Mungbean mutant multi-location trials The objective of this study was to evaluate grain yield and adaptability of introduced mungbean mutants and their parents. A total number of 18 mungbean accessions including introduced mutants, their parents and three Thai check varieties were tested for their yield and adaptability in the central region of the Kingdom, Chai Nat FCRC (15o15’N lat., 100o15’E lon., 16m alt.) and Kasetsart University, Kamphaeng Saen Campus (14o01’N lat., 99o58’E lon., 5 m alt.). Details of experiment carried out are shown in [9]. The highest yielding variety across five trials during 2003-2005 was a Thai mutant, Chai Nat 72. It produced large seed of 70 g per 1,000 seeds which is a desirable trait for Thai and international markets. However, this mutant is susceptible to powdery mildew dise9ase. An introduction from the Philippines, LM19-Native Variety, showed resistance to the disease. It can be utilized for further mungbean breeding programme in Thailand [9].