Chunyou 284 is a medium- japonica hybrid combination,as well as an indica-japonica subspecific hyrbid with super-high yield,which was developed from Chunjiang 23A,a thermo-sensitive CMS line with very early anthesis time,and C84,an indica-japonica intermediate type restorer line with wide compatibility.This combination has the advantages of high yield potential,early maturity,excellent comprehensive agronomic traits and wide adaptability.It was approved by Jiangsu Provincial Crop Variety Approval Committee in June,2018.The breeding process,main characteristics,cultivation techniques and seed production points of the combination were introduced.