Speed Breeding with Early Harvest Shortens the Growth Cycle of Barley

Speed breeding, where environmental conditions such as photoperiod, temperature, and nutrient availability are manipulated to accelerate plant development and reduce breeding cycle length, can be especially beneficial in crops such as barley. Speed breeding combined with early harvest shortens the development cycle in some species, but it has not been successfully developed for barley. This study aimed to investigate whether a speed breeding system (SBS) combined with early harvest could further shorten the development cycle of barley for more efficient utilization in breeding programs. Eleven genotypes were evaluated under two systems: an SBS (photoperiod: 22 h; temperatures: 22 °C in the day, 16 °C at night) and normal breeding system (NBS, photoperiod: 16 h; temperatures: 22 °C in the day, 12 °C at night). On average, flowering occurred 15 days earlier in the SBS compared to the NBS. In the SBS, harvest at 21 days after flowering (DAF) achieved high germination rates and enabled a reduction in the cycle by 20%. When utilizing speed breeding with early harvest, the breeding cycle was complete in 88 days (21 DAF—SBS) compared to 110 days (28 DAF—NBS), which in turn will facilitate the faster development of targeted barley varieties and cultivars in the northern United States. This study is the first report of early-harvest success in barley when speed breeding conditions are used.