Tolerance of soybean genotypes to aluminum in solution

The knowledge of the soybean (Glycine max L.) genotypes reaction to aluminu m (AI) present in acid soils is important for the development of efficient breeding programs. A series of experiments were carried out to determine th e levels of Al and calcium (Ca) in low salt solutions and the most appropri ate time for screening. The next experiments were conducted to rank Brazili an soybean cultivars and breeding lines according to their tolerance to Al with some American cultivars, considered as standards. A solution with 0.2 mg L-1 of Al and 50 mg L-1 of Ca was used and the primary root length obtai ned in the ninth day was utilized to screen 148 soybean genotypes for Al to lerance. Among these genotypes, 21 were Al-tolerant : Biloxi, Bragg, BRAS85 -1736, BRAS86-3672, BR-13 (Maravilha), BR-37, Cobb, EMGOPA-302, EMGOPA-304 (Campeira), FT-1, FT-5 (Formosa), FT-6 (Veneza), FT-Guaira, FT-Manaca, IAS 4, IPAGRO-21, Ivai, MSBR-17 (Sao Gabriel), OCEPAR-6, Planalto and Tiaraju. Seventy three genotypes had intermediate tolerance and 54 were non-tolerant to Al.