A project on developing monoecious pistachio (Pistacia vera L.) populations and determination of sex mechanism in Pistacia

Abstract

Exceptional wild P. atlantica populations with several monoecious trees were recently found in the Yunt Mountains of the Manisa province of Turkey. This project aims to develop monoecious P. vera cultivars, and to determine sex mechanism and inheritance in Pistacia by inter- and intra-specific hybridization using these trees. Two monoecious P. atlantica genotypes were used both as male and female parents: One is “fully monoecious” i.e., they bore a mixture of male and female inflorescences. Another genotype has several branches with only staminate flowers, while the rest of the branches bore pistillate inflorescences. One P. atlantica genotype and two P. vera cultivars ('Ohadi' and 'Siirt') were used as other female parents. One P. atlantica and one P. vera genotypes were used as male parents as well. Altogether, 20 intra- and inter-specific crosses between 5 female and 4 male genotypes were performed. Four of the crosses will mainly serve to breed monoecious P. vera genotypes and the rest of them will help to understand sex inheritance mechanisms in Pistacia. The crosses between P. atlantica genotypes were done in the spring of 2001 and the hybridizations between P. vera and monoecious P. atlantica genotypes were performed in the spring of 2002. The plants of 2001 crosses are now one year old and they were morphologically characterized. The seeds from 2002 crosses were germinated and transplanted into plastic bags. The orchard will be established with approximately 3000 plants. About 1500-1600 plants are hybrids between P. vera cultivars and monoecious P. atlantica genotypes and the rest of them are from the other combinations. The breeding orchard will be set up in the Pistachio Research Institute in Gaziantep province with drip irrigation in the autumn of 2003.