ADVANCES IN LOW-CHILLING PEACH BREEDING AT INSTITUTO AGRONÔMICO, SÃO PAULO STATE, BRAZIL

Abstract

Peach (Prunus persica L. Batsch), a typically temperate fruit tree, was introduced in Brazil through Portuguese colonization in the 1530s. Peach trees established at low latitude regions require climatic adaptation to subtropical-temperate conditions of low-chilling. The first Brazilian peach breeding program was initiated by O. Rigitano in the late 1940s at the Instituto Agronomico (IAC). Research continued at IAC, aiming at full adaptation of selections to different climates of Sao Paulo State and other similar ecosystems. Pioneering peach crosses involved local and North American germplasm material of medium chilling requirement. Various low-chill and productive cultivars with high quality fruits were released. In the last decades, the best IAC cultivars (F 1 and F 2 hybrids) were intercrossed with peach and nectarine selections from the University of Florida. Fifty eight cultivars were released for areas with 0-200 chilling hours (below 7.2°C). The main fruit traits are: epidermis - green ('Talisma', 'Nectar', 'Cristal'), yellow ('Canario'), pink ('Joia-1 and 2'), red ('Centenario'); flesh - yellow ('Petisco-2', 'Dourado-1'), white ('Natal', 'Delicioso Precoce', 'Joia-4'); texture - firm, non-melting ('Aurora-1'), soft ('Tutu', 'Catita', 'Joia-3'); stone - cling ('Colibri', 'Brasao'), free ('Dourado-2', 'Joia-5'); flavor - sweet ('Supermel', 'Ouromel-2'), sweet-acid ('Petisco', 'Arlequim'), canning ('Regis', 'Biuti'); maturation - early ('Tropical-1 and 2'), medium ('Aurora-2', 'Docura-2'), late ('Bolao', 'Momo'); extra-large size ('Douradao'), and others, as shape - globose, oblong, round, with or without tip; pubescence - high, medium, low; dual purpose (fresh-canning). About 46% of 58 cultivars has yellow flesh, 54% white flesh, 47% rose and red skin, 53% green and yellow skin, 65% are freestone and 35% clingstone, being 10% canning. IAC peach harvest occurs from August to February, about 80-180 days after full bloom. These cultivars, and other genotypes with better pomological characteristics, have been widely accepted by fruit growers and consumers, due to the adequate evolution of peach cultivation in subtropical areas.