Single plant selection of F1 lines for yield and quality of sweed potato tubers in Andosols, Malang (Indonesia)

Single plant selection of F1 lines for yield and quality of sweet potato tubers in Andosols, Malang. Single plant selection on F1 in sweet potato breeding will define the following. Selection steps since it is vegetatively cultivated. Then the selected single plants are vegetatively multiplied for the next selection purpose. The selection in initial step is objected to characterize yield and tuber performance such as shape, size, surface condition, skin and tuber's color. The F1 selection for 949 lines obtained from crossing was conducted in Jambegede during early dry season 1999. The plot size was a single ridge with 5 m long, with 1 m distance between ridges and 25 cm within the ridge. Three stems for each line were planted where 1 plant was chosen later whenever the tuber yield was higher than 500 g/plant with smooth tuber's surface. The basal fertilizers of 100 kg Urea + 75 kg SP-36 + 100 kg KCl/ha were applied, irrigation was applied in every 2 weeks until 2 months after planting. The growth of canopy of all lines varied from dance to widely spread. Tuber's yield ranged from 0 to 2103 g/plant with 716 g/plant in averages, standard derivation of 36,2 g and coefficient of variation of 50.7 percent. Based on yield and performance of tubers, there were 117 lines chosen with mean value of 1047 g/plant, standard deviation of 30.54 g, and coefficient of variation of 29.2 percent. The minimum and maximum tuber weight were 500 and 2103 g/plant, respectively. While the number of branches and tubers, shoot weight, harvest index, diameter and length of tubers were between 2-12, 2-9, 89-966, 61.4-93.1, 4.08-11.2 and 8-22 cm, respectively. The minimum and maximum dry material content of tubers were 24.1 and 42.4 percent respectively. Among 117 lines selected, there were 99 lines that produced the fresh tubers higher than 750 g/plant. When the population density is 40.000 plants/ha, the tuber yield of 30 t/ha could be obtained. Steamed processing for these tubers resulted in 54 lines that had good taste. There were 5 lines (547-22, 547-51, 559-3, 561-18, and 618-1) suitable for rice substitution as the tubers was less sweet but tasty (gurih) with "potato-like". These tubers have good prospect to be developed for special dish because the tuber's specific smell were less. These lines were then vegetatively multiplied for further selection