Redomesticating Almond to Meet Emerging Food Safety Needs.

Thomas M Gradziel

doi:10.3389/fpls.2020.00778

Abstract

Almond is a desirable and high-quality food source where the presence of nut allergens and a vulnerability to aflatoxin and Salmonella contamination represent threats to consumer safety. In 2019, over 1 billion kg. of almonds, representing over 80% of the world total, were produced in California from a relatively few varieties with a very narrow genetic base. To address emerging needs mandated by cultural and climate changes, new germplasm has been introduced combining peach as well as wild peach and wild almond species. Advanced breeding selections incorporating exotic germplasm into a genetic background compatible with commercial production in California have demonstrated sizable reductions in level of kernel immunoreactivity as well as opportunities for improved control of aflatoxin and Salmonella. Breeding strategies employed include direct selection for reduced kernel immunoreactivity from an introgression enriched germplasm, the integration and pyramiding of resistance to multiple components of the aflatoxin disease-insect complex, and introduction of novel nut and tree traits to facilitate mechanized catch-frame field harvesting to avoid contamination with soil-borne pathogens such as Salmonella and Escherichia coli, as well as agrochemical residues.

Highlights

A diverse germplasm, including 10 commercial varieties, seven related Prunus species and 47 inter-species hybrids and introgression lines from the University of California, Davis (UCD) genetic improvement program that had been selected for self-fertility and local adaptability but not kernel nutrient quality were evaluated for kernel and nut quality, soluble protein, and kernel immunoreactivity (Table 1)
Variability for all traits evaluated, including size, shape, soluble protein content and ELISA immunoreactivity was documented in this diverse germplasm (Table 1 and Figure 1)
The lower immunoreactivity scores were more strongly associated with interspecific hybridization lineages having peach or the wild almond species P. argentea or P. webbii

Summary

INTRODUCTION

Amygdalus dulcis Mill., Prunus amygdalus (L.) Batsch, and Amygdalus communis L.] represents a nutritious, desirable, and relatively nonperishable food item as well as a durable propagation source for expanding plantings. These qualities made it commercially as well as horticulturally desirable, even in ancient times. Redomesticating Almond successfully sequencing the almond genome, have identified the genetic mutation controlling kernel sweetness that allowed almond’s domestication as a food crop. In addition to domesticated almond, sweet kernels of apricots (Prunus armeniaca and P. mandshurica), plums (Prunus domestica), peaches (Prunus persica), and wild almond species would have been consumed in ancient times as they are to this day (Gradziel, 2011). Previously published and unpublished data on allergenicity and susceptibility to aflatoxin and Salmonella contamination are evaluated in breeding germplasm derived from interspecies crosses in order to determine whether resynthesized or redomesticated germplasms can be identified with improved nutritional and food safety qualities

MATERIALS AND METHODS

35 Nickels

RESULTS AND DISCUSSION

CONCLUSION

DATA AVAILABILITY STATEMENT