ThexTriticosecale Wittmack ‘Shinjoseong’ variety was developed for use as a whole-crop silage obtained from a cross between CTSS93Y00058S-5Y-0Y-0B with early heading, lodging, and resistance to barley yellow mosaic virus and Suwon24 with winter-hardy and lodging-resistance traits by the National Institute of Crop Science (Wanju, Korea) in 2019. Shinjoseong has medium-sized green leaves, slightly short-length spikes with a light-yellow color, and slightly large seeds with a light yellow-brown color. Compared to the comparable cultivar, Shinyoung, Shinjoseong had a heading date of three days earlier (April 22^nd, nationwide), stronger cold and lodging resistances, and the same level of disease resistance. Its average dry matter yield was 17.18 t/ha, 5% higher than that of the comparable cultivar. The crude protein, acid and neutral detergent fiber, and total digestible nutrient contents of Shinjoseong were 6.5%, 34.9%, 58.8%, and 61.3%, respectively, slightly higher than those of the comparable cultivar. However, the silage grade of Shinjoseong was 2, the same as that of the comparable variety. The grain yield of Shinjoseong was 7.36 t/ha, 13% higher than that of Shinyoung (Grant No. 9757).

Consumer demand for Triticale cultivars as a winter forage crop in Korea has been increasing because of its ability for high and stable yield. However, more than 10 years are required to develop new varieties with conventional breeding programs. A speed breeding system using long-day photoperiodic treatment has recently been suggested and applied in wheat and barley, but not in the triticale breeding program in Korea. To evaluate the availability of the established speed breeding system for triticale breeding programs in Korea, we used nine domestic triticale cultivars to investigate their growth characteristics under a 22 h photoperiod. The average days to heading (DTH) of the nine cultivars was 38 days, and Gwangyoung and Minpung showed the most delayed DTH at 42 days. Therefore, all nine triticale cultivars were able to shorten the growth duration under the tested photoperiod condition. One productive tiller and more than 10 seeds were obtained from each cultivar. The germination percentage was over 82% when the spikes were harvested 20 days after heading, dried, and chilled for a week to break dormancy. These results suggest that in Korea, the rapid generation advancement system with simple long-day photoperiodic treatment can be applied to triticale breeding programs to reduce the breeding time.