Indirect measurement of the traits related to N2 -fixation may be useful as selection criteria for high nitrogen fixation. The objectives of this study were to determine the association between parameters indicative of nitrogen fixation and agronomic traits and to identify peanut genotypes with good nitrogen fixing ability and agronomic traits. Seven peanut genotypes were planted in a randomized complete block design with 4 replications under rainfed conditions in 2001 and 2002. Nitrogen fixation parameters were recorded as leaf color score, nodule dry weight, shoot dry weight, total dry weight, total nitrogen and fixed nitrogen while agronomic data were recorded as pod number per plant, pod weight per plant, seed number per plant, seed number per pod, seed weight per plant, 100-seed weight, shelling percentage and harvest index. Difference between years was significant for most traits except for shoot dry weight and 100-seed weight. Variety x year interactions were also significant for most traits except for shelling percentage. KKU 72-1 was the best genotypes for nitrogen fixation parameters in 2001. KKU 1 did not perform well in nitrogen fixation traits, but did for most agronomic traits, especially in 2002 except for 100-seed weight. Leaf color score and shoot dry weight may be useful as alternative means for determining nitrogen fixing ability of peanut under field evaluation. High association among nitrogen fixation parameters were found in both years. However, correlations between nitrogen fixation parameters and agronomic traits were not strong in 2002.
