Evaluation of four white yam (Dioscorea rotundata Poir.) cultivars for seed yam production in Obio Akpa, South Eastern Nigeria

Abstract

Some yam cultivars respond poorly to the yam minisett technology. In South Eastern Nigeria, farmers involved in seed yams production  are often faced with problem of choice among the available cultivars of the white yam. To solve this problem, a field experiment was  conducted at the Teaching and Research Farm of the Faculty of Agriculture, Akwa Ibom State University, Obio Akpa Campus, from May,  2020 to October 2021, to evaluate the effects of cultivars and setts weight on the growth and yield of the white yam. The experiment  consisted of four cultivars of the white yam; Atam, Nwopoko, Afara and TDr 89/02665, and three setts weight categories; (20-25g),  (26-30g) and (31-35g). TDr89/02665 is an improved cultivar of white yam sourced from the National Root Crops Research Institute,  Umudike. The other cultivars were sourced from local yam farmers in Obioakpa community. The experiment was a 4 x 3 factorial,  replicated three times. The yam setts were planted at 1 x 0.25 m, corresponding to 40,000 stands/ha. Results showed that cultivars and  setts weight significantly affected all the growth and yield parameters considered in the experiment; percentage establishment, days to  first sprout emergence, number and length of vines as well as the number and yield of tubers. TDr89/02665 had the highest percentage  establishment (88.92 in 2020, and 89.93 in 2021), it also produced the longest vines (147.67 cm in 2020, and 149.61 cm in 2021). There  were no significant differences in percentage establishment and length of vines between TDr89/02665 and Atam. The shortest vines  (95.44 cm) were produced on Nwopoko in 2021. Atam produced the highest yields (7.65 tons/ha in 2020). In 2021, the highest yields (7.73  tons/ha) were produced by TDr89/02665. Setts weight categories (31-35g) performed better than the other two categories (26- 30g and  20-25g) in all the parameters under consideration; it had the highest establishment percentage, number and length of vines as well as  the number and yield of tubers; Results also indicated that there were significant interaction effects between the yam cultivars and setts  weight; TDr89/02665(31-35g) consistently produced the best yields (9.31 tons/ha in 2020 and 8.33 tons/ha in 2021) and was therefore  recommended to farmers in the study area.