Abstract
Twenty experiments were carried out with 20 sweet potato clones in five locations differing in altitude, from sea level to 2000 m in Cameroon over a period of four years to study their response to altitude and to investigate the stability of their performance across environments. The clones did not show any different response to a range of altitudes from 80 to 2000 m. The high-yielding clones- 1112, 048, 1611,Tlb 1, 502 and TIS 2544- gave the most satisfactory performance at all altitudes, producing mean yields of 14.8, 14.3, 13.3, 12.6, 11.8 and 11.6 t ha-1, respectively. The highest mean yield (17 t ha-1) was produced at the lowest elevation; mean yields (about 9 t ha-1) did not differ between 450 and 1330 m, but sharply declined to 5 t ha-1 at 2000 m. The four statistical models used to assess stability differed in detecting stable clones. Clones TIS 2544, 1592, Tlb 1, TIS 2498, 002, 1639, 1602, 1597 and Njombe, were rated as stable by all stability methods. Other observations regarding cultivar performance across environments are discussed.
