Breeding and utilization of orchardgrass ‘Esajiman’ with high WSC (water-soluble carbohydrate) content and high nutritional yield

Abstract

The water-soluble carbohydrates (WSC) content of genetic resources in orchardgrass was evaluated to improve WSC content, and significant genetic variation for WSC content was found among them. ‘Esajiman’, a new cultivar of orchardgrass (Dactylis glomerata L.), was developed by Hokkaido Agricultural Research Center, NARO, in collaboration with Snow Brand Seed Co., Ltd. using these genetic resources as breeding material. The heading date of ‘Esajiman’ was 2 June and was a medium late maturity as well as ‘Harujiman’. The total dry matter yield across three years in regional performance testing in ten locations averaged 4% higher than that of ‘Harujiman’. The water-soluble carbohydrate (WSC) content was 3 percentage points higher than that of ‘Harujiman’ across three years and four locations. Its fiber contents were lower than those of ‘Harujiman’. The estimated total digestible nutrient content of ‘Esajiman’ was 2 percentage points higher than that of ‘Harujiman’, and its total digestible nutrient yield was 9% higher. The value of fermentation quality of ‘Esajiman’ silage, measured as the V-score, was higher than that of ‘Harujiman’ silage. Milk production was 4% higher than that of ‘Harujiman’ when the silage of ‘Esajiman’ was fed to milking cows. Following ‘Esajiman’, early maturity cultivar ‘Wasejiman’ and very late maturity cultivar ‘Kitajiman’ with high WSC content were bred. These varieties with a high WSC content can contribute to an increase in the productivity and quality of self-sufficient feed in the Hokkaido and Tohoku regions.