Effect of dialyzing tubing and glassine pollinating bags on seed set and seed weight of barley and wheat hybrids

A field study was conducted to evaluate the effect of clear dialyzing tubing and translucent glassine bag as different pollinating bag types on percent seed set and average seed weight of hybrid seed of barley (Hordeum vulgare L.) and wheat (Triticum aestivum L. em. Thell). Diallel crosses including reciprocals were set up using five winter barley cultivars ('Volbar', 'Harrison', 'Clayton', 'Keowee' and Mo. B2632) and four winter wheat cultivars ('Arthur', 'Sullivan', 'Blueboy' and 'Pioneer S76'). The degree of success in crossing the chosen cultivars was evaluated. The approach method of pollination was used for both barley and wheat. Control treatments, consisting of emasculation without pollination, were used to test the efficiency of the emasculation treatments in preventing selfing.

In the wheat study, the clipping method of emasculation was used resulting in a low selfing rate of 0.67%. The overall crossing success rate was 58.18%. There were no significant differences observed in percent seed set between bag types, however, seed produced under glassine bags were significantly heavier (P 0.05) than those produced under clear dialyzing tubing. There was significant variation in percent seed set and average seed weight produced by the different operators (workers doing emasculating and pollinating). The percent seed set and average seed weight were also significantly different among crosses and among cultivars used as female parents.

In the barley study, the scissors method of emasculation resulted in a low selfing rate of 0.05%. The overall crossing success rate was low, 1.13%. This was principally due to weather conditions during the pollination period. The percent seed set produced under glassine bags was significantly higher (P - 0.05) than that produced under dialyzing tubing. However, there was no significant difference in the average hundred seed weight between the two bag types. There was significant variation among operators for percent seed set but not for average seed weight.

It was found that the glassine bag was more effective in producing higher percent seed set in barley and heavier seed weight in wheat when manual emasculation and pollination was done to obtain hybrid seed. There was significant variation among crosses in seed set. Weather conditions had some influence on the success of crossing.