INFLUENCE OF GENOTYPE, MEDIA COMPOSITION, COLD PRETREATMENT AND THEIRINTERACTIONS ON ANDROGENESIS IN DURUM-WHEAT (TRITICUM-TURGIDUM)

The effect of genotype, liquid and solid medium, ancymidol in liquid m edium, spike cold pretreatment and their interaction was investigated in two tetraploid wheat genotypes. In each treatment approximately 100 0 anthers were studied. Pollen embryoid induction frequency in liquid medium with 0.1 mg/l of ancymidol (growth retardant) was 2 times highe r than control liquid medium and approximately 5 times more than solid medium. Cold pretreatment of spikes (7 days at 4 degrees C +/- 1) usu ally reduced embryo yield. The highest frequency of embryoid formation per 100 anthers was obtained in the liquid medium containing 0.1 mg/l of ancymidol without cold pretreatment in Dicoccoides noir genotype ( 79.72). Green and total regenerations per 100 embryos were influenced by genotypes. The use of ancymidol decreased green regeneration when c ompared with control liquid medium. Liquid medium improved total regen eration when compared with solid medium (4.04 to 7.68%). In liquid med ium the number of embryoids and green regeneration was increased for b oth genotypes and by using this medium, at least one plantlet per 100 to 200 cultured anthers should be obtained, and these two genotypes ca n be no more considered as recalcitrants.