Complex sentence: Most cultivars require between 600 and 1,000 hours of chilling; cultivars with chilling requirements of 250 hours (10 days) or less have been developed enabling peach production in warmer climates.
Split into simpler sentences: Most cultivars require between 600 and 1,000 hours of chilling around. Cultivars with chilling requirements of 250 hours (10 days) or less have been developed enabling peach production in warmer climates.