Chemical composition and physico-mechanical properties of perennial cereal seeds as a factor of their economic longevity

Abstract

The aim and tasks of the study. To determine dependence of seed longevity of rare grasses, depending on their chemical composition and physico-mechanical properties.

Materials and methods. We studied varieties of cereal grasses bred in the Institute of Feed Research and Agriculture of Podillya NAAS and entered in the State Register for the first time in Ukraine: crested wheatgrass Agropyron cristatum  (L.) Gaertn. – Petrivskyi, hair fescue Festuca tenuifolia Sibth. – Barva, meadow brome Bromus riparia Rehm. – Boian, intermediate wheatgrass Elytrigia intermedia (Host) Nevski – Khors and slender wheatgrass Roegneria trachycaulon (Link) Nevski  – Kolumb. The research was conducted at the above-mentioned institute during 2008-2014.

Results and discussion. The study determined that the economic longevity of seeds with typical chemical composition of the test species during storage was 40-≥54 months for hair fescue, 46-54 months for intermediate wheatgrass, 32-42 months for meadow brome, 28- 42 months for crested wheat grass, and 32-34 months for slender wheatgrass. The peculiarity of chemical composition of hair fescue seeds is high starch content and low protein content; intermediate wheatgrass seeds are rich in starch and fat and poor in protein; meadow brome seeds have the lowest starch and fat contents and the highest protein content; crested wheatgrass seeds are characterized by moderate contents of basic reserve substances in comparison with the other test species; slender wheatgrass seeds are rich in protein and poor in starch. No relationships were found between the seed shape, length, 1000-seed weight and their longevity. The most long-lived species – intermediate wheatgrass and hair fescue – were noticeable for contradictory values of the seed length and 1000-seed weight. In addition, these species differ by the seed shape: hair fescue has lanceolate seeds, intermediate wheatgrass – elongated ones. The fill mode for seeds of the test species depended on their physico-mechanical properties, indicating that the air/seed ratio upon in bulk storage affects physiological processes during storage.

Conclusions. The longevity of seeds depended on their chemical composition. The most long-lived seeds distinguished by high starch content, a key ingredient in stored cereal seeds. The physico-mechanical properties affected the fill mode and physiological processes during seed storage. The fill mode for the most long-lived species (intermediate wheatgrass and hair fescue) was characterized by the lowest seed amount.