Abstract Detail

Crops and Wild Relatives

Watts, Sophie [1], Migicovsky, Zoe [2], Myles, Sean [3].

Quantifying variation across 1000 diverse apples.

The apple, Malus domestica, is an important fruit crop globally and breeding new cultivars with improved fruit quality and climate adaptability is crucial to ensuring a sustainable source of apples in the future. Capitalizing on the immense diversity available across M. domestica and its wild progenitor species, M. sieversii, can enable the development of improved cultivars. Here we characterized and quantified apple diversity across over 1,000 accessions of M. domestica and M. sieversii from Canada’s Apple Biodiversity Collection (ABC). We evaluated over 20,000 individual apples to quantify variation across 39 fruit quality and phenology phenotypes at harvest and after three months of storage. We observed a wide range of variation in phenotypic traits across accessions. For example, apples can differ by nearly 57-fold in weight, 18-fold in acidity and nearly 100-fold in phenolic content. After three months of storage we quantified significant changes to apple physiology and found that on average, apples lost 39% of their firmness, 31% of their acidity and 9% of their weight, but gained 7% in soluble solids. An apple’s firmness is positively correlated with harvest date, flowering date and time to ripen, which indicates that fruit texture is linked in part by phenological events throughout the growing season. We find that on average M. domestica accessions flowered, ripened and were harvested later than M. sieversii accessions. In addition, M. domestica apples were 250% heavier and had 67% less phenolic content than M. sieversii apples. We observe a significant decline in phenolic content over the past 200 years of apple breeding: cultivars released after 1940 had 30% lower phenolic content than those released before 1940. This suggests that intensified apple breeding has resulted in a reduction in the nutritional content of new apple cultivars. Our results demonstrate the immense phenotypic variation available among apples that can be exploited in breeding programs to develop improved cultivars. The quantification of apple diversity presented here not only provides insights into apple biology, but also provides a foundation for future genetic mapping studies and genomics-assisted breeding.

1 - Dalhousie University, Plant, Food and Environmental Science, 62 Cumming Dr. , Truro, NS, B2N 5E3, Canada
2 - Dalhousie University
3 - Dalhousie University, 62 Cumming Dr., Truro, NS, B2N 5E3, Canada

Keywords:
biodiversity
Horticulture
Crop wild relatives.

Presentation Type: Oral Paper
Session: CW2, Crops and Wild Relatives II
Location: /
Date: Wednesday, July 21st, 2021
Time: 4:00 PM(EDT)
Number: CW2005
Abstract ID:685
Candidate for Awards:None