Studies on Deterioration and Germination of Bitter Gourd Seed (Momordica charantia L.) during Storage

Bitter gourd is a vegetable grown for its edible fruit and also popular due to its medicinal properties. Though seeds are being used for propagation, thick seed coat and high seed deterioration rate are major problems associated low field germination. Hence, a study was planned to establish the relationship between seed deterioration, electrical conductivity and oil content of stored seeds and to identify the optimum seed soaking treatment to overcome low germination due to seed coat thickness. The study was conducted in two experiments. In experiment I, seeds of local bitter gourd varieties stored for one to seven years in a refrigerator were used for oil extraction and seed leachate was measured for electrical conductivity. In experiment II, six priming treatments (viz, Control, 24 h soaking, 24 h soaking + partial removal of the seed coat, total removal of the seed coat, hot water treatment at 40 degrees C, and priming with KNO3 or vinegar solution) were used for one variety (N-1). Data were analyzed using simple linear regression and logistic linear model for experiments I and II, respectively. Results revealed that the electrical conductivity of the seed leachate and the oil content of the seed can be used to determine germinability. The oil content (ranged from 22.1 to 39.3%) and electrical conductivity (ranged from 55.7 to 118.0 mu S cm(-1) g(-1)) significantly increased with the increase in storage duration. Germination percentage was remarkably decreased from 85% (seeds stored for one year) to 0% (seeds stored for 7 years). Priming of seeds in 0.3% KNO3 or 0.2% KNO3 or in household vinegar (pH - 3.7) for a 2 h period induced higher germination of 90 and 80%, respectively. Therefore, it is concluded that bitter gourd seeds stored up to one year maintained high germination percentage but deteriorate rapidly afterwards. However, to achieve higher percentage of germination from seed stored for one year, it is recommended to prime seeds before planting using house hold vinegar or KNO3. The general availability of vinegar enable farmers to use this material as a convenient seed treatment.