Amy Iezzoni, Project Director, Michigan State University
Maturity date differences among fresh market sweet cherry cultivars allow growers to choose cultivars that will allow them to capitalize on high prices at the start or end of the fresh market season. Having a range of maturity dates also benefits consumers seeking a continuous summer supply of sweet cherries. Sweet cherry breeders target specific maturitydates to fill gaps where only less desirable cultivars are available.
Having genetic knowledge of what crosses will yield a higher proportion of seedlings predicted to be in target maturity date classes would help breeders more efficiently reach their maturity date goals. In peach, an important locus was identified on peach chromosome 4 (Dirlewanger et al., 2012; http://bit.ly/1xnSvqp). In sweet cherry, a maturity date locus was also identified in the same genomic position. This locus is heterozygous in ‘Lapins’ and was identified based on segregation in the cross ‘Regina’ × ‘Lapins’, where it explained ~20% of the phenotypic variation. Alleles for this locus uncovered in other sweet cherry cultivars also contribute to maturity date variation, such as the very early ripening of ‘Cristobalina’ and ‘Early Burlat’, and the late ripening of ‘Sweetheart’ (P. Sandefur and C. Peace, pers. comm.).
With genetic knowledge of which cherry seedlings will ripen at specific maturity times, breeders can plan crosses to maximize the probability of obtaining candidate cultivars that mature at the desired time of the season. Such an approach helps redirect resources to other critically important consumer-related traits. Therefore, because knowledge of this genetic region will lead to the more efficient breeding of sweet cherry cultivars, it is chosen as one of RosBREED’s “Jewels in the Genome.”
Dirlewanger E, Quero-Garcia J, Le Dantec L, Lambert P, Ruiz D, Dondini L, Illa E, Quilot-Turion B. 2012. Comparison of the genetic determinism of two key phenological traits, flowering and maturity dates in three Prunus species: peach, apricot and sweet cherry. Heredity 109: 280-292.