Standardization of drying methods for improved seed quality of groundnut and sesame seeds

Abstract

India is one of the important oilseeds grower and importer of edible oils. Oil crops are rich sources of oils, proteins, minerals, vitamins and dietary fibers. Oilseed crops like groundnut, sesame and sunflower are the second most important determinant of agricultural economy, next to cereals within the segment of field crops India stands fourth in oil production next to USA, China & Brazil. Drying of seeds plays a major role in maintaining the quality of seeds. Drying of Rabi harvested Groundnut as well as Sesame seeds is a very big challenge as far as Tindivanam is concerned. Since the seeds were exposed to very hot sun, it leads to cracking of seed coat which in turn leads to poor germination. Hence, to avoid exposing the groundnut as well as sesame seeds to very high temperature, the seed drying method is to be standardized for each seeds. To find the suitable seed drying methods for Groundnut TMV 13 and Sesame TMV 7, the seeds of Groundnut TMV 13 and Sesame TMV 7 were subjected to three methods of drying viz., Sun drying (Completely under sun), Shade drying (under tree shade)and Partial shade drying (morning under shade and evening under sun). The pods were dried to the uniform moisture content of 9% and packed in cloth bags and stored under ambient condition for ten month at Oilseeds Research Station, Tindivanam.  The seeds were evaluated for Moisture content, Germination percentage, Shoot length, Root length, Vigour index, Dry Matter production, Electrical Conductivity and Field Emergence at monthly interval. Seed storage studies revealed that the decrease in germination was faster in seeds groundnut seeds. The germination per cent decreased from 95.7 to 49.3 per cent during 10 months of storage. The vigour parameters like root and shoot length, dry matter production of seedlings, vigour index values and field emergence per cent decreased with increase in storage period. The seeds dried under shade registered maximum germination percent (79.4 percent), vigour index (2098), Dry matter Production (2.89 mg/seedling), Electrical Conductivity 0.312 ds/m and Field emergence (72.5 percent). Similar trend has been observed for Sesame seeds also.  In sesame, Minimum fluctuation in seed moisture content was observed in sesame seeds under different drying methods. The shade dried sesame seeds with initial moisture content of 8 per cent, stored in cloth bag recorded the highest germination (83.8 per cent), longest root and shoot length, maximum dry matter accumulation (34.4 mg),  maximum vigour index (1219) and field emergence (80.8 per cent) at end of tenth month of storage.