A study was carried out in the Rio Bravo Experimental Station during the 1992-93 fall-winter cycle to evaluate two maintainer lines (susceptible and tolerant to weathering), four restorer lines, and the eight hybrids resulting from crossing these lines. Trials were conducted on lines and hybrids exposed to weathering, and grains were harvested 0, 11, 22, and 33 days after they were physiologically mature. Results indicated that the LRB-ll8B tolerant line showed greater weight/volume ratio and seeding vigor that the LRB-l04B susceptible line, and conferred these advantages on its hybrids. Significant differences were not found for the weight of 1,000 seeds and standard germination.