Effects of light stress on wheat and rye varieties grain composition

Integrating woody perennials and agricultural crops combined is a centuries-old practice, nowadays called agroforestry. Because agroforestry is being promoted by public administrations, it is essential to obtain scientific knowledge about the effect of different factors (e.g. tree shade) on crop characteristics. In this study, the effects of light intensity variation on the nutrient composition of wheat (Triticum aestivum L,) and rye (Secale cereale (L.) M. Bieb.) grain were analyzed, focusing on the concentration of macronutrients such as N, P and Mg and micronutrients such as Zn, Mn and Fe. To evaluate nutritional quality, 17 wheat and 11 rye varieties, grouped by t their flowering time (precocity), were studied. A randomized complete block design with four replications per variety and light intensity was used to carry out this study. These varieties were grown, in pots, under greenhouse conditions, during 2016-2017. To simulate different intermediate (IS) and high shade (HS) conditions, polyurethane meshes of different hole diameter sizes 0.0075 cm2 and 0.0026 cm2, respectively; applied in April, were used. In both species, an increase in nutrient concentration was observed under HS conditions. Micronutrients showed the greatest sensitivity to the variation in light intensity, especially Zn and Fe in wheat and Zn and Mn in rye.