Shifting sowing of camelina from spring to autumn enhances the oil quality for bio-based applications in response to temperature and seed carbon stock

Camelina [Camelina sativa (L.)Crantz]is an emerging oilseed crop that is attracting the interest of farmers in relation to its high environmental adaptability and low-input request. Camelina oil is an outstanding feedstock for the bio-based industry, since its unique composition allows multiple applications. Being spring camelina biotypes able to grow as both an autumn and spring crop in mild climates, and sowing date directly influences the temperature occurring during the seed filling stage, which likewise influences the final seed quality in terms of seed weight, oil and fatty acid (FA)content. A detailed study on the response of spring camelina to the effects of autumn and spring sowing is reported herein. The spring variety Midas was sown at six different sowing dates at the experimental farm of Bologna University (Italy)during two consecutive growing seasons (2015-16 and 2016-17). In parallel, three experiments were also carried out in a growth chamber with different ranges of temperatures during the seed filling period. Samplings of immature seeds over time, in both controlled environment and open field trials, allowed identification of a “time frame” in which the main variations in FA kinetics occurred. A “critical period”, from 350 to 540 growing degree day after the start of flowering (GDD-AF)was identified as that in which the closest relation between the final camelina FA composition and temperature, during the seed filling stage, occurred. The adoption of this empirical model permitted early evaluation (about 10 d before harvest)of the final camelina oil composition with relevant implications for the bio-based industry. Autumn sowing dates were associated with increased plant aboveground biomass, seed yield, seed oil content, seed weight (TKW), and content of linolenic and eicosenoic acid. Since eicosenoic acid is a valuable feedstock for the bio-based industry, growing spring camelina, as an autumn crop, in the Mediterranean region allows significantly increase the quantity of this infrequent FA.