Growth of immature peach (Prunus persica (L.) Batsch.) embryos on different media

Embryo culture is a valuable in vitro technique to rescue immature embryos. The present experiment investigates the influence of media (MS, Knopp and Woody Plant=WP), sucrose levels (20 g/1 and 30 g/1), hormones (0,2 mg/1 of BAP and 0,1 mg/1 of GA3) and casein (200 mg/1 and 500 mg/1) on germination and plant development of immature peach and nectarine [Prunus persica (L.) Batsch] embryos (8,6 to 14,3 mm long). The media were prepared using the published levels of salt constituents, the WP vitamins, casein hydrolysate (200 mg/1), ascorbic acid (2 mg/1) and panthotenic acid (1 mg/1). Cultured embryos were stratified at -4.4 °C for 60 days. After stratification embryos were placed at 25±1°C with 12-h photoperiod. After 30 days the number of roots and plant fresh weights were recorded. Embryos cultured on WP with 3% of sucrose had better germination and growth than those on Knops or MS media. Growth regulators (BAP and GA3) did not influence the seedling rate, although they decreased the root number by 50%. Visually the addition of casein had a beneficial effect on plant growth but there was no statistical difference for seedling rate or fresh weight among the levels tested although at 200 mg/1 a higher seedling rate was recorded.