Abstract: In a laboratory study, indica and japonica rice (Oryza sativa L.) seeds were exposed to thermal hardening (heating followed by chilling followed by heating; chilling followed by heating followed by chilling;...Abstract: In a laboratory study, indica and japonica rice (Oryza sativa L.) seeds were exposed to thermal hardening (heating followed by chilling followed by heating; chilling followed by heating followed by chilling; heating followed by chilling or chilling followed by heating). In indica rice, heating followed by chilling followed by heating resulted in decreased mean germination time, time to start germination, electrical conductivity of seed leachates, and time to 50% germination, as well as increased germination index, energy of germination, radicle and plumule length, root length, root/shoot ratio, root fresh and dry weight, radicle and plumule growth rate, and shoot fresh weight. In japonica rice, chilling followed by heating followed by chilling performed better than all other treatments, including control.展开更多
The development of transgenic rice with novel traits in China can increase rice productivity, but transgene flow to improved or weedy rice has become a major concern. We aimed to evaluate the potential maximum frequen...The development of transgenic rice with novel traits in China can increase rice productivity, but transgene flow to improved or weedy rice has become a major concern. We aimed to evaluate the potential maximum frequencies of transgene flow from glufosinate-resistant rice to improved rice cultivars and weedy rice. Treatments were arranged in randomized complete blocks with three replicates. Experiments were conducted between 2009 and 2010 at the Center for Environmental Safety Supervision and Inspection for Genetically Modified Plants, China National Rice Research Institute, Hangzhou, China. Glufosinate-resistant japonica rice 99-1 was the pollen donor. The pollen recipients were two inbred japonica rice （Chunjiang 016 and Xiushui 09）, two inbred indica rice （Zhongzu 14 and Zhongzao 22）, two indica hybrid rice （Zhongzheyou 1 and Guodao 1）, and one weedy indica rice （Taizhou weedy rice）. The offspring of recipients were planted in the field and sprayed with a commercial dose of glufosinate. Leaf tissues of survivors were analyzed by polymerase chain reaction to detect the presence of the transgene. The frequency of gene flow ranged from 0 to 0.488%. In 2009, the order of gene flow frequency was as follows： weedy rice 〉 Chunjiang 016 〉 Xiushui 09 and Zhongzu 14 〉 Guodao 1, Zhongzheyou 1 and Zhongzao 22. Gene flow frequencies were generally higher in 2009 than in 2010, but did not differ significantly among rice materials. Gene flow frequency was the highest in weedy rice followed by the inbred japonica rice. The risk of gene flow differed significantly between years and year-to-year variance could mask risk differences among pollen recipients. Gene flow was generally lesser in taller pollen recipients than in shorter ones, but plant height only accounted for about 30% of variation in gene flow. When flowering synchrony was maximized, as in this study, low frequencies of gene flow occurred from herbicide-resistant japonica rice to other cultivars and weedy rice. Averaged across years, the risk展开更多
Thirty isolates of Magnaporthe grisea collected from 18 provinces/cities representing 21 pathotypes and 9 different lineages were inoculated to rice varieties with known resistance genes and some hybrid rices, convent...Thirty isolates of Magnaporthe grisea collected from 18 provinces/cities representing 21 pathotypes and 9 different lineages were inoculated to rice varieties with known resistance genes and some hybrid rices, conventional early indica and late japonica varieties cultivated recently in China. Virulence spectrum of the 30 isolates was very different, showing that they recognize numerous different resistance genes. Varieties also revealed very different resistance patterns showing that they carry different resistance genes or combinations of resistance genes. On the basis of comparisons with international differential varieties with known resistance genes, resistance genes in certain Chinese varieties could be speculated. The results indicated that some of them were resistant to most of the isolates tested and that they could be of interest as resistance sources for hybrid parents or to be planted in the field directly.展开更多
文摘Abstract: In a laboratory study, indica and japonica rice (Oryza sativa L.) seeds were exposed to thermal hardening (heating followed by chilling followed by heating; chilling followed by heating followed by chilling; heating followed by chilling or chilling followed by heating). In indica rice, heating followed by chilling followed by heating resulted in decreased mean germination time, time to start germination, electrical conductivity of seed leachates, and time to 50% germination, as well as increased germination index, energy of germination, radicle and plumule length, root length, root/shoot ratio, root fresh and dry weight, radicle and plumule growth rate, and shoot fresh weight. In japonica rice, chilling followed by heating followed by chilling performed better than all other treatments, including control.
基金funded by the China Agriculture Research System (Grant No. CARS-01)Zhejiang Science and Technology Project of China (Grant No. 2008C22086)
文摘The development of transgenic rice with novel traits in China can increase rice productivity, but transgene flow to improved or weedy rice has become a major concern. We aimed to evaluate the potential maximum frequencies of transgene flow from glufosinate-resistant rice to improved rice cultivars and weedy rice. Treatments were arranged in randomized complete blocks with three replicates. Experiments were conducted between 2009 and 2010 at the Center for Environmental Safety Supervision and Inspection for Genetically Modified Plants, China National Rice Research Institute, Hangzhou, China. Glufosinate-resistant japonica rice 99-1 was the pollen donor. The pollen recipients were two inbred japonica rice （Chunjiang 016 and Xiushui 09）, two inbred indica rice （Zhongzu 14 and Zhongzao 22）, two indica hybrid rice （Zhongzheyou 1 and Guodao 1）, and one weedy indica rice （Taizhou weedy rice）. The offspring of recipients were planted in the field and sprayed with a commercial dose of glufosinate. Leaf tissues of survivors were analyzed by polymerase chain reaction to detect the presence of the transgene. The frequency of gene flow ranged from 0 to 0.488%. In 2009, the order of gene flow frequency was as follows： weedy rice 〉 Chunjiang 016 〉 Xiushui 09 and Zhongzu 14 〉 Guodao 1, Zhongzheyou 1 and Zhongzao 22. Gene flow frequencies were generally higher in 2009 than in 2010, but did not differ significantly among rice materials. Gene flow frequency was the highest in weedy rice followed by the inbred japonica rice. The risk of gene flow differed significantly between years and year-to-year variance could mask risk differences among pollen recipients. Gene flow was generally lesser in taller pollen recipients than in shorter ones, but plant height only accounted for about 30% of variation in gene flow. When flowering synchrony was maximized, as in this study, low frequencies of gene flow occurred from herbicide-resistant japonica rice to other cultivars and weedy rice. Averaged across years, the risk
文摘Thirty isolates of Magnaporthe grisea collected from 18 provinces/cities representing 21 pathotypes and 9 different lineages were inoculated to rice varieties with known resistance genes and some hybrid rices, conventional early indica and late japonica varieties cultivated recently in China. Virulence spectrum of the 30 isolates was very different, showing that they recognize numerous different resistance genes. Varieties also revealed very different resistance patterns showing that they carry different resistance genes or combinations of resistance genes. On the basis of comparisons with international differential varieties with known resistance genes, resistance genes in certain Chinese varieties could be speculated. The results indicated that some of them were resistant to most of the isolates tested and that they could be of interest as resistance sources for hybrid parents or to be planted in the field directly.
