Complex sentence: The wine and grape industry in Nebraska began in the late 19th century, by the end of which of grapes were in production, with most vineyards located in the counties of southeastern Nebraska adjacent to the Missouri River.
Split into simpler sentences: The wine and grape industry in Nebraska began in the late 1800s. By the end of the 19th century, of grapes were in production, with most vineyards located in the counties of southeastern Nebraska adjacent to the Missouri River.