Effect of planting pattern and season on some agronomic performances and yield of sweet potato cv. Japanese Orange

Abstract

Sweet potato (Ipomoea batatas (L.) is one of the most important root crops in the world. It is primarily grown as a second crop during the dry season in Thailand. Several cultivars are produced with some being imported from Japan, especially cv. Japanese Orange, Yellow and Purple which are popular because they have high value and are rich in phytochemicals. Thai farmers use only one planting pattern for production although there are five recommended patterns available. The objectives of this study were to investigate the effect of different planting patterns on yield, agronomic traits, and determine associations among agronomic traits of sweet potato cv. Japanese Orange. The experiments were conducted during the rainy and dry seasons of 2017. An RCBD with 5 planting patterns and 3 replications were used. Tuber yield, no. of tuber/plant, no. of tuber/ha, no. branch/plant, tuber diameter and tuber fresh weight were measured. The results revealed that during the rainy season, pattern 5 (three vines per hole) had highest tuber yield (11.2 ton/ha), no. of tubers/plant (7.7) and number of tubers/ha (408.9×103) whereas pattern 3 (one vine) had highest no of branches/plant (4.7) and tuber diameter (36.9 mm). In the dry season, patterns 1, 5 and 3 had the highest yields (7.13, 6.71 and 6.48 ton/ha, respectively) pattern 1 had significantly higher tuber fresh weight (84.17 g) than the other four patterns. Pattern 5 had the highest number of tubers/plant and number of tubers/ha during the dry season. We found positive correlations between tuber yield and number of tuber per plant, number of tuber per ha, vine length, vine girth, number of nodes per plant at 60 and 75 DAP.