Effect of seed spacing and sowing date on Sugar beet Root Rot.

The effect of seed spacing and sowing dates on sugar beet root rot and yield components in a naturally infested soil with multiple sailborne Pathogens in two growing seasons in Marvdasht and Kavar counties were studied. The experiment was conducted in a split plot design with four replications. The main plot consisted of sowing date as follows: P1= 20 th of Esfand P2= 10 th of Farvardin. P3= 30 th of Farvardin. P4= 20 th of ordibehsht. The subplots consisted of 6 seed spacings d1= 50 cm row, 15 cm intra row spacings. d2= 50 cm row, 20 cm intra row spacings. d3= 50 cm row, 25 cm intra row spacings. d4= 60 cm row, 15 cm intra row spacings. d5= 60 cm row, 20 cm intra row spacings. d6= 60 cm row, 25 cm intra row spacings. Plot size consisted of 4 lines with 10-meter length. The effect of sowing date and plant seed spacing on sugar beet root rot, root yield, and sucrose content in two growing season showed that the percentage root rot was greater in early than the late sown crop. The highest root rot was observed on the 20th of Esfand and the lowest on the 20th of Ordibehsht in both Marvdasht and Kavar counties. The highest root yield and sucrose content was also obtained from sugar beet sown on Ordibehsht and lowest from the earliest sown sugar beet crops. The difference among the experimental treatments was not always significant statistically. No significant difference was found in sugar beet root rot among different sowing dates in the first growing season, although root rot was slightly lower in the late than the early sown sugar beet crop. The interaction of seed spacings and sowing dates on root yield, sucrose content and sugar beet root rot showed that the highest yield , sucrose content and lowest root rot was obtained from the late sown crop(20th ordibehsht) with the highest plant densities treatments( P4d1, P4d2, P4d3), and the lowest root yield, sucrose content ,and the highest root rot was obtained from the earliest sown sugar beet (20th Esfand) with the lowest density treatment(P1d6).