In 2010, Chinese maize yields increased from 961.5 kg ha-1 in 1949 to 5 453.8 kg ha-L This increase is the result of genetic improvements, an increase in nitrogen application, and refinement of planting densities. The...In 2010, Chinese maize yields increased from 961.5 kg ha-1 in 1949 to 5 453.8 kg ha-L This increase is the result of genetic improvements, an increase in nitrogen application, and refinement of planting densities. The objective of this study was to provide a theoretical basis for maize production research by analyzing the maize yield gain characteristics. Six varieties of maize were selected for the study; each selection is representative of a typical or commonly used maize variety from a specific decade, beginning from the 1950s and continuing through each decade into the 2000s. The selections and their corresponding decade were as follows： Baihe, 1950s; Jidan 101, 1960s; Zhongdan 2, 1970s; Yedan 13, 1980s; Zhengdan 958, 1990s; and Xianyu 335, 2000s. Each variety was planted under four different densities （37 500, 52 500, 67 500, and 82 500 plants ha-0 and four different nitrogen applications （0, 150, 225, and 300 kg ha-1 to study the effects on yield gain characteristics. The obtained results demonstrated that there was a maize yield increase of 123.19% between the 1950s variety and the 2000s variety. Modern Chinese maize varieties had a higher yield advantage. They also displayed the additional potential to acquire higher yield under increased planting densities and nitrogen applications. At the present cultivation levels （planting at 67 500 plants ha-~ with 225 kg ha-1 nitrogen application）, the contribution types and corresponding yield increase percentages were as follows： genetic improvement, 45.37%; agronomic-management improvement, 30.94%; and genotype× agronomicmanagement interaction, 23.69%. At high-yielding cultivation levels （planting at 82 500 plants ha-1 with 300 kg ha-1 nitrogen application）, the contribution types and corresponding yield increase percentages were as follows： genetic improvement, 31.30%; agronomic-management improvement, 36.23%; and genotype × agronomic-management interaction, 32.47%. The contribution of agronomic-management and genotype ×agronomic-management interaction to yield increase would be larger with the corresponding management improvement. To further increase maize grain yield in China, researchers should further examine the adaptation of variety to agronomic-management. effects of agronomic-management on maize yield and the展开更多
Wheat breeders in Turkey have been developing new varieties since the 1920 s, but few studies have evaluated the rates of genetic improvement. This study determined wheat genetic gains by evaluating 22 winter/facultat...Wheat breeders in Turkey have been developing new varieties since the 1920 s, but few studies have evaluated the rates of genetic improvement. This study determined wheat genetic gains by evaluating 22 winter/facultative varieties released for rainfed conditions between 1931 and2006. The study was conducted at three locations in Turkey during 2008-2012, with a total of 21 test sites. The experimental design was a randomized complete block with four replicates in2008 and 2009 and three replicates in 2010-2012. Regression analysis was conducted to determine genetic progress over time. Mean yield across all 21 locations was 3.34 t ha^(-1) but varied from 1.11 ha^(-1) to 6.02 t ha^(-1) and was highly affected by moisture stress. Annual genetic gain was 0.50% compared to Ak-702, or 0.30% compared to the first modern landmark varieties. The genetic gains in drought-affected sites were 0.75% compared to Ak-702 and0.66% compared to the landmark varieties. Modem varieties had both improved yield potential and tolerance to moisture stress. Rht genes and rye translocations were largely absent in the varieties studied. The number of spikes per unit area decreased by 10% over the study period,but grains spike^(-1) and 1000-kemel weight increased by 10%. There were no significant increases in harvest index, grain size, or spike fertility, and no significant decrease in quality over time. Future use of Rht genes and rye translocations in breeding programs may increase yield under rainfed conditions.展开更多
Barley breeding program in Brazil has focused on characteristics associated with malting for beer purposes as the main economic application for this crop. The breeding process focused on selection for grain yield, dis...Barley breeding program in Brazil has focused on characteristics associated with malting for beer purposes as the main economic application for this crop. The breeding process focused on selection for grain yield, disease resistance and malting quality. The objective of this work was to quantify the genetic gain in barley grain yield from 1968 and 2008 in Brazil and to identify the physiological characteristics associated with the increase of grain yield. Field experiments with five 2-row barley cultivars were tested from 2011 to 2013 in the absence of biotic and abiotic stresses and with mechanical restriction to lodging. The ANOVA showed no genetic gain until 1980 with average grain yield of 4.632 kg/ha. After 1980, there was a productivity increase of 59.9 kg/ha/year. No correlation was observed between total maturity biomass and the year of release of the cultivars, while harvest index and plant height, were significantly improved. The main component associated with grain yield was the number of grains/m2, due to the higher number of spikes/m2 associated to a greater contribution of the tillers in the modern cultivars.展开更多
以田间试验为基础,对直接种植法的不同方法进行分析,以期找到适合我国的评估方法,为遗传产量增益的研究提供理论支持。以1970s—2000s期间大面积推广的杂交种为材料,分别于2005—2006年(试验1)以及2007—2008年(试验2)在新疆农业科学院...以田间试验为基础,对直接种植法的不同方法进行分析,以期找到适合我国的评估方法,为遗传产量增益的研究提供理论支持。以1970s—2000s期间大面积推广的杂交种为材料,分别于2005—2006年(试验1)以及2007—2008年(试验2)在新疆农业科学院和北京顺义试验基地进行。每个试验设置3种密度。依据1970年代单交种在3.0万株hm-2密度下的产量与2000年代的单交种在6.0万株hm-2密度下的年均单位面积的产量差异,计算得到1970s—2000s期间我国玉米遗传产量年增益速率为94.7 kg hm-2。在7.5万株hm-2密度下,2000年代单交种较1970年代单交种的产量增值是遗传因素作用的结果。1970年代单交种在1.5万株hm-2密度下的产量与2000年代单交种在7.5万株hm-2密度下的产量差值是育种与栽培共同作用的结果。由二者的比值得到育种对总产量增益的贡献率为52.9%。Duvick的直接种植法适用于我国评估遗传产量增益速率,Tollnaar的试验设置方法适用于评估我国玉米遗传贡献率。展开更多
提高产量是大豆育种的主要目标。研究大豆产量及其相关性状的遗传进展,对于今后制定高产育种策略有重要参考意义。本研究随机选择近30年河南主要育成品种中的18个大豆品种,进行两年产量评价试验的研究。结果表明,产量随育种年份增加总...提高产量是大豆育种的主要目标。研究大豆产量及其相关性状的遗传进展,对于今后制定高产育种策略有重要参考意义。本研究随机选择近30年河南主要育成品种中的18个大豆品种,进行两年产量评价试验的研究。结果表明,产量随育种年份增加总体呈递增趋势,遗传进展为17.39 kg hm^(–2),年递增率是0.7%;有效分枝、主茎节数、百粒重、株高有弱的正向遗传进展,而单株荚数和每荚粒数表现弱的负向遗传进展,但均不显著。百粒重、主茎节数和株高与产量有显著的遗传相关与表型相关,环境相关均不显著,表明这3个性状具有较大的遗传力,随产量性状的遗传改良,这3个性状均协同提高,且不易受环境条件的影响;而有效分枝、单株荚数、每荚粒数与产量的遗传相关和表型相关均没达到显著水平,这是它们与百粒重、主茎节数、株高有极显著负遗传相关所致。展开更多
选用18只青山羊泌乳母羊及其羔羊随机分成3组,分别按推荐量的120%,100%和80%供给代谢能(ME),进行前后两期共70天的饲养试验,结果证明:(1)在本试验3个能量水平下,青山羊泌乳母羊在整个泌乳期内体重无明显变化(P>0.5),母羊泌乳量受日粮...选用18只青山羊泌乳母羊及其羔羊随机分成3组,分别按推荐量的120%,100%和80%供给代谢能(ME),进行前后两期共70天的饲养试验,结果证明:(1)在本试验3个能量水平下,青山羊泌乳母羊在整个泌乳期内体重无明显变化(P>0.5),母羊泌乳量受日粮ME 水平的影响,一定范围内,提高日粮 ME 水平可增加泌乳量。(2)青山羊母羊的平均泌乳量为575±74gFCM/只天,某日或整个泌乳期的泌乳量可用下式预测:Y= dx(Y:泌乳量,g/d;x:日龄)。(3)要保证母羊较高的泌乳量和羔羊最大日增重,理想的日粮 ME 水平分别为前期10680kJ/kgDM 和后期9372kJ/kgDM。(4)母羊 ME 水平不同可明显影响羔羊日增重和断奶体重;双羔中任一羔羊在哺乳期内的日增重(△W)可根据母羊泌乳量(M)用下式估计:△W(g/d)=16.962+0.0712·M(g/d)展开更多
基金supported by the National Basic Research Program of China (2009CB118605)
文摘In 2010, Chinese maize yields increased from 961.5 kg ha-1 in 1949 to 5 453.8 kg ha-L This increase is the result of genetic improvements, an increase in nitrogen application, and refinement of planting densities. The objective of this study was to provide a theoretical basis for maize production research by analyzing the maize yield gain characteristics. Six varieties of maize were selected for the study; each selection is representative of a typical or commonly used maize variety from a specific decade, beginning from the 1950s and continuing through each decade into the 2000s. The selections and their corresponding decade were as follows： Baihe, 1950s; Jidan 101, 1960s; Zhongdan 2, 1970s; Yedan 13, 1980s; Zhengdan 958, 1990s; and Xianyu 335, 2000s. Each variety was planted under four different densities （37 500, 52 500, 67 500, and 82 500 plants ha-0 and four different nitrogen applications （0, 150, 225, and 300 kg ha-1 to study the effects on yield gain characteristics. The obtained results demonstrated that there was a maize yield increase of 123.19% between the 1950s variety and the 2000s variety. Modern Chinese maize varieties had a higher yield advantage. They also displayed the additional potential to acquire higher yield under increased planting densities and nitrogen applications. At the present cultivation levels （planting at 67 500 plants ha-~ with 225 kg ha-1 nitrogen application）, the contribution types and corresponding yield increase percentages were as follows： genetic improvement, 45.37%; agronomic-management improvement, 30.94%; and genotype× agronomicmanagement interaction, 23.69%. At high-yielding cultivation levels （planting at 82 500 plants ha-1 with 300 kg ha-1 nitrogen application）, the contribution types and corresponding yield increase percentages were as follows： genetic improvement, 31.30%; agronomic-management improvement, 36.23%; and genotype × agronomic-management interaction, 32.47%. The contribution of agronomic-management and genotype ×agronomic-management interaction to yield increase would be larger with the corresponding management improvement. To further increase maize grain yield in China, researchers should further examine the adaptation of variety to agronomic-management. effects of agronomic-management on maize yield and the
基金supported by CRP WHEATthe Turkish Ministry of Food, Agriculture, and Livestock
文摘Wheat breeders in Turkey have been developing new varieties since the 1920 s, but few studies have evaluated the rates of genetic improvement. This study determined wheat genetic gains by evaluating 22 winter/facultative varieties released for rainfed conditions between 1931 and2006. The study was conducted at three locations in Turkey during 2008-2012, with a total of 21 test sites. The experimental design was a randomized complete block with four replicates in2008 and 2009 and three replicates in 2010-2012. Regression analysis was conducted to determine genetic progress over time. Mean yield across all 21 locations was 3.34 t ha^(-1) but varied from 1.11 ha^(-1) to 6.02 t ha^(-1) and was highly affected by moisture stress. Annual genetic gain was 0.50% compared to Ak-702, or 0.30% compared to the first modern landmark varieties. The genetic gains in drought-affected sites were 0.75% compared to Ak-702 and0.66% compared to the landmark varieties. Modem varieties had both improved yield potential and tolerance to moisture stress. Rht genes and rye translocations were largely absent in the varieties studied. The number of spikes per unit area decreased by 10% over the study period,but grains spike^(-1) and 1000-kemel weight increased by 10%. There were no significant increases in harvest index, grain size, or spike fertility, and no significant decrease in quality over time. Future use of Rht genes and rye translocations in breeding programs may increase yield under rainfed conditions.
文摘Barley breeding program in Brazil has focused on characteristics associated with malting for beer purposes as the main economic application for this crop. The breeding process focused on selection for grain yield, disease resistance and malting quality. The objective of this work was to quantify the genetic gain in barley grain yield from 1968 and 2008 in Brazil and to identify the physiological characteristics associated with the increase of grain yield. Field experiments with five 2-row barley cultivars were tested from 2011 to 2013 in the absence of biotic and abiotic stresses and with mechanical restriction to lodging. The ANOVA showed no genetic gain until 1980 with average grain yield of 4.632 kg/ha. After 1980, there was a productivity increase of 59.9 kg/ha/year. No correlation was observed between total maturity biomass and the year of release of the cultivars, while harvest index and plant height, were significantly improved. The main component associated with grain yield was the number of grains/m2, due to the higher number of spikes/m2 associated to a greater contribution of the tillers in the modern cultivars.
文摘以田间试验为基础,对直接种植法的不同方法进行分析,以期找到适合我国的评估方法,为遗传产量增益的研究提供理论支持。以1970s—2000s期间大面积推广的杂交种为材料,分别于2005—2006年(试验1)以及2007—2008年(试验2)在新疆农业科学院和北京顺义试验基地进行。每个试验设置3种密度。依据1970年代单交种在3.0万株hm-2密度下的产量与2000年代的单交种在6.0万株hm-2密度下的年均单位面积的产量差异,计算得到1970s—2000s期间我国玉米遗传产量年增益速率为94.7 kg hm-2。在7.5万株hm-2密度下,2000年代单交种较1970年代单交种的产量增值是遗传因素作用的结果。1970年代单交种在1.5万株hm-2密度下的产量与2000年代单交种在7.5万株hm-2密度下的产量差值是育种与栽培共同作用的结果。由二者的比值得到育种对总产量增益的贡献率为52.9%。Duvick的直接种植法适用于我国评估遗传产量增益速率,Tollnaar的试验设置方法适用于评估我国玉米遗传贡献率。
文摘提高产量是大豆育种的主要目标。研究大豆产量及其相关性状的遗传进展,对于今后制定高产育种策略有重要参考意义。本研究随机选择近30年河南主要育成品种中的18个大豆品种,进行两年产量评价试验的研究。结果表明,产量随育种年份增加总体呈递增趋势,遗传进展为17.39 kg hm^(–2),年递增率是0.7%;有效分枝、主茎节数、百粒重、株高有弱的正向遗传进展,而单株荚数和每荚粒数表现弱的负向遗传进展,但均不显著。百粒重、主茎节数和株高与产量有显著的遗传相关与表型相关,环境相关均不显著,表明这3个性状具有较大的遗传力,随产量性状的遗传改良,这3个性状均协同提高,且不易受环境条件的影响;而有效分枝、单株荚数、每荚粒数与产量的遗传相关和表型相关均没达到显著水平,这是它们与百粒重、主茎节数、株高有极显著负遗传相关所致。
文摘选用18只青山羊泌乳母羊及其羔羊随机分成3组,分别按推荐量的120%,100%和80%供给代谢能(ME),进行前后两期共70天的饲养试验,结果证明:(1)在本试验3个能量水平下,青山羊泌乳母羊在整个泌乳期内体重无明显变化(P>0.5),母羊泌乳量受日粮ME 水平的影响,一定范围内,提高日粮 ME 水平可增加泌乳量。(2)青山羊母羊的平均泌乳量为575±74gFCM/只天,某日或整个泌乳期的泌乳量可用下式预测:Y= dx(Y:泌乳量,g/d;x:日龄)。(3)要保证母羊较高的泌乳量和羔羊最大日增重,理想的日粮 ME 水平分别为前期10680kJ/kgDM 和后期9372kJ/kgDM。(4)母羊 ME 水平不同可明显影响羔羊日增重和断奶体重;双羔中任一羔羊在哺乳期内的日增重(△W)可根据母羊泌乳量(M)用下式估计:△W(g/d)=16.962+0.0712·M(g/d)
