Since the combining ability was proposed in 1942, efforts to uncover the genetic basis underlying this phenomenon have been ongoing for nearly 70 yr, with little success. Some breeding strategies based on evaluation o...Since the combining ability was proposed in 1942, efforts to uncover the genetic basis underlying this phenomenon have been ongoing for nearly 70 yr, with little success. Some breeding strategies based on evaluation of combining ability have been produced, and are still extensively used in hybrid breeding. In this review, the genetic basis underlying these breeding strategies is discussed, and a potential genetic control of general combining ability （GCA） is postulated. We suggested that GCA and the yields of inbred lines might be genetically controlled by different sets of loci on the maize genome that are transmitted into offspring. Different inbred lines might possess different favorable alleles for GCA. In hybrids, loci involved in multiple pathways, which are directly or indirectly associated with yield performance, might be regulated by GCA loci. In addition, a case of GCA mapping using a set of testcross progeny from introgression lines is provided.展开更多
Information on the genetic relationship between tropical maize (Zea mays L), germplasm and temperate maize germplasm is of great value to maize breeding. The objective of this study was to determine the combining abil...Information on the genetic relationship between tropical maize (Zea mays L), germplasm and temperate maize germplasm is of great value to maize breeding. The objective of this study was to determine the combining ability and genetic relationship of 25 inbreds extracted from five tropical maize populations and a land race, with four temperate maize inbreds (Huangzaosi, Mol7, B73 and Dan 340). The 25 tropical inbreds were crossed with the four temperate inbreds and evaluated. Lines from Suwanl and POP28 had high general combining ability (GCA) for grain yield. The lines from POP32 (ETO) had the highest special combining ability (SCA) with B73; the average SCA value of the 5 lines was 879 kg/ha. The lines from Suwanl had the second-highest SCA (584 kg/ha) with Huangzaosi. The lines from Suwanl had the greatest relative heterosis (20%) with B73, followed by the lines from POP32 (ETO) with B73 (19%). Five heterotic patterns have been identified from this study: Suwanl × Reid, ETO × Reid, POP28× Reid, POP28× Ludahong-gu, and Suwan1× Lancaster.展开更多
Lycopene is a red pigment in tomato with purported antioxidant properties. As the amount of lycopene has been reported to differ in different colored tomatoes or even absent in non-red tomatoes, the objective of this ...Lycopene is a red pigment in tomato with purported antioxidant properties. As the amount of lycopene has been reported to differ in different colored tomatoes or even absent in non-red tomatoes, the objective of this study was to investigate the inheritance of lycopene content and the color parameters of hybrids using a 10 parent diallel excluding reciprocals. Parents differed in general combining ability (GCA) for lycopene and color parameters. “Chocolate Stripe” (purple and brown striped) had the highest lycopene content followed by NC 1CS (red colored with the crimson gene) with the best general combining ability among parental lines. Hybrids differed in lycopene content and color parameters across two summer and greenhouse experiments, with no interaction between experiments indicating that the lycopene content was consistent. Narrow-sense heritability for lycopene was only 9% whereas broad-sense heritability was estimated to be 25%. The order of dominance for lycopene content was found as purple-brown > red > blue > yellow > green. Heritability estimates for color parameters were close to those for lycopene. This information may be useful in developing specialty type tomatoes or increasing lycopene content in tomatoes.展开更多
The assessment of heterotic F1 combinations is a basic requisite for hybrid seed development. A set of 30 F1 hybrids along with their parental inbred lines were evaluated under both normal and water deficit conditions...The assessment of heterotic F1 combinations is a basic requisite for hybrid seed development. A set of 30 F1 hybrids along with their parental inbred lines were evaluated under both normal and water deficit conditions for various physiological and agronomic traits. Highly significant mean squares due to general combining ability, specific combining ability and reciprocal effect were observed for all traits under both water regimes. Components of variation exhibited greater estimates for GCA variance (б2g) than SCA variance (б2s) for majority of the traits under both normal and stress conditions depicting the predominant role of additive genetic component. Inbred lines NCIL-20-20, D-157 and OH-8 were found to be the best general combiner on the basis of performance regarding grain yield per plant under water deficit condition. The F1 combinations namely, NCIL-20-20 × D-109, NCIL-20-20 × OH-8 and D-157 × NCIL-20-20 were out-performers based on yield and yield attributes under water deficit conditions. On the basis of our results, we recommend these hybrids for further exploitation to assess their potential for commercial cultivation under water deficit condition.展开更多
The collection of alfalfa in the context of ecology-geographical groups was studied, consisting of 1,078 samples, including 985 samples of the cultivated species--M, sativa L. and M. varia Mart., and 93 samples for ot...The collection of alfalfa in the context of ecology-geographical groups was studied, consisting of 1,078 samples, including 985 samples of the cultivated species--M, sativa L. and M. varia Mart., and 93 samples for other wild species. Highly productive samples are allocated in the three-year cycle of using the grass stand in the haymaking regime. Individual genotypes of isolated samples are used for selection of inbred lines required for the formation of synthetic varieties. Inbred lines were created by forced self-pollination on genotypes with signs of self-fertility. Methodical experiments established the efficiency of bringing inbred lines to generations J2 and J3. In this case, the overall combinational ability reaches a potential value, and further incubation outside of J2 and J3 does not significantly affect its value. With the selection of the best inbred lines in J2 and J3, the lucerne varieties： Kokorai, Osimtal and Kokbalausa, which are protected by patents and author＇s certificates, have been created in accordance with the general combination ability and their inclusion in the structure of synthetic varieties.展开更多
基金supported by the National Basic Research Program of China (2011CB100100)the National Natural Science Foundation of China (30971791)
文摘Since the combining ability was proposed in 1942, efforts to uncover the genetic basis underlying this phenomenon have been ongoing for nearly 70 yr, with little success. Some breeding strategies based on evaluation of combining ability have been produced, and are still extensively used in hybrid breeding. In this review, the genetic basis underlying these breeding strategies is discussed, and a potential genetic control of general combining ability （GCA） is postulated. We suggested that GCA and the yields of inbred lines might be genetically controlled by different sets of loci on the maize genome that are transmitted into offspring. Different inbred lines might possess different favorable alleles for GCA. In hybrids, loci involved in multiple pathways, which are directly or indirectly associated with yield performance, might be regulated by GCA loci. In addition, a case of GCA mapping using a set of testcross progeny from introgression lines is provided.
基金funded by the Natural Science Foundation of Yunnan Province(980006Z).
文摘Information on the genetic relationship between tropical maize (Zea mays L), germplasm and temperate maize germplasm is of great value to maize breeding. The objective of this study was to determine the combining ability and genetic relationship of 25 inbreds extracted from five tropical maize populations and a land race, with four temperate maize inbreds (Huangzaosi, Mol7, B73 and Dan 340). The 25 tropical inbreds were crossed with the four temperate inbreds and evaluated. Lines from Suwanl and POP28 had high general combining ability (GCA) for grain yield. The lines from POP32 (ETO) had the highest special combining ability (SCA) with B73; the average SCA value of the 5 lines was 879 kg/ha. The lines from Suwanl had the second-highest SCA (584 kg/ha) with Huangzaosi. The lines from Suwanl had the greatest relative heterosis (20%) with B73, followed by the lines from POP32 (ETO) with B73 (19%). Five heterotic patterns have been identified from this study: Suwanl × Reid, ETO × Reid, POP28× Reid, POP28× Ludahong-gu, and Suwan1× Lancaster.
文摘Lycopene is a red pigment in tomato with purported antioxidant properties. As the amount of lycopene has been reported to differ in different colored tomatoes or even absent in non-red tomatoes, the objective of this study was to investigate the inheritance of lycopene content and the color parameters of hybrids using a 10 parent diallel excluding reciprocals. Parents differed in general combining ability (GCA) for lycopene and color parameters. “Chocolate Stripe” (purple and brown striped) had the highest lycopene content followed by NC 1CS (red colored with the crimson gene) with the best general combining ability among parental lines. Hybrids differed in lycopene content and color parameters across two summer and greenhouse experiments, with no interaction between experiments indicating that the lycopene content was consistent. Narrow-sense heritability for lycopene was only 9% whereas broad-sense heritability was estimated to be 25%. The order of dominance for lycopene content was found as purple-brown > red > blue > yellow > green. Heritability estimates for color parameters were close to those for lycopene. This information may be useful in developing specialty type tomatoes or increasing lycopene content in tomatoes.
文摘The assessment of heterotic F1 combinations is a basic requisite for hybrid seed development. A set of 30 F1 hybrids along with their parental inbred lines were evaluated under both normal and water deficit conditions for various physiological and agronomic traits. Highly significant mean squares due to general combining ability, specific combining ability and reciprocal effect were observed for all traits under both water regimes. Components of variation exhibited greater estimates for GCA variance (б2g) than SCA variance (б2s) for majority of the traits under both normal and stress conditions depicting the predominant role of additive genetic component. Inbred lines NCIL-20-20, D-157 and OH-8 were found to be the best general combiner on the basis of performance regarding grain yield per plant under water deficit condition. The F1 combinations namely, NCIL-20-20 × D-109, NCIL-20-20 × OH-8 and D-157 × NCIL-20-20 were out-performers based on yield and yield attributes under water deficit conditions. On the basis of our results, we recommend these hybrids for further exploitation to assess their potential for commercial cultivation under water deficit condition.
文摘The collection of alfalfa in the context of ecology-geographical groups was studied, consisting of 1,078 samples, including 985 samples of the cultivated species--M, sativa L. and M. varia Mart., and 93 samples for other wild species. Highly productive samples are allocated in the three-year cycle of using the grass stand in the haymaking regime. Individual genotypes of isolated samples are used for selection of inbred lines required for the formation of synthetic varieties. Inbred lines were created by forced self-pollination on genotypes with signs of self-fertility. Methodical experiments established the efficiency of bringing inbred lines to generations J2 and J3. In this case, the overall combinational ability reaches a potential value, and further incubation outside of J2 and J3 does not significantly affect its value. With the selection of the best inbred lines in J2 and J3, the lucerne varieties： Kokorai, Osimtal and Kokbalausa, which are protected by patents and author＇s certificates, have been created in accordance with the general combination ability and their inclusion in the structure of synthetic varieties.
