PRODUCTION OF A MICROSPORE-DERIVED CALLUS POPULATION FROM SWEET CHERRY

Microspore-derived callus cultures were obtained by anther culture of 'Emperor Francis' sweet cherry (Prunus avium L.). Branches were remove d from the field in January and March and forced in the laboratory. Wh en the microspores reached the uninucleate stage, anthers were placed on modified Quoirin and Lepoivre liquid culture medium containing 4.4 mu M BA and 4.5 mu M 2,4-D. After approximate to 60 days, callus that emerged from the anthers was placed on woody plant medium supplemented with 1 mu M 2,4-D and 3 mu M 2iP and routinely transferred. The resul ting 270 callus cultures were screened for two allozymes heterozygous in 'Emperor Francis', Pgi-2 and 6-Pgd-1. Of the 270 callus cultures, 1 54 expressed only one allele each for Pgi-2 and 6-Pgd-1; thus, they we re considered microspore-derived. The microspore-derived callus cultur es can be used as a linkage mapping population. Chemical names used: 6 -benzyladenine (BA); 2,4-dichlorophenoxyacetic acid (2,4-D); N6-(2-iso pentenyl)-adenine (2iP).