تلخیص
In a pot culture experiment, seven mungbean advanced genotypeskultivars (NM-20-21, 6601, NHM-36, N11111-37, NHM-45, NHM-51 and NHM-54) were screened for their natural modulation and nitrogen fixing potential using "N isotope dilution technique. The results revealed that number of nodules, nodules dry weight/plant and percent nitrogen in shoot were higher and statistically equal in the mutant lines NM-20-21 and 6601, than the other mutant lines tested. Nitrogen fixation potential as estimated by atom percent "N excess also revealed that NM-20-2I was the most efficient line followed by 6601, whereas NHM-54 exhibited the least nitrogen fixing potential.