Interspecific hybridization of Prunus persica with P. armeniaca and P. salicina using embryo rescue

Abstract

Embryo rescue technique was used successfully to produce interspecific hybrids by crossing peach (P. persica) as a female parent with apricot (P. armeniaca) and plum (P. salicica). In those crosses that had 'Yuhualu' or 'Zhonghuashoutao' as female parents, hybrid embryos aborted from the 7th or 8th week after pollination mainly due to post-pollination incompatibility. An embryo rescue protocol was established to rescue such embryos and recover hybrid plants. Modified half-strength MS medium containing 4 mg l -1 6-BA and 0.5 mg l -1 IBA produced up to 90% germination in the embryos. Modified MS medium with 1.0 mg l -1 6-BA and 1.0 mg l -1 IBA gave the highest bud induction and multiplication whereas modified MS medium containing 0.5 mg l -1 IAA and 0.2 mg l -1 NAA gave the best rooting percentage. All the hybrids obtained using this embryo rescue technique were verified using simple sequence repeat (SSR) markers. A series of pollen treatments were carried out to partially overcome pre-pollination incompatibility, and it was found accidentally that pollen treatment with electrostatic field not only improved pollen germination but also increased the multiplication coefficient of embryo-induced shoots.

Effect of Developmental Stage and Medium on Embryo Culture of Low Chill Peach Hybrids

“…Plant growth regulators play an important role in embryo culture and enhance the embryo growth 11,12 . Liu et al 13 successfully cultured the embryos of peach (Prunus persica), apricot (P. armeniaca) and plum (Prunus salicina) in modified MS medium supplemented with 1.0 mg/l 6-BA and 1.0 mg/l IBA. Hence, it was hypothesized that the growth stages and medium will affect embryo germination of low chill peach hybrids.…”

“…When BAP and IBA were applied simultaneously, the per cent germination of immature embryos was more when compared to those when applied separately 12 . Liu et al 13 also studied different medium and concentrations of hormones for successful embryo culture and suggested that the abortion of embryo occurs due to improper growth regulators balance whereas excess growth regulators can often induce formation of callus 16 . In our experiment, lower concentration of growth regulators showed better germination.…”

Efecto de la temperatura, medios de cultivo y reguladores de crecimiento en la germinación de embriones cigóticos de durazno (Prunus pérsica) var. Diamante

“…La superioridad del medio 1/2MS sobre los otros ensayados está relacionada con la menor concentración de sales del primero que ya se había reportado previamente como favorable para la germinación de embriones de durazno alcanzando un porcentaje de germinación de hasta un 90 % [14].…”

“…Previamente se ha reportado como favorable la presencia de citoquininas en la germinación de embriones de durazno debido a que concentraciones moderadas de estas hormonas (0.5-1mg/L) promueven la división celular, contrarrestan el efecto de dormancia provocado por el ácido abscísico y de esta manera aceleran la germinación de la semilla [7,13,14].…”

Studies on the interspecific crossing compatibility among three Prunus species and their hybrids

“…The reason for the low effectiveness of distant hybridization is the existence of numerous morphological, anatomical, and physiological and biochemical barriers (Zenkteler 1990). These barriers prevent fertilization and the formation of embryo (pre-zygotic barriers) or impair its growth (post-zygotic barriers) (Perez, More 1985;Rubio-Cabates, Socias 1996;Liu et al 2007). A way to increase the effectiveness of distant hybridization is to introduce into the cross-breeding programme species that are genetically closely related, that is, belonging to the same genus, or even subgenus (Layne, Sherman 1986), and with the same ploidy level and the same number of chromosomes (Okie, Weinberger 1996).…”