Selection for Yield and its Components in a Winter Wheat Population under Different Environmental Conditions in Albania

Wheat breeding programmes in Albania depend upon the use of diverse genetic material of local origin and on special environmental conditions; the present study being conducted under drought stress conditions. Grain yield, yield components, plant height and test weight were estimated in an F₅ generation of a winter wheat population at Kamez in 1989—90 and 1990—91 and at Lushnje in 1989—90. The highest values of heritability were observed for plant height, kernel weight and spike length. Due to drought stress the heritability of kernels per spike was low. None of the correlated responses was higher than the direct response for yield. Maximum genetic gain was expected when yield, plant height, spike length, kernels/spike and kernel weight were included in the index.     

Potential Yields and On-Farm Ethanol Production Cost of Corn, Sweet Sorghum, Fodderbeet, and Sugarbeet

Field experiments were conducted during 1980-82 at the Agronomy Farm of the University of California, Davis, to compare fermentable carbohydrate production and cost of potential ethanol from fodderbeet, sweet sorghum, sugarbeet, and corn in relation to the requirements of these crops for fertilizer nitrogen and irrigation. The response of hexose yields of these crops to fertilizer N varied in the two experiments. When all crops responded, sweet sorghum and sugarbeet required 36 % and fodderbeet 68 % of the fertilizer N needed for corn. Twelve weeks following a mid-season irrigation cut off, hexose yield of sugarbeet was decreased by 18 % as compared to an adequately watered crop. Water stressed sweet sorghum extracted higher amounts of soil moisture, increased in hexose concentration and produced 29 % higher hexose yield than when adequately watered. Stressed sugarbeet, however, had a higher hexose yield due to its higher sugar concentration.
When fertilized and irrigated adequately, fodderbeet produced 13.4, sugarbeet 11.9, sweet sorghum 10.0, and corn 8.15 Mg hexose ha⁻¹. Comparative on-farm ethanol production costs of these four crops were very close ($0.38 to 0.40 L⁻¹). Thus, growing established crops like corn and sugarbeet for which processing facilities and alternative markets already exist would be preferred.     

High Frequencies of Fertilization and Haploid Seedling Production in Crosses Between Commercial Hexaploid Wheat Varieties and Maize

Nineteen commercial hexaploid wheat varieties were crossed with the maize F₁ hybrid ‘Seneca 60’. Fertilization frequencies ranged from 32.1 % to 47.5 % of pollinated florets (mean 39.5 %) in the 14 winter wheat varieties and from 40.7 % to 51.4 % (mean 47.8 %) in the five spring wheat varieties. In some cases only an endosperm was formed and the frequencies of embryo formation were therefore slightly lower, being 28.2 % to 45.9 % (mean 36.4 %) for winter wheats and 39.8 % to 48.6 % (mean 45.1 %) for spring wheats. Mean values were significantly higher in the spring wheats but no significant variation was found between varieties within the spring or winter categories. In the five spring wheats the mean yield of embryos, and hence the potential yield of haploid plants, was 3.4-fold higher than with the tetraploid Hordeum bulbosum clone PB179. For the 14 winter wheats the figure was 10.9-fold higher. These differences were highly significant (p < 0.001) in all varieties. A single 2,4-D treatment given to spikes one day after pollination with maize enabled embryos to be recovered from all 19 varieties. A total of 311 embryos were recovered from 950 florets (an average of 7.3 embryos per spike) of which 191 germinated, giving an average yield of one haploid plant for every 5.0 florets pollinated (4.4 haploid plants per spike).     

Relationship between Grain Yield and Remotely-Sensed Data in Wheat Breeding Experiments

Data from aerial infrared photographs have recently been proposed as a complementary analytical tool for evaluating genotype performance in breeders' trials. Our objective was to establish the relationships between spring wheat grain yield and remotely-sensed data in a variety experiment. Large genotype differences (P ≤ 0.05) in grain yield, red, and near infrared reflectance values occurred. Significant (P ≤ 0.05) regressions between grain yield and remoteley-sensed data were observed for two dates of flight, but these functions varied between dates of flight. A normalized difference vegetative index, as an estimate of crop productivity, indicated that spring wheats with the highest grain yields may show correspondingly high dry matter production. However, low r² values for the remotely-sensed values suggest that much of the variability is not explained by these models. Future research must develop more accurate methods of remotely-sensed analysis, including standardizing the images, identifying the correct time with respect to stage of crop development for infrared photographs, incorporating crop harvest index data into the models, and adjusting for identified spatial variation.     

Analysis of Wheat Cultivar Differences in Grain Yield, Grain Nitrogen Yield and Nitrogen Utilization Efficiency.

More detailed information on the causes of yield variability among wheat cultivars is needed to further increase wheat yield. Field studies were conducted in Northern Greece over the two cropping seasons of 1985—1986 and 1986—1987 to assess the effects of nitrogen fertilizer and application timing of the various component traits that determine grain yield, grain nitrogen yield and nitrogen utilization efficiency of two bread ( Triticum aestivum L.) and two durum ( Triticum durum Desf.) wheat cultivars, using yield and yield component analysis. Nitrogen at a rate of 150 kg ha^-1 was applied before planting or 100 N kg ha^-1 before planting and then 50 N kg ha^-1 top dressed at early boot stage. Nitrogen and cultivars affected all traits examined, while split nitrogen application affected only some of the traits. Grain yields in the most cases were correlated with number of grains per unit area and grain weight and grain nitrogen yields in all cases with grain number per unit area. The contribution of the number of grains per spike to total variation in grain yield among cultivars was almost consistent (37 to 55 %), while the contribution of grain weight was more significant (up to 55 %) in high yields (>6.500kg ha^-1) and number of spikes per unit area (>500). The number of grains per spike contributed from 60 to 83 % to the total variation in grain nitrogen per spike. Increased grain nitrogen concentration resulted in a reduction of its contribution in grain nitrogen yield variation. Nitrogen utilization efficiency was higher during grain filling than during vegetative biomass accumulation. The contribution of nitrogen harvest index to the variation of utilization efficiency for grain yield was higher in plants receiving nitrogen application.     

Energy Input and Output Analysis of four Field Crops in California1

Four crops, corn (Zea mays L.), sweet sorghum (Sorghum bicolor L.), fodder beet (Beta vulgaris L.) and sugarbeet (Beta vulgaris L.) were grown in irrigated plots at the experimental farm of the University of California, Davis, in 1980 and 1981. Six fertilizer N levels ranging from 0 to 280 kg ha^?1 were used to estimate the most efficient N input for each of the tested crop in terms of energy input and output analysis. Calculations of cultural energy input costs in relation to potential ethanol yield showed production requirements of: corn 30.9 GJ ha^?1, sweet sorghum 30.4 GJ ha^?1, fodder beet 49.4 GJ ha^?1 and sugarbeet 41.0 GJ ha^?1. Highest average energy inputs were for liquid fuels for operations 35%, irrigation 23% and fertilizer nitrogen 19%. Fodder beet had the highest fermentable carbohydrate yield at 13.05 Mg ha^?1 followed by sugarbeet at 11.5 Mg ha^?1. Sweet sorghum and corn yields were lower at 9.71 and 8.09 Mg ha^?1, respectively. Crop production inputs of energy per liter of potential ethanol were: corn 6.42 MJL^?1 sweet sorghum 5.25 MJL^?1, fodder beet 6.35 MJL^?1 and sugarbeet 5.95 MJL^?1.     

小麦区域试验产量性状及其稳定性分析

为了评价小麦品种的丰产性和稳定性,运用作物品种区域试验非平衡资料的统计分析方法,利用2008年和2009年的江苏省淮北地区小麦区域试验资料,对各参试品种的产量性状及其稳定性进行了分析。方差分量分析结果表明,试点和年份×试点互作对产量及其构成因素的影响较大。参试小麦品种的平均产量变幅为7078.35~7798.11 kg/hm2,品种V2、V3、V13和V14的产量显著高于对照,其中品种V13的平均产量居首位,比对照品种V21增产500.97 kg/hm2,增产率为6.87%;品种V8和V18的产量较低但与对照品种的差异未达显著水平。产量的稳定性方面,品种V14对环境指数的反应较敏感,品种V4和V6的一致性表现较差,其余参试品种的稳定性表现相似。综观参试小麦品种两年的产量表现,丰产性和稳产性较好的品种有V2和V13,品种V14的产量较高但稳定性表现较差。此外,开展多年多点试验,对于客观评价小麦区试参试品种的产量性状及其稳定性是十分必要的。     

Yield Stability in Long-term Released Maize Hybrids FAO 100 and 200

The purpose of this study was to assess changes in yield stability of tnaize hybrids during a 20-year period and to relate them to yield changes. The data on FAO 100 and FAO 200 hybrids, released by the former Yugoslav Committee for Releasing Varieties, were utilized. Most ofthe released hybrids fell into the first and the second stability group (Francis and Kannenberg 1978). The b_i values (Finlay and Wilkinson 1963) of the released hybrids, except two from FAO 100 and four from FAO 200 group, did not differ significantly from 1.0. Also, all but one from FAO 100 and one from FAO 200 released hybrids did not differ in aj value (Shukla 1972) significantly from 0. Values of A, and aj stability parameters changed only slightly during the 20-year period. During the same time the yield ofthe FAO 100 hybrids did not change. In the FAO 200 group the yield increased, but the genetic gain was not significant. The stability parameters were not in a significant correlation with the yield.     

A Dynamic Model for Water and Nitrogen Limited Growth in Spring Wheat to Predict Yield and Quality

Annual variation of bread wheat ( Triticum aestivum L.) yield and quality has caused problems for agronomic policy in northern regions. Yield prediction methods based on visual assessment of crop may be inaccurate as they are not based on quantitative data. The aim of this study was to develop a simple dynamic model, based on daily climatological data, enabling prediction of crop growth, and changes in crop yield, and grain protein concentration and starch quality. The model was built using field data collected in 1972–88. Spring wheat cultivars included in the study were Kadett and Ruso. The calibration of growth and Hagberg falling number (used as a measure of starch quality) sub-models resulted in a highly significant positive correlation between measured and calculated values. The calibration of nitrogen sub-models failed, however, with poor correlation between measured and calculated values. The model was tested against independent field data collected during 1989–90, and results correlated with calibration results. The yield predictions based on independent field data were accurate, and the same as or similar to field trial results. However, the independent Hata revealed flaws in soil-water and Hagberg falling number sub-models.     

不同类型超级小麦产量构成因素及籽粒产量的通径分析

以8个不同类型的超级小麦新品种（系）为材料,研究了不同土壤肥力条件下3种类型超级小麦的产量构成因素变化及其对籽粒产量的相关分析和通径分析。结果表明,在高肥地力下,大穗型品种和中间型品种的产量高于多穗型品种;而中、低肥力下,多穗型品种的产量又显著高于大穗型品种。在本试验条件下,大穗型和多穗型品种的穗数、     

Production of Doubled Haploids by Anther Culture and Wheat X Maize Method in a Wheat Breeding Programme

Utilization of the doubled haploid method of breeding usually shortens the time to cultivar release, and methods of haploid production need evaluation in a breeding programme. Thirty-eight different three-way crosses were tested for anther culture response. On average 5.8 percent of the anthers cultured produced calli. Three crosses were found recalcitrant for callus induction. Overall, the anther culture method produced 0.6 plantlet per 100 anthers cultured. Five crosses with an average of 5.8 and 2.8 percent of anthers producing calli and plantlets, respectively, were compared using anther culture and wheat × maize crosses. Non-responsive genotypes for callus induction and plantlet formation in the anther culture method proved to be good parental material in wheat × maize crosses. The average percentages of embryo formation and plantlet production in wheat × maize crosses were 10.3 and 4.7, respectively. Anther-derived plants were cytologically unstable, whereas all the plants regenerated from wheat × maize crosses were haploids (n = 21 chromosomes). The chromosome numbers of the polyhaploids were doubled with a colchicine treatment. Improvement of the two haploid production methods to facilitate their efficient use in a breeding programme is discussed.     

Improvement of Salt Tolerance in Maize by Selection and Breeding

Genetic variation for NaCl tolerance at the vegetative stage was assessed in nutrient solution culture in maize (Zea mays L.). Shoot growth, and plant fresh and dry weight of the two cultivars, Akbar and Sadat were severely reduced after three weeks growth in 120, 150, and ISO mol m^?3 NaCl. There was however considerable variability between seedlings. Ten-thousands seeds of cv. Akbar were therefore screened for shoot growth at 180 mol m^?3 NaCl after four weeks growth in sand culture. A selection intensity of 0.42 % was achieved. Eighteen selected plants were polycrossed for estimation of narrow-sense heritability based on female parent-progeny regression. A narrow-sense heritability estimate of 0.54 was obtained. The progeny of the salt-tolerant selection line and selfed progeny plants of the unselccted control lines of cvs Akbar and Sadat were grown for six weeks in 0, 30, 60, 90, 120, 150, and 180 mol m^?3 NaCl in sand culture. The tolerant line produced significantly greater fresh and dry biomass and had greater shoot length than the unselected cv. Akbar, but the selection line derived from cv. Akbar was equal to the salt tolerant cv. Sadat in all the growth parameters measured. These data suggest that in maize, improvement in salt tolerance could be obtained through further cycles of selection and breeding.     

Yield Stability of Winter Wheat (Triticum sp.) Cultivars and Lines

The purpose of this study was to compare responsiveness to environment as well as the stability of newly developed promising lines with traditional commercial cultivars. Subject research was conducted in Ankara between 1983-1989 on common and durum wheat cultivars and lines. Regression coefficient (b) was used as the criterion of genotypes' responsiveness to environment whereas deviation from regression (S²d) and coefficient of determination (r²) were used as stability parameters. Each experiment year was regarded as an environment and yield average of each year was used as the environmental index.
In consequence of the research, it was determined that new varieties with high yield, adaptable to diverse environments could be developed by means of hybridizations between parents having different genetic characteristics which were provided from diverse ecological regions.     

Yield and Yield Stability in a Balanced System of Widely Differing Population Structures in Zea Mays L.

With the view to study heterozygosity and heterogeneity as to their effects and interactions on yield and yield stability in maize, the following four types of population structure were formed from eight inbred lines: Homogeneous populations of homozygous plants (the eight inbred lines themselves); heterogeneous populations of homozygous plants (four blends containing four lines each); homogeneous populations of heterozygous plants (16 single crosses); heterogeneous populations of heterozygous plants (four blends containing four single crosses each, and four double crosses). This material was grown in three environments (years). At both levels of heterozygosity, the blends did not outyield the means of their respective components grown in pure stands. yield stability of the various structural groups was ranked differently by ecovalence and the mean square for deviations from regression. By transforming the deviation mean squares into coefficients of variation it was possible to reveal improvements of stability not only by heterogeneity but also by heterozygosity, and additionally, an interaction of both factors in the sense of a diminishing return.     

小麦新品种临麦4号丰产性稳产性及适应性分析

为了更全面详细地了解小麦新品种临麦4号的生产特性,以2005～2006年度山东省小麦高肥1组区域试验的结果为依据,通过产量、变异系数、高稳系数和回归系数分别对临麦4号和对照品种潍麦8号的丰产性、稳定性和适应性进行比较、分析,以促进该品种在生产中的推广应用。结果表明,临麦4号丰产性能高、稳定性能好、适应范围广,是一个比较理想的高产小麦新品种。     

高产、双抗型小麦新品种‘川麦51’产量、抗病性等特征分析

为了明确新品种的增产潜力和加快新品种的推广应用,实现新品种的应用价值,通过方差分析、多重比较等方法对小麦新品种--‘川麦51’的产量、抗病性等特征进行比较分析。‘川麦51’是四川省农科院作物研究所选育的一个中筋小麦品种,该品种在2年的区试试验中分别比对照增产12.6%和14.2%,生产试验中比对照增产11.4%。采用DPS软件进行区域试验分析的结果表明,‘川麦51’具有良好的丰产性、稳产性和稳定性。抗病性鉴定结果表明,‘川麦51’高抗条锈病和中抗白粉病,能够抵御频繁爆发条锈病和偶发白粉病的四川气候条件。综合评价认为‘川麦51’具有较高的推广应用价值。     

江苏花生新品种鉴定和产量稳定性分析

为了准确、客观地评价江苏花生新品种鉴定试验参试品种（系）的特征特性,促进江苏花生新品种的推广应用,采用高稳系数法分别对淮南、淮北组的12个参试品种（系）进行丰产性和稳产性分析,并进行品质、抗性及主要农艺性状调查。结果显示：各参试品种均具有中等以上的耐旱性、耐涝性、叶斑病及锈病抗性。具体来说,淮南组的‘宁泰9922’产量较高,且稳产性较好;‘苏花0537’种皮深红色,熟期早,适应性广,粗蛋白含量较高;淮北组的‘连1001’、‘赣榆10-6’、‘东花9号’及‘徐0627’分别较对照‘徐花13号’增产4.7%~7.4%,同时产量稳定性优于对照。因此认为以上品种可以进一步示范和推广应用,同时也表明用高稳系数法评价花生品种（系）的高产稳产性是可行的。     

Progress since the 1930s in Breeding for Yield, its Components, and Quality Traits of Spring Wheat in Finland

The contribution of improvements in morphophysiological traits to increased gram yield in spring wheat (Triticum aestivum L.) and the achievements of breeding for high bread-making quality in Finland since the 1930s were assessed. Ten wheat cultivars released in Finland between 1939 and 1990 were evaluated in Held experiments at the Viikki Experimental Farm, University of Helsinki, Finland (60°13′N) in 1991 and 1992. Twenty-two traits representing maturity, plant architecture, plant stand structure and N accumulation, and nine quality traits, including protein concentration and protein quality, were assessed. A 20 % increase in grain yield arising from cultivar improvement was associated with a 7 % reduction in height, an 80 % improvement in lodging resistance, and a 15 % higher harvest index (HI). Ear weight was 30 % higher in the modern cultivars. The higher ear weight of the modern cultivars was a result of more grains per ear and a higher spikelet weight. No decrease in vegetative phytomass in modern cultivars was recorded in this study. Grain yield and total N accumulation increased simultaneously and a positive correlation between year of cultivar release and nitrogen index was established. Although use of high N fertilizer application rates resulted in significantly improved baking quality of the flour, no trend between baking quality and year of cultivar release was recorded. The relatively low HI recorded in this study suggests that further yield increases art-likely to be achieved by selecting for higher HI.     

Yield, Grain Weight and Height Relationships in Two Random Samples of Early Semi-Dwarf Genotypes of Spring Wheat (Triticum aestivum L.)

The objective of this work is to study the association between the genotypic differences in mean grain weight and grain yield, the relationship of yield and grain weight with culm length, and the differences between the effects of the Rht1 and Rht2 dwarfing alleles on these characters. Yield, grain weight, grains m^-2 and culm length were evaluated in two random samples of 19 semi-dwarf early lines, selected in F₅ and tested in F₂, from two different crosses between cultivars differing in the Rht allele controlling their semi-dwarf ness. The lines of each cross were tested in 4-replicated field trials at two different sites. Phenotypic, genotypic, partial and multiple correlations as well as hertability estimates were computed. In each cross the lines differed significantly in their mean values of all the characters tested. In both crosses there was no apparent association between grain weight and grain yield. It therefore seems that in wheat of the type investigated in this study, grain yield and grain weight are independent controlled and that high grain yield is not restricted to any particular range of mean grain weight. A rather high positive correlation between culm length and grain weight was found in one cross but not in the other indicating the dependence of this relationship on the genetic background. In both crosses no significant differences were found between the performance of the lines carrying the Rht1 dwarfing allele and those carrying the Rht2 allele.     

Osmotic Adjustment in Maize (Zea mays L.): Changes with Ontogeny and its Relationship with Phenotypic Stability

Genetic variation for osmotic adjustment was examined in a group of maize hybrids during vegetative and silking stages. Estimates of osmotic adjustment were derived from measurements of leaf relative water content (RWC) and osmotic potential (Ψ o ) before day-break. The degree of adjustment was estimated from the In RWC/In Ψ o relationship. All cultivars examined showed some degree of osmotic adjustment and significant differences (P < 0.05) were found among them. The utility of measurements in early vegetative stages as a mean of selection for osmotic adjustment in silking stage was established. A positive tendency was observed between osmotic adjustment and phenotypic stability.