Apple Progeny Research Articles

An overview of the red-fleshed apple: History and its importance for horticulturists, gardeners, nurserymen, and consumers

The present review summarizes the information on the botany, breeding, genetic features, cultivation, and nutraceutical values of red-fleshed apples. Malus sieversii var. niedzwetzkyana or Niedzwetzky’s apple became widely known after the publication of Georg Dieck in the last XIX century. It is characterized by anthocyanin coloration of all organs. Another source of red flesh is the ancient variety ‘Surprise’, which differs from the Niedzwetzky’s apple by a mutation in another gene. These two mutated genes, MYB10 and MYB110a, are located on chromosomes 9 and 17, respectively. Their expression correlated with the anthocyanin accumulation. In type 1 red-fleshed apples, which belong to the Niedzwetzky’s apple progeny, the transcription factor MYB10 confers extensive anthocyanin accumulation in fruit flesh and skin, flowers, leaves, and stems. In type 2 red-fleshed apples, the ‘Surprise’ progeny, only the flesh is red, determined by the transcription factor MYB110а. A new combination Malus domestica f. niedzwetzkyana comb. nov. has been proposed for orchard apples, originated from Niedzwetzky’s apple. The apple cultivars which are progeny of Niedzwetzky’s apple and ‘Surprise’ apple can be placed to Malus Niedzwetzkyana Group and Malus Surprise Group, respectively. All red-fleshed cultivars of orchard apple can be grouped together into Malus domestica Red Flesh Group. Many dozens of new ornamental apple trees have been developed for of European and North American conditions, including the most famous red-flowered centennial apple varieties such ‘Aldenhamensis’, ‘Lemoinei’, ‘Makamik’, and ‘Oekonomierat Echtermeyer’. Rootstocks ‘MB’, ‘PB9’, ‘54-118’, ‘62-396’ and others have become popular in nurseries for the propagation of dwarf and semi-dwarf apple trees thanks to their red leaves, which are useful when removing scion shoots from budded plants. In the F3-F4 and next generation, the new high-quality red-fleshed cultivars have been developed by crossing both Niedzwetzky’s apple and ‘Surprise’ apple with the best orchard apple varieties. Marker-assisted breeding shows great promise for accelerating the development of new red-fleshed cultivars with outstanding traits. The use of the Redlove®, Red Moon®, Kissabel®, and Lucy™ apples brands will ensure the red-fleshed apples’ best path to the consumer as well as the fruit quality and production volume of these novelties. Increasing the consumption of red-fleshed apples is essential for a healthy diet.

Genetic analysis and QTL mapping of aroma volatile compounds in the apple progeny 'Fuji' × 'Cripps Pink'.

Aroma is an essential trait for apple fruit quality, but the understanding of biochemical mechanisms underlying aroma formation is still limited. To better characterize and assess the genetic potential for improving aroma quality for breeding, many efforts have been paid to map quantitative trait loci (QTLs) using a saturated molecular linkage map. In the present study, aroma profiles in ripe fruit of F1 population between 'Fuji' and 'Cripps Pink' were evaluated by gas chromatography-mass spectrometry (GC-MS) over 2019 and 2020 years, and the genetics of volatile compounds were dissected. In total, 38 volatile compounds were identified in 'Fuji' × 'Cripps Pink' population, including 23 esters, 3 alcohols, 7 aldehydes and 5 others. With the combination of aroma phenotypic data and constructed genetic linkage map, 87 QTLs were detected for 15 volatile compounds on 14 linkage groups (LGs). Among them, a set of QTLs associated with ester production identified and confirmed on LG 6. A candidate gene MdAAT6 in the QTL mapping interval was detected. Over-expression of MdAAT6 in tomato and apple fruits showed significantly higher esters accumulation compared to the control, indicating it was critical for the ester production. Our results give light on the mode of inheritance of the apple volatilome and provide new insights for apple flavor improvement in the future.

MdMYB305-MdbHLH33-MdMYB10 regulates sugar and anthocyanin balance in red-fleshed apple fruits.

Sugar and anthocyanin are important indicators of fruit quality, and understanding the mechanism underlying their accumulation is essential for breeding high-quality fruit. We identified an R2R3-MYB transcription factor MdMYB305 in the red-fleshed apple progeny, which was positively correlated with fruit sugar content but negatively correlated with anthocyanin content. Transient injection, stable expression [overexpressing and clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9)], and heterologous transformation of tomato confirmed that MdMYB305 promotes the accumulation of sugar and inhibits the synthesis of anthocyanin. A series of molecular experiments (such as electrophoretic mobility shift and luciferase assays) confirmed that MdMYB305 combines with sugar-related genes (MdCWI1/MdVGT3/MdTMT2) and anthocyanin-related genes (MdF3H/MdDFR/MdUFGT), promoting and inhibiting their activities, and finally regulating the sugar and anthocyanin content of fruits. In addition, the study also found that MdMYB305 competes with MdMYB10 for the MdbHLH33 binding site to balance sugar and anthocyanin accumulation in the fruits, which provides a reference value for exploring more functions of the MYB-bHLH-MYB complex and the balance relationship between sugar and anthocyanin in the future.

Molecular Screening of Some Apple Progenies for Detection Vf Gene Using Marker Assisted Selection


 Apple scab, caused by Venturia inaequalis is one of the most damaging pathogens that affects apple species. Cross combinations were made between Auriu de Bistrița cv. (female genitor) - a valuable local variety in terms of fruit quality but only tolerant to scab, and Florina cv. (male genitor) used as a donor of Vf resistance gene. It was first detected in Malus floribunda Clone 821, which was later transferred to commercial varieties by different breeding programs. To confirm the presence of Vf gene, progenies resulting from the mentioned combination were tested with MAS (Marker Assited Selection), using two dominant primers pairs (AM19, U1400), and another one codominant (AL07) used to distinguish homozygous and heterozygous genotypes. After the crossing combination, a number of twenty-six hybrids were obtained, of which 50% (13 hybrids) were clasified as resistant (heterozygous), respectively 50% (13 hybrids) as susceptible (recessive homozygotes), so the Mendelian ratio was confirmed.

Deciphering morpho-agronomic determinants of the juvenile-mature phase change in apple progenies

Various external and internal factors affect the transition from juvenile to mature phase in tree species as well as herbaceous annual plants. The comprehensive study of the evaluation of juvenility based upon physiological and morphological descriptors in deciduous trees is of crucial importance to provide accurate and consistent assessments regarding the duration of juvenile phase. In this sense, this study aimed at investigating the morpho-agronomic factors that affect the transition from juvenile to mature phase in two segregating apple progenies (‘Braeburn’בAmasya’ and ‘Granny Smith’בAmasya’) over the first two years of flowering. Both progenies showed similar patterns of data distribution among traits over two consecutive years. However, a notable difference between flowering and non-flowering seedlings was recorded in 2019 comparing to in 2018 for all traits, which can be attributed to either a large number of flowering individuals, tree age, climatic conditions or a combination of them. ‘Granny Smith’ as a female parent outperformed for shortening the juvenility phase. It was found that the plant height, trunk cross-sectional area, the number of lateral branches and branch cross-sectional area in flowering seedlings was significantly higher than of non-flowering seedlings, and can provide a reliable indication to identify juvenile or mature phase. Surprisingly, vigour balance did not show significant differences between flowering and non-flowering seedlings for the progenies and their mean in both two years. As expected, considerable variation was found in all the studied traits for all progenies in both years. The transition points from juvenile to mature phases occurred at about 70th to the 75th node in seedlings of ‘Braeburn’בAmasya’ and 93th to 104th node in seedlings of ‘Granny Smith’×’Amasya’ during two consecutive years.

Evaluation of the scab immune apple varieties and hybrids suitable for juice production

Based on the technological evaluation of 105 immune V f and highly resistant V m to scab apple varieties of the All-Russia Research Institute for Horticultural Plant Breeding suitable for juice production, 16 varieties perspective for raw material production are specified with the juice output from 70.4% (Orlovskoe Poles’e) to 65% (Rozhdestvenskoe), the content of the soluble dry substances not lower than 11%, and organoleptic properties higher (4.5–4.3 points) than in the control variety Antonovka obyknovennaya. A higher juice output is reliably defined in the summer varieties as compared to the winter ones. The character of appearance of some technological features of the fruits (juice output, content of soluble dry substances, organic acids, P-active catechins) is specified in the scab immune hybrid apple progeny of 28 hybrid families.

Contribution of high-resolution remotely sensed thermal-infrared imagery to high-throughput field phenotyping of an apple progeny submitted to water constraints

The genetic variability of fruit trees in response to drought stress is scarcely studied. As adaptation of scion cultivars to abiotic constraints constitutes a new challenge for fruit production, in particular where water scarcity is likely to occur, development of high-throughput phenotyping strategies applicable in the field to assess the tree response to soil drought among large populations is needed, overcoming the limitations of usual in-planta measurements. In this research, remotely sensed images were acquired by ultra-light aircraft (ULA) and an unmanned aerial vehicle (UAV) during 4 years in a field trial where an apple progeny (122 hybrids) was studied under contrasted summer irrigation regimes. Ortho-images were simultaneously acquired in visible (RGB), near-infrared (NIR) and thermalinfrared (TIR) bands. After rthorectification, georeferencing and mosaicking, RGB and NIR images were used to compute different vegetation indices over the field trial, while TIR imaging allowed extraction of the vegetation surface temperature (Ts), which was calibrated at ground level by using hot and cold reference targets. The Morans'f water deficit index (WDI), which combines the surface minus air temperature (Ts-Ta) and the normalized difference vegetation index (NDVI), was used as a stress phenotypic variable. WDI estimates the ratio of actual to maximal evapotranspiration (WDI=1.ETact/ETmax) in discontinuous plant covers. Like the Ts-Ta variable, it significantly discriminated the tree water statuses and genotypes. On the basis of different plant- and image-based indices, individual tree behaviour trends (isohydric vs. anisohydric) can be distinguished among the progeny, irrespective of tree vigour. This opens potential applications for plant breeding, and genetic bases of apple tree response to water stress are currently investigated through quantitative trait locus (QTL) detection. Making use of ULA with flights performed at 40-60 m altitude made it possible to strongly improve the TIR image resolution ('10 cm) and to limit the number of vegetation/soil mixed pixels. However, it will require careful image posttreatment, possibly including classification and/or segmentation.

Reconstructing relationship matrices from dense SNP arrays for the prediction of genetic potential in unreplicated multilocation plantings of apple progeny

Prediction of the genetic potential of a candidate cultivar is fundamental to achieving a response to selection in plant breeding. In the early phases of advanced selection plantings, a common strategy to increase selection intensity is field testing of many candidates at multiple locations with incomplete or limited replication among trials. Genetic analyses that incorporate genetic relationships among candidates can be used to improve the prediction accuracy, and indirectly predict performance at locations where a candidate is not planted. Here, we report on the prediction of breeding value for sensory crispness for unreplicated apple candidate progeny and parents established at three locations across the USA (Minnesota, New York State, Washington State) using relationships constructed from (i) pedigree records and (ii) 8K single nucleotide polymorphism (SNP) array data. The correlation between relationship coefficients estimated from either historical pedigree or SNP arrays was 0.76. Estimates of phenotypic variation and heritability were similar among three analyses (i.e., full data using pedigree relationship matrix, reduced data for only individuals with SNP genotypes available using a pedigree-based relationship matrix, or reduced data using a genomic relationship matrix estimated from the SNP arrays). Significant G×E was detected with all analyses, although there were some differences in the estimates of additive genetic correlation among locations from different analyses. This study demonstrates that dense SNP marker arrays may be used to predict breeding values for incompletely or unreplicated candidate cultivars established across multiple locations. This approach will be particularly valuable where the cost or logistics of replication at multiple locations is prohibitive and when pedigree records are incomplete and are not able to fully characterize the diversity of a candidate population.

Precocity and a long-term cropping in apple progenies grown on M 9 rootstock

The fruiting of 23 apple progenies, in total 756 genotypes grafted on M 9 rootstock, was evaluated for 11 years (2005-2015). The most precocious was the progeny obtained by the crossing of genotype HL1737 and Pink Lady cultivar, seedlings of which achieved fruiting stage just between the first and second year after planting. The least precocious was the progeny Freedom × Antonovka o.p., in which seedlings started fruiting on average just in the 5th and 6th year after planting. The most productive in the study was the progeny HL782 × Topaz, having a mean rating of 5.33 points on a 1-9 scale. Behind this leader, in decreasing order, were the progenies HL782 × HL665, Resista × Pink Lady, Resista × HL2219 and HL665 × HL782. The progenies Resista × Benet and Idleless × HL665 were distinguished with the highest level of biennial bearing (above 81%). The most valuable for utilisation in breeding is the progeny HL665 × HL782. Other noteworthy donors to be considered for distinctly more regular cropping are the cultivars Pink Lady, Discovery and HL2219.

Heritability of powdery mildew and scab resistance within apple progenies

Blažek J., Zelený L., Křelinova J. (2016): Heritability of powdery mildew and scab resistance within apple progenies. Plant Protect. Sci., 52: 123–127. The occurrence of both diseases was evaluated for four years in a selected orchard where 22 different apple progenies, totalling 699 seedlings were planted. During this period, no chemical protection against the diseases was applied in the orchard, and the incidence of the diseases was rated using a 9-point scale (from 9 = not infected to 1 = very highly infected). For the finalisation of the results, each seedling was characterised by the highest rate of infection from all four years of the evaluation. The lowest mean level of mildew infection equal to 7.47 was observed in the progeny of Resista × McIntosh Wijcik. Concerning the scab, the best was the progeny of Resista × Karmina having a rating equal to 8.27. The highest level of segregation of seedlings having joint resistance to both diseases was found out in the progenies obtained by crossings of HL665 × HL782 and Resista × HL447.

Heritability of flowering time within apple progeny

Blažek J., Paprstein F., Křelinova J. (2015): Heritability of flowering time within apple progeny. Czech J. Genet. Plant Breed., 51: 23–28. The flowering onset of 19 apple progeny was evaluated in 2005–2014 on a total number of 715 seedlings in comparison with their parents and grandparents. A very low flower set delays generally the onset of flowering by one day in comparison with a higher flower set. The maximum span between the first flowering onset and the last one within all the progeny of the study was 11 days. With one exception, the incidence of the first flowering dates of all the progeny fluctuated only within four days – April 28 and May 1. Among them, the great majority of the seedlings had the first flowering date span of not more than ± one day. The progeny of Pink Lady × Discovery was the most exceptional having the mean day on the April 17 and the span about two days longer. The means of the first flowering dates within seedling populations and corresponding dates of both their parents and grandparents were very highly correlated (r = 0.926 for parents and r = 0.877 for grandparents). The incidence of flowering onset dates in almost all progeny followed a typical Gaussian distribution, in which the majority of seedlings start flowering within 3 or 4 days. The maximum difference between both extremes (found only in one progeny) was 11 days. The share of seedlings in both extremes was, however, very small – less than 2%.

Preparatory work for the pest categorisation of three bacteria listed in the annexes of the Council directive 2000/29/EC Erwinia amylovora Winslow et al. Xylophilus ampelinus (Panagopoulos) Willems et al. Clavibacter michiganensis subsp. insidiosus(McCulloch) Davis et al

Preparatory work for the pest categorisation of three bacteria listed in the annexes of the Council directive 2000/29/EC Erwinia amylovora Winslow et al. Xylophilus ampelinus (Panagopoulos) Willems et al. Clavibacter michiganensis subsp. insidiosus(McCulloch) Davis et al

QTL analysis and candidate gene mapping for the polyphenol content in cider apple.

Polyphenols have favorable antioxidant potential on human health suggesting that their high content is responsible for the beneficial effects of apple consumption. They control the quality of ciders as they predominantly account for astringency, bitterness, color and aroma. In this study, we identified QTLs controlling phenolic compound concentrations and the average polymerization degree of flavanols in a cider apple progeny. Thirty-two compounds belonging to five groups of phenolic compounds were identified and quantified by reversed phase liquid chromatography on both fruit extract and juice, over three years. The average polymerization degree of flavanols was estimated in fruit by phloroglucinolysis coupled to HPLC. Parental maps were built using SSR and SNP markers and used for the QTL analysis. Sixty-nine and 72 QTLs were detected on 14 and 11 linkage groups of the female and male maps, respectively. A majority of the QTLs identified in this study are specific to this population, while others are consistent with previous studies. This study presents for the first time in apple, QTLs for the mean polymerization degree of procyanidins, for which the mechanisms involved remains unknown to this day. Identification of candidate genes underlying major QTLs was then performed in silico and permitted the identification of 18 enzymes of the polyphenol pathway and six transcription factors involved in the apple anthocyanin regulation. New markers were designed from sequences of the most interesting candidate genes in order to confirm their co-localization with underlying QTLs by genetic mapping. Finally, the potential use of these QTLs in breeding programs is discussed.

Polyphenol variability in the fruits and juices of a cider apple progeny

Polyphenols have a favourable antioxidant potential on human health, suggesting that their high content in apple is responsible for the beneficial effects of apple consumption. They are also linked to the quality of apple juices and ciders since they are predominantly responsible for astringency, bitterness and colour. Major phenolic compounds were quantified by liquid chromatography in fruits and juices from a cider apple progeny harvested for 3 years. The total content of procyanidins and their average degree of polymerisation (DPn) were also determined in fruits by phloroglucinolysis. Variability and extraction yield of these compounds were determined. The variability observed in the progeny was representative of the variability observed in many cider apple varieties. Hydroxycinnamic acids were the most extractable group, with an average extraction yield of 67%, whereas flavonols and anthocyanins were the least. This study is the first to introduce variability and extraction yields of the main phenolic compounds in both fruits and juices of a cider apple progeny. This dataset will be used for an upcoming QTL mapping study, an original approach that has never been undertaken for cider apple.

A Multidisciplinary Approach Providing New Insight into Fruit Flesh Browning Physiology in Apple (Malus x domestica Borkh.)

In terms of the quality of minimally processed fruit, flesh browning is fundamentally important in the development of an aesthetically unpleasant appearance, with consequent off-flavours. The development of browning depends on the enzymatic action of the polyphenol oxidase (PPO). In the ‘Golden Delicious’ apple genome ten PPO genes were initially identified and located on three main chromosomes (2, 5 and 10). Of these genes, one element in particular, here called Md-PPO, located on chromosome 10, was further investigated and genetically mapped in two apple progenies (‘Fuji x Pink Lady’ and ‘Golden Delicious x Braeburn’). Both linkage maps, made up of 481 and 608 markers respectively, were then employed to find QTL regions associated with fruit flesh browning, allowing the detection of 25 QTLs related to several browning parameters. These were distributed over six linkage groups with LOD values spanning from 3.08 to 4.99 and showed a rate of phenotypic variance from 26.1 to 38.6%. Anchoring of these intervals to the apple genome led to the identification of several genes involved in polyphenol synthesis and cell wall metabolism. Finally, the expression profile of two specific candidate genes, up and downstream of the polyphenolic pathway, namely phenylalanine ammonia lyase (PAL) and polyphenol oxidase (PPO), provided insight into flesh browning physiology. Md-PPO was further analyzed and two haplotypes were characterised and associated with fruit flesh browning in apple.

New insights for estimating the genetic value of segregating apple progenies for irregular bearing during the first years of tree production

Because irregular bearing generates major agronomic issues in fruit-tree species, particularly in apple, the selection of regular cultivars is desirable. Here, we aimed to define methods and descriptors allowing a diagnostic for bearing behaviour during the first years of tree maturity, when tree production is increasing. Flowering occurrences were collected at whole-tree and (annual) shoot scales on a segregating apple population. At both scales, the number of inflorescences over the years was modelled. Two descriptors were derived from model residuals: a new biennial bearing index, based on deviation around yield trend over years and an autoregressive coefficient, which represents dependency between consecutive yields. At the shoot scale, entropy was also considered to represent the within-tree flowering synchronicity. Clusters of genotypes with similar bearing behaviours were built. Both descriptors at the whole-tree and shoot scales were consistent for most genotypes and were used to discriminate regular from biennial and irregular genotypes. Quantitative trait loci were detected for the new biennial bearing index at both scales. Combining descriptors at a local scale with entropy showed that regular bearing at the tree scale may result from different strategies of synchronization in flowering at the local scale. The proposed methods and indices open an avenue to quantify bearing behaviour during the first years of tree maturity and to capture genetic variations. Their extension to other progenies and species, possible variants of descriptors, and their use in breeding programmes considering a limited number of years or fruit yields are discussed.

Study on inheritance of mildew resistance (Podosphaera leucotrica (Ell. Everh.) Salm. in progenies of apple varieties of different crown type

The dominant influence of gene additive effects in the determination of a mildew resistance character is revealed based on the genetic and statistical analysis of apple progenies from topcross crossings; moreover, this character and columnar growth habit are inherited in a progeny independently. Gene donors and cross combinations with high common and specific combination ability of mildew resistance are distinguished to be used in the breeding process.

Comparison of Two Methods, UHPLC-UV and UHPLC-MS/MS, for the Quantification of Polyphenols in Cider Apple Juices

The aim of this study was to develop faster and more efficient phenotyping methods for in-depth genetic studies on cider apple progeny. The UHPLC chromatographic system was chosen to separate polyphenolic compounds, and quantifications were then simultaneously performed with a UV-PDA detector and an ESI-triple quadrupole mass analyzer (SRM mode). Both quantification methods were validated for 15 major compounds using two apple juice samples, on the basis of linearity, limits of detection and quantification, recovery and precision tests. The comparison between UV and SRM quantifications in 120 different samples of a cider apple progeny showed an excellent correlation for major compounds quantified with both methods. However, an overestimation was revealed for five compounds with the UV detector and the mass analyzer. Co-elution and matrix effects are discussed to explain this phenomenon. SRM methods should therefore be considered with restrictions in some cases for quantification measurements when several phenolic compounds are simultaneously quantified in complex matrices such as apple juices. For both methods, analyses were carried out over short periods of time while maintaining a high quality for the simultaneous quantification of phenolic compounds in apple juice. Each method is relevant for more in-depth genetic studies of the polyphenol content of apple juice.

Molecular cloning and analysis of apple HcrVf resistance gene paralogs in a collection of related Malus species

Few complete genes belonging to the receptor-like protein class of plant resistance (R) genes (called HcrVf genes in Malus) have been cloned from apple cultivars. To date, the HcrVf2 gene from the Rvi6 locus of ‘Florina’, a derivative of Malus × floribunda 821, is the only cloned apple scab R gene with a proven function. The breakdown of the Rvi6 scab resistance in several apple growing regions has forced the search for new resistance sources for R gene pyramiding through traditional and biotechnological breeding. Marker-assisted breeding is aimed at the selection of the desired R gene combinations but might be extended for monitoring putative risks of resistance breakdown in potential scab R gene donors. Here we report on a marker-based screen of Rvi6 homologues supplemented by a polymerase chain reaction (PCR)-based full-length cloning of HcrVf paralogs. Known Rvi6 markers were analysed in a sub-set of accessions selected by a preceding SSR-based genetic relationship analysis from a large Malus species germplasm collection, which has been evaluated for scab resistance in an unsprayed orchard for a period of 3 years. The Rvi6 breakdown in several M. × floribunda accessions was confirmed, and several other Malus species putatively related to M. × floribunda were also infected by scab. The selected sub-cluster consisting of 40 accessions, including all M. × floribunda, two Malus × micromalus and two Malus baccata accessions, was screened for Rvi6 markers CH-Vf1-SSR and AL07-SCAR and for the presence of HcrVf2 by using gene-specific primers. The two M. × micromalus accessions, which proved to be identical genotypes, were found to be closely related to M. × floribunda. They also displayed the Rvi6 markers and could be infected by race (5,6,7) scab isolate Vi158. To verify the assumed existence of the HcrVf2 gene in M. × micromalus, a PCR-based cloning method was used to clone full-length HcrVf paralogs from this species and additionally from a scab-susceptible M. baccata genotype also showing the Rvi6 markers. The M. × micromalus gene MAM31 was identified as an identical copy of HcrVf2. Another HcrVf-like gene (MAM6) newly cloned from M. × micromalus showed 95 % similarity to HcrVf2. MAM6 was chosen for the development of a gene-specific PCR marker, which was analysed in the selected apple group and additionally mapped in an apple progeny derived from a cross with M. × micromalus. The cloning method described in this paper might be used in future to mine for more HcrVf gene variants to develop highly specific markers for R gene deployment in traditional breeding and to use cloned genes for gene transfer and functional studies.

Variability of cell wall polysaccharides composition and hemicellulose enzymatic profile in an apple progeny

The genetic variability of apple cell walls polysaccharides chemical composition and structure was assessed in a progeny of 141 individuals harvested over 2 years. The variability of the hemicelluloses oligosaccharides released by glucanase was analyzed by MALDI-TOF MS. The genetic contribution was distinguished from harvest year as well as from parental crossing patterns and scab resistance selection. Results showed that harvest year had a major impact on cell wall polysaccharide composition and structure. Within each harvest, genetic effect impact more significantly cell wall polysaccharide chemistry than does reciprocal crossing or early scab selection. Uronic acids, glucose, galactose and xylose contents as well as some glucomannan and xyloglucan structures have a high heritability. This first cell wall chemotyping of an apple progeny opens the way for future searches of genetic markers for the chemical variability of cell wall polysaccharides.