Red bayberry(Morella rubra)is an evergreen fruit tree found in southern China whose whole-genome sequence has recently been published.We updated the linkage map of the species by adding 118 SSR markers and the females...Red bayberry(Morella rubra)is an evergreen fruit tree found in southern China whose whole-genome sequence has recently been published.We updated the linkage map of the species by adding 118 SSR markers and the femalespecific marker MrFT2_BD-SEX.The integrated map included eight linkage groups and spanned 491 cM.Eleven sexassociated markers were identified,six of which were located in linkage group 8,in agreement with the previously reported location of the sex-determining region.The MrFT2_BD-SEX marker was genotyped in 203 cultivated accessions.Among the females of the accessions,we found two female-specific alleles,designated W-b(151 bp)and W-d(129 bp).We previously found that‘Dongkui’,a female cultivar,could produce viable pollen(we refer to such plants‘Dongkui-male’)and serve as the paternal parent in crosses.The genotypes of the MrFT2_BD-SEX marker were W-b/Z in‘Biqi’and W-d/Z in‘Dongkui-male’.The progeny of a cross between these parents produced a 3:1 female(W-)to male(ZZ)ratio and the expected 1:1:1:1 ratio of W-b/W-d:W-b/Z:W-d/Z:Z/Z.In addition,the flowering and fruiting phenotypes of all the F1 progeny fit their genotypes.Our results confirm the existence of ZW sex determination and show that the female phenotype is controlled by a single dominant locus(W)in a small genomic region(59 kb and less than 3.3 cM).Furthermore,we have produced a homozygous“super female”(WW)that should produce all-female offspring in the F2 generation,providing a foundation for commercial use and presenting great potential for use in modern breeding programs.展开更多
Zuili plum （Prunus salicina L.） trees usually set fruit poorly, although they produce high quality fruit. To elucidate the causes of the poor fruit set, pollen tube growth into pistils and fruit set percentage were ...Zuili plum （Prunus salicina L.） trees usually set fruit poorly, although they produce high quality fruit. To elucidate the causes of the poor fruit set, pollen tube growth into pistils and fruit set percentage were investigated after cross-, self- and open-pollination. Ovule development in Zuili pistils was also investigated. Pollen tube penetration into the ovules via the obturator and micropyle was best when Zuili pistils were pollinated by cv. Black Amber （P. domestica） pollen grains, although cross-pollinations with Hongxinli and Miili （P. salicina） pollen were more effective than self- and open-pollination. The fruit set percentage was also highest in pistils pollinated with Black Amber pollen grains. Morphological observation of Zuili pistils revealed that the trees produce ＂double pistils＂, developing two ovaries from a basal pistil, at a rate as high as 28%. In such abnormal pistils, most ovules were lacking an embryo sac or were entirely degenerated. The percentage of normally developed ovules was 24.3% and 8.9% in normal and double pistils, respectively. From these results, we conclude that the main causes of poor fruit set of Zuili plums are a lack of effective cross-pollination and the production of high percentages of double pistils in which normally developed ovules are scarcely formed.展开更多
Chinese bayberry （Myrica rubra Sieb. et Zucc.） is one of the important subtropical fruit crops native to the South of China and Asian countries. In this study, 107 novel simple sequence repeat （SSR） molecular mark...Chinese bayberry （Myrica rubra Sieb. et Zucc.） is one of the important subtropical fruit crops native to the South of China and Asian countries. In this study, 107 novel simple sequence repeat （SSR） molecular markers, a powerful tool for genetic diversity studies, cultivar identification, and linkage map construction, were developed and characterized from whole genome shotgun sequences. M13 tailing for forward primers was applied as a simple method in different situations. In total, 828 alleles across 45 accessions were detected, with an average of 8 alleles per locus. The number of effective alleles ranged from 1.22 to 10.41 with an average of 4.08. The polymorphic information content （PIC） varied from 0.13 to 0.89, with an average of 0.63. Moreover, these markers could also be amplified in their related species Myrica cerifera （syn. More/la cerifera） and Myrica adenophora. Seventy-eight SSR markers can be used to produce a genetic map of a cross between ＇Biqi＇ and ＇Dongkui＇. A neighbor-joining （N J） tree was con- structed to assess the genetic relationships among accessions, and the elite accessions ＇Y2010-70＇, ＇Y2012-140＇, and ＇Y2012-145＇, were characterized as potential new genotypes for cultivation.展开更多
In order to investigate the cause of poor fruit set in 'Zuili' plums,anatomical examinations of post-bloom pistils were conducted and the dates of young fruit drop were recorded during the growing seasons of 2...In order to investigate the cause of poor fruit set in 'Zuili' plums,anatomical examinations of post-bloom pistils were conducted and the dates of young fruit drop were recorded during the growing seasons of 2008 and 2009.Pistils of cv.'Black Amber' were also examined as an abundant setting control.Two major dropping periods were detected in 'Zuili':one during the first 5 d after full bloom (DAF) and another between 10 and 17 DAF.Anatomical analyses of the pistils at the full bloom stage revealed that half of the ovules had not developed embryos,which may have caused their early drop.In most dropped pistils collected at 17 DAF,the micropyle had not been penetrated by a pollen tube,indicating that they were not fertilized.'Zuili' ovules initiated embryo division at 10-12 DAF,although thereafter embryo development was retarded when compared to the rates observed in 'Black Amber'.Ovule fertilization failure and inactive embryo development after ovule fertilization may be the major causes of the later fruit drop observed in 'Zuili' plum trees.展开更多
基金support from the Natural Science Foundation of China(31972364)Yuyao Forestry Technology Extension Center.H.M.J.was supported by the National Natural Science Foundation of China(31901985).Z.S.G.,Y.J.,C.Y.C.were funded by a Ningbo Science and Technology Research Grant(contract no 2016C10021).
文摘Red bayberry(Morella rubra)is an evergreen fruit tree found in southern China whose whole-genome sequence has recently been published.We updated the linkage map of the species by adding 118 SSR markers and the femalespecific marker MrFT2_BD-SEX.The integrated map included eight linkage groups and spanned 491 cM.Eleven sexassociated markers were identified,six of which were located in linkage group 8,in agreement with the previously reported location of the sex-determining region.The MrFT2_BD-SEX marker was genotyped in 203 cultivated accessions.Among the females of the accessions,we found two female-specific alleles,designated W-b(151 bp)and W-d(129 bp).We previously found that‘Dongkui’,a female cultivar,could produce viable pollen(we refer to such plants‘Dongkui-male’)and serve as the paternal parent in crosses.The genotypes of the MrFT2_BD-SEX marker were W-b/Z in‘Biqi’and W-d/Z in‘Dongkui-male’.The progeny of a cross between these parents produced a 3:1 female(W-)to male(ZZ)ratio and the expected 1:1:1:1 ratio of W-b/W-d:W-b/Z:W-d/Z:Z/Z.In addition,the flowering and fruiting phenotypes of all the F1 progeny fit their genotypes.Our results confirm the existence of ZW sex determination and show that the female phenotype is controlled by a single dominant locus(W)in a small genomic region(59 kb and less than 3.3 cM).Furthermore,we have produced a homozygous“super female”(WW)that should produce all-female offspring in the F2 generation,providing a foundation for commercial use and presenting great potential for use in modern breeding programs.
文摘Zuili plum （Prunus salicina L.） trees usually set fruit poorly, although they produce high quality fruit. To elucidate the causes of the poor fruit set, pollen tube growth into pistils and fruit set percentage were investigated after cross-, self- and open-pollination. Ovule development in Zuili pistils was also investigated. Pollen tube penetration into the ovules via the obturator and micropyle was best when Zuili pistils were pollinated by cv. Black Amber （P. domestica） pollen grains, although cross-pollinations with Hongxinli and Miili （P. salicina） pollen were more effective than self- and open-pollination. The fruit set percentage was also highest in pistils pollinated with Black Amber pollen grains. Morphological observation of Zuili pistils revealed that the trees produce ＂double pistils＂, developing two ovaries from a basal pistil, at a rate as high as 28%. In such abnormal pistils, most ovules were lacking an embryo sac or were entirely degenerated. The percentage of normally developed ovules was 24.3% and 8.9% in normal and double pistils, respectively. From these results, we conclude that the main causes of poor fruit set of Zuili plums are a lack of effective cross-pollination and the production of high percentages of double pistils in which normally developed ovules are scarcely formed.
基金supported by the Ningbo Science and Technology Bureau(No.2012C10012)the Science and Technology Project of Zhejiang Province(No.2012C12904)the Yuyao Financial Bureau for Chinese Bayberry Breeding Program,China
文摘Chinese bayberry （Myrica rubra Sieb. et Zucc.） is one of the important subtropical fruit crops native to the South of China and Asian countries. In this study, 107 novel simple sequence repeat （SSR） molecular markers, a powerful tool for genetic diversity studies, cultivar identification, and linkage map construction, were developed and characterized from whole genome shotgun sequences. M13 tailing for forward primers was applied as a simple method in different situations. In total, 828 alleles across 45 accessions were detected, with an average of 8 alleles per locus. The number of effective alleles ranged from 1.22 to 10.41 with an average of 4.08. The polymorphic information content （PIC） varied from 0.13 to 0.89, with an average of 0.63. Moreover, these markers could also be amplified in their related species Myrica cerifera （syn. More/la cerifera） and Myrica adenophora. Seventy-eight SSR markers can be used to produce a genetic map of a cross between ＇Biqi＇ and ＇Dongkui＇. A neighbor-joining （N J） tree was con- structed to assess the genetic relationships among accessions, and the elite accessions ＇Y2010-70＇, ＇Y2012-140＇, and ＇Y2012-145＇, were characterized as potential new genotypes for cultivation.
基金Project(No.20031007)supported by the Jiaxing Municipal Science and Technology Projects,Zhejiang Province,China
文摘In order to investigate the cause of poor fruit set in 'Zuili' plums,anatomical examinations of post-bloom pistils were conducted and the dates of young fruit drop were recorded during the growing seasons of 2008 and 2009.Pistils of cv.'Black Amber' were also examined as an abundant setting control.Two major dropping periods were detected in 'Zuili':one during the first 5 d after full bloom (DAF) and another between 10 and 17 DAF.Anatomical analyses of the pistils at the full bloom stage revealed that half of the ovules had not developed embryos,which may have caused their early drop.In most dropped pistils collected at 17 DAF,the micropyle had not been penetrated by a pollen tube,indicating that they were not fertilized.'Zuili' ovules initiated embryo division at 10-12 DAF,although thereafter embryo development was retarded when compared to the rates observed in 'Black Amber'.Ovule fertilization failure and inactive embryo development after ovule fertilization may be the major causes of the later fruit drop observed in 'Zuili' plum trees.
