Micrografts have proven a very useful technique when the early propagation of plant material is desired either to invigorate weak material, multiply selected genotypes, or obtained virus-free shoots. This is the situation with the recovery of haploid almond embryos, which occur at low frequency with sexual embryos in twin seeds (i.e., multiple embryos within the same seedcoat). Often these haploid plants show weak growth due to their haploid condition and their poorly developed state within twin seeds. Very little information is presently available, however, concerning the effectiveness of different micrografting techniques for almond. In this work, we examine the success of in vivo micrografting of `Nonpareil' almond seedlings under different conditions. Variables included type of micro-scion, the rootstock genotype, and the growth stage of the rootstock. Microscions tested included small (3 mm) micro-wedges from either unsprouted or recently sprouted buds. Rootstocks evaluated included the `Hanson' (peach × almond) hybrid, and Nemared and Nemaguard peach rootstocks. Rootstocks were grafted after either ≈3 weeks of growth, when the tissue was still herbaceous, or after ≈3 months of growth, when the tissue had become woody. Results show significant differences between the treatments. Findings will be discussed both in terms of effectiveness of different approaches and the advantages and disadvantages of their use in breeding programs.
Pedro Martinez-Gomez, Mary Ann Thorpe, and Thomas M Gradziel
Federico Dicenta, Teresa Cremades, Pedro José Martínez-García, Pedro Martínez-Gómez, Encarnación Ortega, Manuel Rubio, Raquel Sánchez-Pérez, Jesús López-Alcolea, and José Egea
The Centro de Edafología y Biología Aplicada del Segura–Consejo Superior de Investigaciones Científicas (CEBAS-CSIC) Almond Breeding Program began in 1971, when the germplasm collection was established, with the aim of obtaining new self-compatible and late-flowering cultivars. The first crosses were carried out in 1985.
Late flowering decreases the risk of late frosts coinciding with flowering or fruit formation, thus avoiding crop losses. Self-compatibility enables a cultivar to produce fruit after pollination with its own pollen, which has enormous advantages for the grower compared with traditional self-incompatible cultivars (
José Egea, Manuel Rubio, José A. Campoy, Federico Dicenta, Encarna Ortega, María D. Nortes, Pedro Martínez-Gómez, Antonio Molina, Antonio Molina Jr, and David Ruiz
‘Mirlo Blanco’, ‘Mirlo Anaranjado’, and ‘Mirlo Rojo’ are very early-season ripening apricot cultivars (
David Ruiz, Manuel Rubio, Pedro Martínez-Gómez, Jesús López-Alcolea, Federico Dicenta, Encarna Ortega, María Dolores Nortes, Antonio Molina, Antonio Molina Jr., and Jose Egea
‘Cebasred’ and ‘Primorosa’ are very early-season ripening apricot cultivars (