Vernalization and genetic performance of spring Chinese cabbage-Guanchun

The new hybrid F1 GUANCHUN(Brassica campestris syn.rapa L.ssp.pekinensis(Lour) Olsson) and its parents were vernalized in germinating seed and growing in normal condition.The results show that the mean bolting days of GUANCHUN is 45 days and mean flowering days is 53 days after vernalization under 45 ℃ for 20 days;The vernalization is consistent between reciprocal cross F1 and orthogonal cross F1,and all are weaker than its parents in winterness,which presents that the bolting resistance of GUANCHUN is controlled by nucleus recessive gene;With the prolonging of vernalization days,the mean days and the duration of bolting is shortened,but days from bolting to flowering has not been affected,so the days of bolting is an important index for spring Chinese cabbage breeding.In addition with incomplete vernalization of 20 d or 25 d,the microgene related to bolting expressed and the variation of bolting in bolting Chinese cabbage are becoming significant,so the minor gene related to bolting may be accumulated by selecting and the bolting resistance will be increased.Under the treatment of 25 d and 30 d,the bolting time and the flowering time are not changed,the vernalization tends to be stable.