Lettuce variety 41-53 RZ

1. A lettuce plant designated 41-53 RZ, representative seed of which having been deposited under NCIMB Accession No. 41536, wherein said plant is a romaine lettuce ( Lactuca saliva L. var. longifolia Lam) plant, and has leaves with a solid main vein, narrow base leaves and resistance to downy mildew ( Bremia lactucae Regal), currant-lettuce aphid ( Nasonovia ribisnigri ) and lettuce mosaic virus (LMV).

2. A seed of the plant of claim 1 .

3. A part of the plant of claim 1 that is suitable for sexual reproduction.

4. The part as described in claim 3 , selected from the group consisting of microspores, pollen, ovaries, ovules, embryo sacs, and egg cells.

5. A part of the plant of claim 1 that is suitable for vegetative reproduction.

6. The part as described in claim 5 selected from the group consisting of cuttings, roots, stems, cells, and protoplasts.

7. A tissue culture of a lettuce plant of claim 1 .

8. The tissue culture as described in claim 7 , which is derived from the group consisting of leaves, pollen, embryos, cotyledon, hypocotyls, meristematic cells, roots, root tips, anthers, flowers, seeds and stems.

9. A plant that has all of the morphological and physiological characteristics of lettuce cultivar 41-53 RZ, representative seed of which having been deposited under NCIMB Accession No. 41536 and is grown from seeds as described in claim 2 .

10. A plant that has all of the morphological and physiological characteristics of lettuce cultivar 41-53 RZ, representative seed of which having been deposited under NCIMB Accession No. 41536 and is regenerated from parts as described in claim 3 .

11. A plant that has all of the morphological and physiological characteristics of lettuce cultivar 41-53 RZ, representative seed of which having been deposited under NCIMB Accession No. 41536 and is regenerated from a tissue culture as described in claim 7 .

12. A F1 progeny of a lettuce plant of claim 1 .

13. A F1 progeny of a lettuce plant of claim 9 .

14. A F1 progeny of a lettuce plant of claim 10 .

15. A F1 progeny of a lettuce plant of claim 11 .

16. A F1 progeny of a lettuce plant of claim 1 , wherein said plant is a romaine lettuce ( Lactuca saliva L. var. longifolia Lam) plant, and has leaves with a solid main vein, narrow base leaves and resistance to downy mildew ( Bremia lactucae Regal), currant-lettuce aphid ( Nasonovia ribisnigri ) and lettuce mosaic virus (LMV) as found in lettuce cultivar 41-53 RZ, representative seed of which having been deposited under NCIMB Accession No. 41536, and is modified in one or more other characteristics.

17. The progeny as described in claim 16 , wherein the modification is effected by mutagenesis.

18. The progeny as described in claim 16 , wherein the modification is effected by transformation with a transgene.

19. A method of producing a hybrid lettuce seed comprising crossing a first parent lettuce plant with a second parent lettuce plant and harvesting the resultant hybrid lettuce seed, wherein said first parent lettuce plant or said second parent lettuce plant is the lettuce plant of claim 1 .

20. A F1 progeny of a lettuce plant of claim 1 , wherein said progeny is produced by sexual reproduction of said lettuce plant, and wherein the progeny has all of the morphological and physiological characteristics of lettuce cultivar 41-53 RZ, representative seed of which having been deposited under NCIMB Accession No. 41536.

21. A progeny of a lettuce plant of claim 1 , wherein said progeny is produced by vegetative reproduction of said lettuce plant or a progeny plant thereof, and wherein the progeny has all of the morphological and physiological characteristics of lettuce cultivar 41-53 RZ, representative seed of which having been deposited under NCIMB Accession No. 41536.