摘要：
Super hybrid rice, Liangyoupeijiu was grown in conventional tillage transplanting (CTTP) and no tillage transplanting (NTTP) at a spacing of 20 x 20 cm with one seedling per hill and conventional tillage direct-seeding (CTDS) and no tillage direct seeding (NTDS) at a seeding rate of 22.5 kg/ha to compare the growth and physiological responses during 2011-12, in Changsha, Hunan Province, China. Our results indicated that leaf area index (LAI) was higher at booting stage (BT) in transplanting (TP) and at HD stage in direct seeding method (DS) both CT (conventional tillage system) and NT (no tillage system). Leaf area duration (LAD) was higher in DS both CT and NT. Specific leaf area (SLA) and leaf area ratio (LAR) were higher at early growth stage both TP and DS either CT or NT then gradually decreased with advancement of time. DS produced more above ground biomass than TP but at maturity, both CTTP and NTDS had higher above ground biomass and N'TTP was the lowest. Crop growth rate (CGR) was higher at PI-BT stage in TP either CT or NT but it was higher at PI-HD in DS. Net assimilation rate (NAR) was 15 and 24% higher in NTTP than CTTP at PI-BT and BT-HD, respectively, but CTTP had 15% higher NAR than NTTP at HD-12 DAH. In CTTP, higher leaf N concentration (2.04%) and uptake (5.9 g/m(2)) were observed at BT stage. In DS, N concentration and uptake were always higher in NT at all growth stages. It was found in the present study that CGR was closely related with LAD at BT-HD stage and grain yield was closely associated with leaf N (%) at HD stage. In DS either CT or NT had higher heat use efficiency (HUE) than TP as well as CT either TP or DS. Though DS had about 24% more number of panicles than TP but grain yield was higher in CTTP due to higher LAI, LAD, above ground biomass and bigger sink size (about 17% higher weight of panicle, higher number of spikelets per unit area and more number of grains per panicle) than DS.
摘要：
Molecular mapping of new blast resistance genes is important for developing resistant rice cultivars using marker-assisted selection. In this study, 259 recombinant inbred lines (RILs) were developed from a cross between Nipponbare and 93-11, and were used to construct a 1165.8-cM linkage map with 131 polymorphic simple sequence repeat (SSR) markers. Four major quantitative trait loci (QTLs) for resistance to six isolates of Magnaporthe oryzae were identified: qPi93-1, qPi93-2, qPi93-3, and qPiN-1. For the three genes identified in 93-11, qPi93-1 is linked with SSR marker RM116 on the short arm of chromosome 11 and explains 33% of the phenotypic variation in resistance to isolate CHE86. qPi93-2 is linked with SSR marker RM224 on the long arm of chromosome 11 and accounts for 31% and 25% of the phenotypic variation in resistance to isolates 162-8B and ARB50, respectively. qPi93-3 is linked with SSR marker RM7102 on chromosome 12 and explains 16%, 53%, and 28% of the phenotypic variation in resistance to isolates CHE86, ARB52, and ARB94, respectively. QTL qPiN-1 from Nipponbare is associated with SSR marker RM302 on chromosome 1 and accounts for 34% of the phenotypic variation in resistance to isolate PO6-6. These new genes can be used to develop new varieties with blast resistance via marker-aided selection and to explore the molecular mechanism of rice blast resistance.
关键词：
Common wild rice;Heat response;Introgression lines;Physiological characteristics;QTL
摘要：
Understanding the responses of rice plants to heat-stress is a challenging, yet crucial, endeavor. A set of introgression lines was previously developed using an advanced backcrossing strategy that involved the elite indica cultivar Teqing as the recipient and an accession of common wild rice (Oryza rufipongon Griff.) as the donor. In this study, we evaluated the responses of 90 of these previously developed introgression lines to heat stress. Five quantitative trait loci (QTLs) related to heat response were detected. The phenotypic variances explained by these QTLs ranged from 6.83% to 14.63%, and O. rufipogon-derived alleles at one locus reduced sensitivity to heat. A heat-sensitive introgression line, YIL106, was identified and characterized. Genotypic analysis demonstrated that YIL106 contained four introgressed segments derived from O. rufipongon and two QTLs (qHTS1-1 and qHTS3) related to heat response. Physiological tests, including measurements of chlorophyll content, electrolyte leakage, malondialdehyde content, and soluble sugar content, were consistent with the heat sensitivity observed in YIL106. Ultrastructural analysis of YIL106 mesophyll cells showed that they were severely damaged following heat stress. This suggests that modification of the cell membrane system is a primary response to heat stress in plants. Identification and characterization of the heat-sensitive line YIL106 may facilitate the isolation of genes associated with the response of rice plants to heat stress.
作者：
Li Di-qin;Tang Qi-yuan*;Zhang Yun-bo;Qin Jian-quan;Li Hu;...
期刊：
农业科学学报(英文),2012年11(1):134-143 ISSN：2095-3119
通讯作者：
Tang Qi-yuan
作者机构：
[Yang Sheng-hai; Qin Jian-quan; Chen Li-jun; Tang Qi-yuan; Zhang Yun-bo; Li Di-qin; Zou Ying-bin; Li Hu] Hunan Agr Univ, State Key Lab Hybrid Rice, Changsha 410128, Hunan, Peoples R China.;[Peng Shao-bing] Huazhong Agr Univ, CPPC, Wuhan 430070, Peoples R China.
通讯机构：
[Tang Qi-yuan] H;Hunan Agr Univ, State Key Lab Hybrid Rice, Changsha 410128, Hunan, Peoples R China.
会议名称：
全国第十四届水稻优质高产理论与技术研讨会
会议时间：
2011-08-01
会议地点：
长沙
会议论文集名称：
全国第十四届水稻优质高产理论与技术研讨会论文集
关键词：
super hybrid rice;real-time N management;fixed-time adjustable-does N management;grain yield;sheath blight;radiation use efficiency;agronomic-nitrogen use efficiency
摘要：
Poor nitrogen use efficiency in rice production is a critical issue in China. Site-specific N managements (SSNM) such as real-time N management (RTNM) and fixed-time adjustable-dose N management (FTNM) improve fertilizer-N use efficiency of irrigated rice. This study was aimed to compare the different nitrogen (N) rates and application methods (FFP, SSNM, and RTNM methods) under with- and without-fungicide application conditions on grain yield, yield components, solar radiation use efficiency (RUE), agronomic-nitrogen use efficiency (AEN), and sheath blight disease intensity. Field experiments were carried out at Liuyang County, Hunan Province, China, during 2006 and 2007. A super hybrid rice Liangyou 293 (LY293) was used as experimental material. The results showed that RTNM and SSNM have great potential for improving agronomic-nitrogen use efficiency without sacrificing the grain yield. There were significant differences in light interception rate, sheath blight disease incidence (DI) and the disease index (ShBI), and total dry matter among the different nitrogen management methods. The radiation use efficiency was increased in a certain level of applied N. But, the harvest index (HI) decreased with the increase in applied N. There is a quadratic curve relationship between grain yield and applied N rates. With the same N fertilizer rate, different fertilizer-N application methods affected the RUE and grain yield. The fungicide application not only improved the canopy light interception rate, RUE, grain filling, and harvest index, but also reduced the degree of sheath blight disease. The treatment of RTNM under the SPAD threshold value 40 obtained the highest yield. While the treatment of SSNM led to the highest nitrogen agronomic efficiency and higher rice yield, and decreased the infestation of sheath blight disease dramatically as well. Nitrogen application regimes and diseases control in rice caused obvious effects on light interception rate, RUE, and HI. Optimal N rate is helpful to get higher light interception rate, RUE, and HI. Disease control with fungicide application decreased and delayed the negative effects of the high N on rice yield formation. SSNM and RTNM under the proper SPAD threshold value obtained high-yield with high efficiency and could alleviate environmental pollution in rice production.
摘要：
Modification of unsaturated fatty acid (FA) levels has been found to accompany multiple abiotic stress acclimations in many plants. Delta 12 fatty acid desaturase (FAD2) plays a critical role in the synthesis of polyunsaturated FAs in plant cells by converting oleic acid (18:1) to linoleic acid (18:2). To better understand the relationship between polyunsaturated FAs metabolism and stress adaptation, the expression of FAD2 gene and changes in the FA compositions under various abiotic stresses and phytohormone treatments in Arabidopsis thaliana was investigated in this study. A 1 423-bp promoter of the FAD2 gene was cloned and characterized from Arabidopsis. Several putative hormone- and stressinducible cis-elements were identified in the cloned promoter, which include salt- and pathogen-inducible GT-1 motifs, low-temperature-responsive MYC element, dehydration-responsive MYB element, and GA signaling related WRKY71OS element. To investigate the fine regulation of FAD2 gene, a recombinant FAD2 promoter-GUS construct was introduced into Arabidopsis plants. Histochemical study showed that the promoter was ubiquitously active and responsive not only to exogenous phytohormones including ABA, 24-eBL, and SA but also to darkness, temperature, salt, and sucrose stresses in Arabidopsis seedlings. Consistent with the expression change, treatments with exogenous 24-eBL, ABA, SA, and NaCl resulted in reduction in polyunsaturated FAs in Arabidopsis seedlings. These findings suggest that the FAD2 gene with a wide variety of putative response elements in its promoter is responsive to multiple phytohormones and abiotic stresses and therefore may play an important role in stress responses of Arabidopsis during plant growth and seed development.
摘要：
Good progress has been made in the super hybrid rice (Oryza sativa L.) breeding in China. However, rice yield not only depends on the genetic characteristics but also on the agronomic practices. No-tillage and direct seeding (NTDS) is a simplified cultivation technology that greatly simplifies both land preparation and crop establishment. Aiming to determine the grain yield performance of super hybrid rice under NTDS and to identify critical factors that determine grain yield, field experiments were conducted in Nanxian, Hunan Province, China in 2009 and 2010. Two super hybrid cultivars, Liangyoupeijiu and Y-liangyou 1, were grown under conventional tillage and transplanting (CTTP) and NTDS. Grain yield, yield components, biomass production, crop growth rate and biomass accumulation during sowing to heading (HD) and HD to maturity were measured for each cultivar. There was no difference in grain yield under NTDS and CTTP. However, grain yield differed with cultivar and year. Y-liangyou 1 produced 4 % higher grain yield than Liangyoupeijiu in 2009, whereas in 2010 both cultivars yielded similarly. Grain yields of both cultivars were higher in 2009 than in 2010. Higher grain yield of Y-liangyou 1 in 2009 was associated with higher spikelet filling (spikelet filling percentage and grain weight), which resulted from higher biomass production. Crop growth rate after HD was critical for biomass production by the super hybrid rice. We suggest that increasing the crop growth rate after HD is an effective approach to increase grain yield of super hybrid rice under NTDS.
摘要：
Brevibacillus brevis X23 is an appropriate biocontrol agent against bacterial wilt caused by Ralstonia solanacearum. We report herein the draft genome sequence (6,566,879 bp) and a circular plasmid (6,600 bp) of B. brevis X23, data which may be helpful for mining the antagonistic activity against R. solanacearum.
摘要：
With 4 figures and 2 tables Abstract The yellow seed is a desirable trait in oilseed Brassica species. However, seed coat colour cannot be observed until the maturation of the seed. Identification of seed coat colour at early seed development will allow for the early detection of yellow‐seeded individual plants in the segregating populations at the same generation and thus speed up yellow‐seeded rapeseed breeding programme. Colour of seed coats from Brassica juncea and Brassica napus can precisely be determined as early as 15 days after pollination by staining with 0.5% vanillin–HCl solution for 5 min, which is shown to be simple, rapid and reliable. Flowering duration of an individual plant usually lasts for approximately 25–35 days in Brassica species and so the seed coat colour of an individual plant can be determined 10–20 days before the end of its flowering. Through this technique, breeding for the yellow‐seeded trait can now be advanced one generation earlier by vanillin staining than by conventional visual observation of testa colour of mature Brassica seeds.
摘要：
An increase in oleic acid (C18:1) content is a desirable trait. Despite the critical roles of the two desaturases, FAD2 and FAD3, in the control of fatty acid desaturation, a dispute remains over whether inactivation of their genes alone is sufficient enough to generate the high-oleic trait. To address this question, we employed microarray technology to investigate the difference in gene expression profile between two different Brassica napus strains with high-C18:1 (71.71%) and low-C18:1 (55.6%) contents, respectively. Our study revealed 562 differentially expressed genes, of which 194 genes were up-regulated and 368 down-regulated. Based on the Gene Ontology classification, these genes were classified into 23 functional categories. Three of the up-regulated genes represent B. napus homologs of Arabidopsis genes encoding a cytosolic isoform of pyruvate kinase (AT3G55810), Δ9 acyl-lipid desaturase (AT1G06080, ADS1) and fatty acyl-ACP thioesterase B (AT1G08510), respectively. Conversely, the homologs of two Arabidopsis sequences encoding Δ9 acyl-lipid desaturase (AT2G31360, ADS2) and FAD3 desaturase (AT2G29980) were down-regulated in the high-oleic acid strain. Furthermore, 60 differentially expressed genes were classified as associated with relevant Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Collectively, our results suggest that expressing the high-oleic acid trait may require a coordinated regulation of diverse regulatory and metabolic gene networks in addition to inactivation of the FAD2 and FAD3 genes in the oilseed. A set of the differentially expressed genes identified in this study will facilitate our efforts to tap the germplasms with the potential to express the high-oleic acid trait.
摘要：
Sheath blight, a disease caused by the fungus Rhizoctonia solani Kuhn (anamorph), has been the most economically significant disease of rice. It was frequently reported that the disease was well-controlled in integrated rice-duck system without the employment of fungicides. However, the effecting factors behind this phenomenon were rarely reported. In this research, experiment was carried out between two treatments, rice combined with ducks (RD) and conventional rice field without ducks rearing (CK) in early season rice paddy, to investigate the variations of sclerotia in floodwater and on rice plant, microclimate 10 cm above the waterline in rice paddy and activity of protective enzymes in rice plants. The results showed that the floating sclerotia in floodwater in RD was 86-91% lower than that in CK, and adhering sclerotia in rice plant in RD was 67-78% lower than that in CK. The relative humidity tested significantly lower and light intensity tested significantly higher in RD. The temperature in the early rice growth stages in RD was slightly lower than that in CK, but it was significantly higher (32.3-36.5°C) in the middle stage rice growth stages. The polyphenoloxidase (PPO) activity in RD were lower than that in CK, but the enhanced activity of phenylalanine ammonia-lyase (PAL), peroxidase (POD) and Chitinase was observed in different stages of rice growth in RD, especially the Chitinase which showed higher activity in all investigating days.
摘要：
To indentify the key factors that are critical to the high grain yield of loosepanicle super hybrid rice, grain yield, yield components and grain-filling characteristics were compared between a loose-panicle (Zhunliangyou 527) and a compact-panicle (Y-liangyou 1) super hybrid rice by using data from three field experiments conducted in Hunan province, China during 2007 to 2011. Average grain yields were 9.56 t/ha for Zhunliangyou 527 and 9.44 t/hafor Y-liangyou 1, showing no significant difference between the two cultivars. Zhunliangyou 527 produced significantly less spikelets per panicle than Y-liangyou 1, which resulted in smaller sink size (spikelets/m2). However, spikelet filling percentage and especially grain weight of Zhunliangyou 527 were significantly higher than those of Y-liangyou 1. High grain capacity, grain-filling rate and source capacity were responsible for the high grain weight of Zhunliangyou 527. Our study suggests that developing cultivars with high grain weight through breeding programme may also be a feasible approach to achieve high rice yield.
关键词：
Direct seeding;internal N efficiency;no-tillage;super hybrid rice
摘要：
This study was conducted to compare internal nitrogen (N) efficiency of super hybrid rice among different. tillage and crop establishment methods. Field experiments were done in Changsha, Hunan Province, China during 2004-09. Super hybrid rice Liangyoupeijiu was grown under a factorial combination of two tillage practices (conventional tillage and no-tillage) and two crop establishment methods (transplanting and direct seeding) in each year. Grain yield, total N accumulation in aboveground biomass, internal N efficiency and N distribution percentage in different plant organs (straw, filled and unfilled spikelets) were measured at maturity for each combination. The results showed that the differences in grain yield, total N accumulation in aboveground biomass and internal N efficiency were insignificant among different tillage and crop establishment methods but were significant among years. Grain yield was closely related with internal N efficiency but not with total N accumulation in aboveground biomass. There was a tight positive correlation between internal N efficiency and N distribution percentage in straw at maturity. Our study suggests that adoption of N management practices that increase the N distribution percentage in straw at maturity will be effective to increase both internal N efficiency and grain yield in super hybrid rice production.
通讯机构：
[Yin, Xiaohong] W;Wuzhou Res Inst Agr Sci, Wuzhou 450404, Peoples R China.
关键词：
Grain yield;N-use efficiency;No-till direct seeded rice;SPAD-based N management
摘要：
This study was aimed at determining whether chlorophyll meter (SPAD) can be used to increase N-use efficiency in no-till direct seeded rice. Field experiments were conducted in Yongzhou and Nanxian, Hunan Province, China in 2010. Two N management treatments were imposed in each site : SPAD-based N management (SBNM) and recommended fix-timing N management (FTNM). Partial factor productivity of applied N (PFPN), grain yield, yield components, biomass production and related physiological traits were measured for each N management. Averaged across two sites, SBNM increased PFPN by 26% compared with FTNM. The higher PFPN in SBNM was attributed to reduced N application rate. Moreover, PFPN differed with site. Nanxian had higher PFPN than Yongzhou, especially in SBNM (a more than 50% increase), because of both lower N application rate and higher grain yield. High soil fertility contributed to the increased grain yield in Nanxian. Nanxian had more panicle number per m(2) and larger panicle size (spikelets per panicle) than Yongzhou, which resulted in greater sink size (spikelets per m(2)). Nanxian produced more aboveground biomass during pre-heading period but less aboveground biomass during post-heading period than Yongzhou, and the former led to higher total aboveground biomass accumulation. Low photosynthetic rate and accelerated leaf senescence were partly responsible for the low aboveground biomass accumulation during post-heading period in Nanxian. Our study suggests that increased PFPN is possible using a SPAD to guide N application on no-till direct seeded rice, and it will be more effective to increase PFPN by using SBNM combined with improving soil fertility and optimizing canopy development.
