Three Brachytic Dwarf Peach Cultivars: Valley Gem, Valley Red, and Valley Sun

Abstract

Abstract These are the first three cultivars to be released from a breeding program, initiated in 1976 at the Univ. of California, Davis (UCD), directed toward the elimination of ladder operations in the commercial production of shipping peaches and nectarines. The recessive dw allele of the Dw/dw gene is being employed to control tree size (4, 5). The recessive allele of this gene reduces internode length from the 1.8 + 0.31 cm found in standard trees to 0.77 ± 0.2 cm, thus compressing the canopy to about one-fifth that of standard cultivars. In addition to controlling tree size, this gene appears to facilitate precocious production and, at maturity, a near doubling of productivity over that of standard cultivars as they are normally grown in California; i.e., at a density of about 264 trees/ha (3). This high productivity appears to be due to these brachytic dwarfs generating about the same number of flowers, fruit, and leaves as standard trees, but on far less wood (3, 4). In our experience, the ripening of fruit on trees dwarfed by this gene is considerably more uniform than that borne on standard trees. We have not studied the basis of this phenomenon.