The development of resistant varieties and hybrid combinations has been the most effective and economical strategy to control blast disease caused by Magnaporthe oryzae.However, the distribution of major R genes and b...The development of resistant varieties and hybrid combinations has been the most effective and economical strategy to control blast disease caused by Magnaporthe oryzae.However, the distribution of major R genes and blast resistance characterization in hybrid rice parents has not been well investigated, resulting in their limited use in hybrid rice blast-resistance breeding. In the present study, 88 elite indica hybrid rice parental lines were evaluated with 30 isolates of M. oryzae collected from the main planting area of indica hybrid rice in China and were characterized for the presence of 11 major resistance genes using molecular markers. The pathogenicity assays showed that four types of hybrid rice parent line showed some resistance to M. oryzae. However, the proportions of highly resistant lines and the mean resistance frequency(RF) varied among the four types, with resistance in decreasing order shown by three-line restorer lines, three-line maintainer lines, two-line sterile lines, and two-line restorer lines. All 88 hybrid rice parental lines carried more than one R gene, but none carried the R genes Pi1 and Pi2. Although Pid3 and Pi9 were present only in three-line restorer lines and Pigm only in three-line maintainer lines, the remaining six R genes(Pib, Pid2, Pi5, Pia, Pi54, and Pita) were present in the four types of hybrid rice parent with significantly different distribution frequencies. The correlation between R genes and resistance reactions was investigated. The results are expected to provide useful information for rational utilization of major R genes in hybrid rice breeding programs.展开更多
The grain yield of maize has increased continuously in past decades, largely through hybrid innovation, cultivation tech-nology, and in particular, recent genetic improvements in photosynthesis. Elite inbred lines are...The grain yield of maize has increased continuously in past decades, largely through hybrid innovation, cultivation tech-nology, and in particular, recent genetic improvements in photosynthesis. Elite inbred lines are crucial for innovating new germplasm. Here, we analyzed variations in grain yield and a series of eco-physiological photosynthetic traits after anthesis in sixteen parental lines of maize (Zea mays L.) released during three different eras (1960s, 1980s, 2000s). We found that grain yield and biomass signiifcantly increased in the 2000s than those in the 1980s and 1960s. Leaf area, chlorophyl , and soluble protein content slowly decreased, and maintained a higher net photosynthesis rate (Pn) and improved stomatal conductance (Gs) after anthesis in the 2000s. In addition, the parental lines in the 2000s obtained higher actual photo-chemistry efifciency (ФPSI ) and the maximum PSII photochemistry efifciency (Fv/Fm), which largely improved light partition-ing and chlorophyl lfuorescence characteristic, including higher photochemical and photosystem II (PSII) reaction center activity, lower thermal energy dissipation in antenna proteins. Meanwhile, more lamel ae per granum within chloroplasts were observed in the parental lines of the 2000s, with a clear and complete chloroplast membrane, which wil greatly help to improve photosynthetic capacity and energy efifciency of ear leaf in maize parental lines. It is concluded that grain yield increase in modern maize parental lines is mainly attributed to the improved chloroplast structure and more light energy catched for the photochemical reaction, thus having a better stay-green characteristic and stronger photosynthetic capac-ity after anthesis. Our direct physiological evaluation of these inbred lines provides important information for the further development of promising maize cultivars.展开更多
Over the past seven decades, the grain yield of maize(Zea mays L.) has increased continuously in China, mostly due to hybridization innovations, particularly recent genetic improvements in photosynthesis. In order to ...Over the past seven decades, the grain yield of maize(Zea mays L.) has increased continuously in China, mostly due to hybridization innovations, particularly recent genetic improvements in photosynthesis. In order to reveal photosynthetic characters of elite inbred lines in different ears, a field experiment was conducted at the North China Plain of Shandong Province in China. Six parental lines of maize introduced in three eras(the 1960 s, 1980 s, and 2000 s) were investigated diurnal variation of gas exchange, chlorophyll fluorescence, and photosynthetic response characteristic at the grain filling stage. Compared to earlier parental lines, the 2000 s parental lines always had higher net photosynthetic rate(Pn) throughout the day, especially at noon, and a mid-day depression in Pn did not occur in all hybrids parental lines. Moreover, the stomatal conductance(Gs) and water use efficiency(WUE) of the 2000 s’ lines showed higher value than those of the 1960 s’ and 1980 s’ lines. The inbred lines differences in photosynthetic parameters were partly owing to their different quantum carboxylation efficiencies and light synthase activities. Simultaneously, the 2000 s parental lines exhibited lower light and CO2 compensation points, and their higher apparent quantum yield, and carboxylation efficiency. These suggested that the modern parental lines required lower light intensity and less CO2 to maintain a relatively high photosynthetic capacity, substantially increasing leaf physical quality and stress resistance. It provided crucial information of high photo-efficiency and stress-resistance breeding in maize.展开更多
The genetic diversity of 41 parental lines popularized in commercial hybrid rice production in China was studied by using cluster analysis of morphological traits and simple sequence repeat (SSR) markers. Forty-one ...The genetic diversity of 41 parental lines popularized in commercial hybrid rice production in China was studied by using cluster analysis of morphological traits and simple sequence repeat (SSR) markers. Forty-one entries were assigned into two clusters (i.e. early or medium-maturing cluster; medium or late-maturing cluster) and further assigned into six sub-clusters based on morphological trait cluster analysis, The early or medium-maturing cluster was composed of 15 maintainer lines, four early-maturing restorer lines and two thermo-sensitive genic male sterile lines, and the medium or late-maturing cluster included 16 restorer lines and 4 medium or late-maturing maintainer lines. Moreover, the SSR cluster analysis classified 41 entries into two groups (i.e, maintainer line group and restorer line group) and seven sub-groups. The maintainer line group consisted of all 19 maintainer lines, two thermo-sensitive genic male sterile lines, while the restorer line group was composed of all 20 restorer lines. The SSR analysis fitted better with the pedigree information. From the views on hybrid rice breeding, the results suggested that SSR analysis might be a better method to study the diversity of parental lines in indica hybrid rice.展开更多
杂种优势群的划分对于拓宽亲本间遗传基础、提高育种效率,培育突破性新品种具有重要的指导作用。本研究利用全基因组重测序技术对55份春播早熟区40余年生产中主推杂交种亲本系进行全基因组扫描,分析其群体结构,估算遗传距离,划分杂种优...杂种优势群的划分对于拓宽亲本间遗传基础、提高育种效率,培育突破性新品种具有重要的指导作用。本研究利用全基因组重测序技术对55份春播早熟区40余年生产中主推杂交种亲本系进行全基因组扫描,分析其群体结构,估算遗传距离,划分杂种优势群,分析主推杂交种的杂种优势模式。结果表明,利用全基因组5×测序,过滤到1,304,623个高质量SNP标记用于群体结构分析和杂种优势类群划分。55份高粱亲本系平均遗传距离为0.704,变幅0.627~0.927。多态信息含量(polymorphism information content,PIC)平均为0.2935,变幅为0.1~0.5。群体结构和主成分分析将55份亲本系划分为4个杂种优势群:都拉群(Durra,D群)、卡佛尔/都拉群(Kafir/Durra,KD群)、俄罗斯/卡佛尔群(Russia/Kafir,RK群)、中国高粱群(Kaoliang,K群)。25个主推杂交种中76%的杂交种杂种优势模式为Kafir/Durra×Kaoliang模式,主推高粱杂交种的不育系主要来源于引自国外的Kafir和Durra群,恢复系多来源于我国自产的Kaoliang群。本研究的群体结构分析及其划分的杂种优势群阐明了春播早熟区高粱亲本系的遗传基础,为亲本系改良和杂种优势模式创新研究提供科学依据。展开更多
基金supported by the Key Research and Development Project of Jiangsu Province for Modern Agriculture (BE2015336)the "333" Project of Jiangsu Province, China (BRA2016145)+2 种基金the Natural Science Foundation for Young Scientists of Jiangsu Province, China (BK20160447)the Natural Science Foundation for Young Scientists of Yangzhou, Jiangsu Province, China (YZ2016103)Yangzhou international technology cooperation project (YZ2015145)
文摘The development of resistant varieties and hybrid combinations has been the most effective and economical strategy to control blast disease caused by Magnaporthe oryzae.However, the distribution of major R genes and blast resistance characterization in hybrid rice parents has not been well investigated, resulting in their limited use in hybrid rice blast-resistance breeding. In the present study, 88 elite indica hybrid rice parental lines were evaluated with 30 isolates of M. oryzae collected from the main planting area of indica hybrid rice in China and were characterized for the presence of 11 major resistance genes using molecular markers. The pathogenicity assays showed that four types of hybrid rice parent line showed some resistance to M. oryzae. However, the proportions of highly resistant lines and the mean resistance frequency(RF) varied among the four types, with resistance in decreasing order shown by three-line restorer lines, three-line maintainer lines, two-line sterile lines, and two-line restorer lines. All 88 hybrid rice parental lines carried more than one R gene, but none carried the R genes Pi1 and Pi2. Although Pid3 and Pi9 were present only in three-line restorer lines and Pigm only in three-line maintainer lines, the remaining six R genes(Pib, Pid2, Pi5, Pia, Pi54, and Pita) were present in the four types of hybrid rice parent with significantly different distribution frequencies. The correlation between R genes and resistance reactions was investigated. The results are expected to provide useful information for rational utilization of major R genes in hybrid rice breeding programs.
基金financial support from the National Natural Science Foundation of China (31401342)the National Basic Research Program of China (973 Program, 2015CB150401)
文摘The grain yield of maize has increased continuously in past decades, largely through hybrid innovation, cultivation tech-nology, and in particular, recent genetic improvements in photosynthesis. Elite inbred lines are crucial for innovating new germplasm. Here, we analyzed variations in grain yield and a series of eco-physiological photosynthetic traits after anthesis in sixteen parental lines of maize (Zea mays L.) released during three different eras (1960s, 1980s, 2000s). We found that grain yield and biomass signiifcantly increased in the 2000s than those in the 1980s and 1960s. Leaf area, chlorophyl , and soluble protein content slowly decreased, and maintained a higher net photosynthesis rate (Pn) and improved stomatal conductance (Gs) after anthesis in the 2000s. In addition, the parental lines in the 2000s obtained higher actual photo-chemistry efifciency (ФPSI ) and the maximum PSII photochemistry efifciency (Fv/Fm), which largely improved light partition-ing and chlorophyl lfuorescence characteristic, including higher photochemical and photosystem II (PSII) reaction center activity, lower thermal energy dissipation in antenna proteins. Meanwhile, more lamel ae per granum within chloroplasts were observed in the parental lines of the 2000s, with a clear and complete chloroplast membrane, which wil greatly help to improve photosynthetic capacity and energy efifciency of ear leaf in maize parental lines. It is concluded that grain yield increase in modern maize parental lines is mainly attributed to the improved chloroplast structure and more light energy catched for the photochemical reaction, thus having a better stay-green characteristic and stronger photosynthetic capac-ity after anthesis. Our direct physiological evaluation of these inbred lines provides important information for the further development of promising maize cultivars.
基金funded by the National Key Research and Development Program of China (2016YFD0300103)the earmarked fund for China Agriculture Research System (CARS-02-12)
文摘Over the past seven decades, the grain yield of maize(Zea mays L.) has increased continuously in China, mostly due to hybridization innovations, particularly recent genetic improvements in photosynthesis. In order to reveal photosynthetic characters of elite inbred lines in different ears, a field experiment was conducted at the North China Plain of Shandong Province in China. Six parental lines of maize introduced in three eras(the 1960 s, 1980 s, and 2000 s) were investigated diurnal variation of gas exchange, chlorophyll fluorescence, and photosynthetic response characteristic at the grain filling stage. Compared to earlier parental lines, the 2000 s parental lines always had higher net photosynthetic rate(Pn) throughout the day, especially at noon, and a mid-day depression in Pn did not occur in all hybrids parental lines. Moreover, the stomatal conductance(Gs) and water use efficiency(WUE) of the 2000 s’ lines showed higher value than those of the 1960 s’ and 1980 s’ lines. The inbred lines differences in photosynthetic parameters were partly owing to their different quantum carboxylation efficiencies and light synthase activities. Simultaneously, the 2000 s parental lines exhibited lower light and CO2 compensation points, and their higher apparent quantum yield, and carboxylation efficiency. These suggested that the modern parental lines required lower light intensity and less CO2 to maintain a relatively high photosynthetic capacity, substantially increasing leaf physical quality and stress resistance. It provided crucial information of high photo-efficiency and stress-resistance breeding in maize.
文摘The genetic diversity of 41 parental lines popularized in commercial hybrid rice production in China was studied by using cluster analysis of morphological traits and simple sequence repeat (SSR) markers. Forty-one entries were assigned into two clusters (i.e. early or medium-maturing cluster; medium or late-maturing cluster) and further assigned into six sub-clusters based on morphological trait cluster analysis, The early or medium-maturing cluster was composed of 15 maintainer lines, four early-maturing restorer lines and two thermo-sensitive genic male sterile lines, and the medium or late-maturing cluster included 16 restorer lines and 4 medium or late-maturing maintainer lines. Moreover, the SSR cluster analysis classified 41 entries into two groups (i.e, maintainer line group and restorer line group) and seven sub-groups. The maintainer line group consisted of all 19 maintainer lines, two thermo-sensitive genic male sterile lines, while the restorer line group was composed of all 20 restorer lines. The SSR analysis fitted better with the pedigree information. From the views on hybrid rice breeding, the results suggested that SSR analysis might be a better method to study the diversity of parental lines in indica hybrid rice.
文摘杂种优势群的划分对于拓宽亲本间遗传基础、提高育种效率,培育突破性新品种具有重要的指导作用。本研究利用全基因组重测序技术对55份春播早熟区40余年生产中主推杂交种亲本系进行全基因组扫描,分析其群体结构,估算遗传距离,划分杂种优势群,分析主推杂交种的杂种优势模式。结果表明,利用全基因组5×测序,过滤到1,304,623个高质量SNP标记用于群体结构分析和杂种优势类群划分。55份高粱亲本系平均遗传距离为0.704,变幅0.627~0.927。多态信息含量(polymorphism information content,PIC)平均为0.2935,变幅为0.1~0.5。群体结构和主成分分析将55份亲本系划分为4个杂种优势群:都拉群(Durra,D群)、卡佛尔/都拉群(Kafir/Durra,KD群)、俄罗斯/卡佛尔群(Russia/Kafir,RK群)、中国高粱群(Kaoliang,K群)。25个主推杂交种中76%的杂交种杂种优势模式为Kafir/Durra×Kaoliang模式,主推高粱杂交种的不育系主要来源于引自国外的Kafir和Durra群,恢复系多来源于我国自产的Kaoliang群。本研究的群体结构分析及其划分的杂种优势群阐明了春播早熟区高粱亲本系的遗传基础,为亲本系改良和杂种优势模式创新研究提供科学依据。