Heritability and phenotypic variation of double seeds in almond (Prunus dulcis)
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In almond, the presence of double seeded nuts significantly reduces their commercial value. For this reason, in breeding programs of this species, seedlings producing double seeds are usually eliminated. In order to avoid this trait in the offspring and increase the efficiency of the breeding programs it is important to know its genetic control. In this work, heritability of double seeds was estimated by midparent–offspring regression (narrow sense, h2) and by variance components analysis (broad sense, H2) for 3 years, in a population with a combination of full-sib and half-sib offspring coming from eight crosses designed for this objective. Heritability was high by both methods every year, and the values calculated by variance components were higher than those estimated by regression. The average ratio h2/H2 0.69 implies some influence of a non-additive effect for this trait, such as dominance and environmental effect. In this case, the influence of the temperatures preceding blooming on the percentage of double seeds can be inferred from our results, with lower temperatures increasing the percentage of double seeds. In the crosses between parents with high percentage of double seeds a normal (Gaussian) phenotypic distribution was observed. For crosses between one parent without double seeds and parents with high-medium percentage of double seeds a right-skew distribution (L-shaped) was observed, and certain transgressive segregation was observed in the descendants. This transgressive segregation was confirmed when both parents presented null percentage of double seeds. The results confirmed the complex architecture of this trait transmitted quantitatively, where additive, non-additive and genotype-by-environment interaction effects play an important role.
KeywordsPrunus dulcis Almond breeding Double seeds Inheritance Quantitative trait
This work has been supported by the project “Mejora Genética del Almendro” from the Spanish “Ministerio de Economía y Competitividad”.
Conflict of interest
The authors declare no conflict of interest.
- Bonferroni CE (1936) Teoria statistica delle classi e calcolo delle probabilità. Pubblicazioni del R. Istituto Superiore di Scienze Economiche e Commerciali di Firenze 8:3–62Google Scholar
- Crossa-Raynaud P, Grasselly Ch (1983) El almendro. Ediciones Mundi-Prensa, MadridGoogle Scholar
- Dicenta F, García JE, Carbonell EA (1993) Heritability of fruit characters in almond. J Hortic Sci 68:121–126Google Scholar
- Falconer DS (1960) Introduction to quantitative genetics. Oliver and Boyd, LondonGoogle Scholar
- González M, Oller del Águila SF, Cuevas J (2005) Maternal and paternal effects on the incidence of double kernelled fruits in ‘Guara’ almond. J Am Pomol Soc 59:97–103Google Scholar
- Grasselly Ch (1972) L’amandier; caracteres morphologiques et physiologiques des variétés, modalit‚ de leurs transmissions chez les hybrides de première génération. These Universit‚ de BordeauxGoogle Scholar
- Grasselly Ch, Gall H (1967) Etude sur la possibilité de combinaison de quelques caractères agronomiques chez l’amandier Cristomorto hybrid, par trois autres variétés. Ann d’Amélioration des Plantes 17:83–91Google Scholar
- Kester DE, Asay RN (1975) Almonds. In: Janick J, Moore JN (eds) Advances in fruit breeding. Purdue University Press, West Lafayette, pp 387–419Google Scholar
- Kester DE, Hansche PE, Beres W, Asay RN (1977) Variance components and heritability of nut and kernel traits in almond. J Am Soc Hortic Sci 102:264–266Google Scholar
- Levene H (1960) Robust tests for equality of variances. In: Olkin I (ed) Contributions to probability and statistics. Stanford University Press, Palo Alto, pp 278–292Google Scholar
- Ortega E (2002) Mejora genética del almendro: Nuevas estrategias para la obtención de variedades autocompatibles. Dissertation, University of MurciaGoogle Scholar
- Spiegel-Roy P (1979) Genetics and breeding of almond and grape. Monogr di Genetica Agraria 4:275–293Google Scholar
- Spiegel-Roy P, Kochba J (1974) The inheritance of bitter and double kernel characters in the almond. Z Pflanzenzuchtg 71:319–329Google Scholar
- Vargas FJ, Romero MA, Rovira M, Girona J (1983) Amelioration de l’amandier par croisement de variétés. Résultats préliminaires a Tarragone (Espagne). Opt Méditerr 1:101–122Google Scholar