Patterns of Saskatoon (Amelanchier alnifolia Nutt.) Fruit and Seed Growth

Abstract

Saskatoon fruit are an emerging horticultural crop across the Canadian prairies. As fruit size varies greatly among cultivars, knowledge of fruit growth patterns and factors that affect fruit size can be used to establish breeding trials and develop orchard management strategies that could enhance the production of this crop. In this study, we 1) determined fruit and seed growth patterns among large-, medium-, and small-fruited cultivars of saskatoon using growing degree days to standardize time to crop development and 2) assessed the role of seed number on fruit size. Fruit growth patterns of four cultivars (Thiessen, Northline, Regent, and Smoky) were determined from weekly measurements of fresh and dry fruit mass during two consecutive seasons. These growth patterns exhibited three phases. The largest fruit at maturity were from `Thiessen', followed by `Northline', `Smoky', and `Regent', in descending order. Pedicel cross-sectional areas 1 week before maturity correlated linearly with increasing fresh and dry fruit mass and seed number per fruit. At maturity, seed number per fruit correlated linearly with fresh and dry fruit mass. `Thiessen' contained significantly more seeds per fruit (4.6) than `Northline' (3.7), `Smoky' (3.2), and `Regent' (3.2). The results of this research suggest potential areas for orchard management improvement and future research directions for saskatoon crop improvement.