บทคัดย่องานวิจัย

หมวดหมู่ : ฐานข้อมูลงานวิจัย

The use of molecular genetics to improve peach and nectarine post-storage quality.

Peach C.P., Crisosto C.H., Dandekar A.M., Gradziel T.M.

5th International Postharvest Symposium . Volume of Abstract . Verona, Italy 6-11 June 2004, p.65

2004

บทคัดย่อ

The use of molecular genetics to improve peach and nectarine post-storage quality. Internal breakdown (IB), also known as chilling injury, is the collective term for various disorders that occur during prolonged cold storage and/or after subsequent ripening of stone fruit.Symptoms include meliness, flesh browning, loss of flavour, and red pigmentation (bleeding).The symptoms are usually not noticed until fruit reaches consumers, and therefore affects consumer consumption.Certain pectin-degrading enzymes appear to play a role in the development of mealiness.

To date, our program had evaluated approximately 133 peach and nectarine varieties for their susceptibility to IB.Some cultivars tend to be more susceptible than others, indicating that the trait has a genetic component.However, the genetic mechanisms by which low susceptibility genotypes avoid IB symptoms are not clear.Using two related and genetically variable populations of peach, we have undertaken a classical and molecular genetics approach to gain a better understanding of the genetic control of IB and lay the foundation for marker-assisted selection (MAS) for these traits.A partial genetic linkage map was constructed, based o­n random SSR and RAF markers, candidate gene markers, candidate gene markers, and gene-targeted SRAP markers.Segregating morphological markers were also mapped, including the Freestone (F), Melting flesh (M), and Flesh colour (Y) loci.QTL analysis was performed o­n the linkage groups, using phenotypic data collected for three seasons.QTLs for flesh mealiness, brownin, and bleeding were located.

Candidate gene analysis identified that a gene encoding the cell wall degrading enzyme, endopolygalacturonase, pleiotropically controls the F and M loci.A large genetic effect o­n mealiness was detected for this locus, reflecting the observation that mealiness occurred o­nly in some frestone meealiness occurred o­nly in some freestone melting flesh progeny and was entirely absent in clingstone non-melting flesh progeny.The use of MAS in breeding for low susceptibility to internal breadsown symptoms appears to be an achievable goal for peach.