Growing Degree Days, Bloom and Harvest Dates, Fruit Quality and Yield of New Yellow and White Nectarines

Abstract

A long-term trial was conducted to investigate growing degree-days (GDD; base temperature of 4.4°C), full bloom and harvest dates, fruit quality, and yield of various yellow-and white-fleshed nectarines [( Prunus persica var. nectarine)] under conditions of southwest Idaho during 2003-07. The average response analyses over these years indicated that ‘Arctic Jay’, ‘Fantasia’, ‘Honey Kist’, and ‘Arctic Pride’ bloomed earlier, while ‘Arctic Mist’, A28.082 (a selection from Burchell Nursery, California), 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’, ‘Arctic Pride’, A28.082, ‘Arctic Snow’ were harvested after the second half of September, and the periods between bloom and harvest for these cultivars were 161, 166, 166, 180, and 181 days, respectively. The difference between the earliest and latest cultivars for full bloom dates was only 4 days or 26.7°C GDD, while the range for harvest dates was 68 days or 1097.1°C GDD. Considering all factors evaluated in this project, ‘Honey Kist’ is suitable as an early cultivar. ‘Arctic Jay’ had an excellent fruit quality and, on average, was harvested on 21 August, and thus recommended as the white-flesh cultivar of choice for that harvest time. ‘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 of 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. ‘Arctic Pride’ and A28.082 are good choices for planting as very-late maturing white-fleshed and yellow-fleshed cultivars, respectively. ‘Arctic Pride’ had moderately large fruit size and high SSC and extremely attractive skin and flesh color, but moderately low yield. A 28.082 had attractive fruit color, high fruit SSC, a high number of fruits per tree with large size, and hence high yield.