In aquaculture,co-culturing rice with fish may mitigate greenhouse-gas emissions.In this study,co-culture of four rice cultivars in a laboratory-scale rice–fish system reduced CH_(4)and N_(2)O emissions relative to f...In aquaculture,co-culturing rice with fish may mitigate greenhouse-gas emissions.In this study,co-culture of four rice cultivars in a laboratory-scale rice–fish system reduced CH_(4)and N_(2)O emissions relative to fish monoculture.Differences in CH_(4)and N_(2)O emissions among rice cultivars primarily stem from the differential effects of rice plants on plant-mediated CH_(4)transport,CH_(4)oxidation and nitrogen absorption.展开更多
Enhanced Cd uptake and Zn depletion in rice grains and high potential for food Cd exposure by the high-yielding hybrid cultivars of China had been addressed. A field experiment was conducted in 2006 to determine the d...Enhanced Cd uptake and Zn depletion in rice grains and high potential for food Cd exposure by the high-yielding hybrid cultivars of China had been addressed. A field experiment was conducted in 2006 to determine the difference in grain Cd and Zn between cultivars. Total 110 cultivars including super rice and common hybrid rice cultivars were grown on a single paddy soil (Entic Haplaquept) with a neutral reaction and low total Cd content. Grain Cd and Zn concentrations were determined with graphite atomic adsorption spectrophotometer (GFAAS) and flame atomic adsorption spectrophotometer (AAS) respectively. Wide variation of Cd content in grain was found in a range of 0.004-0.057 mg/kg, while the Zn content in a range of 10.25-30.06 mg/kg among the cultivars. Higher Cd but lower Zn concentration in grains of super rice cultivars was observed compared to the common hybrid ones. A highly significant positive linear correlation of grain Cd/Zn with grain Cd was found for super rice and common hybrid cultivars, meanwhile much higher slope for these hybrid cultivars than the reported non-hybrid cultivars was also observed. Using the limit value of the Chinese chemical guidelines for foods (MOHC and SSC, 2005), calculated potential risk of food Cd exposure with "Zn hungry" through diet intake was prominent with all the studied 110 hybrid rice cultivars, possessing high potential health problems for rice production in South China using the super rice cultivars. Breeding of genotypes of rice cultivars with low grain Cd and low Cd/Zn ratio is needed for rice production in acidic red soils where Cd bioavailability is prevalently high.展开更多
It is imperative to derive an appropriate cadmium (Cd) health risk toxicity threshold for paddy soils to ensure the Cd con-centration of rice grains meet the food safety standard. In this study, 20 rice cultivars from...It is imperative to derive an appropriate cadmium (Cd) health risk toxicity threshold for paddy soils to ensure the Cd con-centration of rice grains meet the food safety standard. In this study, 20 rice cultivars from the main rice producing areas in China were selected, and a pot-experiment was conducted to investigate transformation of Cd in paddy soil-rice system with 0 (CK), 0.3 mg kg–1 (T1) and 0.6 mg kg–1 (T2) Cd treatments in greenhouse. The results showed that Cd concentrations of rice grains existed signiifcant difference (P<0.05) in 20 rice cultivars under the same Cd level in soil. The Cd concentrations of rice grains of the CK, T1 and T2 treatments were in the range of 0.143–0.202, 0.128–0.458 and 0.332–0.806 mg kg–1, respectively. Marked differences of the ratios of Cd concentration for soil to rice grain (BCFs) and transfer factors (TFs, root to grain and straw to grain) among the tested cultivars were observed in this study. The bioconcentration factors (BCFgrain) and TFs of the 20 rice cultivars were 0.300–1.112 and 0.342–0.817, respectively. The TFs of Cd from straw to grain ranged from 0.366 to 1.71, with signiifcant differences among these 20 rice cultivars. The bioconcentration factors (BCFgrain) and TFs among the 20 rice cultivars ranged from 0.300–1.112 and 0.342–0.817, respectively. The species-sensitivity distribu-tion (SSD) of Cd sensitivity of the rice species could be iftted wel with Burr-III (R2=0.987) based on the data of BCFs. The toxicity threshold of Cd derived from SSD for the paddy soil was 0.507 mg kg–1 in the present study.展开更多
The variations of grain cadmiun(Cd) concentrations, translocation factors(TFs) of Cd from roots to shoots/grains of six rice cultivars, characterized with different Cd-sensitivities in polluted soil were studied, ...The variations of grain cadmiun(Cd) concentrations, translocation factors(TFs) of Cd from roots to shoots/grains of six rice cultivars, characterized with different Cd-sensitivities in polluted soil were studied, the selected rice cultivars were Xiangzao 17(R1), Jiayu 211(R2), Xiangzao 42(R3), Zhuliangyou 312(R4), Zhuliangyou 611(R5), and Jinyou 463(R6), respectively. The Cd subcellular distribution and Cd binding characteristics on subcellular fractions of rice root cell wall(CW) were further investigated. The results showed that the rice grain Cd contents varied significantly, with a maximum variation of 47.0% among the cultivars, the largest grain Cd content was observed with cultivar R1(Cd-sensitivity cultivar) and the smallest with R5(Cd-tolerance cultivar). The translocation factors of Cd from roots to shoots(TF_(shoot)) and roots to grains(TF_(grain)) varied greatly among the cultivars. In general, the TFgrain of the cultivars followed the order of R1〉R2〉R3〉R4〉 R6-R5. The Cd concentration(mg kg^(–1) FW) in the fraction of root CW, the fraction of cell wall removing pectin(CW-P) and the fraction of cell wall removing pectin and hemicellulose(CW-P-HC) of the cultivars generally followed the order of CW-P〉CW〉CWP-HC; the ratios of Cd concentration(mg kg–1 FW) in the fraction of CW-P to that of CW were mostly more than 1.10, while the ratios of Cd concentration in the fraction of CW-P-HC to that of CW were mostly less than 0.60, indicating that Cd was mainly stored in the hemicellulose of the root CW. The ratios of Cd of CW-P-HC to CW generally followed the descending order of R1~R2〉R3〉R4〉R5~R6 for the cultivars, which implied that hemicellulose is probably the main subcellular pool for transferring Cd into rice grain, and it restrains the translocation of Cd from shoot to the grain, especially for the Cd-tolerance cultivars(R5 and R6), the compartmentation of more Cd in hemicellulose in root CW is probably one of the main mechanisms for Cd tolerance of rice cultivars.展开更多
Two japonica rice (Oryza saliva L.) cultivars, Xiushui 48 and S. Andrea, differing in their ability to accumulate Se in the grain (as high as a three-fold difference), were compared for selenium (Se) accumulation in t...Two japonica rice (Oryza saliva L.) cultivars, Xiushui 48 and S. Andrea, differing in their ability to accumulate Se in the grain (as high as a three-fold difference), were compared for selenium (Se) accumulation in their shoots when their growth media was supplied with different forms of Se. Results indicated that when treated with 0.25μmol L-1 Na2SeO3, Xiushui 48 accumulation of Se in the shoots was significantly more rapid (P≤0.05) than S. Andrea, probably because of greater Se uptake and transport in Xiushui 48. Xiushui 48 rice seedlings had a higher shoot-Se accumulation rate and absorbed selenocysteine (Se-Cys) more rapidly than S. Andrea seedlings. However, when treated with Se as 0.25 f33mol L-1 selenomethionine (Se-Met), the S. Andrea seedlings' accumulation rate was significantly greater (P≤0.05) than that of Xiushui 48. Possibly, the high Se accumulation rate of Xiushui 48 seedling shoots compared to S. Andrea shoots was the result of a higher capacity of Xiushui 48 to transform selenite to organic Se compounds and a higher selenite uptake rate.展开更多
Field experiments were conducted during the wet seasons of 2006 and 2007 at the Agricultural Experimental Farm of the Indian Statistical Institute, Giridih, a part of eastern plateau region of India. The study was des...Field experiments were conducted during the wet seasons of 2006 and 2007 at the Agricultural Experimental Farm of the Indian Statistical Institute, Giridih, a part of eastern plateau region of India. The study was designed to investigate the effect of planting geometry and nutrient management practices on productivity of two hybrid rice cultivars. Split-plot design with three replications was adopted to carry out the experiment by allocating combinations of treatments of planting geometry and rice cultivar in main-plots and nutrient management treatments in sub-plots. “CNRH-3” rice proved its efficiency in terms of grain yield that was also reflected in yield attributing characters such as number of productive tillers, number of grains per panicle, length of panicle, panicle weight, test weight and harvest index. Higher rice grain yield was registered when the cultivars grown in 20 cm × 20 cm planting geometry. Rice cultivars grown with the application of inorganic fertilizers alone produced maximum grain yield and also recorded higher values of ancillary characters. The maximum amount of N, P and K was taken up by the “CNRH-3” rice, whereas maximum residual soil fertility was recorded in “Pro Agro 6201” rice. Maximum N, P and K uptake values were recorded in 20 cm × 20 cm crop geometry and inorganic fertilizers treatment.展开更多
Developing high-yielding rice(Oryza sativa L.)cultivars depends on having a better understanding of nitrogen(N) accumulation and translocation to the ear during the reproductive stage.Field experiments were carried ou...Developing high-yielding rice(Oryza sativa L.)cultivars depends on having a better understanding of nitrogen(N) accumulation and translocation to the ear during the reproductive stage.Field experiments were carried out to evaluate the genetic variation for N accumulation and translocation in different Japonica rice cultivars at different N rates and to identify any relationship to grain yield in southeast China.Four Japonica cultivars with similar agronomic characteristics were grown at two experimental sites in 2004 with three N rates of 0,60,and 180 kg N ha^(-1).Dry weights and N contents of rice plants were measured at tillering,initiation,anthesis,and maturity.Grain yields exhibited significant differences (P<0.05)among the cultivars and N application rates.Increasing N rates improved N uptake at anthesis and maturity in all four cultivars(P<0.05).N translocation from vegetative organs to the grains increased with enhanced N rates (P<0.05).N translocation to the grains ranged from 9 to 64 kg N ha^(-1)and N-translocation efficiency from 33% to 68%. Grain yield was linear to N uptake at anthesis(r^2=0.78^(**))and N translocation(r^2=0.67^(**)).Thus,cultivars with a high N uptake at anthesis,low residual N in the straw at maturity,and appropriate low N fertilizer supply in southeast China should efficiently increase N-recovery rate while maintaining grain yield and soil fertility.展开更多
Compared to drought-susceptible rice cultivars(DSRs),drought-resistance rice cultivars(DRRs)could drastically reduce the amount of irrigation water input and simultaneously result in higher grain yield under water-sav...Compared to drought-susceptible rice cultivars(DSRs),drought-resistance rice cultivars(DRRs)could drastically reduce the amount of irrigation water input and simultaneously result in higher grain yield under water-saving irrigation conditions.However,the mechanisms underlying these properties are unclear.We investigated how improved agronomic traits contribute to higher yield and higher water use efficiency(WUE)in DRRs than in DSRs under alternate wetting and drying(AWD).Two DRRs and two DSRs were field-grown in 2015 and 2016 using two different irrigation regimes:continuous flooding(CF)and AWD.Under CF,no statistical differences in grain yield and WUE were observed between DRRs and DSRs.Irrigation water under the AWD regime was 275–349 mm,an amount 49.8%–56.2% of that(552–620 mm)applied under the CF regime.Compared to CF,AWD significantly decreased grain yield in both DRRs and DSRs,with a more significant reduction in DSRs,and WUE was increased in DRRs,but not in DSRs,by 9.9%–23.0% under AWD.Under AWD,DRRs showed a 20.2%–26.2% increase in grain yield and an 18.6%–24.5% increase in WUE compared to DSRs.Compared to DSRs,DRRs showed less redundant vegetative growth,greater sink capacity,higher grain filling efficiency,larger root biomass,and deeper root distribution under AWD.We conclude that these improved agronomic traits exert positive influences on WUE in DRRs under AWD.展开更多
A total of 408 inbred rice cultivars bred in the last decade were analyzed for 24 SSR markers. The results showed the genetic diversity of indica cultivars was higher than that of japonica cultivars, and the genetic d...A total of 408 inbred rice cultivars bred in the last decade were analyzed for 24 SSR markers. The results showed the genetic diversity of indica cultivars was higher than that of japonica cultivars, and the genetic diversity of new cultivars raised in recent years was lower. Among the six rice cropping regions (RCRs) in China, genetic diversity was the highest in the central rice region (RCR-II) and the southwest rice region (RCR-III). Genetic differences among subpopulations of japonica were more complex than those in indica. Differentiation among seasonal ecotypes and RCRs in indica populations was unclear, but differentiation between RCR-II and northeast rice region (RCR-V) was more distinct for japonica cultivars. Considering the North rice region (RCR-IV) has very low genetic diversity among the tested cultivars, it is important to broaden the genetic background for future cultivars in rice breeding programs.展开更多
Drought is the most critical abiotic factor reducing rice yield in rainfed and drought prone areas. Majority of rice cultivated area in south Asia are under rainfed, where water stress at any of the critical growth st...Drought is the most critical abiotic factor reducing rice yield in rainfed and drought prone areas. Majority of rice cultivated area in south Asia are under rainfed, where water stress at any of the critical growth stage causes sharp decline in yield. Research was conducted in western Nepal at farmers field around the close vicinity of Regional Agriculture Research Center (RARS) Nepalgunj. Ten different rice cultivars were evaluated under drought stress and non-stress condition during the year 2017 to identify superior stress tolerant cultivars. Different drought tolerance indices like stress tolerance (TOL), Stress tolerance index (STI), Stress susceptibility index (SSI), were tested in screening superior rice cultivars. Significant reduction in mean grain yield was observed under drought stress in all rice cultivars under the study. The rice cultivars with high STI values and low TOL and SSI were identified as superior drought tolerant cultivars. Based on results of different tolerance indices, Sukha series of rice, Sukha Dhan 1-6 and Radha-4 showed low TOL and SSI and high STI values and were identified as drought tolerant cultivars. The present study reveals that selection based on drought tolerance indices can be an efficient tool in identification of superior drought tolerant cultivars with higher yield and stability.展开更多
The waxy(Wx)gene of rice encodes the granule-bound starch synthase(GBSS),which was required in the synthesis of amylose in endosperm.Theamylose content(AC)of rice endosperm played an important role in grain yield,pala...The waxy(Wx)gene of rice encodes the granule-bound starch synthase(GBSS),which was required in the synthesis of amylose in endosperm.Theamylose content(AC)of rice endosperm played an important role in grain yield,palatability,and processing quality.Our previous researehes showed that en-dosperm AC and GBSS contents were correlated with the ability of excising intron1 from the leader sequence of the Wx transcript.Cultivars with high endosperm展开更多
In irrigated agricultural systems,nitrogen(N)and water are the vital resources for sustainability of the crop production in the modern era of climate change.The current study aimed to assess the impact of water and N ...In irrigated agricultural systems,nitrogen(N)and water are the vital resources for sustainability of the crop production in the modern era of climate change.The current study aimed to assess the impact of water and N management on the productivity of irrigated rice cultivars.In the context,a field observation was done at the research farm of Bangladesh Agricultural University,Mymensingh,during dry seasons in consecutive two years(2018–2019 and 2019–2020).The experiments were set up following split-plot design assigning water management in the main plots,nitrogen management in the sub-plots,and the cultivars were approved in the split-split plot with three replications.After two years observation,it was revealed that rice cultivar Binadhan-8 gave the maximum value of leaf area index,number effective tillers hill-1 and grains panicle-1 which lead to the higher grain yield(GY).Substantial relationships were observed among the concentration of N,growth,total dry matter(TDM)and N content,N uptake,N utilization effectiveness,and GY.However,with little exception,the Combined effect of water and N,cultivars and water management were varied significantly for all parameters.Finally,the results of the current study concluded that application of irrigation at 8 days after the disappearance of ponded water and source of 105 kg N ha-1 from PU+Poultry manure are the best management approach for the excellent performance of rice cultivar Binadhan-8.展开更多
The morphological characters, physiological characters, yield traits and yield per plant of total 49 rice cultivars from Ningxia were investigated under conditions of water stress and non-water stress so as to determi...The morphological characters, physiological characters, yield traits and yield per plant of total 49 rice cultivars from Ningxia were investigated under conditions of water stress and non-water stress so as to determine the relationship between each trait and yield per plant under water stress and the relationship between each relative character and drought resistance coefficient under water stress and non-water stress. The correlation, grey correlation, stepwise regression and path analyses showed that the tiller number per plant, plant height, grain density, effective panicle number per plant and grain number per panicle, total 5 traits, were significantly correlated with the drought resistance of rice, and they could be used to identify the drought resistance of rice in Ningxia. In addition, the drought resistance of rice was graded qualitatively according to the subordinate function value of corresponding drought resistance coefficient. The results showed that among the 49 rice cultivars from Ningxia,6 rice cultivars were highly drought resistant, and 9 rice cultivars were moderately drought resistant, suggesting that the evaluation method was feasible and effective.展开更多
To develop basis for strategic or arranged decision making towards crop yield improvement in Thailand, a new method in which crop models could be used is essential. Therefore, the objective of this study was to measur...To develop basis for strategic or arranged decision making towards crop yield improvement in Thailand, a new method in which crop models could be used is essential. Therefore, the objective of this study was to measure cultivar specific parameters by using DSSAT (v4.7) Cropping Simulation Model (CSM) with five upland rice genotypes namely Dawk Pa-yawm, Mai Tahk, Bow Leb Nahng, Dawk Kha 50 and Dawk Kahm. Experiment was laid out in a Completely Randomized Design (CRD) with split plot design. Results showed that five upland rice genotypes had significantly affected each other by different temperature treatments (28°C, 30°C, 32°C) with grain yield, tops weight, harvest index, flowering, and maturity date. At the same time, all the phenological traits had highly significant variation with the genotypes. The cultivar specific parameters obtained by using a temperature tolerant cultivar (Basmati 385) with five upland genotypes involved in the DSSAT4.7-CSM. Model evaluation results indicated that utilizing the estimated cultivar coefficient parameters, model simulated well with varying temperature treatments as indicated by the agreement index (d-statistic) closer to unity. Hence, it was estimated that model calibration and evaluation was realistic in the limits of test cropping seasons and that CSM fitted with cultivar specific parameters can be used in simulation studies for investigation, farm managing or decision making. This electronic document is a “live” template. The various components of your paper [title, text, heads, etc.] are already defined on the style sheet, as illustrated by the portions given in this document.展开更多
Degradation of the natural resource base has led to decline in crop yields or stagnation that caused food shortages at varying degrees among mountain families. Rice, the major staple food in Asia,is suffering from lac...Degradation of the natural resource base has led to decline in crop yields or stagnation that caused food shortages at varying degrees among mountain families. Rice, the major staple food in Asia,is suffering from lack of suitable cultivar and N fertilizer management, when grown near mountainous slopes under rain-fed agro-ecosystem.An investigation through a field experiment and simulation study was conducted at United Nations University, Tokyo to select suitable rice cultivars and N fertilizer level for the rice grown near mountainous slopes in Orissa, India. The field experiment was conducted during wet season (June to November) of 2001 at Kasiadihi village of Dhenkanal district, Orissa,India with eight popular rice cultivars of medium (120~130 d) and long duration (135~150 d) group and Ranjit of long duration group followed by 4,730group, across N levels. CERES-Rice model was used to simulated grain yield of these two selected cultivars using historical weather data of the past 18years (1983~2000). Long duration cultivar Ranjit registered higher yield with lower stability as compared medium duration cultivar Mahamaya over the past 18 years. An optimum N fertilizer level of 80rain-fed ecosystem near mountainous slopes in Orissa,India to attain optimum yield potential of cultivar.展开更多
研究滴灌条件下施氮量对不同氮效率品种关键生育时期干物质积累和氮素吸收转运及产量的影响,为干旱半干旱区滴灌水稻高产高效生产提供技术参考。试验于2021—2022年开展,以氮高效品种(T-43)和氮低效品种(LX-3)为供试材料,采用裂区设计;...研究滴灌条件下施氮量对不同氮效率品种关键生育时期干物质积累和氮素吸收转运及产量的影响,为干旱半干旱区滴灌水稻高产高效生产提供技术参考。试验于2021—2022年开展,以氮高效品种(T-43)和氮低效品种(LX-3)为供试材料,采用裂区设计;设置4个施氮水平,分别为N0(0 kg hm^(-2))、N1(150 kg hm^(-2))、N2(300 kg hm^(-2))和N3(450 kg hm^(-2))。分析滴灌水稻在抽穗期和成熟期干物质积累、氮素吸收利用及产量对施氮量的响应差异。结果表明:(1)施用氮肥可以增加滴灌水稻干物质积累量(1.99%~26.02%)和氮素积累量(25.67%~97.69%),提高水稻产量(23.75%~66.75%);但过量施氮(450 kg hm^(-2))会减小对干物质积累的促进作用,导致结实率和穗粒数下降,使氮素主要集中在秸秆中,最终降低水稻对氮素的利用效率。(2)在同一施氮条件下,T-43的有效穗数、结实率、抽穗期叶片和穗部干物质及氮素积累量均高于LX-3(分别为1.65%~5.19%、0.42%~8.47%、7.61%~19.68%、19.81%~40.73%、19.81%~30.23%和20.14%~49.65%),最终产量高于LX-3(4.23%~28.47%)。(3)氮素利用效率对施氮量的响应存在品种间差异(P<0.05)。与LX-3相比,T-43有更高的氮肥农学利用效率、氮素回收率和氮肥偏生产力(分别高1.05%~25.23%、5.86%~20.05%和10.09%~18.01%)。综上所述,在滴灌栽培条件下,选用氮高效品种(T-43),配施300 kg hm^(-2)氮肥表现出更佳的氮素吸收转运能力和更高的产量,能更好地利用养分资源,是本试验最佳的品种和施氮量组合方式。展开更多
基金supported by the National Natural Science Foundation of China(42177455)“Pioneer”and“Leading Goose”R&D Program of Zhejiang(2022C02008 and 2022C02058)+1 种基金Central Public-interest Scientific Institution Basal Research Fund(CPSIBRF-CNRRI-202305)the Agricultural Science and Technology Innovation Program(ASTIP)。
文摘In aquaculture,co-culturing rice with fish may mitigate greenhouse-gas emissions.In this study,co-culture of four rice cultivars in a laboratory-scale rice–fish system reduced CH_(4)and N_(2)O emissions relative to fish monoculture.Differences in CH_(4)and N_(2)O emissions among rice cultivars primarily stem from the differential effects of rice plants on plant-mediated CH_(4)transport,CH_(4)oxidation and nitrogen absorption.
基金supported by the Ministry of Science and Technology of China (No. 2006BAD17B06)the Ministry of Education of China (No. B200613).
文摘Enhanced Cd uptake and Zn depletion in rice grains and high potential for food Cd exposure by the high-yielding hybrid cultivars of China had been addressed. A field experiment was conducted in 2006 to determine the difference in grain Cd and Zn between cultivars. Total 110 cultivars including super rice and common hybrid rice cultivars were grown on a single paddy soil (Entic Haplaquept) with a neutral reaction and low total Cd content. Grain Cd and Zn concentrations were determined with graphite atomic adsorption spectrophotometer (GFAAS) and flame atomic adsorption spectrophotometer (AAS) respectively. Wide variation of Cd content in grain was found in a range of 0.004-0.057 mg/kg, while the Zn content in a range of 10.25-30.06 mg/kg among the cultivars. Higher Cd but lower Zn concentration in grains of super rice cultivars was observed compared to the common hybrid ones. A highly significant positive linear correlation of grain Cd/Zn with grain Cd was found for super rice and common hybrid cultivars, meanwhile much higher slope for these hybrid cultivars than the reported non-hybrid cultivars was also observed. Using the limit value of the Chinese chemical guidelines for foods (MOHC and SSC, 2005), calculated potential risk of food Cd exposure with "Zn hungry" through diet intake was prominent with all the studied 110 hybrid rice cultivars, possessing high potential health problems for rice production in South China using the super rice cultivars. Breeding of genotypes of rice cultivars with low grain Cd and low Cd/Zn ratio is needed for rice production in acidic red soils where Cd bioavailability is prevalently high.
基金support of the National Natural Science Foundation of China (41271490, 21077131)
文摘It is imperative to derive an appropriate cadmium (Cd) health risk toxicity threshold for paddy soils to ensure the Cd con-centration of rice grains meet the food safety standard. In this study, 20 rice cultivars from the main rice producing areas in China were selected, and a pot-experiment was conducted to investigate transformation of Cd in paddy soil-rice system with 0 (CK), 0.3 mg kg–1 (T1) and 0.6 mg kg–1 (T2) Cd treatments in greenhouse. The results showed that Cd concentrations of rice grains existed signiifcant difference (P<0.05) in 20 rice cultivars under the same Cd level in soil. The Cd concentrations of rice grains of the CK, T1 and T2 treatments were in the range of 0.143–0.202, 0.128–0.458 and 0.332–0.806 mg kg–1, respectively. Marked differences of the ratios of Cd concentration for soil to rice grain (BCFs) and transfer factors (TFs, root to grain and straw to grain) among the tested cultivars were observed in this study. The bioconcentration factors (BCFgrain) and TFs of the 20 rice cultivars were 0.300–1.112 and 0.342–0.817, respectively. The TFs of Cd from straw to grain ranged from 0.366 to 1.71, with signiifcant differences among these 20 rice cultivars. The bioconcentration factors (BCFgrain) and TFs among the 20 rice cultivars ranged from 0.300–1.112 and 0.342–0.817, respectively. The species-sensitivity distribu-tion (SSD) of Cd sensitivity of the rice species could be iftted wel with Burr-III (R2=0.987) based on the data of BCFs. The toxicity threshold of Cd derived from SSD for the paddy soil was 0.507 mg kg–1 in the present study.
基金financially supported by the National Natural Science Foundation of China(41271490,21077131)the National Key Research and Development Program of China(2016YFD0800707)
文摘The variations of grain cadmiun(Cd) concentrations, translocation factors(TFs) of Cd from roots to shoots/grains of six rice cultivars, characterized with different Cd-sensitivities in polluted soil were studied, the selected rice cultivars were Xiangzao 17(R1), Jiayu 211(R2), Xiangzao 42(R3), Zhuliangyou 312(R4), Zhuliangyou 611(R5), and Jinyou 463(R6), respectively. The Cd subcellular distribution and Cd binding characteristics on subcellular fractions of rice root cell wall(CW) were further investigated. The results showed that the rice grain Cd contents varied significantly, with a maximum variation of 47.0% among the cultivars, the largest grain Cd content was observed with cultivar R1(Cd-sensitivity cultivar) and the smallest with R5(Cd-tolerance cultivar). The translocation factors of Cd from roots to shoots(TF_(shoot)) and roots to grains(TF_(grain)) varied greatly among the cultivars. In general, the TFgrain of the cultivars followed the order of R1〉R2〉R3〉R4〉 R6-R5. The Cd concentration(mg kg^(–1) FW) in the fraction of root CW, the fraction of cell wall removing pectin(CW-P) and the fraction of cell wall removing pectin and hemicellulose(CW-P-HC) of the cultivars generally followed the order of CW-P〉CW〉CWP-HC; the ratios of Cd concentration(mg kg–1 FW) in the fraction of CW-P to that of CW were mostly more than 1.10, while the ratios of Cd concentration in the fraction of CW-P-HC to that of CW were mostly less than 0.60, indicating that Cd was mainly stored in the hemicellulose of the root CW. The ratios of Cd of CW-P-HC to CW generally followed the descending order of R1~R2〉R3〉R4〉R5~R6 for the cultivars, which implied that hemicellulose is probably the main subcellular pool for transferring Cd into rice grain, and it restrains the translocation of Cd from shoot to the grain, especially for the Cd-tolerance cultivars(R5 and R6), the compartmentation of more Cd in hemicellulose in root CW is probably one of the main mechanisms for Cd tolerance of rice cultivars.
基金Project supported by the National Natural Science Foundation of China (No. 40371063)the National Key Basic Research Support Foundation of China (No. G1999011808).
文摘Two japonica rice (Oryza saliva L.) cultivars, Xiushui 48 and S. Andrea, differing in their ability to accumulate Se in the grain (as high as a three-fold difference), were compared for selenium (Se) accumulation in their shoots when their growth media was supplied with different forms of Se. Results indicated that when treated with 0.25μmol L-1 Na2SeO3, Xiushui 48 accumulation of Se in the shoots was significantly more rapid (P≤0.05) than S. Andrea, probably because of greater Se uptake and transport in Xiushui 48. Xiushui 48 rice seedlings had a higher shoot-Se accumulation rate and absorbed selenocysteine (Se-Cys) more rapidly than S. Andrea seedlings. However, when treated with Se as 0.25 f33mol L-1 selenomethionine (Se-Met), the S. Andrea seedlings' accumulation rate was significantly greater (P≤0.05) than that of Xiushui 48. Possibly, the high Se accumulation rate of Xiushui 48 seedling shoots compared to S. Andrea shoots was the result of a higher capacity of Xiushui 48 to transform selenite to organic Se compounds and a higher selenite uptake rate.
文摘Field experiments were conducted during the wet seasons of 2006 and 2007 at the Agricultural Experimental Farm of the Indian Statistical Institute, Giridih, a part of eastern plateau region of India. The study was designed to investigate the effect of planting geometry and nutrient management practices on productivity of two hybrid rice cultivars. Split-plot design with three replications was adopted to carry out the experiment by allocating combinations of treatments of planting geometry and rice cultivar in main-plots and nutrient management treatments in sub-plots. “CNRH-3” rice proved its efficiency in terms of grain yield that was also reflected in yield attributing characters such as number of productive tillers, number of grains per panicle, length of panicle, panicle weight, test weight and harvest index. Higher rice grain yield was registered when the cultivars grown in 20 cm × 20 cm planting geometry. Rice cultivars grown with the application of inorganic fertilizers alone produced maximum grain yield and also recorded higher values of ancillary characters. The maximum amount of N, P and K was taken up by the “CNRH-3” rice, whereas maximum residual soil fertility was recorded in “Pro Agro 6201” rice. Maximum N, P and K uptake values were recorded in 20 cm × 20 cm crop geometry and inorganic fertilizers treatment.
基金Project supported by the National Natural Science Foundation of China(Nos.30390082 and 3027079)the Science and Technology Committee of Jiangsu Province,China(No.BE2005369).
文摘Developing high-yielding rice(Oryza sativa L.)cultivars depends on having a better understanding of nitrogen(N) accumulation and translocation to the ear during the reproductive stage.Field experiments were carried out to evaluate the genetic variation for N accumulation and translocation in different Japonica rice cultivars at different N rates and to identify any relationship to grain yield in southeast China.Four Japonica cultivars with similar agronomic characteristics were grown at two experimental sites in 2004 with three N rates of 0,60,and 180 kg N ha^(-1).Dry weights and N contents of rice plants were measured at tillering,initiation,anthesis,and maturity.Grain yields exhibited significant differences (P<0.05)among the cultivars and N application rates.Increasing N rates improved N uptake at anthesis and maturity in all four cultivars(P<0.05).N translocation from vegetative organs to the grains increased with enhanced N rates (P<0.05).N translocation to the grains ranged from 9 to 64 kg N ha^(-1)and N-translocation efficiency from 33% to 68%. Grain yield was linear to N uptake at anthesis(r^2=0.78^(**))and N translocation(r^2=0.67^(**)).Thus,cultivars with a high N uptake at anthesis,low residual N in the straw at maturity,and appropriate low N fertilizer supply in southeast China should efficiently increase N-recovery rate while maintaining grain yield and soil fertility.
基金the National Key Research and Development Program of China (2016YFD0300507,2016YFD0300108)the National Natural Science Foundation of China (31671630,31671638,31501264)the China Agriculture Research System (CARS-01)
文摘Compared to drought-susceptible rice cultivars(DSRs),drought-resistance rice cultivars(DRRs)could drastically reduce the amount of irrigation water input and simultaneously result in higher grain yield under water-saving irrigation conditions.However,the mechanisms underlying these properties are unclear.We investigated how improved agronomic traits contribute to higher yield and higher water use efficiency(WUE)in DRRs than in DSRs under alternate wetting and drying(AWD).Two DRRs and two DSRs were field-grown in 2015 and 2016 using two different irrigation regimes:continuous flooding(CF)and AWD.Under CF,no statistical differences in grain yield and WUE were observed between DRRs and DSRs.Irrigation water under the AWD regime was 275–349 mm,an amount 49.8%–56.2% of that(552–620 mm)applied under the CF regime.Compared to CF,AWD significantly decreased grain yield in both DRRs and DSRs,with a more significant reduction in DSRs,and WUE was increased in DRRs,but not in DSRs,by 9.9%–23.0% under AWD.Under AWD,DRRs showed a 20.2%–26.2% increase in grain yield and an 18.6%–24.5% increase in WUE compared to DSRs.Compared to DSRs,DRRs showed less redundant vegetative growth,greater sink capacity,higher grain filling efficiency,larger root biomass,and deeper root distribution under AWD.We conclude that these improved agronomic traits exert positive influences on WUE in DRRs under AWD.
基金supported by the Basic Research for Science and Technology of the Ministry of Sciecne and Technology,China (2008FY220200)
文摘A total of 408 inbred rice cultivars bred in the last decade were analyzed for 24 SSR markers. The results showed the genetic diversity of indica cultivars was higher than that of japonica cultivars, and the genetic diversity of new cultivars raised in recent years was lower. Among the six rice cropping regions (RCRs) in China, genetic diversity was the highest in the central rice region (RCR-II) and the southwest rice region (RCR-III). Genetic differences among subpopulations of japonica were more complex than those in indica. Differentiation among seasonal ecotypes and RCRs in indica populations was unclear, but differentiation between RCR-II and northeast rice region (RCR-V) was more distinct for japonica cultivars. Considering the North rice region (RCR-IV) has very low genetic diversity among the tested cultivars, it is important to broaden the genetic background for future cultivars in rice breeding programs.
文摘Drought is the most critical abiotic factor reducing rice yield in rainfed and drought prone areas. Majority of rice cultivated area in south Asia are under rainfed, where water stress at any of the critical growth stage causes sharp decline in yield. Research was conducted in western Nepal at farmers field around the close vicinity of Regional Agriculture Research Center (RARS) Nepalgunj. Ten different rice cultivars were evaluated under drought stress and non-stress condition during the year 2017 to identify superior stress tolerant cultivars. Different drought tolerance indices like stress tolerance (TOL), Stress tolerance index (STI), Stress susceptibility index (SSI), were tested in screening superior rice cultivars. Significant reduction in mean grain yield was observed under drought stress in all rice cultivars under the study. The rice cultivars with high STI values and low TOL and SSI were identified as superior drought tolerant cultivars. Based on results of different tolerance indices, Sukha series of rice, Sukha Dhan 1-6 and Radha-4 showed low TOL and SSI and high STI values and were identified as drought tolerant cultivars. The present study reveals that selection based on drought tolerance indices can be an efficient tool in identification of superior drought tolerant cultivars with higher yield and stability.
文摘The waxy(Wx)gene of rice encodes the granule-bound starch synthase(GBSS),which was required in the synthesis of amylose in endosperm.Theamylose content(AC)of rice endosperm played an important role in grain yield,palatability,and processing quality.Our previous researehes showed that en-dosperm AC and GBSS contents were correlated with the ability of excising intron1 from the leader sequence of the Wx transcript.Cultivars with high endosperm
基金Bangladesh Agricultural Research Council(BARC),Bangladesh and the Taif University Researchers Supporting Project No.(TURSP-2020/85),Taif University,Taif,Saudi Arabia.
文摘In irrigated agricultural systems,nitrogen(N)and water are the vital resources for sustainability of the crop production in the modern era of climate change.The current study aimed to assess the impact of water and N management on the productivity of irrigated rice cultivars.In the context,a field observation was done at the research farm of Bangladesh Agricultural University,Mymensingh,during dry seasons in consecutive two years(2018–2019 and 2019–2020).The experiments were set up following split-plot design assigning water management in the main plots,nitrogen management in the sub-plots,and the cultivars were approved in the split-split plot with three replications.After two years observation,it was revealed that rice cultivar Binadhan-8 gave the maximum value of leaf area index,number effective tillers hill-1 and grains panicle-1 which lead to the higher grain yield(GY).Substantial relationships were observed among the concentration of N,growth,total dry matter(TDM)and N content,N uptake,N utilization effectiveness,and GY.However,with little exception,the Combined effect of water and N,cultivars and water management were varied significantly for all parameters.Finally,the results of the current study concluded that application of irrigation at 8 days after the disappearance of ponded water and source of 105 kg N ha-1 from PU+Poultry manure are the best management approach for the excellent performance of rice cultivar Binadhan-8.
基金Supported by Natural Science Foundation of Ningxia(NZ1189)National Rice Industrial Technology System(CARS-01-84)
文摘The morphological characters, physiological characters, yield traits and yield per plant of total 49 rice cultivars from Ningxia were investigated under conditions of water stress and non-water stress so as to determine the relationship between each trait and yield per plant under water stress and the relationship between each relative character and drought resistance coefficient under water stress and non-water stress. The correlation, grey correlation, stepwise regression and path analyses showed that the tiller number per plant, plant height, grain density, effective panicle number per plant and grain number per panicle, total 5 traits, were significantly correlated with the drought resistance of rice, and they could be used to identify the drought resistance of rice in Ningxia. In addition, the drought resistance of rice was graded qualitatively according to the subordinate function value of corresponding drought resistance coefficient. The results showed that among the 49 rice cultivars from Ningxia,6 rice cultivars were highly drought resistant, and 9 rice cultivars were moderately drought resistant, suggesting that the evaluation method was feasible and effective.
文摘To develop basis for strategic or arranged decision making towards crop yield improvement in Thailand, a new method in which crop models could be used is essential. Therefore, the objective of this study was to measure cultivar specific parameters by using DSSAT (v4.7) Cropping Simulation Model (CSM) with five upland rice genotypes namely Dawk Pa-yawm, Mai Tahk, Bow Leb Nahng, Dawk Kha 50 and Dawk Kahm. Experiment was laid out in a Completely Randomized Design (CRD) with split plot design. Results showed that five upland rice genotypes had significantly affected each other by different temperature treatments (28°C, 30°C, 32°C) with grain yield, tops weight, harvest index, flowering, and maturity date. At the same time, all the phenological traits had highly significant variation with the genotypes. The cultivar specific parameters obtained by using a temperature tolerant cultivar (Basmati 385) with five upland genotypes involved in the DSSAT4.7-CSM. Model evaluation results indicated that utilizing the estimated cultivar coefficient parameters, model simulated well with varying temperature treatments as indicated by the agreement index (d-statistic) closer to unity. Hence, it was estimated that model calibration and evaluation was realistic in the limits of test cropping seasons and that CSM fitted with cultivar specific parameters can be used in simulation studies for investigation, farm managing or decision making. This electronic document is a “live” template. The various components of your paper [title, text, heads, etc.] are already defined on the style sheet, as illustrated by the portions given in this document.
文摘Degradation of the natural resource base has led to decline in crop yields or stagnation that caused food shortages at varying degrees among mountain families. Rice, the major staple food in Asia,is suffering from lack of suitable cultivar and N fertilizer management, when grown near mountainous slopes under rain-fed agro-ecosystem.An investigation through a field experiment and simulation study was conducted at United Nations University, Tokyo to select suitable rice cultivars and N fertilizer level for the rice grown near mountainous slopes in Orissa, India. The field experiment was conducted during wet season (June to November) of 2001 at Kasiadihi village of Dhenkanal district, Orissa,India with eight popular rice cultivars of medium (120~130 d) and long duration (135~150 d) group and Ranjit of long duration group followed by 4,730group, across N levels. CERES-Rice model was used to simulated grain yield of these two selected cultivars using historical weather data of the past 18years (1983~2000). Long duration cultivar Ranjit registered higher yield with lower stability as compared medium duration cultivar Mahamaya over the past 18 years. An optimum N fertilizer level of 80rain-fed ecosystem near mountainous slopes in Orissa,India to attain optimum yield potential of cultivar.
文摘研究滴灌条件下施氮量对不同氮效率品种关键生育时期干物质积累和氮素吸收转运及产量的影响,为干旱半干旱区滴灌水稻高产高效生产提供技术参考。试验于2021—2022年开展,以氮高效品种(T-43)和氮低效品种(LX-3)为供试材料,采用裂区设计;设置4个施氮水平,分别为N0(0 kg hm^(-2))、N1(150 kg hm^(-2))、N2(300 kg hm^(-2))和N3(450 kg hm^(-2))。分析滴灌水稻在抽穗期和成熟期干物质积累、氮素吸收利用及产量对施氮量的响应差异。结果表明:(1)施用氮肥可以增加滴灌水稻干物质积累量(1.99%~26.02%)和氮素积累量(25.67%~97.69%),提高水稻产量(23.75%~66.75%);但过量施氮(450 kg hm^(-2))会减小对干物质积累的促进作用,导致结实率和穗粒数下降,使氮素主要集中在秸秆中,最终降低水稻对氮素的利用效率。(2)在同一施氮条件下,T-43的有效穗数、结实率、抽穗期叶片和穗部干物质及氮素积累量均高于LX-3(分别为1.65%~5.19%、0.42%~8.47%、7.61%~19.68%、19.81%~40.73%、19.81%~30.23%和20.14%~49.65%),最终产量高于LX-3(4.23%~28.47%)。(3)氮素利用效率对施氮量的响应存在品种间差异(P<0.05)。与LX-3相比,T-43有更高的氮肥农学利用效率、氮素回收率和氮肥偏生产力(分别高1.05%~25.23%、5.86%~20.05%和10.09%~18.01%)。综上所述,在滴灌栽培条件下,选用氮高效品种(T-43),配施300 kg hm^(-2)氮肥表现出更佳的氮素吸收转运能力和更高的产量,能更好地利用养分资源,是本试验最佳的品种和施氮量组合方式。