What is the difference between winter and spring barley, and what the *%^&(+ is a facultative barley?
Growth habit of barley is simple to describe but harder to define. There are three growth habit classes – winter, facultative and spring. A winter barley is planted in late fall and is harvested the following summer (e.g. 9-10 months from planting to harvest). A spring barley is planted in the spring and harvested the same summer (e.g. 4 – 5 months). If you plant a winter barley in spring, it will not flower, or it will flower so late that the yield will be abysmal. If you plant a spring barley in the fall, it will (in many temperate environments) die from low temperature injury. A facultative barley can be planted in the spring or the fall. Growth habit is controlled by many genes but there are three principal physiological traits involved: vernalization sensitivity, photoperiod sensitivity, and low temperature tolerance. Vernalization sensitivity means the plant needs exposure to low temperature before it can flower. Winter barleys are vernalization-sensitive whereas facultative and
