Sensory evaluation as a selection tool in apple breeding

Several conventional sensory methods were adapted to provide aprocedure that is suitable for screening apple (Malus × domestica) breeding selections for dessert quality. Trained judges were presented with randomized coded samples (apple slices) and asked to rate them on 0 to 9 bipolar hedonic (liking) scales for texture and flavour, and 0 to 9 unipolar intensity scales for skin toughness, crispness, hardness, juiciness, aroma, sweetness and sourness. Appearance liking was rated on coded samples of five whole apples, using the 0 to 9 hedonic scale. A minimum panel size of eleven judges was generally sufficient to obtain statistical discrimination of one point on the 0 to 9 scales. Panel mean scores for breeding selections relative to standards have been consistent from panel to panel and year to year. A subset of selections and cultivars was rated for appearance and taste by consumers in blind taste tests. In-house panel findings were comparable to consumer ratings for taste and appearance liking, with a few exceptions in appearance. Panel mean scores for texture and flavour liking were regressed on texture and flavour components. Crispness accounted for about 90% of the variation in texture liking. Juiciness, aroma, sweetness and sourness were all important to flavour liking, but their relative importance changed from year to year and in total accounted for only about 60% of variation in flavour liking. Perceived sweetness and sourness were better predictors of liking than analytical measurements of soluble solids and titratable acidity. Formal sensory evaluation can be used successfully for screening breeding selections, and may provide more reliable data than the opinions of only one or two people.     

Optimal sampling strategies for evaluating fruit softening after harvest in apple breeding

Environmental variance components associated with year, tree, and harvest date were estimated for fruit softening after harvest in apple (Malus × domestica Borkh.) to determine their relative importance and design optimum sampling strategies to discriminate genotypes in apple breeding. Fruit were stored after harvest under 20± 2 ^∘C and 80± 5%RH. Softening was evaluated by adapting the change in firmness during storage to a linear regression and defining the regression coefficient as the softening rate. Environmental variances associated with genotype × year interaction, among trees, year × tree interaction, and among harvest dates were all very small, namely, 2.7, 0.1, 5.2, and 5.7%, respectively, to the total variance obtained from the analysis of variance for the softening rate. The variance associated with genotype, at 57.3%, was very large. On the basis of the number of fruit necessary for firmness measurements, two times harvest is an efficient strategy to determine a genotype mean for the softening.     

苹果不同生育期综合气象资源对产量的影响研究——以天水市秦州区为例

为定量确定综合气候资源对苹果产量的影响,运用1981—2010 年秦州区苹果单产资料及苹果主要生育期（4—8 月）平均气温、降水量、日照时数资料,建立了综合气象资源指数,分析了苹果不同生育阶段气候因子的变化规律及对苹果产量的影响。结果表明,近30 年苹果生长前期的热量因子的变化幅度大于生长后期。坐果之前,开花时的低温冷害对苹果产量影响较大。苹果前期生长阶段（4—6 月）降水量呈下降趋势,后期生长阶段（7—8 月）降水量线性变化趋势不明显。后期降水量与产量相关性明显。苹果前期生长阶段（4—6 月）日照时数为随时间呈上升趋势,后期生长阶段（7—8 月）日照线性变化趋势不明显。综合资源指数与苹果产量的变化有较好的一致性。20 世纪90 年代,综合气候资源不利于苹果产量的形成,从21 世纪初综合气候资源指数开始增加,苹果产量也开始上升。未来气候变化趋势利于苹果生产。     

Inheritance and selection of some fruit characters of apple. II. The relation between leaf and fruit pH as a basis for preselection

Summary The leaf pH of two year old apple seedlings was found to be sufficiently related to the fruit pH, measured when the seedlings were six to seven years old, to serve as a basis for pre-selection. Discarding all seedlings with an above average leaf pH (40% of the total) eliminated the majority (74%) of seedling with low-acid cum sweet fruits. The method was not effective for reducing the proportion of seedlings with high-acid cum sour fruits.     

覆盖对果园土壤水热状况及树体生长发育的影响

通过对不同生态环境的果园调查研究表明，覆盖可以显著减少土壤蒸发，维持较高的土壤水分含量，并使得土温的日变化和季节变化发生改变，在冷凉的环境条件下，长期覆盖使得翌年苹果树生长发育延迟，生长量减少。     

苹果叶片蒸腾速率动态模拟

为了解不同小气候条件下苹果叶片的蒸腾速率（Tr）动态变化,构建了气孔-蒸腾耦合模型,并进行模拟研究。其中,叶片Tr根据Penman-Monteith公式计算,气孔导度（Gs）根据气孔的半机理模型计算。利用在‘富士’苹果园（Malus domestica Borkh. cv. ‘Fuji’）观测数据拟合了相关模型参数。模拟结果表明,Tr随空气温度和叶片水势（Ψl）的增加而迅速增加,随CO2浓度的增加而降低。当光合有效辐射（PAR）低于光合作用的光饱和点时,Tr随PAR的增加而线性增加,超过光饱和点后Tr的增加不显著。结果显示,蒸腾作用主要是由饱和水气压差和Gs驱动,气孔变化是影响蒸腾的主要因素。不同小气候因子对Tr的影响各不相同,且它们之间还存在强烈的交互作用。在一天当中,Tr随Gs的增加（降低）而增加（降低）。在晴天,一天中单位面积的苹果上层叶片能蒸发2.7 L水,其最大Tr约4 mmol/(m2?s)。研究表明,通过构建叶片Tr和Gs耦合模型可模拟出不同小气候条件和Ψl下苹果叶片Tr的动态响应。     

Vigour evaluation for genetics and breeding in rose

Breeding of cut and pot rose cultivars for efficient production under low-energy conditions in greenhouses will be facilitated by understanding the inheritance of vigour. To get insight into the genetic variation of vigour-related traits, a diploid rose population was employed for an evaluation study in greenhouses in The Netherlands and Denmark. For all the traits investigated the population showed a continuous quantitative variation as well as a considerable transgression. For most of the traits, the genetic variation found among the tested entries was highly significant and tended to be large in comparison to the effects of genotype by environment interaction. The heritability based on means of the traits was high and ranged from 68 to 92%. Strong simple correlations (r = 0.65 to 0.95) were found among the traits shoot length, leaf area, leaf dry weight, stem dry weight, total dry weight and growth rate. The total dry weight and leaf area are suggested to be good parameters for early selection of rose genotypes with vigorous growth under suboptimal growth conditions.     

Genetic resources in apple,pear and vineyard peach populations in former Yugoslavia

Summary During the period 1988–90, several germplasm collecting trips were made to all republics of former Yugoslavia. A total of 56 old apple cultivars, many of which are represented in up to 5 types, 38 old pear cultivars and 367 genotypes of vineyard peaches were collected. The availability of so much genetic and genotypic wealth made it possible to start apple disease resistance breeding and peach cultivar and rootstock breeding programmes.     

Variation for nitrogen use efficiency traits in current and historical great plains hard winter wheat

Wheat genotypes that efficiently capture and convert available soil nitrogen into harvested grain protein are key to sustainably meeting the rising global demand for grain protein. The purposes of this study were: to characterize the genetic variation for nitrogen use efficiency (NUE) traits within hard winter wheat adapted to the Great Plains of the United States and evaluate trends in the germplasm with year of release; to explore relationships among traits that may be used for selection within breeding programs; and to identify quantitative trait loci associated with NUE traits in this germplasm. NUE traits were measured in a panel of 299 hard winter wheat genotypes, representing historically important and contemporary germplasm, from across the growing region. Trials were grown in two years at two levels of nitrogen fertility. Genotype and genotype × year interaction effects were highly significant for NUE traits, while genotype × nitrogen rate interactions were non-significant. Strong genetic correlations of plant height and flowering date with NUE traits were observed. Wheat breeders have improved NUE: the subset of 183 genotypes that were released as cultivars after 1960 demonstrated significant trends with year of release for improved grain N yield, grain yield, nitrogen harvest index, nitrogen uptake efficiency, nitrogen utilization efficiency, and post-anthesis nitrogen uptake. In genome-wide association analyses, plant height and flowering date were important covariates in the mixed models, and plant height and flowering date substantially explained the variation in NUE traits in this germplasm. Marker-trait associations were identified that may prove useful in breeding.     

Estimates of combining ability for resistance of winter rye to Fusarium culmorum head blight

Summary Head blight caused by Fusarium culmorum and F. graminearum is damaging in all winter rye (Secale cereale L.) growing areas. For hybrid breeding, the relative magnitude of general (GCA) and specific combining ability (SCA) is a crucial parameter for developing appropriate selection procedures. Forty single-cross hybrids were produced by crossing six and seven inbred lines of the Petkus and Carsten gene pool, respectively, in a factorial design. Hybrids were evaluated in two years with artificial F. culmorum inoculation. Resistance traits were head blight rating and grain weight relative to the non-inoculated control. Both resistance traits were closely correlated across both years (r-0.8, P=0.01). Significant genotypic variation was found for both traits with medium to high estimates of heritability (h²=0.6-0.8). Components of variance for GCA were, across years, 10 and 6 times larger than those for SCA for head blight rating and relative grain weight, respectively. Significant SCA effects were found for 15 to 20% of all cross combinations across both traits in each year. SCA effects were, however, inconsistent over years leading to a high SCA-year interaction. In conclusion, resistance to Fusarium head blight among the interpool hybrids tested was conditioned mainly by additive gene action that could be utilized by recurrent selection in multi-environment trials.Abbreviations GCA general combining ability - SCA specific combining ability     

Heterosis in landrace-based topcross hybrids of pearl millet across arid environments

This study quantified the magnitude of heterosis in pearl millet (Pennisetum glaucum) topcross hybrids produced by crossing 16 diverse landraces and three high yielding open-pollinating varieties on two homozygous male-sterile lines. Hybrids and pollinators were grown in 12 year ×;location combinations in India that were grouped into three zones. Genetic components of variance quantifying the differences among these hybrids were estimated. The hybrids showed a conspicuous heterosis for grain yield, earliness and biomass yield but not for straw yield. The level and direction of heterosis for time to flowering depended strongly on the earliness of the male-sterile line. In the terminal drought stress zone hybrids made on the early maturing male-sterile line 843A had the highest level of heterosis for grain yield (88%). This was partly due to escape from terminal stress. In the other two zones the heterosis for grain yield was on average 30%. Heterosis for biomass yield and biomass yield per day was on average also positive in all three zones. For all traits, except time to flowering and biomass yield per day, pollinator effects were the only significant source of variation. Differences between hybrids were mostly caused by additive genetic effects. Significant amount of heterosis observed in landrace-based topcross hybrids for grain yield and other productivity-related traits suggested that substantial improvement in pearl millet productivity in and environments can be obtained by topcrossing locally adapted landraces on suitable male-sterile lines. This revised version was published online in July 2006 with corrections to the Cover Date.     

The performance of double or mixed pollinations with compatible and self-incompatible or incongruous pollen of pear and apple

Summary Six pear and five apple trials were carried out to ascertain the outcome of combinations of compatible pollen (C) with self (S) or incongruous pollen (I) as to the pollination index (PI=seeds/pollinated flower). The PI of the mixture C+I (1:5) was consistently depressed as compared to that of the control C. The results of the double pollinations S/C and I/C were affected by the temperature at pollination; their PI's at <15°C were twice as high as those at >15°C, being well above and below the PI of C in the former and latter case respectively. The opposite was true for the C/S combination, the PI of which increased with the pollination temperature; the PI of C/I did not differ much from the PI of C, irrespective of temperature. The conclusion was reached that the interaction previously and presently found between compatible and self-incompatible pollen also exists to a fair extent between compatible and incongruous pollen. However, in pear neither the mentor nor the pioneer pollen technique proved to aid its hybridization with apple, the formation of self seed was not observed either. In apple the production of apple × pear hybrids was likewise doubtful, but the double pollinations S/C and C/S formed 4–10% self seed.     

矮化中间砧红星苹果树各器官营养元素含量变化研究

研究表明,红星苹果树在年周期内各器官营养元素的含量变动很大,不同砧穗组合也有一定差异.矮化中间砧树叶片、果实和发育枝内多数营养元素含量高于乔砧树.红星苹果产量与叶内氮、磷的含量呈正相关,而与叶内钾的含量呈负相关.文中还讨论了营养元素在器官间存在的相关性.     

Genetic variation in bitter pit and fruit calcium concentrations within a diverse apple germplasm collection

Summary Genetic variability in the apple [Malus] fruit disorder bitter pit and fruit calcium concentrations ([Ca]) was determined in 25 seedling families at each of two sites from 1999 to 2000 and again for one site, in 2001. Most trees were free of pit or had low pit incidence, which could be approximated by an over-dispersed binomial distribution. A genetic component to external and internal pit incidence was found across both sites and all years. This effect was irrespective of the use of several cropping factors, average fruit weight or fruit mineral concentrations as covariates in the analyses. Year and/or site always had substantial effects on pit incidence. Interactions of genetic effects with site or year were also detected with large differences in mean pit incidence between sites or years for some families but not others. No relationship was found between mean family pit incidence and mean family [Ca] or mean family harvest date. However fruit [Ca] and harvest date were usually important predictors of within-family variation in pit incidence. For any one seedling, family had the largest effect on bitter pit incidence followed by site and [Ca] and the smallest effect was that of harvest date. [Ca] showed a strong genetic component and estimated family means of [Ca] were consistent at different sites and years. These results suggest that susceptibility of apple genotypes to bitter pit in breeding programmes may be best assessed through screening across multiple sites and seasons. Fruit [Ca] might be useful as an indirect selection index for bitter pit within, but not among families.     

Comparison of tree architecture using tree edit distances: application to 2-year-old apple hybrids

In fruit trees, understanding genetic determinisms of architectural traits is considered as a promising manner to control vegetative development and yield regularity. In this context, our study aimed to classify 2-year-old apple hybrids on the basis of their architectural traits. From a fine phenotyping, trees were described as tree graphs, including topological and geometric information. To evaluate the similarity between trees, comparison methods based on edit operations (substitution, insertion and deletion) were carried out. Distance between two tree graphs was computed by minimising the sum of the costs of the edit operations applied to transform one tree into another. Two algorithms for the comparison of unordered and partially ordered tree graphs were applied to a sub-sample of the population, taking into account several geometric attributes. For each comparison, a dissimilarity matrix was computed, and subsequently trees were clustered. A local interpretation of the matched entities was proposed through schematic representations of the trees, and similarities between trees were analysed within and between clusters. The tree graphs, both unordered or partially ordered and whether the attributes were considered or not, were grouped, by clustering, according to the number of entities per tree. The robustness of the unordered comparison was demonstrated by its application to the whole population, since it provided results similar to those obtained on the sub-sample. Further developments towards a higher relative weight of geometric versus topological information are discussed in the perspective to define an architectural ideotype in apple.     

A comparison of apple and pear seedlings with reference to the juvenile period I. Seedling growth and yield

Summary Several thousand apple and pear seedlings of many progenies were studied in connection with their juvenile period (J.P.). The initially significant inverse relation between the vigour (stem diameter) and the J.P. of the seedlings became insignificant as the trees grew older, due to a retardation of growth occurring when the seedlings become generative. This relation can be used effectively in pre-selecting for vigour in the nursery. Cumulative yields were higher when the J.P. was shorter, but there was no evident link between the J.P. and annual yield in full bearing, that is to say, precocity and preductivity are not directly connected. Better growing conditions and pre-selection have shortened the mean progeny J.P. of either crop by three years since the 1950's. Generally, the pear seedlings appear to grow faster, to become generative slower and to yield lower than comparable apple seedlings. The mean J.P. of apple and pear progenies averaged 4.2 and 6.0 years respectively. The difference between apple and pear may be attributable to a greater selection pressure on both precocity and productivity with apple than with pear.This possibly also led to a smaller tree in the productive phase on the assumption that tree size at first flowering-small at a short, large at a long J.P.-expresses reproductive efficiency and as such is reflected in the size of the adult tree.Also presented at the Juvenility Symposium held at West-Berlin, November 1976.     

Genotype x environment interaction for root traits in maize,as analysed with factorial regression models

Summary The efficiency of genotopic and climatic characteristics in accounting for the interaction between genotypes and environments has been assessed in a three-year trial involving a set of genotypes presenting a range of root morphology characteristics (number and size). Climatic information on rainfall and temperature was recorded during the experiments, together with extra data on the growth and development of the genotypes. Their effects have been tested in factorial regression models.Climatic covariates were very powerful in accounting for the genotype by year interaction as well as the year main effect alone. For the number of adventitious roots on internode 7, the main effect of year could be described as a linear function of the average temperature and precipitation that occurred during the period of root initiation and growth. For internode 6, no clear conclusion was possible. For the root traits studied, 74 to 98% of the interaction could be explained by one climatic covariate. The regression coefficients can be considered as measures of genotypic stability.The genotypic covariates describing aerial development performed rather poorly, compared with environmental ones, even though the physiological and functional relationships between root and shoot are well known. Neither genotype main effect nor genotype by year interaction could be described sufficiently by factorial regression. Still, the genotypic covariates performing best clearly differed between root counts and size. Also the best genotypic covariates differed for main effect and interaction.     

Morphological characteristics associated with winter survival of five growth types of tetraploid red clover

Summary The aim of this study was to correlate flowering response of tetraploid red clover (Trifolium pratense L.) in the year of seeding with winter survival and other characteristics (vigour, bloom date). In two different years about 2000 plants of two different cultivars (Hungaropoly and Tapiopoly) were established and in the fall were classified into five growth types based on rosette formation and flower production. Non-flowering types were shorter and had few petioles at 6–8 weeks of age, but showed better survival than flowering types. Hungaropoly non-flowering types were more vigorous and bloomed earlier in the second year but Tapiopoly non-flowering types were less vigorous and bloomed later. Although non-flowering in the seeding year was associated with better survival in the second year, there was adequate variation within both types for selection for improved persistence.     

污泥施用对油菜生长和土壤重金属积累的影响

为污泥农业资源化利用提供更为可靠的理论依据,采用盆栽试验的方法,对污泥施用后的油菜产量指标、盐分及植株和土壤中的Hg、As和Zn 3种重金属累积变化规律进行了研究。结果表明：污泥用量为中用量（50 g污泥/盆）时可以明显提高盆栽油菜的产量和根/冠比指标,当污泥用量加大到大用量（100 g污泥/盆）时,污泥对盆栽油菜产量的提高效果会明显降低。污泥比化肥和鸡粪更能促进油菜对N和P的吸收,但对K的吸收却不及鸡粪效果明显。污泥能增加土壤的盐分含量,且高于化肥和鸡粪,但效果不明显。污泥施用后的油菜和土壤中的Hg、As和Zn 3种重金属含量都比化肥和鸡粪有增加,其中Hg增加比较明显。油菜和土壤中的Hg、As和Zn含量均没超过国家相关蔬菜安全标准（GB18406.1-2001,GB15201-94）和土壤质量安全标准（GB15618-1995）。     

Screening fruit tree genetic resources in Belgium for disease resistance and other desirable characters

Summary The wide diversity of old fruit-tree cultivars originating or introduced into Belgium during the 18 ^th and 19 ^th centuries was collected as far as feasible over the last fifteen years at the State Plant Pathology Station in Gembloux. Out of the 2400 accessions now collected, one quarter was recovered from old public collections, and three quarters came from farms or gardens. The initial intention was to screen the material for disease resistance and other characters of agronomic interest with a view to using the best cultivars as breeding parents. However, as the collection developed, genetic resources conservation also became an objectiveper se. The collection presently contains 1150 apple, 850 pear and 300 plum accessions, and smaller numbers of other fruit species. Each accession is evaluated in an experimental orchard for at least ten years. In view of the growing public interest in old fruit-tree cultivars, the Plant Pathology Station has for several years been releasing to the nursery trade the better cultivars emerging from the evaluation, namely nine apple and four plum cultivars, and one peach cultivar. The principal features of the apple cultivars are presented in this paper. Since 1988, old apple and plum cultivars have been being used at the Station as parents in a breeding programme, with both controlled and open pollination. In some instances, old apple cultivars have also been crossed with a modern parent carrying the Vf gene for scab resistance. The preliminary observations on some of these seedlings are presented.