[Objective] This study aimed to investigate the correlation between yield and quality traits of rape. [Method] Taking "Sanbei 98" and "Youyan 599" as ex- periment materials, correlation between yield and quality t...[Objective] This study aimed to investigate the correlation between yield and quality traits of rape. [Method] Taking "Sanbei 98" and "Youyan 599" as ex- periment materials, correlation between yield and quality traits of Brassica napus L. cultivars was explored by orthogonal rotation method. [Result] The results showed that: 1 In both the two varieties-Sanbei98 and Youyan599, erucic acid content had the largest coefficient of variation, but its average content was lower than 2% in both the two varieties (0.90% in Sanbei98 and 1.24% in Youyan599), and the palmitic acid content had the smallest coefficient of variation. 2 In terms of the dif- ferences in quality traits at different yield levels, only the mean of eicosenoic acid content revealed significant difference in Sanbei98, and only the mean of seed-pro- tein content revealed significant difference in Youyan599, and there was no signifi- cant difference in any combined quality traits in both the two varieties. 3 The yield was negatively correlated with the erucic acid content or oil content, and posi- tively correlated with the content of seed-protein, linoleic acid, or linolenic acid, and the coefficient of correlation between the yield and either of the contents of glucosi- nolates, oleic acid, palmitic acid, stearic acid, and eicosenoic acid was smaller. ~, when the yield of a variety increased considerably, there was a certain decreasing trend in erucic acid content, oil content, the total amount of erucic chain fatty acids (El & Er), while there was an increasing trend in seed-protein content, linoleic acid content, linolenic acid content, saturated fatty acids (SFA), the total amount of fat and protein (P & F), unsaturation index (IUFA), unsaturated fatty acids (UFA), the total amount of 18 carbon fatty acids (18-C FA), unsaturated fatty acids [UFA/(Ei & Er) ], and the sum of oleic acid and linoleic acid (OI & Li). 5 When the seed-pro- tein content is increased, the quality of rape oil cake is also improved; when the unsaturated index is increased, the oil stability is decreased. The increase in the total amount of unsaturated fatty acids, oleic acid and linoleic acid helps to increase in the total amount of fatty acids absorbed by human bodies. [Conclusion] This study provides a theoretical foundation for the cultivation of high-yielding and top- quality hybrid rape cultivars.展开更多
[Objective] The aim of this work was to analyze the N fertilization on the vegetative growth and N uptake of different winter rapeseed varieties at wintering stage. [Method] In two consecutive years (2009-2011), two...[Objective] The aim of this work was to analyze the N fertilization on the vegetative growth and N uptake of different winter rapeseed varieties at wintering stage. [Method] In two consecutive years (2009-2011), two winter rapeseed varieties (B. napus L.), an early maturity variety Zhongyou 116 (ZY116) and a middle-late application maturity variety Zhongyouza 12 (ZYZ12) were employed. Field experiments with different N levels (0, 90, 180, 270, 360 kg N/hm 2 ) were designed. At the wintering stage, the dry matter weight, the nitrogen content and concentration of plants, leaf nitrate reductase activity (NRA) and seed yields were investigated. [Result] The shoot dry matter of ZY116 increased rapidly when N rate ranged from 0 to 180 kg/hm 2 , and it raised slightly when N rate ranged from 180 to 360 kg/hm 2 . The shoot dry matter of ZYZ12 were changed in a single peak curve; the peak of shoot dry matter appeared at 270 kg N/hm 2 . The N concentration and N content in shoot and root increased rapidly when the N rate changed from 90 to 180 kg/hm 2 . Moreover, the N concentration and N content root of in ZYZ12 were much higher than that of ZY116. Present study revealed that the changed trend of leaf nitrate reductase activities (NRA) were significantly increased at the N rate of 180 kg/hm 2 in ZY116 and ZYZ12 compared with the N rate of 90 kg/hm 2 in two years. [Conclusion] Optimal nitrogen application significantly increased the dry weights and N uptake at wintering stage as well as increasing the yield of winter oilseed rape.展开更多
China is one of the most important rapeseed producing countries in the world. Effective mechanical harvesting time for decreasing harvesting loss of winter oilseed rape has been becoming a critical factor. An elite cu...China is one of the most important rapeseed producing countries in the world. Effective mechanical harvesting time for decreasing harvesting loss of winter oilseed rape has been becoming a critical factor. An elite cultivar Zhongshuang 11 (Brassica napus L.) was employed in two rounds of field experiments from 2009 to 2011. Seeds were sown with machine, three combine harvesting times namely combine harvesting A, B, and C (CHA, CHB, and CHC) were designed and manual harvesting (MH) as control was performed at maturity. The harvesting treatments were determined according to color of pod and seed in the field. Seed yield loss and quality in different treatments were evaluated. Results showed that both seed yields and harvesting losses in 2009-2010 were higher than that in 2010-2011, whereas seed oil contents in 2010-2011 were higher than that in 2009-2010. The highest yield appeared in CHB, which was significantly higher than that in MH. Furthermore, harvesting loss in CHB were 50% that in MH. Seed oil content and chlorophyll exhibited no obvious difference between CHB and MH. Economic profit analysis demonstrated that mechanical sowing/combine harvesting (MS/CH) showed an input/output ratio of 1:1.6, and it was 1:1.2 in mechanical sowing/manual harvesting (MS/MH). Labor-cost accounted for more than 70% of the total cost in MS/MH, which led to low profitability to a great extent. Our results suggested that CHB was the optimum harvesting time for winter oilseed rape along the Yangtze River.展开更多
Direct-sowing establishment method has great significance in improving winter oilseed rape(Brassica napus L.) production and guaranteeing edible oil security in China. However, nutrient responses on direct sown wint...Direct-sowing establishment method has great significance in improving winter oilseed rape(Brassica napus L.) production and guaranteeing edible oil security in China. However, nutrient responses on direct sown winter oilseed rape(DOR) performance and population development dynamic are still not well understood. Therefore, five on-farm experiments were conducted in the reaches of the Yangtze River(RYR) to determine the effects of nitrogen(N), phosphorus(P), and potassium(K) deficiencies on population density, dry matter production, nutrient uptake, seed yield, and yield components of DOR plants. Four fertilization treatments included the balanced NPK application treatment(NPK, 180 kg N, 39.3 kg P, 100 kg K, and 1.8 kg borax ha–1) and three nutrient deficiency treatments based on the NPK treatment, i.e., –N, –P, and –K. The results indicated that DOR population density declined gradually throughout the growing season, especially at over-wintering and pod-development stages. Nutrient deficiency decreased nutrient concentration in DOR plants, limited dry matter production and nutrient uptake, and thereby exacerbated density reduction during plants growth. The poor individual growth and reduced population density together decreased seed yield in the nutrient deficiency treatment. Averaged across all the experiments, seed yield reduced 61% by N deficiency, 38.3% by P deficiency, and 14.4% by K deficiency. The negative effects of nutrient deficiency on DOR performances followed the order of –N–P–K, and the effects were various among different nutrient deficiencies. Although N deficiency improved DOR emergence, but it seriously limited dry matter production and nutrient uptake, which in turn led to substantial plants death and therefore resulted in a very low harvested density. The P deficiency significantly reduced initial density, limited plants growth, and exacerbated density reduction. The K deficiency mainly decreased individual growth and yield, but did not affect density dynamic. Our results highlighted the importance of balanced NPK application in DOR production, suggesting that management strategy of these nutrients should be comprehensively considered with an aim to build an appropriate population structure with balanced plant density and individual growth.展开更多
China is one of the major rapeseed production countries in the world,but harvesting mechanization was still backward,and high harvest loss was a key inhibiting factor for rapeseed production.To obtain optimum harvesti...China is one of the major rapeseed production countries in the world,but harvesting mechanization was still backward,and high harvest loss was a key inhibiting factor for rapeseed production.To obtain optimum harvesting date for winter rape in the Yangtze River Valley of China,artificial simulated combine harvesting and artificial two-stage harvesting were adopted to find correlations between harvesting date,rape variety,seed oil content,protein content,grain moisture rate,rapeseed straw moisture content,rapeseed unthreshing rate,grain drop loss rate,thousand seeds weight(TSW),and harvesting economic coefficient(HEC).Analysis of variance showed that rapeseed oil content,protein content and TSW were correlated with rape variety;HEC was correlated with harvesting method and rape variety.Rape variety was the dominant factor of rapeseed oil content,protein content,TSW and HEC.Grain moisture rate,un-threshing rate,grain drop loss rate and straw moisture content were correlated with harvesting method and date.Harvesting date was the dominant factor of rapeseed moisture rate,un-threshing rate,grain drop loss rate and straw moisture rate.Single factor tests further proved that harvesting date had less impact on rapeseed oil content,protein content,TSW and HEC.It showed little correlation with rapeseed quality except grain moisture rate.The optimum harvesting date could be known by change in straw moisture content.The combined harvesting should be carried out during the grain moisture content of 15%-20%with TSW stabilized in the highest level.The twostage harvesting cutting should be carried out at the grain moisture content of 35%-40%.This research offered a reference to harvesting method and date for rape cultivated in the Yangtze River Valley.展开更多
Using tracer techniques with the radioisotope 45Ca, the effects of boron supply from soil and nutrient solution on the retranslocation of 45Ca from leaves to other parts of rape plants were studied. Results indicated ...Using tracer techniques with the radioisotope 45Ca, the effects of boron supply from soil and nutrient solution on the retranslocation of 45Ca from leaves to other parts of rape plants were studied. Results indicated that only a small portion of foliar-applied 45Ca could be retranslocated to other parts of the rape plant. There was no pronounced effect of boron level in the soil on 45 Ca retranslocation. Increasing boron concentrations in the nutrient solution significantly reduced 45 Ca radioactivity in root and stem, but increased 45Ca uptake and 45 Ca translocation to the upper leaves of rape plants. It was suggested that45 Ca absorbed by newly developed roots was easily distributed to upper leaves of rape plants. Boron may alter distribution of calcium via its effect on root development or growth of newly developed roots.展开更多
Nitrogen (N) is one of the most important nutrients for oilseed rape (Brassica napus L . ) , but there is a lack of quick diagnosis and recommended fertilization. Three field experiments were con-ducted to see...Nitrogen (N) is one of the most important nutrients for oilseed rape (Brassica napus L . ) , but there is a lack of quick diagnosis and recommended fertilization. Three field experiments were con-ducted to seek the best diagnostic method and establish a fertilizer rate recommendation model. For ex-periment 1, six treatments as application N 0,90,180,240,300 and 400kg ha -1 were designed, and the general N nutrition diagnosis method as SPAD -502 chlorophyll meter, RQflex plus 10 nitrate reflectrom- eter and GreenSeeker - 505 spectrometer were used at eight leaf stage, tenth leaf stage and bolting stage of rape to determine the suitable nitrogen rapid diagnosis method and establish the model of yield forecast and N rate recommendation as topdressing. The experiment 2 was designed to validate the veracity of yield forecast model obtained from experiment 1. The experiment 3 was designed to test the accuracy of N rate recommendation model come from experiment 1. The results indicated that there is a preferable inter-relation between N application rates and rape yield for experiment 1 ( y = - 0. 0176x2 + 11. 136x +797. 88 ,R2 =0. 9905 * * ) , which conform to the performance of yield variation with N application levels as shortage, appropriate and excessive rapeseed. For three diagnosis methods, nitrate reflectrometer could reflect rape N nutrition status to some extent, but which influenced by rapeseed physiological char-acteristics such as lower biomass at seedling stage and luxury absorption of N at bolting stage, and the re-liability and stability of diagnosis were inferior. Spectrometer is suitable for quick N nutrition diagnosis at bolting stage, but the stage of topdressing is too late to meet the demand of N support. SPAD meter could more suitable in quick N diagnosis of oilseed rapes since it could reflect rape N nutrition preferable, and it has some advantages such as the strong stability, easy measuring and lower cost in detection. By SPAD meter, model of yield forecast yforeCastyield =370. 517xSPAD value -13310.3 (x 〈42. 54) and recommended N rate yR_dedNrate =162.7-[(370.517xSPADTflliie- 13 10. 3 )/10. 0617 - 76. 7398 ] (x〈42.54) were established. For experiment 2, the actual yield and forecast yield showed good correlation (y = 0. 5022 +2244. 3x, R2 =0. 7852 * ) . For experiment 3 , the amount of topdressing N calculate from recommended N rate model were put forward, and the yield for different treatments had no significant difference. Total-ly ,SPAD chlorophyll meter could be used in quick N nutrition diagnosis, forecast yield and N recommen-dation of oilseed rape.展开更多
Long developmental stage and late harvest time of winter rapeseed (Brassica napus L.) have great negative effects on rice planting of rice-rapeseed farming system in China. Early maturity improvement of rapeseed is ne...Long developmental stage and late harvest time of winter rapeseed (Brassica napus L.) have great negative effects on rice planting of rice-rapeseed farming system in China. Early maturity improvement of rapeseed is necessary. ‘Zhongshuang 11’, an elite winter rapeseed cultivar, was used in consecutive field experiments during 2010-2012. At initial flowering stage, plants were consecutively sprayed with 0.1 mg/L 2-4-Epibrassinolide(BR) for 3 d. Two hundred sampling pods from different plants were randomly collected to measure seed related indexes with a 4 d interval from 7 to 47 d after peak anthesis (DAPA).Seed color turned light brown at 31 or 35 DAPA after BR treatment, seed dry weight (DWT)was increased while seed moisture content (SMC) was decreased during seed development.DWT almost reached the maximum value when SMC was 33.20% at 31 DAPA in 2010-2011 and 35.29% at 35 DAPA in 2011-2012 growing season after BR treatment. Similarly,the maximum values of standard germination test (SGT), accelerated aging test (AAT)and cold test (CT) were observed at 31 or 35 DAPA after BR treatment respectively. The high yield and seed oil content appeared at 31 or 35 DAPA accompanied with rapid decrease in total non-structural carbohydrate (TNC) in stems and leaves. Our study indicated that BR application advanced maturity of winter rapeseed by 4 to 8 days.展开更多
基金Supported by the Special Fund for the Industrial Technology System Construction of Modern Agriculture(nycytx-00563)Department of Science and Technology of Guizhou Province[QinkeheNY(2010)3087]+2 种基金Department of Agriculture of Guizhou Province[Qinnongyu(2009)007]Guizhou Academy of Agricultural Sciences[ZX(2007)015]Special Fund of Guizhou Academy of Agricultural sciences[Qinnongke(2009)030]~~
文摘[Objective] This study aimed to investigate the correlation between yield and quality traits of rape. [Method] Taking "Sanbei 98" and "Youyan 599" as ex- periment materials, correlation between yield and quality traits of Brassica napus L. cultivars was explored by orthogonal rotation method. [Result] The results showed that: 1 In both the two varieties-Sanbei98 and Youyan599, erucic acid content had the largest coefficient of variation, but its average content was lower than 2% in both the two varieties (0.90% in Sanbei98 and 1.24% in Youyan599), and the palmitic acid content had the smallest coefficient of variation. 2 In terms of the dif- ferences in quality traits at different yield levels, only the mean of eicosenoic acid content revealed significant difference in Sanbei98, and only the mean of seed-pro- tein content revealed significant difference in Youyan599, and there was no signifi- cant difference in any combined quality traits in both the two varieties. 3 The yield was negatively correlated with the erucic acid content or oil content, and posi- tively correlated with the content of seed-protein, linoleic acid, or linolenic acid, and the coefficient of correlation between the yield and either of the contents of glucosi- nolates, oleic acid, palmitic acid, stearic acid, and eicosenoic acid was smaller. ~, when the yield of a variety increased considerably, there was a certain decreasing trend in erucic acid content, oil content, the total amount of erucic chain fatty acids (El & Er), while there was an increasing trend in seed-protein content, linoleic acid content, linolenic acid content, saturated fatty acids (SFA), the total amount of fat and protein (P & F), unsaturation index (IUFA), unsaturated fatty acids (UFA), the total amount of 18 carbon fatty acids (18-C FA), unsaturated fatty acids [UFA/(Ei & Er) ], and the sum of oleic acid and linoleic acid (OI & Li). 5 When the seed-pro- tein content is increased, the quality of rape oil cake is also improved; when the unsaturated index is increased, the oil stability is decreased. The increase in the total amount of unsaturated fatty acids, oleic acid and linoleic acid helps to increase in the total amount of fatty acids absorbed by human bodies. [Conclusion] This study provides a theoretical foundation for the cultivation of high-yielding and top- quality hybrid rape cultivars.
基金Supported by the Special Funds for Modern Agricultural (oilseed rape) Technical System (MATS) of Chinathe National Natural Science Foundation of China (NSFC) (31071372)~~
文摘[Objective] The aim of this work was to analyze the N fertilization on the vegetative growth and N uptake of different winter rapeseed varieties at wintering stage. [Method] In two consecutive years (2009-2011), two winter rapeseed varieties (B. napus L.), an early maturity variety Zhongyou 116 (ZY116) and a middle-late application maturity variety Zhongyouza 12 (ZYZ12) were employed. Field experiments with different N levels (0, 90, 180, 270, 360 kg N/hm 2 ) were designed. At the wintering stage, the dry matter weight, the nitrogen content and concentration of plants, leaf nitrate reductase activity (NRA) and seed yields were investigated. [Result] The shoot dry matter of ZY116 increased rapidly when N rate ranged from 0 to 180 kg/hm 2 , and it raised slightly when N rate ranged from 180 to 360 kg/hm 2 . The shoot dry matter of ZYZ12 were changed in a single peak curve; the peak of shoot dry matter appeared at 270 kg N/hm 2 . The N concentration and N content in shoot and root increased rapidly when the N rate changed from 90 to 180 kg/hm 2 . Moreover, the N concentration and N content root of in ZYZ12 were much higher than that of ZY116. Present study revealed that the changed trend of leaf nitrate reductase activities (NRA) were significantly increased at the N rate of 180 kg/hm 2 in ZY116 and ZYZ12 compared with the N rate of 90 kg/hm 2 in two years. [Conclusion] Optimal nitrogen application significantly increased the dry weights and N uptake at wintering stage as well as increasing the yield of winter oilseed rape.
基金supported by the Special Funding for Modern Agricultural Technical System of China (Rapeseed)the National Natural Science Foundation of China (31071372)
文摘China is one of the most important rapeseed producing countries in the world. Effective mechanical harvesting time for decreasing harvesting loss of winter oilseed rape has been becoming a critical factor. An elite cultivar Zhongshuang 11 (Brassica napus L.) was employed in two rounds of field experiments from 2009 to 2011. Seeds were sown with machine, three combine harvesting times namely combine harvesting A, B, and C (CHA, CHB, and CHC) were designed and manual harvesting (MH) as control was performed at maturity. The harvesting treatments were determined according to color of pod and seed in the field. Seed yield loss and quality in different treatments were evaluated. Results showed that both seed yields and harvesting losses in 2009-2010 were higher than that in 2010-2011, whereas seed oil contents in 2010-2011 were higher than that in 2009-2010. The highest yield appeared in CHB, which was significantly higher than that in MH. Furthermore, harvesting loss in CHB were 50% that in MH. Seed oil content and chlorophyll exhibited no obvious difference between CHB and MH. Economic profit analysis demonstrated that mechanical sowing/combine harvesting (MS/CH) showed an input/output ratio of 1:1.6, and it was 1:1.2 in mechanical sowing/manual harvesting (MS/MH). Labor-cost accounted for more than 70% of the total cost in MS/MH, which led to low profitability to a great extent. Our results suggested that CHB was the optimum harvesting time for winter oilseed rape along the Yangtze River.
基金supported by the National Key Technologies R&D Program of China during the 11th Five-Year Plan period (2010BAD01B05)the Earmarked Fund for China Agriculture Research System (CARS-13)+1 种基金the Program for Changjiang Scholars and Innovative Research Team in University of China (IRT1247)the Fundamental Research Funds for the Central Universities,China (2013PY113)
文摘Direct-sowing establishment method has great significance in improving winter oilseed rape(Brassica napus L.) production and guaranteeing edible oil security in China. However, nutrient responses on direct sown winter oilseed rape(DOR) performance and population development dynamic are still not well understood. Therefore, five on-farm experiments were conducted in the reaches of the Yangtze River(RYR) to determine the effects of nitrogen(N), phosphorus(P), and potassium(K) deficiencies on population density, dry matter production, nutrient uptake, seed yield, and yield components of DOR plants. Four fertilization treatments included the balanced NPK application treatment(NPK, 180 kg N, 39.3 kg P, 100 kg K, and 1.8 kg borax ha–1) and three nutrient deficiency treatments based on the NPK treatment, i.e., –N, –P, and –K. The results indicated that DOR population density declined gradually throughout the growing season, especially at over-wintering and pod-development stages. Nutrient deficiency decreased nutrient concentration in DOR plants, limited dry matter production and nutrient uptake, and thereby exacerbated density reduction during plants growth. The poor individual growth and reduced population density together decreased seed yield in the nutrient deficiency treatment. Averaged across all the experiments, seed yield reduced 61% by N deficiency, 38.3% by P deficiency, and 14.4% by K deficiency. The negative effects of nutrient deficiency on DOR performances followed the order of –N–P–K, and the effects were various among different nutrient deficiencies. Although N deficiency improved DOR emergence, but it seriously limited dry matter production and nutrient uptake, which in turn led to substantial plants death and therefore resulted in a very low harvested density. The P deficiency significantly reduced initial density, limited plants growth, and exacerbated density reduction. The K deficiency mainly decreased individual growth and yield, but did not affect density dynamic. Our results highlighted the importance of balanced NPK application in DOR production, suggesting that management strategy of these nutrients should be comprehensively considered with an aim to build an appropriate population structure with balanced plant density and individual growth.
基金financial support provided by the National Key Research and Development Program of China (2016YFD0702100)the Special Funds for the Construction of Modern Agricultural Industrial Technology System (CARS-13)
文摘China is one of the major rapeseed production countries in the world,but harvesting mechanization was still backward,and high harvest loss was a key inhibiting factor for rapeseed production.To obtain optimum harvesting date for winter rape in the Yangtze River Valley of China,artificial simulated combine harvesting and artificial two-stage harvesting were adopted to find correlations between harvesting date,rape variety,seed oil content,protein content,grain moisture rate,rapeseed straw moisture content,rapeseed unthreshing rate,grain drop loss rate,thousand seeds weight(TSW),and harvesting economic coefficient(HEC).Analysis of variance showed that rapeseed oil content,protein content and TSW were correlated with rape variety;HEC was correlated with harvesting method and rape variety.Rape variety was the dominant factor of rapeseed oil content,protein content,TSW and HEC.Grain moisture rate,un-threshing rate,grain drop loss rate and straw moisture content were correlated with harvesting method and date.Harvesting date was the dominant factor of rapeseed moisture rate,un-threshing rate,grain drop loss rate and straw moisture rate.Single factor tests further proved that harvesting date had less impact on rapeseed oil content,protein content,TSW and HEC.It showed little correlation with rapeseed quality except grain moisture rate.The optimum harvesting date could be known by change in straw moisture content.The combined harvesting should be carried out during the grain moisture content of 15%-20%with TSW stabilized in the highest level.The twostage harvesting cutting should be carried out at the grain moisture content of 35%-40%.This research offered a reference to harvesting method and date for rape cultivated in the Yangtze River Valley.
基金supported by the Nationa1 Natura1 Science Foundation of China(39770439).
文摘Using tracer techniques with the radioisotope 45Ca, the effects of boron supply from soil and nutrient solution on the retranslocation of 45Ca from leaves to other parts of rape plants were studied. Results indicated that only a small portion of foliar-applied 45Ca could be retranslocated to other parts of the rape plant. There was no pronounced effect of boron level in the soil on 45 Ca retranslocation. Increasing boron concentrations in the nutrient solution significantly reduced 45 Ca radioactivity in root and stem, but increased 45Ca uptake and 45 Ca translocation to the upper leaves of rape plants. It was suggested that45 Ca absorbed by newly developed roots was easily distributed to upper leaves of rape plants. Boron may alter distribution of calcium via its effect on root development or growth of newly developed roots.
文摘Nitrogen (N) is one of the most important nutrients for oilseed rape (Brassica napus L . ) , but there is a lack of quick diagnosis and recommended fertilization. Three field experiments were con-ducted to seek the best diagnostic method and establish a fertilizer rate recommendation model. For ex-periment 1, six treatments as application N 0,90,180,240,300 and 400kg ha -1 were designed, and the general N nutrition diagnosis method as SPAD -502 chlorophyll meter, RQflex plus 10 nitrate reflectrom- eter and GreenSeeker - 505 spectrometer were used at eight leaf stage, tenth leaf stage and bolting stage of rape to determine the suitable nitrogen rapid diagnosis method and establish the model of yield forecast and N rate recommendation as topdressing. The experiment 2 was designed to validate the veracity of yield forecast model obtained from experiment 1. The experiment 3 was designed to test the accuracy of N rate recommendation model come from experiment 1. The results indicated that there is a preferable inter-relation between N application rates and rape yield for experiment 1 ( y = - 0. 0176x2 + 11. 136x +797. 88 ,R2 =0. 9905 * * ) , which conform to the performance of yield variation with N application levels as shortage, appropriate and excessive rapeseed. For three diagnosis methods, nitrate reflectrometer could reflect rape N nutrition status to some extent, but which influenced by rapeseed physiological char-acteristics such as lower biomass at seedling stage and luxury absorption of N at bolting stage, and the re-liability and stability of diagnosis were inferior. Spectrometer is suitable for quick N nutrition diagnosis at bolting stage, but the stage of topdressing is too late to meet the demand of N support. SPAD meter could more suitable in quick N diagnosis of oilseed rapes since it could reflect rape N nutrition preferable, and it has some advantages such as the strong stability, easy measuring and lower cost in detection. By SPAD meter, model of yield forecast yforeCastyield =370. 517xSPAD value -13310.3 (x 〈42. 54) and recommended N rate yR_dedNrate =162.7-[(370.517xSPADTflliie- 13 10. 3 )/10. 0617 - 76. 7398 ] (x〈42.54) were established. For experiment 2, the actual yield and forecast yield showed good correlation (y = 0. 5022 +2244. 3x, R2 =0. 7852 * ) . For experiment 3 , the amount of topdressing N calculate from recommended N rate model were put forward, and the yield for different treatments had no significant difference. Total-ly ,SPAD chlorophyll meter could be used in quick N nutrition diagnosis, forecast yield and N recommen-dation of oilseed rape.
文摘Long developmental stage and late harvest time of winter rapeseed (Brassica napus L.) have great negative effects on rice planting of rice-rapeseed farming system in China. Early maturity improvement of rapeseed is necessary. ‘Zhongshuang 11’, an elite winter rapeseed cultivar, was used in consecutive field experiments during 2010-2012. At initial flowering stage, plants were consecutively sprayed with 0.1 mg/L 2-4-Epibrassinolide(BR) for 3 d. Two hundred sampling pods from different plants were randomly collected to measure seed related indexes with a 4 d interval from 7 to 47 d after peak anthesis (DAPA).Seed color turned light brown at 31 or 35 DAPA after BR treatment, seed dry weight (DWT)was increased while seed moisture content (SMC) was decreased during seed development.DWT almost reached the maximum value when SMC was 33.20% at 31 DAPA in 2010-2011 and 35.29% at 35 DAPA in 2011-2012 growing season after BR treatment. Similarly,the maximum values of standard germination test (SGT), accelerated aging test (AAT)and cold test (CT) were observed at 31 or 35 DAPA after BR treatment respectively. The high yield and seed oil content appeared at 31 or 35 DAPA accompanied with rapid decrease in total non-structural carbohydrate (TNC) in stems and leaves. Our study indicated that BR application advanced maturity of winter rapeseed by 4 to 8 days.