Phenological Characteristics, Yield, and Fruit Quality of Yellow-Fleshed Nectarines under High Desert Conditions of the Northwestern United States over Five Years

An increasing world population and the competitive nature of the stone fruit market, particularly nectarines [(Prunus persica var. nectarine)], demand the selection of fruit with high quality attributes, flavor, and a wide range of maturity. Information on this subject is limited at the present time. In search of superior nectarines, a trial was conducted to study growing degree days (GDD), full bloom and harvest dates, fruit quality attributes, and yield of 11 yellow-fleshed nectarines under the high desert conditions of southwest Idaho in the northwestern region of the United States; these factors were studied over a span of 5 years. The average response analyses results over these years revealed that ‘Fantasia’ and ‘Honey Kist’ bloomed earlier, while A28.082 and ‘Summer Fire’ bloomed later than other cultivars. ‘Diamond June’ and ‘Honey Kist’ were the earliest cultivars to harvest and needed 110 and 114 days between full bloom and harvest, respectively. On average, ‘Sparkling Red’ and A28.082 were harvested after the second half of September, and the periods between bloom and harvest for these cultivars were 161 and 166 days, respectively. The difference between the earliest and latest cultivars for full bloom dates was only 4 days or 26.7oC GDD, while the range for harvest dates was 57 days or 943.7oC GDD. Considering all factors evaluated in this project, ‘Honey Kist’ is suitable as an early cultivar. ‘Summer Grand’ would be a good choice as a yellow-fleshed cultivar with moderately high soluble solids concentration (SSC), while ‘Fantasia’ would be an excellent choice for a yellow-fleshed cultivar if fruit appearance, large size, and high yield are the main objectives of nectarine production during the period of late-August to early-September. A28.082 was a good choice for planting as a very-late maturing yellow-fleshed cultivar. It had attractive fruit color, high fruit SSC, a high number of fruit per tree and large fruit size, and hence high yield.