Black rice is one type of rice that has high nutritional content and is beneficial for body health. However, black rice is still very rarely cultivated because of the many obstacles encountered in the field. Constraints in cultivation on land are caused by the weaknesses of black rice such as long plant age, low productivity, and high plant habitus. Those can be dealt with by modern plant breeding, one of which is mutation breeding by using gamma-ray radiation induction. Improvement of plant properties through gamma-ray irradiation with doses of 200 grays and 300 grays was carried out on black rice of the Cempo Ireng variety in previous studies. This research was conducted to test the yield of selected lines that were stable and uniform in previous studies. The research was carried out on Agricultural Land in Pakahan Village, Jogonalan Sub-district, Klaten Regency. The environmental design used was a single factor completely randomized block design (RCBD) consisting of 6 early maturity black rice lines and 3 comparison varieties with 4 repetitions. The data were analyzed by using variance based on the F test at a 5% level and continued with DMRT at 5% error level. The results show that the lines had better yields than the comparison varieties. The expected early maturity mutant lines of black rice that were irradiated by gamma rays had a shorter lifespan but higher productivity than those of controls.