et al., 1971). Fresh or frozen vegetable soybean can be cooked just like sweet pea (Pisum sativum L.) or lima Edamame (pronounced eh-dah-MAH-meh) are large-seeded soybean (Phaseolus limensis L.), either stir fried or added bean [Glycine max (L.) Merr.] harvested as green pods at the R6 stage when the seed are approximately 80% matured. The demand to stews and soups. They are nutritious and rich in phyfor edamame as fresh or frozen vegetable is increasing worldwide. tochemicals beneficial to humans. Masuda (1991) com-Currently, lack of adapted edamame cultivars is one of the major pared vegetable soybean quality with that of green peas factors limiting its commercial production in the southeastern USA.(P. sativum) and reported nearly 56% more protein A need exists, therefore, to evaluate and identify Asian vegetable content for vegetable soybean than that of green peas. soybean genotypes for potential production and/or as a source of The combination of low oil content and the relatively vegetable traits for breeding suitable cultivars. In a 4-yr study, six high protein content of fresh green soybean seeds makes Japanese edamame cultivars, four large-seeded Japanese plant introthem particularly desirable to the health conscious peoductions, two Chinese vegetable soybean cultivars, and two adapted ple seeking low fat, high protein snacks (Brar and Car-U.S. cultivars were evaluated for fresh green pod and seed yields and ter, 1993). The USA currently imports more than 10 000 seed composition at the R6 stage. The genotypes were planted in a randomized complete block with four replications and were harvested Mg of frozen edamame each year and this is estimated to at the R6 stage. The mean fresh pod and seed yields were 18.5 and increase to 25 000 Mg by 2005 (Lin, 2001). Soybean 9.6 Mg ha Ϫ1 , respectively. The PI 181565, 'Tambagura', 'Shangrao with 78 to 220 g isoflavone g Ϫ1 dried seed weight, de-Wan Qingsi', and PI 200506 with fresh pod and seed yields in excess pending upon isoflavone type (Mohamed et al., 2001), of 20 and 10 Mg ha Ϫ1 , respectively, offer potential for commercial is one of the few natural sources of isoflavones. Messina production in Georgia. The seed oil and protein contents ranged from (2001) summarized the results of several clinical studies 130.7 to 155.8 and 333.2 to 386.0 g kg Ϫ1 , respectively. The mean glucosethat showed the association of soyfoods, particularly soy content was 67.1 g kg Ϫ1 , whereas the mean phytate content was 12.6 isoflavones with reduction in blood serum cholesterol gkg Ϫ1 . Fresh pod weight was the major yield determinant (R 2 ϭ 0.88).

Comparisons among cultivars of leaf CO2 exchange rate (CER) based on leaf area may be confounded by leaf characteristics not usually accounted for in such comparisons. One such confounding characteristic appears to be leaf size. Correlation coefficients between leaf CER and leaf area (LA) were determined for genotypes of peanut (Arachis hypogaea L.), soybean [Glycine max (L.) Merr.], and sweet potato (Ipomoea batatas L.) and were compared with correlations for other crops reported in the literature. There were negative correlations between CER and LA in all crops examined. Significant negative correlations between LA and dark respiration were observed for wheat (Triticum sp.), alfalfa, (Medicago sativa L.), and peanut. Leaf area was negatively correlated with transpiration per unit LA and with leaf conductance for soybean. The relationship between leaf size and specific leaf weight was inconsistent in most crops. Comparisons of CER for genotypes having different leaf sizes may not represent the inherent differences in photosynthetic potential. Negative correlations between LA and CER may be one of the causes for the absence of consistent relationships between CER and yield.

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.

Two experiments were conducted to assess the effects of water stress on net photosynthesis (Pn) in peanut (Arachis hypogaea L.), since indications from earlier reports were that peanut photosynthesis might be less affected by water stress than in other crop species. Three genotypes of peanut were grown in pots in the greenhouse in 1973 (Experiment 1) and two were grown outside pots in 1974 (Experiment 2). Soybean [Glycine max (L.) Merr.] was included in Exp. 2 for comparison. Net photosynthesis and transpiration were measured on single leaves during a 5 or 6‐day drying cycle with assimilation chambers and relative leaf water content (RLWC) was determined by floating leaf discs on water. Diffusive resistance was calculated from transpiration data and also measured with a diffusion porometer. Water potential was determined on leaves and immature pods on the last 2 days of Exp. 2. Decreases in Pn of stressed plants during the drying cycle were closely related to decreases in RLWC and transpiration. The relationship between Pn and RLWCw as similar for peanut and soybean in Exp. 2. The diffusive resistance determined with a porometer or from transpiration varied between 0.5 and 2.5 sec cm‐1 for control plants, while the diffusive resistance of stressed plants reached maximum values of 18 to 20 sec cm‐1 in Exp. 1 and between 30 and 35 sec cm‐1 for peanut and soybean in Exp. 2. No differences appeared among genotypes of peanut in the response of Pn to water stress. Water potential of immature pods was equal to, or slightly higher than that of leaves at the end of Exp. 2. Comparison of the data for peanut with that from soybean and also with published data indicates that Pn of peanut is controlled by water stress in a manner quantatively similar to that of other crop species.