Short answers, pulled from the story.
Pliny the Elder wrote about rye as a poor food source in the year 1536. He described the grain as mixed with emmer to mitigate its bitter taste and noted that it was most unpleasant to the stomach.
Evidence from the Epipalaeolithic site of Tell Abu Hureyra suggests that rye was among the first cereal crops to be systematically cultivated around 13,000 years ago. This claim remains controversial due to inconsistencies in radiocarbon dates and identifications based solely on grain rather than chaff.
Rye plants withstand cold better than other small grains by surviving snow cover that would kill winter wheat. This resilience is assisted by the production of antifreeze polypeptides by the leaves of winter rye, which allows growth during warmer days of the winter when sunlight temporarily warms the plant above freezing.
Consumption of ergot-infected rye by humans and animals results in ergotism, which causes convulsions, miscarriage, necrosis of digits, hallucinations, and death. Historically, damp northern countries that depended on rye as a staple crop were subject to periodic epidemics of this disease, often referred to as St. Anthony's Fire.
The Roggenwolf, or rye wolf, is a carnivorous corn demon or Feldgeist shaped like a wolf in European folklore. This field spirit steals children and feeds on them, and the last grain heads are often left at their place as a sacrifice for the agricultural spirits.
In 2023, world production of rye was 12.7 million tonnes, led by Germany with 25% of the total. Poland and Russia served as major secondary producers, while Europe produced around half of the world's rye.