We briefly review the limited application of marker assisted selection in past wheat breeding programmes, and contrast the current situation, where increasingly it has become feasible to tag almost any gene with a microsatellite assay. Although this capability is having an impact on the conduct of large breeding programmes, a much more profound change in breeding strategy will become possible when SNP technology has matured sufficiently so that the throughput of molecular marker-based genotyping will be able to keep pace with the numbers of plants that breeders can handle in the field. We discuss the considerations that will need to be addressed in the generation of a new breeding paradigm to take advantage of the genomics revolution.
Molecular markers have become a useful tool simplifying and speeding up breeding work. They are also helpful in the genetic analysis of complex agronomic traits. The investigations concern the use of already available SCAR markers for molecular analysis of breeding materials. The markers are the apple powdery mildew resistance gene Pl2, originating from Malus zumi, and the apple scab resistance gene Vf, from M. floribunda 821. The clone U 211 was found to be highly resistant to mildew under field conditions and transmitted a high level of resistance to the majority of its progeny. The presence of the Vf gene conferring resistance to scab was confirmed by molecular analysis. As the molecular markers for the Pl2 gene are not present in the DNA of U 211, it is probable that the clone U 211 is a new source of mildew resistance.
Great advances have been made in recent years in marker detection systems and in the techniques used to identify markers linked to useful traits. While RFLP markers have been the basis for most work in crop plants, useful markers have been generated using RAPD and AFLP methods. More recently, microsatellite or simple sequence repeat (SSR) markers have been developed for major crop plants and this marker system is predicted to lead to even more rapid advances in both marker development and implementation in breeding programs. Identification of markers linked to useful traits has been based on complete linkage maps and bulked segregant analysis. However, alternative methods, such as the construction of partial maps and combination of pedigree and marker information, have also proved useful in identifying marker/trait associations. The value of markers in analysing the inheritance of traits in crop plants and understanding genome structure and organization is now well established. The different properties of markers systems and their applications in genome analysis and molecular breeding of cereals species are discussed.
Honeyberry’s popularity has been increasing because of its valuable traits: nutritional value of fruits (a high amount of ascorbic acid, potassium and polyphenolic compounds), early ripening (14 days before strawberry), exceptional hardiness and easy cultivation. However, there is still little known about the pollination biology of this species, which is essential for practical breeding purposes. In this study we evaluated pollen fertility in five cultivars and three breeding clones of this species. The impact of the manner of pollination on the fruit set and forming seeds has also been studied. The highest percentage of viable pollen was found in cultivars ‘Duet’ and ‘Wojtek’ (96%), whereas the pollen of ‘Chelyabinka’ cultivar had the lowest fertility (90%). The percentage of blue honeysuckle fruits obtained from open-pollinated flowers was high (on average 94.7%) compared to isolated flowers (on average 8.6%). The effect of cross-pollination with cv. ‘Duet’ indicates that the percentage of the fruit set, fruit weight and mass of produced seeds was higher when this cultivar was applied as maternal than paternal form. The number of seeds affected significantly the weight of the fruit in the case when cv. ’Duet’ was used as a paternal (correlation coefficient r = 0.45) or maternal form (r = 0.66), while for other methods of pollination this effect was insignificant. These results may be used to the most efficient establishment of plantations as well as for the realization of the breeding program of this valuable species.
This paper reports the construction a map based on Amplified Fragment Length Polymorphic DNA (AFLP) in Scots pine (Pinus sylvestris L.). The main purpose of map construction was its application to quantitative traits loci (QTL) mapping for breeding traits economically important in Scots pine breeding program such as tree height and diameter at breast height, number of needles and their length, width, and area. Genomic DNA of needles and haploid megagamethophytes from seeds originating from a single tree were amplified with 25 AFLP primer-enzyme combinations with three or four selective nucleotides. Sixteen of them generated easily readable patterns and revealed a polymorphism. Each analyzed marker was tested for the expected 1 : 1 segregation ratio using χ2 – test and only 6 were significant with (α ≤ 0.05). The total map size equaled 291,7 cM and all markers were distributed within one linkage group. For all traits only one QTL associated with tree height (H) was detected.
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