Asian pear tree breeding for subtropical areas of Brazil

Abstract

--Introduction. In São Paulo State in Brazil, there is a demand for pear tree varieties that present fruit complementary characteristics and high adaptation for a subtropical-tropical climate. Thus, our study aimed at evaluating variety selections with better fruit quality and mainly adapted to the different areas of the São Paulo State. Materials and methods. Crosses among Asian [Pyrus pyrifolia (Burm.f.) Nakai] and European (P. communis L.) pear cultivars were made in Brazil from 1992 to 1998 aiming at finding new pear types for subtropical areas of the country. The first interspecific hybrids of the IAC pear breeding program were planted in various regions of São Paulo State, at latitudes from 21°11' S to 24°11' S and (11 to 200) chilling units (CU). About 20 phenological characteristics were evaluated. The hybrids and their parents were genetically characterized through RAPD markers. Results and discussion. In the progeny of 'Okusankichi' × 'D'água', the mean age for the first bearing and fruit development period (FDP) were 3.8 years and 137 days, respectively. The fruit characters early ripening, rounded shape, russet-brown skin and crisp flesh were dominant in all crosses of Asian × Asian and Asian × European pear trees. Twenty-six hybrids were selected, of which twelve are still being tested in a subtropical-tropical climate (0-80 CU). Their main characteristics are fruit with rounded, oblate, oblong or pyriform shapes, russet-brown or green skin, and crisp or soft flesh, and plants with medium-high vigor, an upright-spreading form and a fruit development period of from (110 to 160) days. Conclusion. The precocity of hybrids is highly dependent on the parental characteristics and the environmental conditions. A fruit development period close to that of the earliest parent was obtained. In F1 generations from crossings among Asian and European pears, certain characteristics were dominant. The RAPD analysis was efficient at identifying cultivar genotypes, selections and hybrids of pear from different botanical groups.Brazil / Pyrus communis / Pyrus pyrifolia / hybrids / tropical zones / adaptation / climatic factors / cold / pomology / RAPD Sélection de poiriers asiatiques pour les régions subtropicales du Brésil.Résumé --Introduction. Dans l'état de São Paulo au Brésil, il existe une demande pour des variétés de poiriers qui présenteraient des caractéristiques de fruit complémentaires et seraient bien adaptées aux climats subtropical et tropical. Notre étude a donc cherché à évaluer des variétés sélectionnées ayant une bonne qualité du fruit tout en étant spécialement bien adaptées aux différents environnements de l'état de São Paulo. Matériel et méthodes. Des croisements entre des cultivars de poiriers asiatiques [Pyrus pyrifolia (Burm.f.) Nakai ] et européens (P. communis L.) ont été effectués au Brésil de 1992 à 1998 afin de trouver de nouveaux types de poiriers pour les régions subtropicales du pays. Les premiers hybrides interspécifiques de poiriers créés par un programme d'amélioration de l'...

Composição do meio de cultura e condições ambientais para germinação de grãos de pólen de porta-enxertos de pereira

“…Ciência Rural, v.40, n.2, fev, 2010. a expansão do cultivo de pera em regiões de inverno ameno. No entanto, verifica-se carência de portaenxertos adaptados às condições climáticas brasileiras, ficando dependentes somente de dois porta-enxertos 'Taiwan Nashi-C' (Pyrus calleryana) e 'Taiwan Mamenashi' (P. betulaefolia) (BARBOSA et al, 1998;2007).…”

Establishment of growth medium and quantification of pollen grains and germination of pear tree cultivars

“…For cultivars that present a lower rate of germination and a smaller amount of pollen grains per flower, one option would be their use as female parents (FIGUEIREDO et al, 2013). Perhaps this would be the most sensible strategy in breeding programs for the pear in regions with mild winters, which seek the quality of European pears with the lower cold requirement of Asian pears (BARBOSA et al, 2007). As the cultivar Packham's Triumph, which has less cold requirement compared to other European pears (BARBOSA et al, 2008), has a large amount of pollen grains per anther and per flower, it could be used as the male parent, and the Asian Hosui pear, which has a smaller amount of pollen grains, as the female parent.…”

“…However, due to increased imports of higher quality pears like 'Rocha' and 'Abate Fetel', breeding programs need to be improved in order to obtain better quality cultivars adapted to the subtropical conditions of Brazil. If this is so, the most sensible strategy in programs for genetic improvement of the pear in regions with mild winters, which seek the quality of European pears with the lower cold requirement of Asian pears (BARBOSA et al, 2007), would be to use the cultivar Packham's Triumph as one of the parent plants, as this has a lower cold requirement compared to other European pears (BARBOSA et al, 2008). However, to select this cultivar as the male parent, it needs to produce viable pollen grains in high quantities; this information is not found in the literature.…”

“…These cultivars were obtained by hybridisation between European pears (high winter cold requirement and excellent fruit quality) and oriental pears (low winter cold requirement and inferior fruit quality), developed in past decades by the Campinas Agronomic Institute (BARBOSA et al, 2007, BETTIOL NETO et al, 2014. SEIFERT et al, 2009).…”