A 3×3 complete diallel cross comprising three families of the clam Meretrix meretrix（P1, P2 and P3） was used to determine the combining ability of parental families and heterosis of F1 under indoor and openair ...A 3×3 complete diallel cross comprising three families of the clam Meretrix meretrix（P1, P2 and P3） was used to determine the combining ability of parental families and heterosis of F1 under indoor and openair environments for growth traits. Analysis of variance for shell length and whole body weight indicated highly significant cross effects, environment effects and the interaction of cross by environment. General combining ability（GCA） and specific combing ability exhibited great variation among crosses and between two environments. Pooled over environments, P2 was the top combiner among the three parental families for both traits studied. The cross of P1 and P3 had the highest SCA. Additionally, significant reciprocal effects were observed. For individual environment, about half of the crossbred combinations showed favorable Mid-parent heterosis（MPH）（〉1%） for the shell length and whole body weight. Our data has shown that non-additive genetic and reciprocal effects constituted the major sources of genetic variation for both shell length and whole body weight, which indicates that crossbreeding among selective families could further explore the heterotic effects.展开更多
The wheatgrass, Thinopyrum intermedium （Host） Barkworth ＆ DR Dewey, shows many beneficial characteristics, such as big spikes and high resistance to many diseases. To transfer the beneficial genes of this species, ...The wheatgrass, Thinopyrum intermedium （Host） Barkworth ＆ DR Dewey, shows many beneficial characteristics, such as big spikes and high resistance to many diseases. To transfer the beneficial genes of this species, many wheat- Thinopyrum intermedium alien chromosome lines were developed. Of them, Shannong 0095 （SN0095）, a disomic substitution, has long spikes and flag-leaves, and thus may be an important genetic resource for wheat yield improvement. In order to realize its heterosis and combining ability on major yield traits, a 7 ×7 complete diallel design was made according to Griffing＇s Method-1. The results showed that heterosis for spike length （SPL）, flag-leaf area （FLA）, number of spikes per plant （NSP）, number of spikelets per spike （NSL）, kernels per spike （KPS）, 1 000-kernel weight （TKW） and grain yield per plant （GYP） existed in all the crosses by SN0095, but heterobeltiosis occurred only for KPS, TKW, and GYP. The relative mid-parent heterosis （RMH） and relative high-parent heterosis （RHH） for GYP, which valued as high as 35.32 and 29.92% respectively, were the highest among all the traits mearsured. Though additive and non-additive gene effects and cytoplasmic effects （or cytoplasmic-nuclear interaction effects） were found in governing all the traits measured above, additive gene action played a predominant role. The results also showed that SN0095 was the best-general combiner for SPL and FLA, and high-general combiner for NSP amongst all the parents. Estimates of specific combining ability （SCA） showed that SN0095 could also make high-SCA combinations for GYP, such as SN0095 × Jimai 19 （JMI9）. SN0095 could be a unique and important parent in hybrid wheat breeding programs.展开更多
Vitamin A deficiency has become a worldwide problem.Biofortified foods can potentially be an inexpensive,locally adaptable,and long-term solution to dietary-nutrient deficiency.In order to improve the β-carotene cont...Vitamin A deficiency has become a worldwide problem.Biofortified foods can potentially be an inexpensive,locally adaptable,and long-term solution to dietary-nutrient deficiency.In order to improve the β-carotene content in maize grain by breeding and minimize vitamin A deficiency,a complete diallel cross was designed with eight inbred lines of maize,and 64 combinations were obtained in this study.The experimental combinations were planted in Yunnan and Sichuan provinces,respectively,with a random complete block design.The β-carotene contents in the grains of the experimental materials were analyzed by high-performance liquid chromatography.Among the tested materials,the effect difference of general combining ability of the β-carotene content was significant;however,the effect difference of the special combining ability and the reciprocal effect were not significant.The β-carotene content of maize grain was not influenced significantly by the cross and the reciprocal cross.There was a significant correlation about the β-carotene content in the maize grains between the F 1 and their parents.The combinations with high β-carotene content were obviously influenced by the environment,and the mean value of β-carotene content for the experimental materials planted in Ya＇an of Sichuan was higher than that planted in Yuanjiang of Yunnan,with the results being significant at the 0.01 level.展开更多
Cross combinations from six rapeseed cultivars and lines were evaluated under waterlogging stress condition in order to understand the genetic mechanism of waterlogging tolerance of Brassica napus L.and provide reason...Cross combinations from six rapeseed cultivars and lines were evaluated under waterlogging stress condition in order to understand the genetic mechanism of waterlogging tolerance of Brassica napus L.and provide reasonable improvement programs.There were six germination traits investigated on combining ability and heritability using complete diallel crossing method designed for 30 combinations from those six cultivars and lines.The traits included relative root length,stem length,fresh weight per plant,survival rate,electrical conductivity,and vigor index.After flooding treatment,the six traits of parents and F1 were analyzed.The general combining ability（GCA） and special combining ability（SCA） of germination traits were analyzed using Griffing I method.Among 30 cross combinations,the GCA was significantly different among six waterlogging resistance traits.The SCA of these traits was significantly different except the SCA of electrical conductivity.As a representative trait of waterlogging tolerance in rapeseed,relative vigor index had the highest narrow heritability and relatively low broad heritability.The cultivars Zhongshuang 9 and P79 had higher tolerance potential to waterlogging stress.It can be concluded that combining ability and genetic effects of relative vigor index during germination stage could be used to identify the waterlogging tolerance of rapeseed in breeding program.展开更多
基金The National High-Tech R&D Program of China(863 Program)under contract No.2012AA10A410the Key Technologies R&D Program of Jiangsu Province under contract No.BE2011372
文摘A 3×3 complete diallel cross comprising three families of the clam Meretrix meretrix（P1, P2 and P3） was used to determine the combining ability of parental families and heterosis of F1 under indoor and openair environments for growth traits. Analysis of variance for shell length and whole body weight indicated highly significant cross effects, environment effects and the interaction of cross by environment. General combining ability（GCA） and specific combing ability exhibited great variation among crosses and between two environments. Pooled over environments, P2 was the top combiner among the three parental families for both traits studied. The cross of P1 and P3 had the highest SCA. Additionally, significant reciprocal effects were observed. For individual environment, about half of the crossbred combinations showed favorable Mid-parent heterosis（MPH）（〉1%） for the shell length and whole body weight. Our data has shown that non-additive genetic and reciprocal effects constituted the major sources of genetic variation for both shell length and whole body weight, which indicates that crossbreeding among selective families could further explore the heterotic effects.
基金supported by the National Natural Science Foundation of China (30571156)
文摘The wheatgrass, Thinopyrum intermedium （Host） Barkworth ＆ DR Dewey, shows many beneficial characteristics, such as big spikes and high resistance to many diseases. To transfer the beneficial genes of this species, many wheat- Thinopyrum intermedium alien chromosome lines were developed. Of them, Shannong 0095 （SN0095）, a disomic substitution, has long spikes and flag-leaves, and thus may be an important genetic resource for wheat yield improvement. In order to realize its heterosis and combining ability on major yield traits, a 7 ×7 complete diallel design was made according to Griffing＇s Method-1. The results showed that heterosis for spike length （SPL）, flag-leaf area （FLA）, number of spikes per plant （NSP）, number of spikelets per spike （NSL）, kernels per spike （KPS）, 1 000-kernel weight （TKW） and grain yield per plant （GYP） existed in all the crosses by SN0095, but heterobeltiosis occurred only for KPS, TKW, and GYP. The relative mid-parent heterosis （RMH） and relative high-parent heterosis （RHH） for GYP, which valued as high as 35.32 and 29.92% respectively, were the highest among all the traits mearsured. Though additive and non-additive gene effects and cytoplasmic effects （or cytoplasmic-nuclear interaction effects） were found in governing all the traits measured above, additive gene action played a predominant role. The results also showed that SN0095 was the best-general combiner for SPL and FLA, and high-general combiner for NSP amongst all the parents. Estimates of specific combining ability （SCA） showed that SN0095 could also make high-SCA combinations for GYP, such as SN0095 × Jimai 19 （JMI9）. SN0095 could be a unique and important parent in hybrid wheat breeding programs.
基金supported by the Harvest-Plus China Program,the National High-Tech R&D Program of China(2011AA10A103)the Sichuan Maize Breeding Program in the 12th Five-Year Plan,China
文摘Vitamin A deficiency has become a worldwide problem.Biofortified foods can potentially be an inexpensive,locally adaptable,and long-term solution to dietary-nutrient deficiency.In order to improve the β-carotene content in maize grain by breeding and minimize vitamin A deficiency,a complete diallel cross was designed with eight inbred lines of maize,and 64 combinations were obtained in this study.The experimental combinations were planted in Yunnan and Sichuan provinces,respectively,with a random complete block design.The β-carotene contents in the grains of the experimental materials were analyzed by high-performance liquid chromatography.Among the tested materials,the effect difference of general combining ability of the β-carotene content was significant;however,the effect difference of the special combining ability and the reciprocal effect were not significant.The β-carotene content of maize grain was not influenced significantly by the cross and the reciprocal cross.There was a significant correlation about the β-carotene content in the maize grains between the F 1 and their parents.The combinations with high β-carotene content were obviously influenced by the environment,and the mean value of β-carotene content for the experimental materials planted in Ya＇an of Sichuan was higher than that planted in Yuanjiang of Yunnan,with the results being significant at the 0.01 level.
基金supported by the National High-Tech Research and Development Program of China (863 Program,2006AA10Z1C2)the Key Technologies R&D Program of China during the 10th Five-Year Plan period (2009BADA8B01,2110BAD01B09)the Natural Science Foundation of Hubei Province,China(2009CDA089)
文摘Cross combinations from six rapeseed cultivars and lines were evaluated under waterlogging stress condition in order to understand the genetic mechanism of waterlogging tolerance of Brassica napus L.and provide reasonable improvement programs.There were six germination traits investigated on combining ability and heritability using complete diallel crossing method designed for 30 combinations from those six cultivars and lines.The traits included relative root length,stem length,fresh weight per plant,survival rate,electrical conductivity,and vigor index.After flooding treatment,the six traits of parents and F1 were analyzed.The general combining ability（GCA） and special combining ability（SCA） of germination traits were analyzed using Griffing I method.Among 30 cross combinations,the GCA was significantly different among six waterlogging resistance traits.The SCA of these traits was significantly different except the SCA of electrical conductivity.As a representative trait of waterlogging tolerance in rapeseed,relative vigor index had the highest narrow heritability and relatively low broad heritability.The cultivars Zhongshuang 9 and P79 had higher tolerance potential to waterlogging stress.It can be concluded that combining ability and genetic effects of relative vigor index during germination stage could be used to identify the waterlogging tolerance of rapeseed in breeding program.
