Treasure the exceptions: opportunities arise from wide crosses!
2017
Anderson, N. O.
Many difficulties arise from wide interspecific crosses in order to achieve new phenotypes, incorporate traits, and achieve genetic enhancement of existing crops. Several techniques can be employed to maximize gain, maintain fertility, create transgressive segregants, and even break up linkage groups. Many plant breeders often do not employ these crossing techniques when their crops could benefit from them. The objective of this paper is to present several classic crossing schemes proven to incorporate wild species genes into cultivated crops and minimize hybrid breakdown (incongruity), based on over 30 years of breeding research. Introgressive hybridization techniques such as congruity backcrossing and F1 hybrid bridging vs. classic recurrent backcrossing, based on Edgar Anderson's Iris evolution, will be used to demonstrate genetic changes possible in Phaseolus, Lilium, and Gladiolus. Direction of crosses to maximize exceptional genetic exchange, ancestral vs. derived species as male or female parents, self incompatibility status of parents, use of cut styles, and removal of transmitting tracts are possible techniques to employ. Use of fast-tracking technique options to hasten generational life cycles in herbaceous perennials can be employed to hasten the rate of progress, e.g., 3 cycles (equivalent to 3 years) truncated into one calendar year for gladioli.
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