Relationship between extract viscosity and kernel size in winter rye

Rye (Secale cereale L.) grain with low extract viscosity (EV) and superior kernel characteristics is desired when used in diets of monogastric animals. Knowledge of the relationship between EV and kernel characteristics is needed to develop an efficient selection strategy for breeding cultivars that meet the two criteria. Grains of 11 open-pollinated population varieties/lines grown in 21 environments were studied to determine the relationship between EV and kernel weight (KWT) among genotypes and environmental effects. Grains of eight out of the eleven varieties/lines were screened into five kernel-size categories, <2.0, 2.0–2.4, 2.4–2.8, 2.8–3.2, >3.2 mm in kernel width, to determine the relationship between EV and kernel width within a genotype. EV was a linear function of KWT; high KWT is indicative of low EV. The degree of the relationship was affected by environment. For example, grains grown at Swift Current had a stronger relationship between EV and KWT than those from Lacombe (b = −1.67 vs. −0.31). For the grain from Swift Current, 60% of variability in EV was attributable to KWT, while for the grain from Lacombe only ≈ 20% of variability in EV was explainable by KWT. Among the various kernel-width categories within a genotype, 60 to 98% of variability in EV was attributable to kernel width, with some genotypes responding to a greater degree than others. In development of winter rye cultivars low in extract viscosity, breeders could combine kernel weight/width into the selection strategy to enhance the selection progress or use kernel weight/width as a reference in selection of extract viscosity trait. Key words: Pentosans, arabinoxylans, kernel weight, Secale cereale