COMPARISON OF BLOOM AND HARVEST DATES, ALTERNATE BEARING INDEX AND NUT QUALITY PARAMETERS OF 'GOLDEN HILLS' AND 'LOST HILLS' PISTACHIO CULTIVARS TO 'KERMAN'

Abstract

From the 1970s through the first years of the 21st century, U.S. growers were completely dependent on the ‘Kerman’ female and ‘Peters’ male pistachio (Pistacia vera L.) cultivars. As a result of a breeding program conducted by University of California researchers from 1989 to 1996, two female pistachio trees, ‘Golden Hills’ and ‘Lost Hills’ were identified as having valuable traits for the U.S. pistachio industry. The ‘Randy’ male cultivar was selected to provide pollen for these earlier blooming females. The performance of these female selections was compared to ‘Kerman’, the industry standard in replicated trials in randomized and replicated trials conducted from 1997 through 2011 in the central and southern San Joaquin Valley of California. Traits compared included yield, bloom and harvest timing, and nut quality parameters. The pollination period for ‘Randy’ overlapped that of ‘Golden Hills’ and ‘Lost Hills’ and these three cultivars were at full bloom about five days earlier than ‘Kerman’ and ‘Peters’. ‘Golden Hill’s and ‘Lost Hills’ were harvestable two weeks earlier than ‘Kerman’, had a higher split nut percentage and fewer blanks. ‘Lost Hills’ demonstrated less alternate bearing and a greater individual nut weight than ‘Kerman’. ‘Golden Hills’ and ‘Randy’ have become established cultivars in California with significant planted acreage.