[en] Mature seeds of 6 mungbean varieties were treated with gamma irradiation at 100, 300, 500 and 700 Gy. Both adaxial and abaxial surfaces of the first true leaves of all plants treated by 500 and 700 Gy irradiation showed severe rough texture. For the 100 Gy treatments, the plants possessed either the severe rough texture or normal first true leaves, and the proportion of the plants with textured first true leaves varied among varieties. However, only very light rough texture of first true leaves of some of the plants was observed when the dose was 300 Gy. While lethality differed between varieties and with irradiation dosage, all of the varieties showed the same type and extent of appearance of textured first true leaves at each of the doses analysed. The rough texture of first true leaves was caused by the rugged surface of those leaves, which most likely resulted from the irregular size and or uneven density of mesophyll cells in the palisade layer. (author)