Sugarbeet seed’s yield and quality as affected by irrigation

Irrigation to the sugar-beet seed crop is a common practice since many years in Emilia Romagna region, even though information on the most suitable ways to irrigate is very limited. The aim of this three-year long experimentation was to evaluate the influence of timing and number of irrigation treatments on seed yield and quality. Treatments at the onset, at full, and at the end of flowering, wit all their possible combinations were compared among themselves and with the non-irrigated control. During the second and third years the water content of the soil was monitored weekly, starting from just before the first treatment to harvest. These measurements indicate that the upper layers (0-20 cm), which are more subjected to evapotranspiration, are more affected by irrigations than the deeper layers (20-40). The effectiveness of irrigation treatments on seed yield was tightly dependent in the distribution of precipitations. The treatments applied in full or late flowering, both separately or together, determined significant increases in yield and in the percentage of seed balls with a diameter higher than 4.0 mm, whereas those at the beginning of flowering did not produced any improvements. No significant effects of the different treatments on 1000-seed weight and germinability were observed, except for a slightly negative influence of irrigations applied at the end of flowering.When all the traits were considered, an overall moderate correlation was detected between seed yield and quality.