Influence of Endosperm Types, Seed Moisture Content and Threshing Methods on Germination and Seedling Vigour of Sorghum

摘要

Sorghum (Sorghum bicolor L. Moench) is the most important cereal crops in the world. It is adaptedto wide agro ecological zones. It has high production compared to most other cereal crops under droughtconditions. The study was conducted to determine the effects of endosperm types, seed moisture content andthreshing methods on germination percent, mean germination time and seedling vigour of sorghum seeds.Two varieties of sorghum were grown in two diverse locations namely Kiboko and Katumani. One varietyKari-mtama 1 has hard (vitreous) endosperm, while other variety Seredo has soft (non-vitreous) endosperm.After harvesting, sorghum panicles were dried in the sun and using oven before threshing. The panicles werethreshed separately for each drying method at two moisture levels namely 18-20% and 13-14%. The threethreshing methods used included beating by wooden stick in tied sack, using wooden mortar and pestle as wellas using threshing machine. The seeds from various treatments were evaluated for germination percent, meangermination time and vigour using ISTA rules in the University of Nairobi Laboratory. The results showed that,the seeds from panicles that were threshed at low moisture content (13%-14%) (M.C) had significantly highergermination percentage, seedling vigour and took significantly short time to germinate than those which werethreshed at high moisture content (18%-20%). Similarly, seeds that were threshed using threshing machine hadsignificantly higher germination percent, seedling vigour and took shorter time to germinate compared tobeating with wooden stick and mortar and pestle The results suggested that, sorghum panicles have to bethreshed at low moisture content (13%-14%) to obtain high seed quality. Threshing by machine is the bestmethod to be used to avoid poor seed quality followed by beating with wooden stick. Wooden mortar andpestle threshing method should be avoided in threshing sorghum panicles because it results into high seedmechanical damage and hence lowering germination and seedling vigour as compared to beating with woodenstick and threshing by machine. There was no genotype by environment interactions for germination andseedling vigour. This shows that, the results are applicable for sorghum crop across the environments.