Breeding for Red Flesh Colour in Apple: Progress and Challenges

Abstract Novel fruit trait introgression is an important part of the HortResearch apple-breeding programme in developing new varieties with high consumer appeal, and red flesh apple breeding is a major component of this objective. Active red flesh breeding began in HortResearch in 1998 by crossing low quality red-fleshed accessions with high quality cultivars and advanced selections that have white flesh. The red-fleshed accessions were mainly grown from open-pollinated seed that were derived from old cultivars and imported into New Zealand in the early 1990s. To date, approximately 10,000 seedlings have been produced in the F 1 populations. Modified BC 1 populations have recently been developed using the best red-fleshed seedlings from highly performing F 1 families. Two distinct red flesh phenotypes, putatively named Type 1 and Type 2, which appear to be controlled by different genetic mechanisms, have been identified in accessions and segregating families. Progress to date in improving fruit quality in red-fleshed apples and towards an understanding of the inheritance of the red flesh character, through the use of phenotypic segregations and molecular markers, is discussed. INTRODUCTION