Effect of seed size, treatment and sowing depth on quality and yield of Ethiopian wheat (Triticum Spp.), faba bean (Vicia faba L.) and chickpea (Cicer arietinum L.) cultivars

[摘要] English: This study was undertaken in an attempt to obtain information on the quality of seed produced by some of the important crops grown in Ethiopia. Bread and durum wheat was chosen amongst cereals while chickpea and faba bean represented pulses. For all crops two cultivars were included except in the case of durum wheat where a third South African cultivar was additionally investigated. All experiments were carried out at the Small Grain Institute, Bethlehem, South Africa under laboratory and field conditions. The main objectives of this study were 1) to classify seeds of each crop into three different sizes (small, medium and large) and to characterize seeds in terms of kernel mass, hectolitre mass, moisture content and protein content where applicable, 2) to determine the differences in germination potential of untreated seeds and seeds treated with different fungicides under laboratory and field conditions, 3) to evaluate the field performances of different seedlots, including yield components, by means of agronomic parameters, 4) to investigate the effect of two different sowing depths on emergence, seed yield and other yield components and 5) to statistically determine cultivar, seed size, fungicide treatment and sowing depth interactions in a variety of ways. Of the two Ethiopian bread wheat cultivars, Mitikie outperformed Kubsa under laboratory and field conditions for most of the seed quality parameters evaluated. The main reason appeared to be the fact that deeper planted seeds performed well, probably due to longer coleoptile lengths of seedlings, which in turn was positively associated with strong and taller plants. When soil moisture is minimal, as is the case in semi-arid regions, it is possible to plant seeds of this variety deeper than normal in order to utilize soil moisture better. On average, small sized bread wheat seeds performed worst of all and large sized seeds best in terms of most of the measured parameters. Large seeds contributed to a 13.8% increase in seedling emergence and produced plants with a 22.1 % higher yield as well as 11.8% increase in above ground biomass. The effect of fungicides on the field performance of bread wheat seeds was less pronounced as compared to that of seed size. Seedling emergence from shallow planted (5 cm) bread wheat seeds was much better than from deep planted (9 cm) ones. However, although the seed protein content of seeds harvested from plants grown from deep plantedseeds were higher than that from shallow planted ones, shallow planting is still recommended for the Eastern Free State area on grounds of the overall performance of these seeds observed in this study. Durum wheat cultivars performed in a similar fashion as bread wheat. Seedlings of semi-dwarf durum wheat cultivars, as was the case for semi-dwarf bread wheat cultivars, showed longer root lengths than did the tall cultivars. Moreover, seeds from the semi-dwarf cultivar, Gerardo, produced taller plants than Orania and outyielded both other cultivars. Some weevil damage was observed in seeds of Kilinto and therefore its true performance could not be evaluated properly. Large sized durum wheat seeds outperformed the medium and small ones in most respects. Fungicide treatments also had an improving effect on seed performance compared to untreated control seeds. Seedling emergence was also greatly improved by shallow planting and this was reflected in significantly higher yields. The seed protein content, as was the case in bread wheat, were significantly higher in seeds harvested from plants grown from deep-planted seeds except in the case of Gerardo. Seed treatment with Vitavax Plus, together with deep planting, had the most significant increasing effect on the protein content in durum wheat seeds. In comparing the two faba bean cultivars, it was clear that Kuse outperformed Cs 20dk in terms of most of the evaluated parameters under both laboratory and field conditions. Similar to the previous two crops, large sized seeds appeared to outperform the other two seed size groups in most respects. However, surprisingly the small sized seeds produced seedlings with longer epicotyls but this had no real effect on the other quality parameters. Moreover, the fungicide Dividend also had some improving effect on the germination of faba bean seeds. Celest, however, significantly reduced the root length of seedlings compared to the other treatments, and also on grounds of the outcome observed by means of other parameters, Celest is not recommended for treatment of faba bean seeds. Deep planted (10-12 cm) faba bean seeds outperformed the shallow planted ones in many respects and deep planting is therefore recommended. In chickpea, none of the fungicide treatments improved the field performance of seeds. Dividend treatment rather reduced seedling root length. As in the case of bean, deepplanted seeds (10 cm) performed better than shallow planted ones (5 cm). In general, and in most respects, laboratory and field data correlated well. Moreover, recently released cultivars of all crops investigated, outperformed the older ones. This emphasises the need for replacing older cultivars with newer ones on a larger scale in Ethiopia. Large sized seeds are preferred to medium and the medium to small ones for all the crops investigated. Shallow planting for Ethiopian wheat cultivars, but deep planting for pulse cultivars, is recommended. Seed treatment with fungicides is imperative in wheat crops but is not as critical in pulse crops.

[发布机构] University of the Free State