Effect of natural and artificial chilling in carrot Daucus carota L. at different locations in Kenya. II. Effect on seed maturity, seedstalk height, umbel number, seed yield and subsequent germination of the harvested seed

altitud altitude calidad carotte carrots clima climat climate cooling cultural methods daucus carota enfriamiento germination graine kenia kenya mode de culture production production de semences quality refroidissement seed production seeds semilla vernalisation vernalization zanahoria