Description
Cultivar development in alfalfa relies on heterosis, that has been mainly exploited by intercrossing selected clones from diverse gemplasm sources; an alternative way was proposed, based on developing double cross cultivars obtained by crossing clones selected for self-sterility, propagated by somatic seed. A different breeding strategy was recently emphasized based on population improvement through inbreeding and recurrent selection; in this case, self-sterility would be selected against. If self-sterility is determined by genetic load, the second strategy should be preferred, and selecting for self-fertility may bring about positive correlated responses for forage yield. Divergent selection for self-fertility was applied in a central Italian alfalfa landrace to test this hypothesis. Ten self-fertile and ten self-sterile plants were selected and hand-crossed without emasculation in a n(n-1) diallel; seeds of reciprocal crosses were pooled, obtaining 45 full-sib families per fertility group. Ten plants per family were evaluated for self-fertility. Selection was effective for self-fertility (h2 R=0.52), but not for self-sterility, a result expected if self-sterility is determined by genetic load. The forage yield of self-fertile progenies was 135% of the unselected control and 123% of the self-sterile progenies in a dense stand trial (first cut, seedling year), indicating that selection for self-fertility could be a tool for population improvement.
Citation
Rosellini, D; Veronesi, F; and Lorenzetti, F, "Selection for Self-Fertility and Self-Fertility in Alfalfa as a Tool for Breeding Strategy Assessment" (2024). IGC Proceedings (1993-2023). 24.
https://uknowledge.uky.edu/igc/1997/session4/24
Included in
Agricultural Science Commons, Agronomy and Crop Sciences Commons, Plant Biology Commons, Plant Pathology Commons, Soil Science Commons, Weed Science Commons
Selection for Self-Fertility and Self-Fertility in Alfalfa as a Tool for Breeding Strategy Assessment
Cultivar development in alfalfa relies on heterosis, that has been mainly exploited by intercrossing selected clones from diverse gemplasm sources; an alternative way was proposed, based on developing double cross cultivars obtained by crossing clones selected for self-sterility, propagated by somatic seed. A different breeding strategy was recently emphasized based on population improvement through inbreeding and recurrent selection; in this case, self-sterility would be selected against. If self-sterility is determined by genetic load, the second strategy should be preferred, and selecting for self-fertility may bring about positive correlated responses for forage yield. Divergent selection for self-fertility was applied in a central Italian alfalfa landrace to test this hypothesis. Ten self-fertile and ten self-sterile plants were selected and hand-crossed without emasculation in a n(n-1) diallel; seeds of reciprocal crosses were pooled, obtaining 45 full-sib families per fertility group. Ten plants per family were evaluated for self-fertility. Selection was effective for self-fertility (h2 R=0.52), but not for self-sterility, a result expected if self-sterility is determined by genetic load. The forage yield of self-fertile progenies was 135% of the unselected control and 123% of the self-sterile progenies in a dense stand trial (first cut, seedling year), indicating that selection for self-fertility could be a tool for population improvement.
