Several workers have studied the effect of harvest time on chemical and nutritional composition of almonds, but the results are partly conflicting, probably due to differences in the cultivars considered and to different agronomic and climatic conditions in the growing areas. In this paper, the influence of harvest time and cultivar on the chemical and nutritional composition of almonds (Prunus dulcis (Mill). D.A. Webb) were evaluated. Ten cultivars were considered, grown in the same orchard and subjected to the same agronomical regime. Almonds were collected at two different harvest times: (i) when the fruits were unripe, but already edible, and showed green and moist hull; and (ii) when the fruits were ripe, with dry brown hull. The analyses of proximate composition, fatty acid profile, total phenolic compounds, and antioxidant activity were carried out.; Results: Lipid content increased (P < 0.001) during ripening, while both protein and carbohydrate content decreased (P < 0.01). Fatty acid composition showed a not univocal behavior during ripening and was highly influenced by cultivar. Total phenolic compounds and antioxidant activity varied among cultivars but increased during ripening with the exception of cv Marcona. The 'Genco' and 'Francoli' cultivars were found to be phenolic rich.; Conclusion: Harvest time and cultivar significantly influenced the chemical and nutritional composition of almonds. Genotype strongly influenced fatty acid composition and total phenolic compounds. The changes of bioactive compounds and antioxidant activity suggest that the synthesis of antioxidants also occurs in the last stage of ripening. Unripe almonds, a valuable niche product, showed interesting nutritional value. © 2018 Society of Chemical Industry.; © 2018 Society of Chemical Industry.

Evaluation of the chemical and nutritional characteristics of almonds (Prunus dulcis (Mill). D.A. Webb) as influenced by harvest time and cultivar.

Regulation of flowering time in almond, as in other Prunus species, is a complex process involving both chill and heat requirements. Following exposure to appropriate consecutive periods of cold and warm temperatures, the buds break dormancy and sprout or flower depending on bud type. To maximize flowering and subsequent vegetative growth and fruit set, chilling and ensuing warm temperature requirements have to be fully satisfied. Because of its potential for very early flowering, flowering time in almond is a major determinant of its adaptation to new environments. In colder regions, Late-flowering is often necessary to avoid frost damage during and just after flowering. Consequently, the selection of delayed flowering times remains an important objective in almond improvement programs. Flowering time is considered a quantitative though highly heritable trait. In addition, a dominant gene (Late flowering, Lb), originally identified in a spontaneous mutation of the Californian almond cultivar ‘Nonpareil’, was also described. The objective of this review is a comparative analysis of the effects of regional adaptation, breeding and mutation on the delay of flowering time in new almond cultivars. Findings indicate that the adaptation of almonds from the Mediterranean basin to colder regions in Northern Europe and America has been mainly achieved through delayed flowering. These adapted late-flowering cultivars have usually been developed by selecting desired quantitative genes within each regional germplasm. Additional progress thus appears achievable with a more comprehensive understanding of the quantitative and qualitative genetics controlling this trait. The use of molecular markers for the early selection of genes conferring late flowering, including both spontaneous mutations as well as unique regional germplasm, should allow development of even later cultivars including ultra-late cultivars flowering as into April.

The delay of flowering time in almond: a review of the combined effect of adaptation, mutation and breeding

The role of phenology in the climate change impacts and adaptation strategies for tree crops: a case study on almond orchards in Southern Europe

Eighty-six almond accessions of diverse geographic origin, ranging from Central Asia to the USA, were genotyped in 15 simple sequence repeat (SSR) loci to compare genetic diversity parameters, characterize genetic differentiation, and examine factors responsible for the maintenance of genetic diversity and population structure in almond. The mean allele number was 18.86 alleles per locus. All but one primer demonstrated polymorphic information content higher than 0.7. Almond genotypes clustered according to their pedigree and geographic origin. STRUCTURE analysis determined nine genetically distinct subgroups within the studied genotypes including the Kyrgyz, Akdamar, Bademli, Hungarian, Monor, Italian, Moroccan, and Californian accessions and wild species and an admixed group. An AMOVA analysis confirmed that considerable genetic variation occurred within populations (71.30%), and genetic variation among populations was also significant (28.70%). The mean values of the fixation index (FST) varied between 0.38 and 0.55, indicating marked genetic differentiation among the populations. The among-population genetic differentiation based on allele sizes (RST) was significantly higher than that based on allele identities (FST) between the most groups, suggesting that stepwise mutations have also contributed to genetic differentiation. A Mantel test and a neighbor-joining tree showed no significant correlation between the geographic distance and the genetic distance (Rxy = 0.173, P = 0.226) and indicated that geographic distance among the assessed populations has little influence on their genetic differentiation (Rxy = 0.248, P = 0.194). Our data show drift, mutations, and massive gene exchange between several wild species and cultivated P. dulcis as crucial components of genetic differentiation. Slight losses of genetic diversity are attributable to geographic isolation, human selection and not to the relatively recent occurrence of self-compatibility. There was no indication of a major decrease in genetic variability in almond germplasm from Asia to Europe. The present results reveal that almond domestication avoided the occurrence of a genetic bottleneck although its risk is present in many subpopulations.

/pdf/genetic-variability-is-preserved-among-strongly-7tskckobwb.pdf

Genetic variability is preserved among strongly differentiated and geographically diverse almond germplasm: an assessment by simple sequence repeat markers

Managed and wild pollinators of different functional groups can provide pollination services in agricultural landscapes. These pollinators differ in their resource requirements and response to the amount and arrangement of different habitat types, that is, landscape composition and configuration. Most current approaches to test landscape effects on pollinators and pollination services are either applied to central individual crop fields or other landscape elements but rarely consider that pollinators depend on and make use of multiple habitat elements in an entire landscape. To capture these complex spatial and temporal interactions between different pollinators and habitat elements at the landscape scale, we propose to apply a combination of experimental and observational approaches across multiple habitat types and seasons.

C. Confolent

Papers

The origin of the self-compatible almond ‘Guara’