Flower age and pollenizer could affect fruit set in late - blooming self - 1 compatible almond cultivars under warm climatic conditions

18 The effect of the pollination time and of the pollen origin was studied in three self-compatible 19 and late-blooming almond genotypes in order to evaluate their effect on fruit set and yield. 20 The full self-compatibility of the three genotypes was clearly assessed as fruit sets after self21 pollination were similar to those obtained after cross-pollination with pollen from two 22 different genotypes. Sets reached the level of a commercial production, ranging from 34.02 to 23 49.98% when the flowers were pollinated at the best pollination time, two days after 24 emasculation. Pollination at later times significantly decreased fruit set, as well as high 25 temperatures, negatively affecting stigma receptivity and, consequently, pollen germination 26 and fruit set. Thus, early pollination is essential for self-compatible almond cultivars, mainly 27 if these cultivars are grown in regions with warm conditions in late winter and early spring. 28 29 30