Integration of somatic embryogenesis in a tree breeding programme: a case study with Picea abies

Abstract

Potential for integration of somatic embryogenesis in a breeding programme of Norway spruce (Picea abies (L.) Karst.), and its limitations, were investigated in a case study with an ordinary breeding population. A standard protocol was used for initiation, proliferation, and cryopreservation of embryogenic cultures; maturation of somatic embryos; and plant regeneration. This is a practical necessity when dealing with a large number of genotypes. Proliferation and maturation were identified as major constraints. Clear differences among families were seen for proliferation and for maturation. For plant regeneration, differences among cell lines within families were considerable while no significant differences were found among families. Significant differences among male parents were obtained for proliferation and maturation. Our calculations show that by using an improved standard protocol, at least one third of the genotypes can be propagated via somatic embryogenesis. No clear relationship was found between embryogenic characters of selected parents based on progenies and corresponding parental breeding values for growth and phenology characters. Three years can be gained by using somatic embryogenesis instead of cuttings in a breeding programme. Maintained propagation ability by including cryopreservation in the breeding programme will provide a very useful link between breeding and mass propagation. The results are encouraging, but further improvement of the standard protocol is necessary.Résumé : Le potentiel et les limites de l'intégration de l'embryogenèse somatique dans un programme d'amélioration génétique de l'épinette de Norvège (Picea abies (L.) Karst.) sont évalués dans une étude de cas d'une population normale de croisements. D'un point de vue pratique, lorsqu'un nombre important de génotypes est considéré, un protocole standard a été utilisé pour l'induction, la maintenance et la cryoconservation des cultures embryogènes, la maturation des embryons somatiques et la régénération en plants. La maintenance et la maturation ont été identifiées comme des contraintes majeures. Des différences claires entre les familles ont été observées pour ces étapes. Pour la régénération en plants, les différences entre lignées cellulaires d'une même famille étaient considérables alors qu'il n'y avait pas de différence significative entre les familles. Des différences significatives entre les parents mâles ont été observées pour la maintenance et la maturation. Nos calculs montrent qu'avec l'utilisation d'un protocole standard amélioré, au moins le tiers des génotypes peut être multiplié par embryogenèse somatique. Aucune relation claire n'a été trouvée entre les caractères embryogènes des parents sélectionnés, basé sur leurs descendances, et les valeurs reproductives correspondantes des parents pour la croissance et les caractères phénologiques. On peut gagner trois ans dans un programme d'amélioration génétique par l'utilisation de l'embryogenèse somatique au lieu du bouturage. Le maintien de la capacité multiplicati...

Somatic Embryogenesis in Parana Pine (Araucaria angustifolia (Bert.) O. Kuntze)

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