The Advent of Precision Breeding: An Advanced Method of Plant Genetic Improvement and Its Utility for Vitis Spp.

Precision breeding (PB) augments and extends conventional plant breeding by allowing only single or few traits to be instilled into otherwise desirable varieties via transfer of genetic fragments with known function between sexually-related species. In contrast to conventional breeding, which combines approximately half of the gene sets from each parent through the variation-inducing meiotic pathway, PB utilizes the mitotic pathway, which is significantly more stable. This allows transfer of parental DNA sequences to create specific new or enhanced traits in target varieties without extraneous variation.  In this way, PB is akin to selection of axillary somatic bud mutations (sports), which gave rise to all nectarines, pink-fleshed citrus and many versions of elite grape varieties. However, as the name implies, PB is much more precise - allowing selection of subtle, desirable traits that could never be identified from sports. PB technology is only recently becoming available for an increasing number of crop species. It’s a "biotechnology" that stems from decades of research aimed at improving crop plants. Its implementation, crop-by-crop, depends on development and merger of the following three technologies: 1) Tissue and cell culture methods aimed at regeneration of whole plants from single (totipotent) cells, 2) Insertion of DNA fragments that express desired traits into such cells, and 3) Advancements in DNA sequencing and computational analysis to determine the exact correlation of DNA sequences to known traits for a given species. In this way, such DNA sequences, when inserted into totipotent cells, results in plants that express the desired traits.