Development of the Urine Sugar Analysis Paper (USAP) method as a rapid tool for seed viability testing in okra (Abelmoschus esculentus L.)

Direct seed quality testing of okra through germination may take up to 21 days. Therefore, a rapid, simple, and inexpensive indirect biochemical method was developed. This study evaluated, for the first time in okra, the Urine Sugar Analysis Paper (USAP) as a rapid, simple, and inexpensive tool for assessing seed quality by measuring cell membrane leakage. The first experiment was to determine the effectiveness of the accelerated aging method at 40 °C compared to 45 °C and to use the aged lots of red okra with various levels of viability for testing using the USAP. Protein leakage, glucose, specific gravity, and pH of seed leachates were measured using USAP and compared with conventional vigor tests and spectrophotometric analyses in the second experiment. Accelerated aging at 45 °C effectively generated high, medium, and low viability seed lots. Incubation method at 35 °C for 18 h provided the clearest separation among viability levels. Under this condition, protein leakage detected by USAP was strongly positively correlated with spectrophotometric protein content and electrical conductivity, and strongly negatively correlated with germination percentage and speed of germination. These relationships indicate that greater protein leakage reflects lower physiological quality. This USAP method offers a rapid and inexpensive biochemical test that can reliably distinguish okra seed lots by viability and vigor, and represents a practical complement to standard germination tests.