Chemical maturation and storage performance of eleven Russet Burbank clones

Abstract

Although introduced as a cultivar from a somaclonal mutation of smooth Burbank in the 19th century, the subsequent identification and commercial selection of distinct Russet Burbank clones or strains has not been evident in the scientific literature. The present study examined chemical maturity of tubers (sucrose rating values and glucose content) and subsequent storage performance over a 3-yr period (1999–2001) of eleven Russet Burbank clones collected from across North America in order to determine if subtle quality traits could be associated consistently with specific clones. Although considered a late maturity cultivar (140 d), all clones were chemically mature (sucrose rating values of approximately 1) at the New Brunswick growing site by 125 d. Exploratory cluster analyses using hierarchical or nonhierarchical methods applied to pre-harvest and harvest sucrose and glucose levels in tubers during the 3-yr study allowed the North American clones to be separated into clusters that reflected geographical biases and this hypothesis was supported by canonical discriminant analysis. Exploratory cluster analysis of post-harvest data, however, did not find any consistent structure in the clones based on sucrose or glucose levels during storage at 4 or 10°C for up to 8 mo or after reconditioning from 4°C. Polymerase chain reaction analysis of 10 selected simple sequence repeat (SSR) regions confirmed that the 11 clones belonged to the cultivar Russet Burbank. The limited geographically featured clustering based on pre-harvest sugar changes observed among the clones may have their origins in cultural practices with somaclonal variation leading to geographical strains of the cultivar. Key words: Potato, Solanum tuberosum, cluster analysis, microsatellite DNA markers