Water shortages have increased growers interest to investigate the effects of
deficit irrigation (DI) levels, i.e. 25, 50 and 75% of irrigation water requirement (IWR)
compared with the full irrigation level (100 % of IWR) on sugarbeet productivity and
on final population size (pf) and reproduction factor (RF) of root – knot nematode,
Meloidogyne incognita, as well as on water use efficiency (WUE) at the end of
growing season, under greenhouse conditions. Results showed that DI at the levels
of 25, 50, and 75% of IWR decreased significantly yield characters (root and gross
sugar yields) and sugar percent of sugarbeet, and increased WUE compared to full
irrigation level (100%) treatment, without significant difference between 75 and
100% DI levels in root yield. The yield characters were greatly reductions at DI
levels of 25 and 50% of IWR. Among the irrigation levels treatments, WUE was
lowest in the 100% irrigation level and highest in the 25% irrigation level. Also, the
results indicated that the pf and RF were significantly lower at irrigation levels of 25,
50, and 75% than 100% level. The 75% irrigation level caused minor reductions in
root yield, gross sugar yield and sugar percent, but significantly reduced nematode
infection (pf and RF) compared to 100% irrigation level. Thus, deficit irrigation to
level of 75% of IWR can be utilized to the management of root- knot nematode, M.
incognita infection without significant reduction in sugarbeet yields.