Abstract

European plum (Prunus domestica L.) production has increased considerably in recent years in Chile. The O’Higgins region represents 67.5% of this crop at the national level, where 95% of the hectares correspond to the ‘d’Agen’ cultivar. In Chile this cultivar has traditionally been used for processing into prunes. Recently, fresh consumption has left better orchard gate prices to the growers than the dehydrated destination. Nevertheless, insufficient knowledge exists about the harvest indexes for the production of fresh consumption, considering the export to distant markets. During the 2020-2021 season, a trial was conducted on the ‘d’Agen’ cultivar in three commercial orchards located in the O’Higgins region. The aim was to evaluate fruit maturity and growth parameters, relate and correlate among them, and define the best harvest index for the export of fresh consumption. In the field, from November 2020 until harvest, to determine fruit growth and maturity, biweekly for 96 fruits the diameter and absorbance index of chlorophyll (IAD) were evaluated. Simultaneously, to correlate these parameters with other destructive and non-destructive fruit quality parameters were characterized other 96 fruits in the laboratory. At harvest, the yield efficiency was estimated. Measurements in the orchard and laboratory did not show significant differences for the different evaluated dates. The IAD during the growing season shows a behavior adjusted to segmented regression (two sections). In addition, this parameter obtained a good correlation with the main parameters of maturity, firmness, and CSS, approximately from seven to five weeks before harvest. Linear and negative regressions for the relationship between IAD and fruit growth were evidenced. In the laboratory, the highest and most significant correlations were obtained between fruit weight and equatorial diameter (r=0.96), Chroma and h (r=0.81), and between fruit firmness measured destructively and non-destructively (r=0.82). Different IAD classes were established, where the most representative at harvest corresponded to values among 1.37-1.64, with 59.4% of harvest fruits.