Cucurbita plant resistant to potyvirus

1. A method for introducing at least one genetic determinant which is capable of directing or controlling resistance to potyvirus into a squash plant lacking said genetic determinant, the method comprising:

a) obtaining a first squash plant comprising at least one genetic determinant which is capable of directing or controlling resistance to potyvirus;

b) crossing said first squash plant with a second squash plant, wherein said second squash plant lacks said genetic determinant; and

c) identifying a plant resulting from the cross exhibiting increased resistance to potyvirus and comprising at least one DNA marker co-segregating with said potyvirus resistance;

wherein

i. the genetic determinant is genetically linked to marker locus ZN, which co-segregates with the ZYMV potyvirus resistance trait and is identified in the genome of said plant in a PCR by amplification of a DNA fragment with the pair of oligonucleotide primers:

forward primer of SEQ ID NO: 1 and reverse primer of SEQ ID NO: 2 followed by detection with SEQ ID NO: 7 and/or SEQ ID NO: 8; and/or

ii. the genetic determinant is genetically linked to marker locus W1 and/or W2, which co-segregates with the MWMV potyvirus resistance trait and is identified in the genome of said plant in a PCR by amplification of a DNA fragment with the pair of oligonucleotide primers:

forward primer of SEQ ID NO: 3 and reverse primer of SEQ ID NO: 4 followed by detection with SEQ ID NO: 9 and/or SEQ ID NO: 10;

and/or forward primer of SEQ ID NO: 5 and reverse primer of SEQ ID NO: 6, followed by detection with SEQ ID NO: 11 and/or SEQ ID NO: 12; and/or

iii. the genetic determinant is genetically linked to marker locus Ni+, which co-segregates with the ZYMV potyvirus resistance trait and is identified in the genome of said plant in a PCR by amplification of a DNA fragment with the pair of oligonucleotide primers:

forward primer of SEQ ID NO: 13 and reverse primer of SEQ ID NO: 14 followed by detection with SEQ ID NO: 15 and/or SEQ ID NO: 16.

2. The method according to claim 1 , wherein the method further comprises isolating the plant of step c).

3. The method according to claim 1 , wherein the method further comprises back-crossing the plant of step c) with the first or second squash plant.

4. The method of claim 1 , wherein said at least one genetic determinant of said first squash plant is obtainable from the genome of Cucurbita moschata.

5. The method of claim 4 , wherein said at least one genetic determinant of said first squash plant is obtainable from the genome of C. moschata var. Nigeria.

6. A method for obtaining seed of a squash plant comprising at least one genetic determinant which is capable of directing or controlling resistance to potyvirus, the method comprising the steps of:

a) obtaining a first squash plant comprising at least one genetic determinant which is capable of directing or controlling resistance to potyvirus;

b) crossing said first squash plant with a second squash plant, wherein said second squash plant lacks said genetic determinant;

c) identifying a plant resulting from the cross exhibiting increased resistance to potyvirus and comprising at least one DNA marker co-segregating with said potyvirus resistance; and

d) harvesting a progeny seed from said cross comprising at least one DNA marker co-segregating with said potyvirus resistance;

wherein

i. the genetic determinant is genetically linked to marker locus ZN, which co-segregates with the ZYMV potyvirus resistance trait and is identified in the genome of said plant in a PCR by amplification of a DNA fragment with the pair of oligonucleotide primers:

forward primer of SEQ ID NO: 1 and reverse primer of SEQ ID NO: 2 followed by detection with SEQ ID NO: 7 and/or SEQ ID NO: 8; and/or

ii. the genetic determinant is genetically linked to marker locus W1 and/or W2, which co-segregates with the MWMV potyvirus resistance trait and is identified in the genome of said plant in a PCR by amplification of a DNA fragment with the pair of oligonucleotide primers:

forward primer of SEQ ID NO: 3 and reverse primer of SEQ ID NO: 4 followed by detection with SEQ ID NO: 9 and/or SEQ ID NO: 10;

and/or forward primer of SEQ ID NO: 5 and reverse primer of SEQ ID NO: 6 followed by detection with SEQ ID NO: 11 and/or SEQ ID NO: 12; and/or

iii. the genetic determinant is genetically linked to marker locus Ni+, which co-segregates with the ZYMV potyvirus resistance trait and is identified in the genome of said plant in a PCR by amplification of a DNA fragment with the pair of oligonucleotide primers:

forward primer of SEQ ID NO: 13 and reverse primer of SEQ ID NO: 14 followed by detection with SEQ ID NO: 15 and/or SEQ ID NO: 16.

7. The method of claim 6 , wherein said at least one genetic determinant of said first squash plant is obtainable from the genome of Cucurbita moschata.

8. The method of claim 7 , wherein said at least one genetic determinant of said first squash plant is obtainable from the genome of C. moschata var. Nigeria.

9. A method for producing a squash plant exhibiting resistance to potyvirus, the method comprising the steps of:

a) selecting a squash plant comprising at least one genetic determinant which is capable of directing or controlling resistance to potyvirus, wherein said genetic determinant is obtainable from the genome of C. pepo cv. 268NiW, representative seed of which is deposited at NCIMB under accession number NCIMB 41727, and is genetically linked to at least one marker locus, which co-segregates with resistance to potyvirus, and is identified in a PCR by at least one pair of PCR oligonucleotide primers comprising:

i. forward primer of SEQ ID NO: 1 and reverse primer of SEQ ID NO: 2 followed by detection with SEQ ID NO: 7 and/or SEQ ID NO: 8 if the marker locus is ZN; and/or

ii. forward primer of SEQ ID NO: 3 and reverse primer of SEQ ID NO: 4 followed by detection with SEQ ID NO: 9 and/or SEQ ID NO: 10 if the marker locus is W1; and/or

iii. forward primer of SEQ ID NO: 5 and reverse primer of SEQ ID NO: 6 followed by detection with SEQ ID NO: 11 and/or SEQ ID NO: 12 if the marker locus is W2; and/or

iv. forward primer of SEQ ID NO: 13 and a reverse primer of SEQ ID NO: 14 followed by detection with SEQ ID NO: 15 and/or SEQ ID NO: 16 if the marker locus is Ni+;

b) crossing said plant of step a) with a squash plant which is susceptible to potyvirus, or exhibits an intermediate level of resistance to at least one of said potyviruses; and

c) selecting a progeny from said cross which exhibits a resistance phenotype to potyvirus, and wherein said resistance phenotype(s) segregates with said at least one marker locus of step a).

10. The method according to claim 9 , wherein the plant selected in step a) comprises at least two genetic determinants which are capable of directing or controlling resistance to potyvirus; and the selected progeny in step c) exhibits a potyvirus resistance phenotype, and wherein said resistance phenotypes segregate with two marker loci of step a).

11. The method according to claim 9 , wherein the plant selected in step a) comprises at least three genetic determinants which are capable of directing or controlling resistance to potyvirus; and the selected progeny in step c) exhibits a resistance phenotype to potyvirus, and wherein said resistance phenotypes segregate with the marker loci of step a).

12. The method according to claim 9 , wherein the donor plant of step a) is a plant of the genome of Cucurbita moschata.

13. The method according to claim 12 , wherein the donor plant of step a) is a plant of the genome of C. moschata var. Nigeria.

14. The method according to claim 9 , wherein the donor plant of step a) is the Cucurbita pepo cv. 268NiW, representative seed of which is deposited at NCIMB under accession number NCIMB 41727.

15. The method according to claim 9 , the method comprising an additional step d) of backcrossing the virus resistant plant obtained in step c) with the susceptible squash plant, or intermediate resistant squash plant, of step b).

16. A method for producing a hybrid seed of a squash plant resistant to potyvirus, the method comprising:

a) planting a male-sterile female squash plant and a male-fertile squash plant, wherein one of said male-sterile female squash plant or male fertile squash plant is a squash plant comprising at least one genetic determinant which is capable of directing or controlling resistance to potyvirus, wherein said genetic determinant is obtainable from the genome of C. pepo cv. 268NiW, representative seed of which is deposited at NCIMB under accession number NCIMB 41727, and is genetically linked to at least one marker locus, which co-segregates with resistance to potyvirus, and can be identified in a PCR by at least one pair of PCR oligonucleotide primers comprising:

i. Forward primer of SEQ ID NO: 1 and reverse primer of SEQ ID NO: 2 followed by detection with SEQ ID NO: 7 and/or SEQ ID NO: 8; and/or

ii. Forward primer of SEQ ID NO: 3 and reverse primer of SEQ ID NO: 4 followed by detection with SEQ ID NO: 9 and/or SEQ ID NO: 10; and/or

iii. Forward primer of SEQ ID NO: 5 and reverse primer of SEQ ID NO: 6 followed by detection with SEQ ID NO: 11 and/or SEQ ID NO: 12; and/or

iv. Forward primer of SEQ ID NO: 13 and a reverse primer of SEQ ID NO: 14 followed by detection with SEQ ID NO: 15 and/or SEQ ID NO: 16;

b) effecting cross pollination between both lines;

c) growing the plant till fruit setting;

d) collecting a fruit; and

e) obtaining a hybrid seed.

17. A method for obtaining a potyvirus resistant squash plant, the method comprising:

a) obtaining a squash plant comprising at least one genetic determinant which is capable of directing or controlling resistance to potyvirus, wherein said genetic determinant is obtainable from the genome of C. pepo cv. 268NiW, representative seed of which is deposited at NCIMB under accession number NCIMB 41727, and is genetically linked to at least one marker locus, which co-segregates with resistance to potyvirus, and is identified in a PCR by at least one pair of PCR oligonucleotide primers comprising:

i. forward primer of SEQ ID NO: 1 and reverse primer of SEQ ID NO: 2 followed by detection with SEQ ID NO: 7 and/or SEQ ID NO: 8; and/or

ii. forward primer of SEQ ID NO: 3 and reverse primer of SEQ ID NO: 4 followed by detection with SEQ ID NO: 9 and/or SEQ ID NO: 10; and/or

iii. forward primer of SEQ ID NO: 5 and reverse primer of SEQ ID NO: 6 followed by detection with SEQ ID NO: 11 and/or SEQ ID NO: 12; and/or

iv. forward primer of SEQ ID NO: 13 and a reverse primer of SEQ ID NO: 14 followed by detection with SEQ ID NO: 15 and/or SEQ ID NO: 16;

b) crossing said plant with a potyvirus susceptible squash plant or an intermediate resistant squash plant;

c) rescuing an embryo resulting from the cross of step b);

d) regenerating a plant from said embryo of step c); and

e) selecting a squash plant of step d) that is resistant to potyvirus.

18. A method for obtaining a squash fruit resistant to potyvirus, the method comprising:

a) sowing a seed of a squash plant comprising at least one genetic determinant which is capable of directing or controlling resistance to potyvirus, wherein said genetic determinant is obtainable from the genome of C. pepo cv. 268NiW, representative seed of which is deposited at NCIMB under accession number NCIMB 41727, and is genetically linked to at least one marker locus, which co-segregates with resistance to potyvirus, and is identified in a PCR by at least one pair of PCR oligonucleotide primers comprising:

i. forward primer of SEQ ID NO: 1 and reverse primer of SEQ ID NO: 2 followed by detection with SEQ ID NO: 7 and/or SEQ ID NO: 8; and/or

ii. forward primer of SEQ ID NO: 3 and reverse primer of SEQ ID NO: 4 followed by detection with SEQ ID NO: 9 and/or SEQ ID NO: 10; and/or

iii. forward primer of SEQ ID NO: 5 and reverse primer of SEQ ID NO: 6 followed by detection with SEQ ID NO: 11 and/or SEQ ID NO: 12; and/or

iv. forward primer of SEQ ID NO: 13 and a reverse primer of SEQ ID NO: 14 followed by detection with SEQ ID NO: 15 and/or SEQ ID NO: 16; and

b) growing said plant in order to produce a fruit and harvesting the fruit produced by said plant.