OF SEED YIELD AND RELATED TRAITS IN BIPARENTAL CROSSES OF OKRA , Abelmoschus esculentus ( L . )

The objective of this project was to evaluate ageing-induced genetic changes during storage of tomato seeds. Seeds of 10 accessions of tomatoes were thus subjected to artificial ageing in chambers conditioned to 55°C and 72±2% RH for 72 hours. Seed survival data were used to estimate probit parameters. Genetic changes during the seed ageing course were evaluated by microsatellite (SSR) analysis using a Direct PCRTM kit., The SSR primer sequences (except SGN-14430) optimized the gene markers for the tomato accessions and are thus recommended for detecting genetic changes during seed storage. Genetic distances were calculated using PASTTM software and percentage genetic integrity was estimated from the genetic distance matrices. Probit analysis showed that P estimates was least in 50 accession LOO169 (7 days) and highest in accession 09/044 (64.4 days). Seeds having lower P estimates showed lower estimates of genetic integrity. Lowest estimate of average 50 genetic integrity was 99.21% when estimates of genetic distances were compared between 0 and 72 hours of artificial ageing. The results showed ageing-induced genetic deterioration during artificial ageing thus suggests possibility of losses in genetic integrity of seeds in storage at a specific physiological (germinability) benchmark. For tomatoes, this study shows that seed germinability benchmark for genetic changes during ageing was approximately 42%. Comparison of tomato seeds stored in the NACGRAB gene bank for 2 years and freshly harvested seeds, validated the artificial seed ageing result and the estimated germination benchmark for declining genetic integrity in tomato seeds.