Genetic variability and pollen effect on the transmission of the chemical components of the almond kernel

Abstract

The chemical components of the almond kernel are traits contributing to almond quality and must be considered in breeding programs searching for high-quality almonds. Thus, total protein, oil content, fatty acid composition and tocopherol content were determined in 200 genotypes from four progenies from the almond (Prunus amygdalus Batsch) breeding program of Centro de Investigación y Tecnología Agroalimentaria de Aragón (CITA), Spain. All components showed significant differences among genotypes, as well also among progenies, showing a significant effect of the pollen parent in the average composition of each family. The protein content ranged between 8.4 and 24.7%, and the oil content between 37 and 67.5% of dry matter (DM). The major fatty acid was oleic, followed by linoleic. Alphatocopherol was predominant among the different tocopherol homologues (α, δ, and γ). Significant correlations were found among some components, such as total oil, oleic acid, and γ-and δ-tocopherol, but not with α-tocopherol. Heritability estimates were high for oil content and γ-tocopherol, medium for linoleic acid and α-tocopherol, and low for the rest of components. These results remark the importance of the genetic background of an individual for the quality profile of its kernels and the significant and positive effect of the pollen on the transmission of most chemical components of the almond kernel.Additional key words: fatty acids; heritability; kernel quality; oil content; protein; Prunus amygalus Batsch; tocopherol. ResumenVariabilidad genética y efecto del polen en la transmisión de los componentes químicos de la pepita del almendro Los componentes químicos de la pepita del almendro son productos que contribuyen a la calidad del almendro y deben considerarse en los programas de mejora para almendras de mayor calidad. Por ello, se determinaron los contenidos en proteína total, en aceite y en tocoferol, así como la composición en ácidos grasos, en 200 genotipos de cuatro familias del programa de mejora genética del almendro (Prunus amygdalus Batsch) del Centro de Investigación y Tecnología Agroalimentaria de Aragón (CITA), España. Todos los componentes mostraron diferencias significativas entre genotipos, así como entre familias, resultando en un efecto significativo del parental masculino en la media de las composiciones en cada familia. El contenido en proteína osciló entre 8,4 y 24,7%, y en aceite entre 37 y 67.5% del peso seco (DM). El ácido graso más abundante fue el oleico, seguido por el linoleico. El α-tocoferol fue el homólogo predominante entre los tres mayoritarios (α, δ, y γ). Se encontraron correlaciones significativas entre algunos componentes, como el aceite total, el ácido oleico y los γ-y δ-tocoferol, pero no con el α-tocoferol. La heredabilidad fue elevada para el contenido en aceite y en γ-tocoferol, media para el ácido linoleico y el α-tocoferol, y baja para el resto de los componentes. Estos resultados resaltan la importancia de la base genética de un individuo para el perfil de calidad de sus p...

Chemometric Characterization of Almond Germplasm: Compositional Aspects Involved in Quality and Breeding

“…Oil content in almond kernel shows a high heritability value of 57% (Font i Forcada et al, 2011), confirming that the genetic Table 1. Oil and fatty acid composition of the kernels of 73 almond cultivars of different geographical origin for 2 crop years.…”

“…All variables were jointly examined and their correlation coefficients are shown in Table 3. No correlations were found between oil content and the percentage of the main fatty acids in both years of study with the only exception of a significant positive correlation between the contents of oil and of palmitic acid in 2008, although previous studies reported that oleic acid is positively correlated with oil content (Font i Forcada et al, 2011;Kodad and Socias i Company, 2008). A high negative correlation was found between palmitic and both the oleic acid and the O/L ratio (Table 3).…”

“…The trend of the modern almond industry in requiring kernels with high-quality attributes as well as that of consumers for foods without synthetic additives involve not only the incorporation of the chemical quality criteria in the evaluation of the new cultivars (Kodad et al, 2004, but also considering these traits in the breeding programs . Several studies have been undertaken to understand the environmental effects on these variables (Abdallah et al, 1998;Kodad et al, 2010;Sathe et al, 2008), the variability of these components in the almond progenies , the correlation among these traits in different almond cultivars and selections (Askin et al, 2007;Font i Forcada et al, 2011;, and their heritability and transmission to the offspring (Font i Forcada et al, 2011). All this information is useful to select the trait to be improved, the parents involved in the cross, and also the sense of the cross.…”

“…Recent studies on the transmission and heritability of oil content, fatty acid composition, and the different tocopherol homologs (Font i Forcada et al, 2011) have shown that oil content presents high heritability values (57%) and linoleic acid a medium value (25%). When heritability estimates are moderate, selection of parents based on their phenotypes should also be effective, as it happens when heritability is high (Hansche et al, 1972).…”

Mapping quantitative trait loci for kernel composition in almond

“…The study of the almond cross ‘Vivot’ × ‘Blanquerna’ (V × B) has allowed a linkage map of this progeny to be constructed [29], and the chemical composition of the kernels of its plants to be determined [22]. Thus, our objective was to identify QTL associated with the different chemical components of the almond kernel and thus establish a genetic tool to be applied in an almond breeding program aiming at increased kernel quality.…”