The continuous growth in world population increases the demand for agricultural products. Cereal crops are particularly important to ensure future food security. However, the increase in the average ambient temperatures due to climate change threaten the crop productivity at the global scale. Barley (Hordeum vulgare L.) is one of the most demanded temperate cereal crops in the world for the production of animal feed, human food and alcoholic beverages. However, similar to other cereal crops, barley is sensitive to environmental changes such as ambient temperature and precipitation. During development, high temperature causes impaired spike development and reduced floret fertility which are the major causes of yield loss in barley. Therefore, in my PhD, I study the molecular and genetic components involved in the regulation of reproductive development in barley. I analyse the genetic, hormone and metabolite networks in shoot apical meristem (SAM) which control the spike development downstream of PHOTOPERIOD 1 (PPD-H1) which is one of the key regulators of photoperiodic flowering and the effects of high ambient temperature on reproductive development in barley.