ACID SOIL TOLERANCE OF SOYBEAN (GLYCINE-MAX L MERR) GERMPLASM FROM THE USSR

Nineteen soybean genotypes (ten from the former USSR, two from Brazil and seven from USA) were tested for aluminum (Al) tolerance by growing them for 21 days in greenhouse pots of acid, Al-toxic, unlimed Tatum (Typic Hapludult) subsoil at pH 4.0 and in limed subsoil at pH 5.1. Al uminum tolerance ranking depended upon the plant traits used in the sc reening process. Based on absolute dry shoot weights at pH 4.0, Giesse ner, Brunatna, and St.-59 (USSR), and Biloxi (USA) were most tolerant; least tolerant entries included Yantarnaya and Smena (USSR), and Davi s (USA). Based on relative shoot dry weights (pH 4.0/pH 5.1 %), Giesse ner, Brunatna, and St.-59 (USSR) were among the most tolerant, Bossier , Biloxi, Essex, and Perry were intermediate, and Salute 216 (USSR), C hief (USA), and Santa Rosa and IAC-9 (Brazil) were more sensitive to t he acid soil. Based on absolute root dry weights, Giessener, and St.-5 9 (USSR), and Biloxi (USA) were among the most tolerant and Smena, Yan tarnaya and Salute 216 (USSR), and Chief (USA) were most sensitive. Ba sed on relative root dry weights (pH 4.0/ pH 5.1 %), Giessener was mos t tolerant and Smena and Salute 216 least tolerant. Preliminary eviden ce indicated that soybean entries screened for Al tolerance on acid Ta tum soil also differed in tolerance to naturally occurring levels of a mbient ozone in greenhouses at Beltsville. The Russian entries VNIIS-2 , Giessener, and Brunatna appeared more sensitive than USA entries Per ry, Biloxi, Davis, and Bossier (USA), and Santa Rosa (Brazil). Aluminu m tolerance and ozone tolerance appeared to coincide in the Perry geno type. Studies on Al-ozone-soybean genotype relationships are being con tinued at Beltsville.