A field experiment was carried out in Mossoró, Rio Grande do Norte State, Brazil, to evaluate the physiological characteristics and yield of sweet-potato cultivars ESAM 1, 2, and 3, harvested at 105, 130, and 155 days after planting date. The experiment was a 3 x 3 factorial in a randomized complete blocks design with four replications. Among the variables that compose the assimilatory apparatus of the cultivars, only leaf size was significantly different. The cultivars harvested at 155 days after planting date (i.e., 25 days after the recommended cycle) presented fever and smaller leaves and showed smaller leaf area ratio. However, they performed more efficiently in photosynthate translocation to storage roots, which increased significantly the number of marketable roots per plant and, consequently, both marketable and total root yields.
Ipomoea batatas; harvest index; plant age; physiological characteristics
