Evaluation of the Carbohydrate Composition of Crabapple Fruit Tissues Native to Northern Asia

A comprehensive comparative analysis of the carbohydrate composition (soluble sugars and pectins) of fruit tissues of Malus baccata, Malus mandshurica, Malus chamardabanica, and Malus sachalinensis, characteristic of the vast territory of Eastern Siberia and the Far East, was carried out. It was shown that a large part of the soluble carbohydrates of the studied species were represented by transport sugars-sorbitol and sucrose. These compounds also provided the main variability in the carbohydrate composition of fruits in the studied material. The polymers pectins and protopectins isolated from the studied fruits were highly methoxylated (up to 60-70%), and their content averaged about 6% of dry weight. The greatest length of pectin polymers was found in the fruit tissues of M. chamardabanica and M. sachalinensis. Data on elemental analysis of fractions of pectins and protopectins of all studied species showed the absence of potentially toxic concentrations of heavy metals. Of note is the rather high content of calcium in both polymer fractions of the four studied species, while its content in protopectin is significantly higher. In addition, in all cases, the presence of low-molecular-weight oligosaccharide molecules with a low-dispersed linear structure was revealed in the tissues of the fruits. It is worth noting that the high content of ascorbic acid was observed in the fruits of all studied species. In addition to being of fundamental interest, information about the carbohydrate composition of the wild Malus species can be useful for apple breeding when choosing sources of genes underlying useful traits

Comparison between IAD and other maturity indices in nine commercially grown apple cultivars

To maintain storage potential as long as possible, it is important to harvest fruit at optimal maturity. Different maturity indices have been developed, including flesh firmness, soluble solids content, starch degradation, ethylene production, and respiration rate. However, many of them are destructive, time consuming, and may be require some laboratory equipment to perform. The portable device DA-meter (measuring index of absorption difference; IAD) can monitor the chlorophyll decline non-destructively in the field, and could potentially save time. To evaluate the IAD in comparison with other maturity indices, nine common commercial cultivars of apple were investigated in a three-year trial. Correlations between IAD and other maturity indices, especially starch degradation and ripening index by Streif were strong in most cultivars, though variation between years lead to weaker correlations were found last year of the trial. The strongest correlations were found between IAD and harvest date showing that IAD decreased with time in all investigated cultivars. Comparison between IAD and ripening index by Streif showed in some cases that the two indices decreased at the same time, suggesting that IAD could be used to monitor maturity when it is rapid. The suitability to use IAD as a maturity index seems to be cultivar-dependent. For cultivars having a more consistent pattern between years in the decrease of IAD, combined with relatively low variation in IAD at any given time, it could be a good complement to other commonly used maturity indices

Omenanviljelyyn kestävyyttä paikallislajikkeista

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Transformation and gene-disruption in the apple-pathogen, Neonectria ditissima

Background Apple production in Sweden and elsewhere is being threatened by the fungus, Neonectria ditissima, which causes a disease known as European canker. The disease can cause extensive damage and the removal of diseased wood and heavily infected trees can be laborious and expensive. Currently, there is no way to eradicate the fungus from infected trees and our knowledge of the infection process is limited. Thus, to target and modify genes efficiently, the genetic transformation technique developed for N. ditissima back in 2003 was modified. Results The original protocol from 2003 was upgraded to use enzymes currently available in the market for making protoplasts. The protoplasts were viable, able to uptake foreign DNA, and able to regenerate back into a mycelial colony, either as targeted gene-disruption mutants or as ectopic mutants expressing the green fluorescent protein (GFP). Conclusions A new genetic transformation protocol has been established and the inclusion of hydroxyurea in the buffer during the protoplast-generation step greatly increased the creation of knockout mutants via homologous recombination. Pathogenicity assays using the GFP-mutants showed that the mutants were able to infect the host and cause disease

Släktforskning bland svenska äppelsorter – ny teknik avslöjar gamla släktband

Äppelodling har en lång historia i Sverige. Genom århundradena har det uppstått en rik flora av sorter runt om i landet, vissa mer framgångsrika än andra. I början av 1900-talet påbörjades försöksverksamhet med frukt i Alnarp, ett arbete som även resulterade i några nya sorter. Senare följde ett renodlat växtförädlingsprogram på Balsgård, som släppte sin första sort ’Alice’ 1963. Men det är först nu som vi med tillgång till moderna genetiska markörer på allvar har kunnat påbörja släktforskningen bland gamla såväl som moderna äppelsorter

Parametric mapping of QTL for resistance to European canker in apple in 'Aroma' x 'Discovery'

Resistance to European canker (Neonectria ditissima) in apple is currently one of the most important breeding targets for commercial production in Sweden. Previous research has identified significant genetic variation in susceptibility to the disease, with the local Swedish cultivar 'Aroma' considered as one of the most resistant cultivars. Identification of genetic regions underlying the resistance of this cultivar would be a valuable tool for future breeding. Thus, we performed Bayesian quantitative trait loci (QTL) mapping for resistance to European canker in a full-sib family of 'Aroma' x 'Discovery'. Mapping was performed with the area under the disease progression curves (AUDPCs) from all seven (AUDPC_All7) and the first four assessments (AUDPC_First4), and three parameters of a sigmoid growth model for lesion length. As a scale for the effect of the different parameters, historic phenotypic data from screenings of a genetically diverse germplasm was compiled and re-analyzed. The parametrization of the data on lesion growth increased the number of QTL that could be identified with high statistical power, and provided some insight into their roles during different stages of disease development in the current experimental setup. Five QTL regions with strong or decisive evidence were identified on linkage groups 1, 8, 15, and 16. The QTL regions could be assigned to either of the parameters lesion length at the first assessment ('LL_A1'), the maximal lesion growth rate (lesion length doubling time, 't_gen'), and the lesion length at girdling ('LL_G'). Three of these QTL were traced along the pedigrees of some known relatives of the FS family, and discussed in relation to future crosses for breeding and genetic research

Evaluation of microsatellite-based genetic diversity, protein and mineral content in chickpea accessions grown in Kyrgyzstan

The genetic diversity of 23 chickpea accessions representing Kyrgyz landraces and cultivars, ICARDA breeding lines, Spanish and Turkish cultivars was characterized using nine microsatellite (SSR) markers which generated a total of 122 alleles. The number of alleles (Na) per locus varied from 9 to 20. The observed heterozygosity (Ho) ranged between 0.05 and 0.43 (average 0.13) whereas both the expected heterozygosity (He) and polymorphic information content (PIC) ranged from 0.71 to 0.90 (average 0.83). Analysis of molecular variance (AMOVA) showed that 62% of the total genetic variation was found within accessions while the remaining 38% was found among accessions. Principal coordinate analysis (PCoA) indicated the presence of two groups. The two Kyrgyz cultivars were found apart from these groups. Cluster analysis generally confirmed the results of PCoA and also separated the Kyrgyz cultivars from the subcluster formed by Kyrgyz landraces and the subclusters formed by breeding lines from ICARDA along with landraces from Turkey and Spain. In addition, protein content and mineral concentration were determined. Protein content and mineral concentrations for Ca, S, Mg, P, K, Fe, Mn, Cu and Zn varied significantly among accessions. The results show that Kyrgyz germplasm provides a source of diversity for improvement of chickpea

Stem Rust Resistance in 1BL.1RS and 2RL.2BS Double Wheat-Rye Translocation Lines

The wheat stem rust pathogen, Puccinia graminis f.sp. tritici, is a significant and devastating disease of wheat crops worldwide. Wheat has many wild relatives in which to source new resistance genes, including the cereal crop of rye in the tertiary genepool. The aim of this study was to assess the reaction of 1BL.1RS and 2RL.2BS double wheat-rye translocation lines to virulent stem rust races from Africa and North America. BC1F3 and BC1F4 populations from a cross between the line KR99-139 (a double wheat-rye translocation line with 1BL.1RS and 2RL.2BS) and the bread wheat cultivar Topper were used in the study. Several of the populations homozygous for 1BL.1RS and heterozygous for 2RL.2BS showed resistance and low severity adult plant resistance (20RMR-50MSS) to the African stem rust race TTKSK in the field. None of the tested populations with varying chromosome combinations showed seedling resistance to any of the tested stem rust races. Thus, these resistant populations likely carry gene/s effective at the adult plant stage since all stage resistance genes with major effect appear to be absent based on the seedling assays. Resistant lines combined three chromosomes (1RS, 2RS and 2BS) which make their direct use in breeding more complicated. Mapping studies followed by potential transfer of genes between 2R and 2B will make the identified minor genes more useful in wheat breeding

Genetic diversity in gooseberry (Ribes uva-crispa), as estimated with SSR markers

European gooseberry (Ribes uva-crispa L.) is a popular berry crop in many European countries, including Sweden, Denmark and Ukraine. There is no active gooseberry breeding programme in either Sweden or Denmark, but a successful programme is operating in Ukraine. In Sweden and Denmark, research on gooseberries is primarily focused on collection and phenotypic evaluation of genetic resources. As part of these activities, a large number of inventory finds have been collected but have not yet been characterised morphologically or molecularly. The goal of this study was thus to characterise gooseberry germplasm with 15 simple sequence repeat (SSR) markers. From 242 accessions analysed, 153 unique genotypes were identified. Cultivars that have been in widespread cultivation in Sweden, such as the Finnish cultivars 'Hinnonma & BULL;en Keltainen' and 'Hinnonma & BULL;en Punainen', had relatively large numbers of synonymous samples. While many inventory finds were identifiable as synonyms of known cultivars, several were found to constitute unique genotypes within the germplasm studied. The studied genotypes clustered relatively well in three posterior groups, consisting of cultivars originating before and after the American gooseberry mildew (Sphaerotheca mors-uvae) outbreak around 1900 and cultivars originating from the territory of the former Soviet Union. A fourth genetic cluster consisting mainly of inventory finds from central and northern Sweden was also identified. In addition, it was possible to verify recorded and stipulated parentages for some of the cultivars studied and to identify three likely parent-parent-child trios. Thus, inventories of local gooseberry germplasm and a subsequent genotyping proved successful in finding unique local genotypes, with potential local adaptation. The data obtained provide a foundation for future studies of gooseberry genetic re-sources, while also illustrating the importance of a well-curated and phenotypically characterised set of reference cultivars for future studies