Effect of Paclobutrazol Spraying and Planting Date on Bolting and Yield of Autumn Sown Sugar Beet

Bolting is always one of the limitations of sugar beet autumn cultivation. In this regard, a factorial experiment based on randomized complete block design with three replications was conducted on semi-resistant cultivar of Sharif at Moghan Research Station during two seasons of 2014-16. Experimental factor A (planting date) with three levels including a1 (10th October), a2 (25th October) and a3 (16 November) and second experiment factor (B) paclobutrazol foliar application with two levels b1 (300 mg / l) and b2 (no spraying). The results of combined analysis of variance showed that the effect of planting date was significant at 5% probability level for the white sugar content, root sodium, extraction coefficient sugar and molasses sugar, and also the interaction between planting date and paclobutrazol was significant for bolting at 5% probability level. Comparison of the mean data showed that the first sowing date showed the highest bolting and root yield with 20.88% and 51.52 ton / ha, respectively, and the second sowing date had 50.8 ton / ha root yield. Which was in the same statistical group as the first planting date. But the bolting on it was 5.29%. The interaction effect of second planting date and consumption of paclobutrazol with 57.44 ton / ha and 4.23% had the highest root yield and the lowest bolting, respectively.Keywords:" Paclobutrazol"," Sugar beet"," Autumn sown"," Bolting"," Root yield"