Abstract:The segregation law of boron(B) nutrition trait in two F2 population crossed between B efficient cultivars and a B inefficient cultivar and its back cross populations in rapeseed(Brassica napus) was studied under field experiment, which soil available boron was deficient. The results showed that a major gene mainly control the B efficient phenotype of rapeseed. Under the condition of boron deficiency in soil, the seed yield of individual in F 2 population was significant negative related to the agronomic traits of bolting date and growth date. This suggested that the growth period (bolting days and growth days) were tightly linked to the boron efficiency (seed yield at boron stress) and the growth period may be used as a assistant index to identify boron efficiency rapeseed and hybrid.