Abstract
For the study on self-and cross-incompatibility, 116 varieties of sweet pota:to were introduced into Agricultural Experiment Station, University of the Ryukyu from the Philippines, Japan, and Ryukyu Agricultural Experiment Station. In 1961, the authors made reciprocal pollinations between these varieties and 10 test varieties which belonged to 4 Oross-incompatibility groups (A, B, C and D) to observe germination of pollen grains on stigma. The results were as fcllows : 1) Out of the 106 varieties, 39 belonged to A group, 44 to B, 18 to C, and none to D. Remaining 5 varieties, i. e., Donyu-5, Gokoku x Shichifuku, Suburan, Taino-27, and Yamashiro, were compatible with all the test varieties. From these results, it was considered that they belonged to another group or groups, which was tentatively called X group in this paper, though it must be ascertained whether they belong to one group or not. 2) Seven of the varieties used were self-compatible and the remainder were self-incompatible. 3) The cross-incompatibility groups studied and the places from where all these varieties were introduced are listed in appendix. Among these varieties, 66 were not reported by FUJISE and YUNOUE (1950), and 13 varieties with the same names were fcund to be different in grouping as to incompatibility or morphological characteristics.
