In this investigation, maize heterotic groups and patterns were analyzed based on theplanting areas from 1992 to 2001 using 84 parent lines of 71 widely extended hybrids andclassification results by SSR markers, in wh...In this investigation, maize heterotic groups and patterns were analyzed based on theplanting areas from 1992 to 2001 using 84 parent lines of 71 widely extended hybrids andclassification results by SSR markers, in which these lines were assigned into sevenheterotic groups based on Ni-LIs genetic distances. The results indicated that acertain extent change for major heterotic groups of maize took place during past decadein China. The major heterotic groups were Lancaster, Reid, Tang SPT, Zi330 and E28 in theearly 1990s, while they became Reid, Tem-tropicⅠ, Zi330, Tang SPT and Lancaster in theearly 21st century. Tem-tropicⅠwas a new heterotic group, which contained tropic maizegermplasm. The changes for heterotic patterns also occurred. Some new heterotic patternscombining with Tem-tropicⅠappeared, such as ReidTem-tropicⅠ, Zi330Tem-tropicⅠ,Tang SPTTem-tropicⅠ, etc.. Another change was the order of heterotic patterns. In theearly and middle 1990s, the top five heterotic patterns were ReidTang SPT, Zi330Lancaster, LancasterTang SPT, LancasterE28 and ReidZi330, while they became ReidTem-tropicⅠ, ReidZi330, ReidTang SPT, Zi330Tem-tropicⅠand LancasterTang SPT inthe early 21 century. ReidTem-tropicⅠand Zi330Tem-tropicⅠwere laid on the firstand forth Chinese heterotic patterns respectively in 2001. These results providedsignificant information to understand the maize heterotic groups and patterns in Chinaat molecular level.展开更多
Understanding the heterosis in multiple environments between different heterotic groups is of fundamental importance in successful maize breeding. A total of 737 hybrids derived from 41 maize inbreds were evaluated ov...Understanding the heterosis in multiple environments between different heterotic groups is of fundamental importance in successful maize breeding. A total of 737 hybrids derived from 41 maize inbreds were evaluated over two years, with the aim of assessing the genetic diversity and their performance between heterotic groups under drought-stressed(DS) and well-watered(WW) treatments. A total of 38 737 SNPs were employed to assess the genetic diversity. The genetic distance(GD) between the parents ranged from 0.05 to 0.74, and the 41 inbreds were classified into five heterotic groups. According to the hybrid performance(high yield and early maturity between heterotic groups), the heterosis and heterotic patterns of Iowa Stiff Stalk Synthetic(BSSS)×Non-Stiff Stalk(NSS), NSS×Sipingtou(SPT) and BSSS×SPT were identified to be useful options in China’s maize breeding. The relative importance of general and specific combining abilities(GCA and SCA) suggests the importance of the additive genetic effects for grain yield traits under the WW treatment, but the non-additive effects under the DS treatment. At least one of the parental lines with drought tolerance and a high GCA effect would be required to achieve the ideal hybrid performance under drought conditions. GD showed a positive correlation with yield and yield heterosis in within-group hybrids over a certain range of GD. The present investigation suggests that the heterosis is due to the combined accumulation of superior genes/alleles in parents and the optimal genetic distance between parents, and that yield heterosis under DS treatment was mainly determined by the non-additive effects.展开更多
The Tangshan Sipingtou (TSSPT) germplasm in inbreds of the Tangshan Sipingtou heterotic group of maize in China was mainly derived from Huangzao4, and the source of TSSPT germplasm was severely restricted by the inbre...The Tangshan Sipingtou (TSSPT) germplasm in inbreds of the Tangshan Sipingtou heterotic group of maize in China was mainly derived from Huangzao4, and the source of TSSPT germplasm was severely restricted by the inbred Tangsipingtou. Except Tangsipingtou, the contents of TSSPT germplasm were only 50% or less in inbreds of this group, with the existence of more than 20 non-TSSPT gennplasms which resulted in abundant genetic diversity in this group. 95.22% inbreds of this group contained both TSSPT and UNS(unknown source) gennplasms in the ratio of 1 :1, with 12. 5 - 50% of each germplasm. The recombination of TSSPT and UNS germplasms had produced Huangzao4, the most important maize germplasm of compact plant form. About 90. 24% of the inbreds in this group were the inbred Huangzao4 and its derivatives. 11.11% of the derivatives contained 25 - 50% of Luda Honggu(LDHG) germplasm, and 16.67% of the derivatives contained 12. 5 - 25% Creole and 6. 25 -28.13% LSC germplasms. In addition, 97. 56% of the inbreds of this group contained one or more non-TSSPT germplasms. This indicates that the germplasm base of inbreds of the TSSPT heterotic group had changed and evolved away from actual TSSPT germplasm.展开更多
Lancaster Surecrop (LSC) germplasm in inbreds of the Lancaster heterotic group in China was mainly provided by the two inbreds Mol7 and Oh43. Furthermore, the source of LSC germplasm was severely restricted in two inb...Lancaster Surecrop (LSC) germplasm in inbreds of the Lancaster heterotic group in China was mainly provided by the two inbreds Mol7 and Oh43. Furthermore, the source of LSC germplasm was severely restricted in two inbreds, C103 and Oh40B. The contents of LSC germplasm are 50% or less in inbreds of the group, with the existence of more than 20 non-LSC germplasms that results in the abundant genetic diversity in the group. Most inbreds of Mol7 subgroup contain 25% - 50% LSC, 12.5% - 25% Reid Yellow Dent (RYD) and 12.5%- 25% Iowa Goldmine germplasms in the ratio of 2:1:1, and most inbreds of Zi330 subgroup contain 12.5% - 25% LSC, 6.25% - 12.5% RYD, 6.25% - 12.5% Minnesota # 13 and 25% - 50% Creole germplasms in the ratio of 2:1:1 4. AH the facts indicated that the germplasm base of the Lancaster heterotic group has stupendously changed and evolved away from actual LSC germplasm.展开更多
Simple sequence repeats (SSRs) were used to detect genetic variation among 21 maize(Zea mays L. ) inbred lines. Forty-three SSR primers selected from 69 primers gave stable amplification profiles, which could be clear...Simple sequence repeats (SSRs) were used to detect genetic variation among 21 maize(Zea mays L. ) inbred lines. Forty-three SSR primers selected from 69 primers gave stable amplification profiles, which could be clearly resolved on 3% Metaphor agarose gel, and produced 127 polymorphic amplified fragments.The average number of alleles per SSR locus was 2.95 with a range from 2 to 7. The polymorphism information content (PIC) for the SSR loci varied from 0.172 to 0.753 with an average of 0.511. Genetic similarities among the 21 lines ranged from 0.480 between the combination of Zhongzi451 vs. K12 up to 0.768 between CA156 vs. Ye478. The cluster analysis showed that 21 inbred lines could be classified into two distinct clusters with several subclusters, which corresponded to the heterotic groups determined by their pedigree information.Eight SSR primers, which had high level of polymorphism, could allow a rapid and efficient identification of 21 inbreds. Consequently, SSR markers could be used for measuring genetic variation of maize inbred lines and assigning them to heterotic groups.展开更多
Heterotic group theory （HGT） has played a major role in supporting hybrid maize breeding for about 100 years. The basic content and studies of HGT, and its application in rice and maize were summarized in this paper...Heterotic group theory （HGT） has played a major role in supporting hybrid maize breeding for about 100 years. The basic content and studies of HGT, and its application in rice and maize were summarized in this paper. Additionally, difficulties and challenges for hybrid rice breeding in China were analyzed, and necessity and urgency in hybrid rice breeding by using HGT were proposed.展开更多
Winter cabbage is an important crop cultivated through winter in the region near the Yangtze River, enabling the supply of fresh cabbage there at that time of year. However, a problem has emerged regarding the newly d...Winter cabbage is an important crop cultivated through winter in the region near the Yangtze River, enabling the supply of fresh cabbage there at that time of year. However, a problem has emerged regarding the newly developed parents of winter cabbage, which is completely different from spring and autumn cabbage, namely, how to combine these parents to breed an elite hybrid. To classify the heterotic groups and improve the efficiency of parent selection in winter cabbage breeding, 20 polymorphic SSR markers were selected to screen 63 winter cabbage inbred lines. Seventeen pairs among the 20 SSR markers amplified polymorphic bands. These primers amplified two to six bands,with an average of 2.8 bands per primer, and a total of 47 polymorphic bands were generated in the 63 inbred lines. These lines included flatheaded morphotype and round-headed morphotype, thus they were separately classified into heterotic groups based on the SSR markers. The flat-headed morphotype contained 21 inbred lines and was classified into three heterotic groups, named Hanchun 4, Jiali, and Dongsheng, in accordance with the representative germplasm contained in each group. The round-headed morphotype contained 42 inbred lines and was classified into five heterotic groups, named Parte, Bejo1039, YK-143, SCA002, and Golden B90. Meanwhile, parent analysis of 20 developed elite combinations showed that their parents were all distributed in different heterotic groups, indicating that the group classification was reasonable,which can provide a basis for further parent selection in winter cabbage breeding. Furthermore, polymorphic SSR primers were successfully used to identify the hybrid purity of three elite varieties.展开更多
基金This work was supported by the National Basic Research Project(2001CB108801)Modern Agricultural Project in National 863 Pragram,China.
文摘In this investigation, maize heterotic groups and patterns were analyzed based on theplanting areas from 1992 to 2001 using 84 parent lines of 71 widely extended hybrids andclassification results by SSR markers, in which these lines were assigned into sevenheterotic groups based on Ni-LIs genetic distances. The results indicated that acertain extent change for major heterotic groups of maize took place during past decadein China. The major heterotic groups were Lancaster, Reid, Tang SPT, Zi330 and E28 in theearly 1990s, while they became Reid, Tem-tropicⅠ, Zi330, Tang SPT and Lancaster in theearly 21st century. Tem-tropicⅠwas a new heterotic group, which contained tropic maizegermplasm. The changes for heterotic patterns also occurred. Some new heterotic patternscombining with Tem-tropicⅠappeared, such as ReidTem-tropicⅠ, Zi330Tem-tropicⅠ,Tang SPTTem-tropicⅠ, etc.. Another change was the order of heterotic patterns. In theearly and middle 1990s, the top five heterotic patterns were ReidTang SPT, Zi330Lancaster, LancasterTang SPT, LancasterE28 and ReidZi330, while they became ReidTem-tropicⅠ, ReidZi330, ReidTang SPT, Zi330Tem-tropicⅠand LancasterTang SPT inthe early 21 century. ReidTem-tropicⅠand Zi330Tem-tropicⅠwere laid on the firstand forth Chinese heterotic patterns respectively in 2001. These results providedsignificant information to understand the maize heterotic groups and patterns in Chinaat molecular level.
基金supported by the National Natural Science Foundation of China(31760424)the Scientific and Technological Project of Xinjiang Production and Construction Corps of China(2019AB021)。
文摘Understanding the heterosis in multiple environments between different heterotic groups is of fundamental importance in successful maize breeding. A total of 737 hybrids derived from 41 maize inbreds were evaluated over two years, with the aim of assessing the genetic diversity and their performance between heterotic groups under drought-stressed(DS) and well-watered(WW) treatments. A total of 38 737 SNPs were employed to assess the genetic diversity. The genetic distance(GD) between the parents ranged from 0.05 to 0.74, and the 41 inbreds were classified into five heterotic groups. According to the hybrid performance(high yield and early maturity between heterotic groups), the heterosis and heterotic patterns of Iowa Stiff Stalk Synthetic(BSSS)×Non-Stiff Stalk(NSS), NSS×Sipingtou(SPT) and BSSS×SPT were identified to be useful options in China’s maize breeding. The relative importance of general and specific combining abilities(GCA and SCA) suggests the importance of the additive genetic effects for grain yield traits under the WW treatment, but the non-additive effects under the DS treatment. At least one of the parental lines with drought tolerance and a high GCA effect would be required to achieve the ideal hybrid performance under drought conditions. GD showed a positive correlation with yield and yield heterosis in within-group hybrids over a certain range of GD. The present investigation suggests that the heterosis is due to the combined accumulation of superior genes/alleles in parents and the optimal genetic distance between parents, and that yield heterosis under DS treatment was mainly determined by the non-additive effects.
文摘The Tangshan Sipingtou (TSSPT) germplasm in inbreds of the Tangshan Sipingtou heterotic group of maize in China was mainly derived from Huangzao4, and the source of TSSPT germplasm was severely restricted by the inbred Tangsipingtou. Except Tangsipingtou, the contents of TSSPT germplasm were only 50% or less in inbreds of this group, with the existence of more than 20 non-TSSPT gennplasms which resulted in abundant genetic diversity in this group. 95.22% inbreds of this group contained both TSSPT and UNS(unknown source) gennplasms in the ratio of 1 :1, with 12. 5 - 50% of each germplasm. The recombination of TSSPT and UNS germplasms had produced Huangzao4, the most important maize germplasm of compact plant form. About 90. 24% of the inbreds in this group were the inbred Huangzao4 and its derivatives. 11.11% of the derivatives contained 25 - 50% of Luda Honggu(LDHG) germplasm, and 16.67% of the derivatives contained 12. 5 - 25% Creole and 6. 25 -28.13% LSC germplasms. In addition, 97. 56% of the inbreds of this group contained one or more non-TSSPT germplasms. This indicates that the germplasm base of inbreds of the TSSPT heterotic group had changed and evolved away from actual TSSPT germplasm.
文摘Lancaster Surecrop (LSC) germplasm in inbreds of the Lancaster heterotic group in China was mainly provided by the two inbreds Mol7 and Oh43. Furthermore, the source of LSC germplasm was severely restricted in two inbreds, C103 and Oh40B. The contents of LSC germplasm are 50% or less in inbreds of the group, with the existence of more than 20 non-LSC germplasms that results in the abundant genetic diversity in the group. Most inbreds of Mol7 subgroup contain 25% - 50% LSC, 12.5% - 25% Reid Yellow Dent (RYD) and 12.5%- 25% Iowa Goldmine germplasms in the ratio of 2:1:1, and most inbreds of Zi330 subgroup contain 12.5% - 25% LSC, 6.25% - 12.5% RYD, 6.25% - 12.5% Minnesota # 13 and 25% - 50% Creole germplasms in the ratio of 2:1:1 4. AH the facts indicated that the germplasm base of the Lancaster heterotic group has stupendously changed and evolved away from actual LSC germplasm.
文摘Simple sequence repeats (SSRs) were used to detect genetic variation among 21 maize(Zea mays L. ) inbred lines. Forty-three SSR primers selected from 69 primers gave stable amplification profiles, which could be clearly resolved on 3% Metaphor agarose gel, and produced 127 polymorphic amplified fragments.The average number of alleles per SSR locus was 2.95 with a range from 2 to 7. The polymorphism information content (PIC) for the SSR loci varied from 0.172 to 0.753 with an average of 0.511. Genetic similarities among the 21 lines ranged from 0.480 between the combination of Zhongzi451 vs. K12 up to 0.768 between CA156 vs. Ye478. The cluster analysis showed that 21 inbred lines could be classified into two distinct clusters with several subclusters, which corresponded to the heterotic groups determined by their pedigree information.Eight SSR primers, which had high level of polymorphism, could allow a rapid and efficient identification of 21 inbreds. Consequently, SSR markers could be used for measuring genetic variation of maize inbred lines and assigning them to heterotic groups.
基金supported by the grant from the program of Introducing Talents of Discipline to University of China(Grant No.B08025)
文摘Heterotic group theory （HGT） has played a major role in supporting hybrid maize breeding for about 100 years. The basic content and studies of HGT, and its application in rice and maize were summarized in this paper. Additionally, difficulties and challenges for hybrid rice breeding in China were analyzed, and necessity and urgency in hybrid rice breeding by using HGT were proposed.
基金supported by grants from the Major State Research Development Program (2016YFD0101702)the Science and Technology Innovation Program of Chinese Academy of Agricultural Sciences (CAAS-ASTIP-IVFCAAS)the earmarked fund for the Modern Agro-Industry Technology Research System, China (nycytx-35-gw01)
文摘Winter cabbage is an important crop cultivated through winter in the region near the Yangtze River, enabling the supply of fresh cabbage there at that time of year. However, a problem has emerged regarding the newly developed parents of winter cabbage, which is completely different from spring and autumn cabbage, namely, how to combine these parents to breed an elite hybrid. To classify the heterotic groups and improve the efficiency of parent selection in winter cabbage breeding, 20 polymorphic SSR markers were selected to screen 63 winter cabbage inbred lines. Seventeen pairs among the 20 SSR markers amplified polymorphic bands. These primers amplified two to six bands,with an average of 2.8 bands per primer, and a total of 47 polymorphic bands were generated in the 63 inbred lines. These lines included flatheaded morphotype and round-headed morphotype, thus they were separately classified into heterotic groups based on the SSR markers. The flat-headed morphotype contained 21 inbred lines and was classified into three heterotic groups, named Hanchun 4, Jiali, and Dongsheng, in accordance with the representative germplasm contained in each group. The round-headed morphotype contained 42 inbred lines and was classified into five heterotic groups, named Parte, Bejo1039, YK-143, SCA002, and Golden B90. Meanwhile, parent analysis of 20 developed elite combinations showed that their parents were all distributed in different heterotic groups, indicating that the group classification was reasonable,which can provide a basis for further parent selection in winter cabbage breeding. Furthermore, polymorphic SSR primers were successfully used to identify the hybrid purity of three elite varieties.
