Improvement of Peach Embryo Culture Through Manipulation of Carbohydrate Source and pH

Carbohydrate source of peach [ Prunus persica (L.) Batsch] embryo culture media affects embryo growth and survival. The first objective of this study was to determine the effect of five carbohydrates (fructose, glucose, maltose, sorbitol, and sucrose) in Woody Plant Medium (WPM) on the germination and survival of peach embryos in vitro. Fructose, glucose, maltose, and sucrose in WPM resulted in better embryo germination and survival than sorbitol. Fructose (2% and 3%) produced greater survival than all other carbohydrates tested in smaller embryos (<10% ovule dry weight). However, sucrose was better than all other carbohydrates tested in the larger embryos (≥10% ovule dry weight). In addition, large embryos (>10% ovule dry weight) on fructose at 1% combined with glucose, maltose, sorbitol, or sucrose at 1% had equivalent or higher survival than did those on either 1% or 2% sucrose in conjunction with the same carbohydrates. Embryo survival on different carbohydrates varied with genotype. The second objective of this study was to determine the effect of three levels of MES buffer (0.0 m m , 4.5 m m , and 9.0 m m ) on medium pH stability and embryo survival. MES buffer at 0.0 m m and 4.5 m m concentration produced significantly better embryo survival than 9.0 m m . The pH stability was better at MES 9.0 m m , however survival decreased significantly. Chemical name used: [2-(N-morpholino)-ethane sulphonic acid] (MES)