Abstract:

To screen for superior Bromus inermis genetic material suitable for cultivation in the area surrounding Qinghai Lake， this study utilized ten wild B. inermis germplasm lines from the Three-River-Source Region. The research was conducted in Haibei Prefecture， Qinghai Province and analyzed and compared agronomic traits of the germplasm lines， including forage yield and seed yield. A structural equation model （SEM） was constructed to identify key agronomic traits influencing yield. Additionally， the TOPSIS multi-criteria decision model was employed for a multi-trait evaluation of the tested B. inermis germplasm， to provide formal testing of B. inermis lines intended for cultivation around Qinghai Lake. It was found： 1） At two years old， variety GN-2210 exhibited greater plant height， stem diameter， leaf area， and seed yield per plant than other lines， measuring 137.20 cm， 5.18 mm， 30.69 cm2， and 114.29 g·plant^-1， respectively. At three years old， the plant height， stem diameter， leaf area， and seed yield per plant of GN-2210 reached their maximum values of 111.80 cm， 4.33 mm， 25.73 cm2， and 106.30 g·plant^-1， respectively. 2） Analysis using a piecewise SEM indicated that leaf area and tiller number were key factors affecting the forage yield of B. inermis， while the key factors influencing its seed yield were leaf area and stem diameter. 3） The TOPSIS multi-criteria decision model demonstrated that the GN-221 germplasm lines was significantly superior to other varieties in terms of biomass accumulation and seed yield per plant， making it suitable for cultivation and promotion in the eastern Qinghai-Tibet Plateau.

Key words: Bromus inermis, production performance, resources, comprehensive evaluation