Genetic analysis of five presumptive isozyme loci in apricot (Prunus armeniaca L. and related species) revealed that the variation observed was controlled by two or three alleles in a simple Mendelian manner. This increases the number of known simply inherited traits in apricot from one to six. Linkage was not detected between MDH-1 and MDH-2.
I would like to clarify the difference between two words that are frequently misused in our publications. I suppose the words “pollenizer” and “pollinator” have been confused since their invention, given their consistent misuse in at least one major pomology text (Tree Fruit Production by Tesky and Shoemaker). A pollinator is the agent of pollen transfer, which, in many species, are bees or some other insects; a pollenizer is the source of pollen, which is usually a flowerproducing plant. One recent paper talks of “planting of pollinators”, which brings up visions of planting bees in the orchard, and of “pollinator frequencies”, which indicates the author is referring to bee hive density, when the author was really referring to the density of trees as pollen sources. Another author was describing parentage of some tree fruits and said that cultivar A “was the progeny of unrelated unknown pollinators of” cultivar B. How fruit trees can be the progeny of fruit insects is beyond me! Of course, the authors meant to use the word “pollenizer”, not “pollinator”. Similar mistakes have been made throughout the literature equally by professionals in a range of disciplines.
Despite the hundreds of existing stone fruit (Prunus spp.) cultivars used for fresh market, there is a continuing need to develop new stone fruit cultivars as the requirements of the industry change. Over the last 20 years there has been a shift toward private breeding as the public sector decreases its support of these long-range programs. As a result there are fewer public breeding programs and many of those still operating protect their releases and partially fund their programs with royalty payments. Other trends that are shaping the development of new stone fruit cultivars are a need for smaller or more easily managed tree architecture, a trend toward the use of fewer agricultural chemicals, the expansion of production zones into the milder winter zones to allow year-round availability of stone fruit, a general diversification of fruit types being marketed, the increased awareness of the health benefits of fruit consumption, the need for better and more consistent quality, and given the global marketing of these fruit the increased need for enhanced postharvest qualities. The breeding programs of the world are responding to these trends and working toward developing the cultivars for the world markets of the future.
The mean inbreeding and coancestry coefficients of Japanese-type plums grown in California and the southeastern United States were one-half or less of those calculated for peach. The three most important founding clones for the major California cultivars were ‘Santa Rosa’, ‘Eldorado’, and ‘Gaviota’; for the plums of the southeastern United States they were ‘Methley’, ‘Santa Rosa’, and ‘Mariposa’. The species background of both groups of plums was ≈50% P. salicina, although the sources of P. salicina differed between groups. For the California cultivars, the other half was composed of P. simonii and P. americana, whereas, for the southeastern group, the major contributing species was P. cerasifera, with lesser contributions from P. simonii, P. americana, P. angustifolia, and P. munsoniana.
The hybrid origin of 23 rose (Rosa spp.) accessions was examined with three isozymes: acid phosphatase (E.C.22.214.171.124), malate dehydrogenase (E.C.126.96.36.199), and phosphoglucose isomerase (E.C.188.8.131.52). All three isozymes were useful for interspecific hybrid verification. This procedure was effective if the putative parents were known and differed in isozyme phenotype. To verify the origin of hybrid species or cultivars with hybrid origins, isozymes were useful but limited by the number of generations since the original hybridization and the number of accessions of the putative parental species assayed.