Seasonal patterns of burr and nut growth were measured in sweet chestnut trees (Castanea sativa Mill.) of the cultivar ‘Marrone di Castel del Rio’. Burr and nut growth expressed as diameter, fresh and dry weight, and dry matter were assessed from mid of June to mid of October. Results evidenced that burr mainly grows in the initial period of the season, while the nut had a rapid growth in the last part of the season (i.e., beginning of September). Dry matter of burrs started decreasing when its accumulation in the nuts was increasing. Burrs with the highest number of nuts (three), experienced a limited nut growth compared to burrs with two or one nuts per burr, but only at the beginning of nut filling phase. Lateral nut evidenced a higher growth in weight (fresh and dry) in the first part of the season with occasionally reduced dry matter compared to central nuts. The burr diameter had a strong positive relationship with the internal nut diameter and with the total nut weight.
Keywords: sweet chestnut, biometric measurements, burr development, nut development, nut quality