Effect of dressing of hot water-steeped and unsteeped seeds on longevity and seedling emergence in Corchorus olitorius L.

Abstract

The study was conducted at the laboratory of the Department of Crop Production, Federal University of Technology Minna. Seeds of cultivars “Amugbadu” and “Oniyaya” of Corchorus olitorius were steeped in hot water at 97°C for five seconds (for the purpose of breaking dormancy) and subsequently air dried to about 10% moisture content (wet weight basis). They were then treated with seed-plus, Apron-star (As) or Wood ash (Wa) at the rate of 10 g per 4 kg seed, packaged in paper envelopes and stored for 20 weeks at 30°C while the unsteeped seeds served as the control. Germination ability and seedling emergence were determined before and during storage. Before storage, 90 and 95% germination levels were recorded for hot-water steeped seeds of “Amugbadu” and “Oniyaya” respectively in contrast to 25 and 33% germination for the unsteeped seeds. There was a general decline in both germinability and seedling emergence with storage period irrespective of treatments. In non-dormant “Amubgadu” seeds, viability was better maintained without seed dressing or when seeds were dressed with wood ash. In “Oniyaya”, viability was poorest in As-dressed seeds. Significantly better seedling emergence was recorded in non-dormant seeds dressed with wood ash. Unsteeped (dormant) seeds germinated poorly throughout the storage period. Dormant seeds from which zero germination was recorded after 12 weeks of storage gave about 75% germinations followed by steeping in hot water. It is postulated from this observation that the poor germination of stored seeds might be due to a decline in the germination energy of the seeds which made their radicle unable to rupture the endospermic tissue and seed coat. This is an indication that the seeds were still viable at this age but required the weakening of the seed coats (which was effected by hot water-steeping) to permit germination.