A simple method for evaluation of sprout characters in soybean

Soybean sprouts are an important year-round vegetable in Asia. Currently, testing of soybean lines for sprout traits is labor intensive and amount of seed required have dictated that testing generally begins after lines have been composited from a plant row in the F-4 or later generations. Sprout testing requires germination of more than 150 seeds, precise watering over several days and movement of seedlings from water baths to growth chambers limiting the number of entries which can be evaluated. The objective of this study was to determine if germinating fewer seeds (10, 20 or 40) on an agar medium is comparable to sprouting over 150 seeds in the traditional method for evaluating soybean genotypes for sprout traits. Sprout growth characteristics were compared for Pungsannamulkong, a known sprout soybean, germinated on 1.0, 1.2, and 1.4% agar medium. Sprout traits 5 days after seeding 20 or 40 seeds on a 1.4% agar medium were very similar to the traditional method. There was no advantage for germinating soaked seeds over dry seeds on the agar medium to determine sprout characteristics. Evaluation of 20 dry seeds on a 1.4% agar medium of eight known sprout cultivars was comparable to the traditional method for measuring sprout characteristics for each cultivar. The agar method requires less labor, fewer seeds, no watering schedules or water baths and less growth chamber space than the traditional method to test genotypes for sprout characteristics. This allows more lines from soybean breeding populations in earlier generations to be evaluated. The agar method will improve the efficiency for evaluating soybean breeding lines for sprout traits.