both in the national and international markets (Carter and Wilson, 1998;Boerma and Mian, 1998). Soyfoods Soybean [Glycine max (L.) Merr.], an important component of have been reported to provide protection against heart the Asian diet, is gaining popularity as a source of vegetable protein and phytochemicals in the USA. However, soybean cultivars with disease, cancer, menopausal symptoms, and other disdesirable agronomic traits and biochemical components that enhance eases (Carter and Wilson, 1998; Messina and Messina, the quality of soyfoods have not been identified for cultivation in the 1991). Because of the nutraceutical value of soybean, USA. Twelve soybean genotypes, including three from Japan, were there is a growing demand for soyfoods, such as soymilk, evaluated for their agronomic performance, genotype ϫ environment several types of tofu, soybean sprouts, and soynuts. Soy-(GE) interactions, and yield stability at four locations in the USA food sales in the USA have been growing steadily at a from 1994 to 1997. At maturity, seed yield, biomass, harvest index rate of 10 to 25% yr Ϫ1 (Kuhn, 1996) and exceeded $600 (HI), and 100-seed dry weight were determined using plants harvested million in 1998. About 9 to 10 million t of soybean seed from the middle two rows of each plot. Genotypic differences for the are imported into Asia for manufacturing soyfoods and traits examined were significant. The mean seed yield across locations for oil extraction. Tofu, a cottage cheese-like soybean and years ranged from 2.0 to 3.0 Mg ha Ϫ1 . The Japanese cultivars had larger seeds but were outyielded by the American genotypes by ≈10% curd, has high nutritional value and is rich in proteins, and up to 35% by 'Hutcheson'. The genotype effects were significantly vitamins, and minerals, particularly Ca. Tofu consumplarger than the location ϫ year effects for plant height, seed weight, tion is growing at an annual rate of 20% in the USA and HI, but not for biomass or seed yield. Biomass and HI were and among health-conscious people around the world important determinants of seed yield. S90-1056, V81-1603, V71-370, (Carter and Wilson, 1998). Thus, the increasing market 'Enrei', 'Nakasennari', 'Ware', and 'York' were stable for seed weight for soyfoods and health benefits associated with them across years. Hutcheson, S90-1056, York, MD86-5788, Nakasennari, indicate the economic potential and emphasize the need and BARC-8 showed yield stability across environments and years.for the identification and development of high-yielding S90-1056, York, and Nakasennari were stable for both seed weight and U.S. soybean cultivars suitable for food processing and seed yield; therefore, they could be used for commercial production in human consumption. the USA or for breeding soybean cultivars suitable for tofu preparation.

Soyfoods are becoming popular among American consumers because of potential health benefits. However, specific information about the kind of soybean [Glycine max (L.) Men.] seed desirable for soyfoods preparation is limited. The objectives of this study were to compare soymilk and tofu prepared from 12 soybean genotypes grown at four locations in the southern USA during 1995 to identify genotypes suitable for soymilk and tofu manufacture and to determine effects of seed traits on yield and quality of soymilk and tofu. Location effects were significant only for soymilk solids and tofu strength. Soymilk yield with a mean value of 5.1 mL g−1 seed was not affected by soybean genotype. Significant genotypic effects were observed on tofu yield, which varied from 0.82 to 0.91 g mL−1 of soymilk. Tofu yield was significantly correlated to seed size (+0.31), seed oil (+0.74), rate of water absorption after 1 and 16 h of soaking (+0.38 and +0.56, respectively), and seed protein (−0.82). Seed protein content, seed size, and soymilk solids were significant determinants of tofu yield (R2 = 0.80). Two variables, soymilk index (SI) and tofu index (TI), were calculated to compare overall suitability of soybean genotypes for soymilk and tofu production. SI was calculated by summing yield, total solids, protein content, and whiteness index of soymilk. TI was calculated by summing yield, protein, whiteness index, and strength of tofu. Seed oil content and size were significant determinants of SI (R2 = 0.41), whereas soymilk color, seed size, and seed protein content were significant determinants of TI (R2 = 0.52). The SI and TI values indicated BARC‐9 to be a desirable genotypes for soymilk and for tofu preparation.

Wild germplasms are often the only significant sources of useful traits for crops, such as soybean, that have limited genetic variability. Before these germplasms can be effectively manipulated they must be characterized at the cytological and molecular levels. Modern soybean probably arose through an ancient allotetraploid event and subsequent diploidization of the genome. However, wild Glycine species have not been intensively investigated for this ancient polyploidy. In this article we determined the number of both the 5S and 18S-28S rDNA sequences in various members of the genus Glycine using FISH. Our results distinctly establish the loss of a 5S rDNA locus from the "diploid" (2n = 40) species and the loss of two from the (2n = 80) polyploids of GLYCINE: A similar diploidization of the 18S-28S rDNA gene family has occurred in G. canescens, G. clandestina, G. soja, and G. max (L.) Merr. (2n = 40). Although of different genome types, G. tabacina and G. tomentella (2n = 80) both showed two major 18S-28S rDNA loci per haploid genome, in contrast to the four loci that would be expected in chromosomes that have undergone two doubling events in their evolutionary history. It is evident that the evolution of the subgenus Glycine is more complex than that represented in a simple diploid-doubled to tetraploid model.

Seventeen determinate soybean (Glycine max L.) cultivars from maturity groups V through VIII were screened for drought tolerance during germination and seedling stages. Germinating seeds and hydroponically‐grown seedlings were subjected to osmotic stresses of ‐0.3 and ‐0.5 MPa using polyethylene glycol M.W. 8000. Genotypic variability was found among the cultivars for all the parameters analyzed in both germination and seedling tests. Germination stress index was lower for seeds exposed to ‐0.5 MPa than for ‐0.3 MPa osmotic stress. Lower osmotic potential in the treatment medium was also correlated with lower leaf water potential in seedlings subjected to it. A significant relationship was found between fresh weight and height stress indices. The cultivars that grew taller under drought stress conditions had greater dry matter accumulation and higher germination stress indices indicating the reliability of height to predict cultivar performance under such conditions. The cultivars Lee‐74 and Wright had higher dry matter accumulation, greater height, and better germination under stress conditions than the other cultivars tested. Conversely, the cultivars Ra 401 and Bay performed poorly in the drought tests at both levels. In the seedling tests, there was no strong relationship between the leaf water potential and the overall performance of the plant suggesting no clear osmoregulatory mechanism. Based on results from germination and seedling tests, the cultivars Lee‐74, Wright, and Ra 401 were selected for further studies in greenhouse and field trials.

High Al in acid subsoils of the Southeastern States often restricts root growth and moisture utilization. Liming subsoil is difficult and expensive. An alternative or substantial approach is to select or breed plant genotypes having greater tolerance to Al. The differential Al tolerances of soybean [ Glycine max(L.) Merr.] representing Maturity Groups V, VI, and VII were determined in a growth chamber using nutrient solutions containing 0 and 8 ppm Al. Screening was also done on acid (4.2) and limed (5.8) in Bladen soil (Typic Albaquult) in the greenhouse. Aluminum sensitive ‘Chief’ and Al‐tolerant ‘Perry’ were included as standard checks. Soybean plants injured by 8 ppm Al in nutrient solution were characterized by narrow leaf blades, leaf chlorosis, reduced plant height, stunted, blackish root tips. In unlimed soil the relative root dry weight seemed a better index of differential Al tolerance among cultivars than top dry weight. Roots of the cv. Perry yielded 20% more dry weight than Chief in unlimed soil. Liming the soil to pH 5.8, increased the yields of sensitive cv. Chief by 40% compared to the unlimed soil. On the unlimed soil, plant symptoms such as cupping and chlorosis of young leaves were observed. The most tolerant and sensitive lines tested were; PI 81042 (V), PI 159322 (VI), Missoy (VII), and PI 88490 (V), PI 85010 Pocahontas, respectively.