Pollen selection \u2014 past, present and future

A series of studies, recently reviewed, has established that approximately 60% of the structural genes which are expressed in the sporophytic portion of the angiosperm life cycle are also expressed and exposed to selection in the pollen. Given the haploidy and large population sizes of pollen grains, a substantial portion of the sporophytic genome could thus be periodically exposed to a bacterial type of mass screening. This extraordinary possibility is often subject to some skepticism which may, of course, be justified. However, recent attempts to apply models appear to be inappropriate in this context, in part because these attempts overlook an important source of genetic variation, and also because they assume fixed values for selection and fitness. More recently, studies of pollen/pollen interactions have suggested that what Linskens termed the \u201cprogramic phase\u201d may represent an arena for important, and largely unexplored phenomena, some of which are discussed here

The use of random amplified polymorphic DNAs to fingerprint apple genotypes

Twenty-five accessions of apple, representing eight cultivars ('Golden Delicious', 'Delicious', 'Gala', 'Jonagold', 'Jonathan', 'Florina', 'Fior di Cassia', and 'Imperatore Dallago') have been characterized with Random Amplified Polymorphic DNAs (RAPD). The reliability of the method was tested by analyzing separate scions of the same clone and also by comparing different accessions of the same cultivar. Using two separate ten bp primers, it was possible to obtain a distinctive fingerprint for each of the cultivars. The method is simple, rapid and should provide a useful system for documenting the identity of clonal material. © 1993