Abstract: Oat is a long-day crop and when cultivated in the field,it needs certain long-day conditions to complete the earing growth period.In this study,6 new oat varieties,which were created by three inter-specific polymerizations and hybridizations,were used to study the differences in phenophase,growth period,panicle traits and agronomic traits at different lengths of sunlight hours.In addition,the effects of different lengths of time on the growth and development of the new strains were analyzed.The results showed that 6 new oat varieties were insensitive to short-day conditions since they completed the whole growth period in 10 hours,let alone 15 h.In contrast,the control varieties consisted of No.5 Pin 5 and No.2 Hongqi,and they completed the growth period at the minimum of 14 h.Sunlight time had effects on vegetative growth and reproductive growth.With the extension of sunlight time,the time needed for earing gradually shortened,and the time from earing-flowering to maturity was different.Sunlight time significantly affected panicle traits and agronomic traits.With the prolongation of sunlight time in the 6 new varieties,the length of panicles,tillers and number of leaves decreased,the length and width of leaves decreased,and the height of the plants decreased.In this research,the requirement of sunlight hours for new oat varieties was determined.It provides theoretical basis for speeding up the process of southern winter breeding,and expanding both the planting area for oat and the applied season.

Key words: Oat;New germplasm;Sunlight hours;Growth stage;Agronomic trait