Late-maturity type of Yongyou japonica/indica hybrids series (LMYS) have shown great yield potential, and are being widely planted in the lower reaches of Yangtze River, China. Knowledge about suitable growing zone ...Late-maturity type of Yongyou japonica/indica hybrids series (LMYS) have shown great yield potential, and are being widely planted in the lower reaches of Yangtze River, China. Knowledge about suitable growing zone and evaluation of yield advantage is of practicall importance for LMYS in this region. Fifteen LMYS, two high-yielding inbred japonica check varieties (CK-J) and two high-yielding hybrid indica check varieties (CK-I) were grown at Xinghua (119.57°E, 33.05°N) of Lixiahe region, Yangzhou (119.25°E, 32.30°N)of Yanjiang region, Changshu (120.46°E, 31.41°N)of Taihu Lake region, and Ningbo (121.31°E, 29.45°N) of Ningshao Plain in 2013 and 2014. The results showed that maturity dates of the 15 were later than the secure maturity date at Xinghua and 6, 14 and 15 LMYS were mature before the secure maturity date at Yangzhou, Changshu and Ningbo, respectively. One variety was identified as high-yielding variety among LMYS (HYYS) at Yangzhou, 8 HYYS in 201:3 and 9 HYYS in 2014 at Changshu, 9 HYYS at Ningbo. HYYS here referred to the variety among LMYS that was mature before the secure maturity date and had at least 8% higher grain yield than both CK-J and CK-I at each experimental site. Grain yield of HYYS at each experimental site was about 12.0 t ha-1 or higher, and was significantly higher than CK varieties. High yield of HYYS was mainly attributed to larger sink size due to more spikelets per panicle. Plant height of HYYS was about 140 cm, and was significantly higher than check varieties. Significant positive correlations were recorded between duration from heading to maturity stage and grain yield, and also between whole growth periods and grain yield. HYYS had obvious advantage over check varieties in biomass accumulation and leaf area duration from heading to maturity stage. Comprehensive consideration about safe matudty and yield performance of LMYS at each experimental site, Taihu Lake region (representative site Changshu) and Ningshao Plain (representative site Ningbo) were thought suitable growing zones for LMYS in the lower reaches of Yangtze River. The main factors underlying high yield ofHYYS were larger sink size, higher plant height, longer duration from heading to maturity stage and whole growth periods, and higher biomass accumulation and leaf area duration during grain filling stage.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
Meeting the demand for high-quality japonica rice is a major challenge facing China's grain security. In the present study, a two-year field experiment was conducted to investigate the yield, quality, and profitab...Meeting the demand for high-quality japonica rice is a major challenge facing China's grain security. In the present study, a two-year field experiment was conducted to investigate the yield, quality, and profitability of japonica rice varieties(including hybrids and inbreds) grown in the late season as compared with local elite indica hybrids in a double rice cropping system of China where indicas are traditionally planted. Indica hybrids had significantly longer vegetative(from sowing to heading) and total(from sowing to maturity) growth durations than japonicas in both2011 and 2012, while reproductive growth duration(from heading to maturity) was longer for indica hybrids than for japonicas in 2011 but not in 2012. Indica hybrids produced higher grain yield than japonicas in 2011, but with no significant differences in 2012. Japonicas had higher brown rice, milled rice, and head rice percentages than indicas, but had lower gelatinization temperature and amylose content,while with no significant differences in gel consistency and protein content. Indica hybrids tended to have lower chalky grain percentage and chalkiness degree than japonicas, though the differences were not statistically significant due to large genotypic variations. The net returns were 16.1% and 9.9% greater for indica hybrids than for japonica hybrids and japonica inbreds in 2011, with only 3.8% and 1.3% in2012, respectively. Thus, our results suggest that replacing indicas with japonica varieties as late rice may not be feasible at the present site unless locally adapted japonica varieties are developed.展开更多
[Objectives]This study was conducted to clarify the appropriate nitrogen fertilizer amount and transplanting density that should be selected for different transplanting dates.[Methods]The effects of nitrogen fertilize...[Objectives]This study was conducted to clarify the appropriate nitrogen fertilizer amount and transplanting density that should be selected for different transplanting dates.[Methods]The effects of nitrogen fertilizer rate and transplanting density on the traits and yield of late japonica rice in the Jianghuai rice-wheat cropping area under different transplanting dates(transplanting at an appropriate time and delayed transplanting)were studied.[Results]The transplanting date significantly affected the heading,maturity and whole growth period of rice,and when the transplanting date of early-maturing late japonica rice was delayed by 15 d,the growth period was shortened by about 10 d.Nitrogen and density interaction obviously affected the dry matter accumulation and effective tillers of rice,and the dry matter production and effective tiller number of rice treated with B_(1)N_(2) were greater than other treatments.Under the timely transplanting date,the best nitrogen and density combination was 225-300 kg/hm^(2) and 250500 holes/hm^(2),and the nitrogen use efficiency was ideal.It suggests that under the condition of transplanting rice in a timely manner,applying nitrogen fertilizer at an appropriate rate while ensuring a reasonable population density is conducive to the coordination of the number of stems and tillers,the number of grains per panicle,etc.,thereby ensuring the best formation of yield factors in the middle and late stages of rice growth.[Conclusions]This study provides technical support and theoretical reference for reasonable nitrogen and density interaction of rice.展开更多
Rice direct seeding has the significant potential to save labor and water,conserve environmental resources,and reduce greenhouse gas emissions tremendously.Therefore,rice direct seeding is becoming the major cultivati...Rice direct seeding has the significant potential to save labor and water,conserve environmental resources,and reduce greenhouse gas emissions tremendously.Therefore,rice direct seeding is becoming the major cultivation technology applied to rice production in many countries.Identifying and utilizing genes controlling mesocotyl elongation is an effective approach to accelerate breeding procedures and meet the requirements for direct-seeded rice(DSR) production.This study used a permanent mapping population with 144 recombinant inbred lines(RILs) and 2 828 bin-markers to detect quantitative trait loci(QTLs) associated with mesocotyl length in 2019 and 2020.The mesocotyl lengths of the rice RILs and their parents,Lijiangxintuanheigu(LTH) and Shennong 265(SN265),were measured in a growth chamber at 30°C in a dark environment.A total of 16 QTLs for mesocotyl length were identified on chromosomes 1(2),2(4),3(2),4,5,6,7,9,11(2),and 12.Seven of these QTLs,including qML1a,qML1b,qML2d,qML3a,qML3b,qML5,and qML11b,were reproducibly detected in both years via the interval mapping method.The major QTL,qML3a,was reidentified in two years via the composite interval mapping method.A total of 10 to 413 annotated genes for each QTL were identified in their smallest genetic intervals of 37.69 kb to 2.78 Mb,respectively.Thirteen predicted genes within a relatively small genetic interval(88.18 kb) of the major mesocotyl elongation QTL,qML3a,were more thoroughly analyzed.Finally,the coding DNA sequence variations among SN265,LTH,and Nipponbare indicated that the LOC_Os03g50550 gene was the strongest candidate gene for the qML3a QTL controlling the mesocotyl elongation.This LOC_Os03g50550 gene encodes a mitogen-activated protein kinase.Relative gene expression analysis using qRT-RCR further revealed that the expression levels of the LOC_Os03g50550 gene in the mesocotyl of LTH were significantly lower than in the mesocotyl of SN265.In conclusion,these results further strengthen our knowledge about rice’s genetic mechanisms of mesocotyl elongation.This investigation’s discoveries will help to accelerate breeding programs for new DSR variety development.展开更多
基金financed by the Special Program of Super Rice of Ministry of Agriculture, China (02318802013231)the National Public Services Sectors (Agricultural) Research Projects, China (201303102)+1 种基金the Major Scientific and Technological Projects, Bureau of Science and Technology of Ningbo, China (2013C11001)the Innovative Training Program of Yangzhou University, China (KYLX15_1371)
文摘Late-maturity type of Yongyou japonica/indica hybrids series (LMYS) have shown great yield potential, and are being widely planted in the lower reaches of Yangtze River, China. Knowledge about suitable growing zone and evaluation of yield advantage is of practicall importance for LMYS in this region. Fifteen LMYS, two high-yielding inbred japonica check varieties (CK-J) and two high-yielding hybrid indica check varieties (CK-I) were grown at Xinghua (119.57°E, 33.05°N) of Lixiahe region, Yangzhou (119.25°E, 32.30°N)of Yanjiang region, Changshu (120.46°E, 31.41°N)of Taihu Lake region, and Ningbo (121.31°E, 29.45°N) of Ningshao Plain in 2013 and 2014. The results showed that maturity dates of the 15 were later than the secure maturity date at Xinghua and 6, 14 and 15 LMYS were mature before the secure maturity date at Yangzhou, Changshu and Ningbo, respectively. One variety was identified as high-yielding variety among LMYS (HYYS) at Yangzhou, 8 HYYS in 201:3 and 9 HYYS in 2014 at Changshu, 9 HYYS at Ningbo. HYYS here referred to the variety among LMYS that was mature before the secure maturity date and had at least 8% higher grain yield than both CK-J and CK-I at each experimental site. Grain yield of HYYS at each experimental site was about 12.0 t ha-1 or higher, and was significantly higher than CK varieties. High yield of HYYS was mainly attributed to larger sink size due to more spikelets per panicle. Plant height of HYYS was about 140 cm, and was significantly higher than check varieties. Significant positive correlations were recorded between duration from heading to maturity stage and grain yield, and also between whole growth periods and grain yield. HYYS had obvious advantage over check varieties in biomass accumulation and leaf area duration from heading to maturity stage. Comprehensive consideration about safe matudty and yield performance of LMYS at each experimental site, Taihu Lake region (representative site Changshu) and Ningshao Plain (representative site Ningbo) were thought suitable growing zones for LMYS in the lower reaches of Yangtze River. The main factors underlying high yield ofHYYS were larger sink size, higher plant height, longer duration from heading to maturity stage and whole growth periods, and higher biomass accumulation and leaf area duration during grain filling stage.
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.
基金Supported by grants from the China National Rice Research Institute and Jiangxi Province(GJJ12215 and 555 Talents Program)
文摘Meeting the demand for high-quality japonica rice is a major challenge facing China's grain security. In the present study, a two-year field experiment was conducted to investigate the yield, quality, and profitability of japonica rice varieties(including hybrids and inbreds) grown in the late season as compared with local elite indica hybrids in a double rice cropping system of China where indicas are traditionally planted. Indica hybrids had significantly longer vegetative(from sowing to heading) and total(from sowing to maturity) growth durations than japonicas in both2011 and 2012, while reproductive growth duration(from heading to maturity) was longer for indica hybrids than for japonicas in 2011 but not in 2012. Indica hybrids produced higher grain yield than japonicas in 2011, but with no significant differences in 2012. Japonicas had higher brown rice, milled rice, and head rice percentages than indicas, but had lower gelatinization temperature and amylose content,while with no significant differences in gel consistency and protein content. Indica hybrids tended to have lower chalky grain percentage and chalkiness degree than japonicas, though the differences were not statistically significant due to large genotypic variations. The net returns were 16.1% and 9.9% greater for indica hybrids than for japonica hybrids and japonica inbreds in 2011, with only 3.8% and 1.3% in2012, respectively. Thus, our results suggest that replacing indicas with japonica varieties as late rice may not be feasible at the present site unless locally adapted japonica varieties are developed.
基金Supported by Major National Research and Development Program(2016YFD0300206-2)。
文摘[Objectives]This study was conducted to clarify the appropriate nitrogen fertilizer amount and transplanting density that should be selected for different transplanting dates.[Methods]The effects of nitrogen fertilizer rate and transplanting density on the traits and yield of late japonica rice in the Jianghuai rice-wheat cropping area under different transplanting dates(transplanting at an appropriate time and delayed transplanting)were studied.[Results]The transplanting date significantly affected the heading,maturity and whole growth period of rice,and when the transplanting date of early-maturing late japonica rice was delayed by 15 d,the growth period was shortened by about 10 d.Nitrogen and density interaction obviously affected the dry matter accumulation and effective tillers of rice,and the dry matter production and effective tiller number of rice treated with B_(1)N_(2) were greater than other treatments.Under the timely transplanting date,the best nitrogen and density combination was 225-300 kg/hm^(2) and 250500 holes/hm^(2),and the nitrogen use efficiency was ideal.It suggests that under the condition of transplanting rice in a timely manner,applying nitrogen fertilizer at an appropriate rate while ensuring a reasonable population density is conducive to the coordination of the number of stems and tillers,the number of grains per panicle,etc.,thereby ensuring the best formation of yield factors in the middle and late stages of rice growth.[Conclusions]This study provides technical support and theoretical reference for reasonable nitrogen and density interaction of rice.
基金supported by grants from the Natural Science Foundation of Heilongjiang Province, China (LH2020C098)the Fundamental Research Funds for the Research Institutes of Heilongjiang Province, China (CZKYF2020A001)+1 种基金the National Key Research and Development Program of China (2016YFD0300104)the Heilongjiang Province Agricultural Science and Technology Innovation Project, China (2020JCQN001, 2019JJPY007, 2020FJZX049, 2021QKPY009, 2021CQJC003)。
文摘Rice direct seeding has the significant potential to save labor and water,conserve environmental resources,and reduce greenhouse gas emissions tremendously.Therefore,rice direct seeding is becoming the major cultivation technology applied to rice production in many countries.Identifying and utilizing genes controlling mesocotyl elongation is an effective approach to accelerate breeding procedures and meet the requirements for direct-seeded rice(DSR) production.This study used a permanent mapping population with 144 recombinant inbred lines(RILs) and 2 828 bin-markers to detect quantitative trait loci(QTLs) associated with mesocotyl length in 2019 and 2020.The mesocotyl lengths of the rice RILs and their parents,Lijiangxintuanheigu(LTH) and Shennong 265(SN265),were measured in a growth chamber at 30°C in a dark environment.A total of 16 QTLs for mesocotyl length were identified on chromosomes 1(2),2(4),3(2),4,5,6,7,9,11(2),and 12.Seven of these QTLs,including qML1a,qML1b,qML2d,qML3a,qML3b,qML5,and qML11b,were reproducibly detected in both years via the interval mapping method.The major QTL,qML3a,was reidentified in two years via the composite interval mapping method.A total of 10 to 413 annotated genes for each QTL were identified in their smallest genetic intervals of 37.69 kb to 2.78 Mb,respectively.Thirteen predicted genes within a relatively small genetic interval(88.18 kb) of the major mesocotyl elongation QTL,qML3a,were more thoroughly analyzed.Finally,the coding DNA sequence variations among SN265,LTH,and Nipponbare indicated that the LOC_Os03g50550 gene was the strongest candidate gene for the qML3a QTL controlling the mesocotyl elongation.This LOC_Os03g50550 gene encodes a mitogen-activated protein kinase.Relative gene expression analysis using qRT-RCR further revealed that the expression levels of the LOC_Os03g50550 gene in the mesocotyl of LTH were significantly lower than in the mesocotyl of SN265.In conclusion,these results further strengthen our knowledge about rice’s genetic mechanisms of mesocotyl elongation.This investigation’s discoveries will help to accelerate breeding programs for new DSR variety development.