A new selection strategy for fruit crops

Early plant breeders based their selection on phenotypic differences among individuals to develop distinctive races and cultivars. Rediscovery of Mendel's work in early 20(th) century and greater appreciation of Darwin's theory of natural selection provided a framework for understanding the genetic basis of inheritance and how selection can cause incremental changes within plant populations. Cyclical selection methods were then developed based on the principles of evolution, Mendelian genetics, and biometry. Emphasis was on capturing non-additive genetic effects (specific combining ability) and additive effects (general combining ability), and the exploitation of important heterotic groups (reciprocal recurrent selection). Depending on crop species, all methods have been successfully employed. Nevertheless, they may not seem to adequately answer the questions of the 21(st) century. Choice of parents at all stages of selection is often based on complex quality traits at the expense of descriptive (qualitative) traits. The latest consumer trends tend towards food for health, convenience and pleasure. There is also concern for genetic diversity. Integration of these mega-trends in cultivar breeding would facilitate sustainable development of cultivars relevant for the times. I propose a selection strategy whereby qualitative (descriptive) traits (e.g., color, shape, habit) will be used as foundation for developing more complex or "selection" traits. Initial parental selection to establish a breeding population will be based on qualitative traits (or genetic stocks) while subsequent selections will be on complex traits within each genetic stock. Each stock will be maintained as a separate subline in a recurrent selection program for general combining ability. Crosses will be restricted within rather than between sublines to maintain the purity and identity of each genetic stock while the population is undergoing improvement for complex traits. In the short term, mass selection can be used to identify outstanding individuals for immediate use in commercial breeding. New cultivars emerging from the program will be promoted based on their genetic stock followed by the improved selection trait. The strategy will more likely ensure maximal production in a sustainable way.