Variability among Vitis vinifera cultivars in micropropagation, organogenesis and antibiotic sensitivity

In vitro culture of 32 Vitis vinifera cultivars and intraspecific hybrids was initiated from axillary buds. The development of roots and shoots was followed during 14 subcultures on two hormone-free micropropagation media. One medium (M64) was used until the 8th subculture, after which it was replaced by G90 medium which was found more suitable for plantlet growth and permitted an increase in the time between subcultures. Large differences in plantlet growth between cultivars were demonstrated on both media. The number of roots had greatest variability between cultivars (CV=39%) as compared with stem length (CV=21-22%) and number of nodes (CV=12-14%). The number of nodes was positively correlated with shoot length whereas root number appeared to be poorly positively correlated with shoot development. Adventitious bud regeneration from leaves was studied for 20 cultivars and averaged 36.7% of regenerative explants with large differences between cultivars (CV=47%). However, organogenic competence was not correlated with micropropagationability. High sensitivity of Vitis vinifera plantlets to kanamycin and hygromycin was demonstrated with a strong interaction between cultivar and antibiotic. At 0.8 mg dm^-3, hygromycin was lethal to plantlets. This effect was only observed at 4 mg dm^-3 for kanamycin, whereas 1 mg dm^-3 stimulated the development of plantlets.Key words: Vitis vinifera, cultivar, micropropagation, antibiotic, organogenesis.