculated that the sugar beet varieties was sterile only when the amplification band of VNTR molecular marker TR1 was homozygous 500 bp,the molecular marker S17 primer associated with Rf1 locus was 1.8kbp,the type of double restriction enzyme digestion was homozygous 4/4 pattern,and the amplification band of molecular marker O7 primer associated with Rf2 locus was homozygous 2.6kbp or 1.8kbp.To sum up,we can use molecular marker technology to identify the fertility of sugar beet in the vegetative growth stage.In the later stage of sugar beet breeding,attention should be paid to the breeding of diversified sugar beet cytoplasmic sterility and polyembryonic maintainer lines should be selected as male parents as far as possible to protect varieties.Improve the homozygous level of varieties,enrich sugar beet germplasm resources,and promote the development and improvement of sugar beet industry.