ABSTRACT.- 'GVU Yvyrá' is a new apple cultivar developed and released by "Grupo Viveros del Uruguay". Trees are rustic, vigorous, with good branch growth behavior, and presenting a low chill requirement. It presents early flowering, starting around September 1st, and its harvest begins before January 15th (in southern Uruguay). Large to very large fruits, with cone shape, approximately 90% red-brown blush and sweet, yellow colored flesh, and a good cold storage potential. Since most commercial apple cultivars need cross-pollination to obtain an efficient production, they are planted together with at least two cross-compatible cultivars. However, due to the 'GVU Yvyrá' early and large period of flowering, the best pollinizers for this cultivar remain unclear. The aim of this study was to evaluate different potential pollinizers for the new cultivar 'GVU Yvyrá' by controlled pollination on a commercial orchard in Uruguay. Treatments consisted of self-pollination (with and without emasculation), and controlled cross-pollination with six different early blooming cultivars. Phenology of all cultivars, and fruit set after the different treatments were evaluated. All genotypes had coincident flowering with 'GVU Yvyrá', differing in the timing of blooming stages (beginning, full and end of bloom). Whereas 'Princesa' and 'Eva' had the beginning, full and end of bloom similar to 'GVU Yvyrá', 'Anna' flowering coincided with the beginning of 'GVU Yvyrá' bloom, and 'Duquesa' flowering coincided with the end of 'GVU Yvyrá' bloom. Self-pollination rates of 'GVU Yvyrá' did not provide commercially profitable fruit set and production showing fruit set rates of 0% (for emasculated flowers) and around 5% (for non-emasculated flowers). Fruit set ranged from around 25% with 'Duquesa' pollen to around 55% of fruit set for 'Eva' pollen. Regardless the cultivars utilized as pollinizer, all the genotypes are efficient for 'GVU Yvyrá' flower fertilization and fruit set and can be used as pollinizers in a commercial orchard. © 2022 International Society for Horticultural Science. All rights reserved.
Instituto Nacional de Investigación Agropecuaria