Abstract

                                A study was conducted to verify whether the validity period of nine months for the certified seed holds good for paddy, groundnut and cotton produced from various locations and stored under ambient conditions at Coimbatore. The validity period of certified seed samples of 29 paddy varieties (eight varieties each from Madurai and Dharmapuri STLs and 13 from Tirunelveli STL), five groundnut varieties (three varieties from Madurai and two from Dharmapuri STLs) and 11 cotton varieties / hybrids (eight varieties hybrids from Madurai and three from Dharmapuri STLs) were assessed. The results clearly indicated that the validity period of nine months for the certified seeds of paddy and cotton is appropriate. However, the validity period of nine months may be reconsidered for groundnut, since in most of the varieties the germination fell below the minimum standard at 8th month itself. The results also indicated that good quality seed with high initial germination could retain desired levels of germination upto a validity period of nine months. Significant differences due to varieties as well as place of production were noticed for validity period in all the three crops tested. In cotton, irrespective of location of seed collection, the hybrids performed better than varieties.

Key words : Paddy, Groundnut, Cotton, Certified seeds, Validity period.