Aneuploid lines of Var. Pb. C 591 are being maintained at the Division of Genetics, IARI. Seeds harvested during the year 1991, 1993 and 2000 were evaluated for their viability, root number, root length, coleoptile length and shoot length. Detailed study of these traits revealed that the germination percentage ranged from 86% to 100% in fresh seeds (2000), 82% to 100% in 1993 seeds and 66% to 100% in 1991 seeds. Means of root length were 12.96 cm in 2000 seeds, 11.50 cm in 1993 seeds and 10.55 cm in 1991 seeds. Means of root number were 5.09, 4.55 and 4.45 in the years 2000, 1993 and 1991 and the means of shoot length for the years 2000, 1993 and 1991 were 18.41 cm, 14.24 cm and 10.88 cm respectively. These observations clearly revealed that the seeds from 1991 showed high significant reduction in all the characters as compared to the fresh seeds (2000).

Introduction

Monosomics of the aneuploid lines of variety Pb. C 591 were reported by Swaminathan et al. (1968). These lines have been used for locating genes on specific chromosomes and are being maintained at the Division of Genetics, IARI, New Delhi. It is known that frequent planting and identification of monosomic lines enhances the chances for the occurrence of univalent shift which means that we should not expose the monosomic lines for frequatent meiotic analysis. It is advantageous to make use of the stored seeds as long as seeds do not loose their viability. With this objective in mind a study was undertaken to evaluate the monosomic seeds harvested from cytologically identified plants from the years 1991, 1993 and 2000, respectively.

Materials and methods

To study the effect of storage on seed germination and other seedling characters seeds of all the monosomic lines of variety Pb.C591 of three different years 1991, 1993 and 2000 were taken. Seeds were wrapped in aluminium foil and covered with polythene and kept in refrigerator to avoid the effect of atmospheric humidity. The outside humidity was maintained at 4-5%. Seeds were taken from the cytologically identified monosomic plants which were stored in the refrigerator at 8 plus or minus 1 ^oC. Twenty five seeds from each monosomic were kept for germination in two different petridishes and enough moisture was provided. Data were recorded on root number, root length, shoot length and coleoptile length on the 10th day of seed imbibition. Seed germination percentage and means of root length, root number, coleoptile length and seedling height were calculated. Statistical analysis of these traits was carried out (Gomez and Gomez 1984).