紫玉米不同组配方式的花青素含量及产量比较

以18个玉米自交系组配成的16个紫玉米杂交组合为试验材料,研究不同组配方式配制的紫玉米籽粒、穗轴、苞叶、雄穗花青素含量及花青素产量。结果表明:(1)不同组配方式的紫玉米籽粒花青素含量、籽粒产量及籽粒花青素产量差异均较大。深紫玉米×深紫玉米,花青素含量最高;深紫非糯玉米×糯玉米,籽粒产量最高;深紫玉米×深紫玉米,籽粒花青素产量最高。(2)深紫玉米×深紫玉米,穗轴花青素含量、花青素产量最高;非紫苞叶×深紫苞叶,紫玉米苞叶花青素含量、花青素产量最高;非紫雄穗×深紫雄穗,紫玉米雄穗花青素含量、花青素产量最高。(3)穗轴花青素含量与籽粒花青素含量呈极显著正相关;雄穗花青素含量与苞叶花青素含量呈极显著正相关。(4)紫玉米花青素总产量(籽粒、穗轴、苞叶、雄穗)为:深紫×深紫>深紫×浅紫>非紫×深紫>浅紫×非紫;籽粒花青素产量对总花青素产量贡献最大。     

Recurrent selection for broad adaptation affects stability of oat

A recurrent selection program for adaptation to diverse environments was successful in improving mean oat (Avena sativa L.) grain yield within and across testing environments. The objectives of this research were to determine if this selection program also resulted in changes in other agronomic traits or altered yield stability. Additionally, we investigated how selection modified the response of genotypes to climatic conditions. We evaluated random samples of 100 families from the original population and each of three selection cycle populations in replicated yield trials in Idaho, Iowa, and Norway for two years. Yield stability was assessed via joint regression analysis and superiority analysis. For each cycle, genetic relationships among yields observed indifferent environments were assessed by estimating phenotypic correlations between pairs of target environments. The effect of climate variables on genotype-by-environment interaction (GEI) responses was determined with partial least squares regression. Selection resulted in a small increase in mean heading date, a decrease in mean test weight, and no change in total above-ground biomass or plant height. Genotypic regression coefficients on environmental indices and deviations from regression were larger in the last cycle population, but superiority analysis demonstrated that selection significantly improved the adaptability of the population to the target testing environments. Improved adaptation was also demonstrated by increased phenotypic correlations among the most divergent pairs of environments in the later cycles. Partial least squares regression of GEI effects on climate variables suggested that later cycle families tended to respond more favorably to cooler than average conditions than the original population. Selection resulted in improved yield stability as well as improved mean yield. This revised version was published online in August 2006 with corrections to the Cover Date.     

The stability of the number of tillers of barley varieties and its relation with consistency of performance under semi-arid conditions

Summary In 1981/82 60 barleys varieties were grown at 18 environments (three locations, three seed rates, two soil fertility regimes) and in 1982/83 22 varieties were grown again at 21 environments (seven locations, three seed rates). Grain yield was recorded only in the second year. The estimates of variances s_x ² (untransformed data) and s² _logx (transformed data) for number of tillers and grain yield varied significantly among varieties. When untransformed data were used, high tillering varieties had a higher variance for number of tillers per unit area than low tillering varieties. When the variation was measured by CV of untransformed data or by s² _logx on transformed data a reverse relation occurred, i.e. the correlation coefficient between number of tillers and the variation of number of tillers was negative.High grain yielding varieties had a high mean number of tillers and a low variance for number of tillers per unit area when transformed data were used to compute variances. All interactions between variety, seed rate and location for grain yield were significant. The regression analysis of variety grain yield (Y) on environment mean grain yield (X) gave regression coefficients, b, ranging from 0.51 to 1.69. There was no significant correlation between regression coefficient and grain yield. The highest yielding varieties had b values around 1.0. High grain yielding varieties had low variance of yield over environments and low values for deviations from the regression when transformed data were used. However, the correlations between mean yield and variance for yield or mean yield and deviations from regression were positive when untransformed data were used.From this study it is concluded that high mean number of tillers per unit area and low variance for number of tillers could be used in selecting varieties with consistently high yield at varying environments. Techniques are proposed for application early in the breeding programme, i.e. in segregating population or in nurseries.     

Performance stability of maize genotypes across diverse hill environments in Nepal

The national maize improvement program in Nepal regularly receives elite maize (Zea mays L.) genotypes from CIMMYT and other countries and tests them for their performance stability in highly diverse environments. Studies were conducted on research stations and farmers’ fields at five sites in three years to determine performance stability of exotic maize genotypes. Replicated on-station and on-farm studies were conducted using 25 and 10 genotypes, respectively, including a local check and an improved check (Manakamana-3), in 2004–2006. We analyzed grain yield, days to flowering, plant and ear height, plant population, husk cover, and plant and ear aspect. Stability and genotype superiority for grain yield was determined using genotype and genotype × environment (GGE) biplot analysis that compares among a set of genotypes with a reference ‘ideal’ genotype, which has the highest average value of all genotypes and is absolutely stable. Several genotypes produced significantly higher grain yield than the local check. Four genotypes (‘Across9942 × Across9944’, ‘Open Ended White Hill Population’, ‘Population 44C10’ and ‘ZM621’), that produced significantly higher grain yield than the improved check, also had other agronomic traits (days to flowering, plant and ear height, number of ears, resistance to leaf blight, plant and ear aspect and husk cover tightness) equal to or better than the improved check. GGE-biplot analysis showed that Across9942 × Across9944 and ZM621 were the most superior genotypes in the on-station and on-farm trials, respectively. The findings from this study provide new information on the stability of the maize genotypes that are also adapted to other regions of the world. Such information could be useful for maize improvement program for the highlands in Nepal and other similar environments.     

Yield and adaptation of hexaploid spring triticale

Summary Gains in yield and stability were analysed using grain yield data from the 8th to the 14th International Triticale Yield Nursery (ITYN) and differences in adaptation between complete and substituted triticales (X Triticosecale Wittmack) were examined. A trend of improving yield and adaptation was observed. As highly significant genotype × site interaction each year was not adequately described using regression analysis, yield stability was examined by ranking genotypes within sites and summarizing scores for individual genotypes across sites. Cluster analysis was used to study the relationships among sites and among genotypes. There was little evidence of sites grouping on a geographical basis. Grouping of genotypes showed a tendency for complete and substituted triticales to perform differently, suggesting that diversity for adaptation is maximized by utilizing both types in breeding.Progress for grain yield is compared with more spectacular gains in test weight and reasons for the different rates of improvement are postulated.Abbreviations CIMMYT International Maize & Wheat Improvement Centre - ITYN International Triticale Yield Nursery contribution from CIMMYT/Agriculture Canada (No. R-002)     

Associations among productivity,production response,and stability indexes in oat varieties

Summary We tested three sets of oat varieties for grain yield in a series of environments and observed that generally more than 80% of the yield variation for individual varieties was due to linear regression response. Mean yields for varieties were significantly variable in all three sets, and regression response indexes were significantly variable in two of them.Mean yields over the three sets were correlated with regression response indexes with r=0.61. Associations of mean yield with the three stability parameters (i.e., coefficient of determination, mean square for deviations from regression, and ecovalence) were low and usually not significant. The correlation of regression response indexes with coefficients of determination was 0.42, but neither of the other stability parameters was associated with the response indexes. The three stability parameters were closely correlated with one another.Our materials were selected varieties, so evidently our results suggest what can be accomplished in breeding for combinations of mean production, production response, and productiom stability.Journal Paper No.J-9092 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa, USA 50011. Project 1752. This work was supported in part by the International Atomic Energy Agency, vienna, Austria, in the form of a fellowship for the senior author.     

Selection environment and environmental sensitivity in barley

Summary Groups of 10 barley genotypes were selected for high grain yield under either high yielding (two groups) or low yielding conditions (two groups). The genotypes had a similar average grain yield across a wide range of yielding conditions, but differed in their linear response over environments (environmental sensitivity). The genotypes selected for high grain yield under low yielding conditions were less sensitive to changing environments than genotypes selected for high grain yield under high yielding conditions. The higher stability of genotypes selected under low yielding conditions was shown by both the linear regression analysis and the comparison of coefficients of variation. The use of a safety-first index showed that the probability of a crop failure of genotypes selected for high grain yield under high yielding conditions was between 1.8 and 2.7 times higher than for genotypes selected for high grain yield under low yielding conditions. The development of new cultivars for areas where a large proportion of the crop is grown by subsistence farmers should therefore be based on selection under low yielding conditions.     

Stability of 1000-grain weight and its relation with other traits of barley in dry areas

Summary The effects of 1000-grain weight, its stability and the correlation coefficients with other traits of 50 barley varieties were studied at 18–20 environments. Additional material was used to study genotypic correlations among traits. Significant differences in stability of 1000-grain weight were found among varieties. Two-row varieties were on average more stable than 6-row varieties. The 1000-grain weight was among the most stable and grain yield the most variable traits. This was discussed in connection with stem reserves translocation to the grain. Consistently high yielding varieties had around average stability of 1000-grain weight. Regression coefficient, b, for 1000-grain weight was positively correlated with variance of log transformed data, both valid estimates for stability of 1000-grain weight. The correlation coefficient of 1000-grain weight with grain yield was positive or non-significant, with number of grains per tiller mainly negative and with volume weight it was positive. In 6-row barley, 1000-grain weight was positively correlated with grain yield, straw yield, total biological yield, and plant height, and negatively with number of tillers per m² and number of grains per tiller.     

重庆市直辖后普通玉米杂交种籽粒产量及相关性状的育种进展

摘 要：【研究目的】为分析重庆市直辖以来自育玉米杂交种籽粒产量和相关性状的主要进展,了解该市玉米育种的主要发展趋势。【方法】以该市1997~2009年玉米区试汇总资料,采用“区试对照法”分析了自育普通玉米杂交种籽粒产量及相关性状的遗传增益。【结果】重庆市普通玉米杂交育种自直辖以来,在不断提高对照品种产量门槛的情况下,参试品种籽粒产量仍在显著增加,同直辖初期对照品种比较,平丘组平均每年提高2.83%,山区组平均每年提高2.01%。与籽粒产量相关的性状的遗传改良效果平丘组品种以穗行数和百粒重最好,生育期无甚变化,其余性状波动性较大;山区组品种以穗长、穗行数和行粒数较好,其余性状波动性也大。【结论】在当前和今后一段时期内,重庆市普通玉米杂交育种策略应在稳定生育期和株高、适度增加穗长和穗行数的前提下,主攻行粒数和百粒重。关键词：玉米;对照品种;参试种;籽粒产量;遗传改良     

应对越区种植不同熟期玉米产量及相关性状研究

近年来,受全球气候变暖和片面追求高产的影响,玉米生产上越区种植现象比较严重。为了杜绝越区种植,避免生育期偏长的品种,确保安全成熟,提高玉米产量和籽粒商品质量,于2010—2013 年连续4 年在山西省早熟玉米区开展了不同熟期玉米产量及相关性状研究,结果表明,中熟品种虽然在一些水热条件较好的年份产量较高,但和早熟品种间并没有显著差异(P＜0.05),如遇早霜年份,产量和百粒重显著低于早熟品种(P＜0.01),分别较早熟品种平均降低10.2%和16.3%,产量和品质显著下降的同时,出籽率和收获指数也明显降低。特早熟品种虽然收获指数和水分利用效率较高,但产量较低,且成熟期较正常年份早霜提前25~28 天,约有≥10℃活动积温300~400℃没有被利用,造成光热水资源的浪费。综合考虑不同熟期玉米品种的安全成熟性、高产稳产性、优质以及资源高效性,早熟品种都优于中熟和特早熟品种,更适宜在该地区推广。     

Adaptation and environmental sensitivity of mungbean genotypes evaluated in the international mungbean nursery

Summary Yield data from the 5th–12th international mungbean nursery (IMN) trials conducted at 23 sites in 15 countries were analyzed by conventional stability analysis—regression of genotype mean on the environmental index, and by segmented regression analysis—fitting separate linear regressions in low yielding and high yielding environments. The gene pool base concept allows comparison of genotypes from different IMN trials grown in different years and sites. A very high positive linear relationship was observed between the regression coefficient and the average yield of cultivars, indicating that high yielding cultivars were less stable across environments. When data points of the regression of genotype mean and site mean for VC 1973A, a high yielding and widely adapted cultivar, were examined, the relationship appeared not to be linear. The segmented regression analysis improved the coefficient of determination (r²) and the genotypes were grouped based on regression coefficients in high yielding and low yielding environments. Different categories of genotypes suitable for high input environments, widely adaptable genotypes, and highly stable genotypes were identified.Texas Agricultural Experiment Station Technical Article 23208.     

长江中下游地区小麦新品种丰产稳产性的评价

为了评价小麦新品种在不同生态条件下的丰产稳定性,应用Francis-Kannenberg模型分析法、线性回归Eberhart-Russell模型分析法、适应性参数法和高稳系数法对长江中下游地区新育成的13个小麦品种的丰产稳产性进行了研究。结果表明,较对照品种扬麦20增产2%以上的小麦品种有8个,占61.5%,但丰产稳产的小麦品种较少,只有微红225和扬辐麦2049,仅占15.4%。用高稳系数法评价小麦新品种的丰产稳产性是可行的,将高稳系数法与3种稳定性参数法相结合则更能准确反映小麦新品种的丰产稳产性。     

不同玉米品种在不同化控剂作用下穗部性状与产量的研究

为不同玉米品种寻找出其最适的化控剂,以6 种不同的玉米杂交品种为主因素,以5 种不同的玉米化控剂处理为次因素,采用随机区组设计研究不同化控剂处理对玉米穗部性状与产量的影响。每个小区随机抽取10 穗考种,测其穗部性状,用其籽粒产量折算其群体产量。研究结果表明：在相同品种下,矮壮素较其他化控剂处理对穗部性状的影响显著,高玉金不适合对试验进行化控处理,产量与轴粗、穗粗和行粒数成正比关系;在不同化控剂处理下穗重、穗粒重与穗长与玉米群体产量密切相关,百粒重对品种的产量影响很小,‘协玉5 号’适合通过化控剂处理来提高穗部性状的表现。不同的玉米品种应采用不同的化控剂,没有一种化控剂可以同时满足各种品种。     

鲁南地区夏玉米产量对气象因子的响应

2017年在临沂市农业科学院试验田以早熟玉米品种华美1号、登海518和中熟玉米品种登海605、郑单958为材料,分期播种,采用灰色关联分析法研究夏玉米产量对气象因子的响应。结果表明：随着播种期推迟,2种熟期玉米生育期均缩短。6月17日播种比6月10日播种的早熟夏玉米产量略降低,播种期再推迟,早熟夏玉米产量显著降低;随着播种期的推迟,中熟夏玉米产量显著降低,日均温、平均土壤温度和气温日较差均降低,有效积温、日照时数均减少;气象因子对早熟夏玉米产量的影响为：有效积温>日照时数>气温日较差>平均土壤温度>日均温>降水量,气象因子对中熟夏玉米产量的影响为：有效积温>日照时数>日均温>平均土壤温度>气温日较差>降水量。生产上,鲁南地区中熟夏玉米适宜播期在6月10日左右,早熟夏玉米品种适宜播期在6月10日至6月17日,夏玉米在麦收后应及早播种,为实现高产和子粒机收创造条件。     

Specific adaptation of barley varieties in different locations in Ethiopia

Barley is one of the most important cereal crops grown for the livelihoods of the poor farmers of Tigray region in northern Ethiopia. As many low input and marginal environments it has benefited less from the yield increases achieved by modern breeding. This has been largely attributed due to genotype × environment intraction (GEI). To investigate the causes of GEI, ten barley varieties including local checks (two farmers developed varieties, four modern varieties and three rare local varieties) were tested over 21 environments. Participatory methods were applied to sample an adequate number of environments spanning the regional diversity. The yielding ability and stability of the varieties was graphically depicted by GGE and PLSR biplot. There were two major groups of environments, the central and northern highlands, the latter with less rainfall and poorer soils. Rainfall per month and total nitrogen level were the environmental variables that differentiated these two groups. In Tigray, rainfall in June and July were negatively correlated with yield, reflecting waterlogging problems. The different varieties were either specifically or widely adapted across the two environments. The variety ‘Himblil’, originating in Tigray, was the highest yielding and also most stable in the region of origin. However, it was inferior to improved varieties (Shege and Dimtu) at high yield levels. The association of earliness with grain yield indicates that the trait can be effectively manipulated within the existing materials. We recommend breeding for drought/water logging resistance based on selection in the target environment as the best strategy to provide stable and high yielding varieties for Tigray.     

Analysis of adaptation of barley,triticale, durum and bread wheat under Mediterranean conditions

Summary Yield data obtained from a comparative small grain cereals trial, grown for five consecutive growing seasons at a total of 23 environments in Cyprus, were subjected to regression analysis. Within each environment, yield trials consisted of a standard set of three cultivars or elite lines of barley, triticale, durum and bread wheat. The regression coefficient (b) of crop mean on the environmental index (I) and the mean square deviation from regression (sd²) were calculated for each crop. Each crop tended to have its own characteristic value of sd² and its magnitude was an excellent indicator of specific crop-environment interaction. The causes of large sd², for two of the four crops, were the susceptibilith of barley to lodging, when favourable conditions were encountered at high yielding environments, and triticale dependence on late season precipitation. Durum wheat and triticale had an average response to different yielding environments (b>1.19) and both were significantly different from those of bread wheat (1.08) and barley (0.54). Hence, barley, bread and durum wheat are specifically adapted to low, average and high yielding Mediterranean environments, respectively. The cultivation of triticale at the expence of durum wheat is not feasible. Furthermore, interactions between crops and environments demonstrated by the regression parameters, should constitute the basis for decision making, regarding crop adaptation in a region. The average yield in all environments should not be considered as a proper criterion for adaptation. In this study, triticale had a similar mean grain yield (3,842 kg/ha) to that of bread wheat, but was significantly higher yielding than barley or durum wheat (5 and 7%, respectively).     

Ontogenetic analysis of yield components and yield stability of durum wheat in water-limited environments

Summary One main reason for the slow improvement of durum wheat in water-limited environments is the lack of clear understanding of the interrelationships among yield components and their compensatory changes under low and erratic moisture availability. Five cultivars, varying in many physiological attributes, were tested under different drought-stress conditions in field and greenhouse experiments. The cause-effect relationships of duration of vegetative period, duration of grain-filling period, number of spikes per m², kernels per spike, kernel weight and grain yield per m² were assessed. Furthermore, yield stability was evaluated. Yield reduction was largest under mid-season stress (58%), followed by terminal stress (30%) and early stress (22%). Cultivar Po was very sensitive to terminal stress.Path-coefficient analysis revealed a complex pattern of relationships among the six variables. An increase in vegetative period reduced the grain-filling period under all conditions. It increased number of kernels per spike under non-stress conditions. The direct effect of spikes per m² on grain yield was significantly positive. However, more spikes per m² resulted in fewer kernels per spike and a low kernel weight and, as a result, a negative relationship with grain yield under early stress. Grain-filling period had a strong influence on grain yield via kernel weight. Kernels per spike had the largest direct effect on grain yield. However, it was negatively correlated with kernel weight, especially under terminal stress. Grain yield heavily depended on kernels per spike under early stress and grain-filling period and kernels per spike under terminal stress.Variation in drought susceptibility index among cultivars was significant under early and terminal stress conditions, but not under mid-stress conditions. Yield potential and stability were not correlated for the different drought-stress conditions.Longer grain-filling period, increased number of kernels per spike and limited spike number per m² can be used as selection criteria for sustainable yield in water-limited environments.     

Environmental Adaptation and Stability Relationships between Grain Yield and some Agronomic Traits in Winter Oat

This study was conducted to determine the stability of grain yield, harvest index, plant height, and panicle length and to determine the association of grain yield with these traits in winter white oat ( Avena sativa L.) genotypes. The genotypes were grown in replicated tests in Ankara in 1985–1991. Each experiment year was regarded as an environment, and entry mean of each year was used as the environmental index. Stability parameters were estimated from the regression analysis as linear regression coefficient (b), deviations from regression (S²d) and coefficient of determination (r²).
Genotypes differed significantly for all traits and significant genotypes X environment interactions occurred for these traits. On the basis of estimates of stability parameters, A-24 genotype was stable for grain yield. Correlation coefficients between traits were inconsistent in good and poor environments except between grain yield and panicle length. The study suggested that these traits are differently affected by environmental changes and selection for panicle length might be effective as selection for grain yield in improving oats with high grain yield for diverse environments.     

Yield and stability factors associated with hybrid wheat

For hybrid wheat to be accepted in the Great Plains of the USA, hybrids must exhibit enhanced yield performance, yield responsiveness, and reasonable yield stability across a wide array of production environments. Agripro has been researching hybrid wheat since 1981 and has an established pureline release history since 1978. Yield data from 1991 to 1995 were examined to compare the trend performance and selection gains of purelines and hybrids in a large scale parallel development effort. This data set (13,739 points) reveals an average 0.454 t ha^-1 or 10.8% hybrid yield advantage over purelines in preliminary regional testing. Entries selected from the preliminary trials show a greater hybrid advantage of 0.652 t ha^-1, or 13.5%. Several factors including enhanced stability over strong yearly environmental effects, improved agronomic and epidemiological expression through complementary inbred trait selection, and improved heat tolerance are likely contributors to this significantly improved selection gain. Yield stability of hybrids and purelines was compared in Agripro Standard Variety Trials and USDA-ARS Southern Regional Performance Nurseries from 1990 to 1995. In addition to having higher means than purelines, hybrid yield advantage increased with improving production conditions. The enhanced responsiveness of hybrids, as indicated by higher slopes in regression analyses, was combined with similar deviations from regression response. Hybrid wheat in the Great Plains of the USA has shown a fundamental yield, responsiveness and selection gain advantage over pureline varieties that could result in acceptance by producers. This revised version was published online in August 2006 with corrections to the Cover Date.     

Grain-yield characteristics of oat lines surviving uniform and shuttle selection strategies

Summary Four selection strategies were used on four sets of oat lines to select for grain yield. Two of these used uniform environments whereby sequential selection of the high-yielding lines occurred in continuous high- or continuous low-productivity environments. These are referred to as high and low uniform selection strategies, respectively. The other two selection strategies were conducted by sequential selection of the high-yielding lines in alternating high- and low-productivity environments. They are referred to as high and low shuttle selection strategies, respectively, with high and low designating the productivity of the first environment in the sequence. After three or four cycles of selection, the surviving lines and a random sample from each set were evaluated for mean grain yield, grain yield response to improving environments, and stability of grain yield, in a range of environments typical of oat production on Iowa farms.Grain yield and regression response for all selection strategies, when calculated across all sets of lines, were significantly greater than corresponding values for random samples. Stability was unchanged. The uniform-high and uniform-low strategies gave the greatest and the smallest gains in mean grain yield, respectively, with the shuttle strategies giving intermediate gains. Shuttle selection in predominantly high-productivity environments increased grain yield more than shuttle selection in predominantly low-productivity environments. The uniform-strategy followed by the shuttle-high strategy identified entries with superior performance in high productivity environments. Increased gain in mean grain yield across all environments was associated with increased number of selection cycles conducted in high-productivity environments.Journal Paper No. J-15252 of the Iowa Agric. and Home Econ. Exp. Stn., Ames, Iowa 50011, USA. Project No. 2447.