Closterovirus-resistant melon plants

1. A Cucurbit Yellow Stunting Disorder Virus (CYSDV)-resistant plant of the species Cucumis melo , said plant comprising a homozygous genetic element from a plant of melon accession PI 313970, which genetic element comprises a CYSDV-resistance-conferring QTL located on a chromosome equivalent to linkage group (LG) 6 of melon accession PI 313970, that stretches from position 25.5 cM to 29.1 cM between AFLP markers E11/M54-156 and E11/M57-278, wherein said QTL is indicated by the presence of at least two AFLP markers linked to said QTL selected from the group consisting of markers E11/M54-156, E14/M54-152, E14/M51-210, E11/M49-239, and E11/M54-169, and the absence of at least one AFLP marker selected from the group consisting of markers E14/M50-262, E14/M51-083, and E11/M49-072, wherein said plant is not melon accession PI 313970.

2. The plant according to claim 1 , wherein said plant of the species Cucumis melo is a melon cultivar or a plant of the group consisting of botanical varieties Cucumis melo var. cantalupensis, Cucumis melo var. reticulatis and Cucumis melo var. inodorus.

3. The plant according to claim 1 , wherein said genetic element is an introgression.

4. The plant according to claim 1 , wherein said plant is a CYSDV-resistant melon cultivar.

5. The plant according to claim 1 , wherein said plant is an inbred plant or hybrid plant.

6. A part of a plant as defined in claim 1 .

7. The plant part according to claim 6 , wherein said plant is an inbred plant or hybrid plant and said plant part is a seed or fruit.

8. A method of producing a CYSDV-resistant melon plant comprising the step of transferring a nucleic acid comprising the CYSDV-resistance-conferring QTL on melon linkage group 6 (LG6) located between markers E11/M54-156 and E11/M57-278, or a CYSDV-resistance-conferring part thereof comprising at least one CYSDV-resistance conferring gene, from a CYSDV-resistant donor melon plant of melon accession PI 313970, or a CYSDV-resistant derivative thereof to a CYSDV-susceptible recipient melon plant, wherein said transfer of said nucleic acid is performed by transformation, by protoplast fusion, by a doubled haploid technique or by embryo rescue.

9. A method of producing a CYSDV-resistant melon plant, said method comprising the steps of:

a) introgressing a nucleic acid comprising the CYSDV-resistance-conferring QTL on melon linkage group 6 (LG6) located between markers E11/M54-156 and E11/M57-278, or a CYSDV-resistance-conferring part thereof comprising at least one CYSDV-resistance conferring gene, from a CYSDV-resistant plant of melon accession PI 313970, or a CYSDV-resistant derivative thereof, to a CYSDV-susceptible recipient melon plant; and

b) determining the presence of said CYSDV-resistance-conferring QTL in the genome of at least one progeny plant by detecting the presence in the DNA of said at least one progeny plants of at least one AFLP marker indicating said QTL wherein said marker is selected from the group formed by E11/M54-156, E14/M54-152, E14/M51-210, E11/M49-239, E11/M54-169, E11/M57-278, and E11/M54-163, and by detecting the absence in the DNA of said at least one progeny plants of at least one AFLP marker selected from the group consisting of E14/M51-083, E14/M50-262, and E11/M49-072.

10. The method according to claim 9 , wherein said step a) comprises the steps of:

crossing a CYSDV-resistant plant of melon accession PI 313970, or a CYSDV-resistant derivative thereof, with a CYSDV-susceptible melon plant;

harvesting seed from said cross;

growing said seed to produce F1 progeny plants;

selfing or backcrossing said F1 progeny plants with the donor or recipient parent to produce F2 seeds, and

growing said F2 seeds to produce F2 progeny plants.

11. The method according to claim 10 , wherein the detection of said molecular marker linked to said QTL is performed in an F2 progeny plant.

12. The method according to claim 9 , wherein said CYSDV-susceptible recipient melon plant is a plant selected from the group consisting of botanical varieties Cucumis melo var. cantalupensis, Cucumis melo var. reticulatis and Cucumis melo var. inodorus.

13. The method according to claim 8 , further comprising selecting from among the offspring plants a plant that comprises in its genome said at least one QTL, or CYSDV-resistance-conferring part thereof.

14. The method according to claim 13 , wherein said selection comprises the marker-assisted selection with a marker linked to said QTL.

15. A CYSDV-resistant melon plant, or part thereof, obtainable by a method according to claim 8 , wherein the plant or part thereof comprises the CYSDV-resistance-conferring QTL, wherein said QTL is indicated by the presence of at least two AFLP markers linked to said QTL selected from the group consisting of markers E11/M54-156, E14/M54-152, E14/M51-210, E11/M49-239, and E11/M54-169, and the absence of at least one AFLP marker selected from the group consisting of markers E14/M50-262, E14/M51-083, and E11/M49-072, wherein said plant is not melon accession PI 313970.

16. A hybrid melon plant, or part thereof, obtainable by crossing a melon plant according to claim 1 with a melon plant that exhibits commercially desirable characteristics.

17. A melon seed produced by growing the melon plant according to claim 1 .

18. A method of detecting a CYSDV-resistant melon plant comprising detecting presence of at least one marker selected from the group consisting of markers E11/M54-156, E14/M54-152, E14/M51-210, E11/M49-239, E11/M54-169, E11/M57-278, and E11/M54-163, and detecting absence of at least one marker selected from the group consisting of E14/M50-262, E14/M51-083, and E11/M49-072 in the DNA of the plant.

19. The plant of claim 1 , wherein the plant is of the species Cucumis melo subspecies melo.

20. The CYSDV-resistant melon plant, or part thereof of claim 15 , wherein the CYSDV-resistant melon plant is of the species Cucumis melo subspecies melo.