Seed Rate and Sowing Method Effects on Seed Quality of Bread Wheat (triticum aestivum L.) Varieties in Horo District, Western Ethiopia

Abstract

Although wheat varieties were released with recommended seed rates, farmers usually apply their specific seed rates for various reasons. A study was conducted in Horo District to determine the effect of seeding rate and sowing methods on the seed quality of bread wheat using field and laboratory experiments, in the 2011 cropping season. The field experiment was conducted at Shambu, Bako agricultural research center sub-site while the seed quality analysis was performed at seed laboratory of Holetta Agricultural Research Center. The field experiment consisted of three factors in a factorial combination of two levels of variety (Molgo which is local and Digelu or HAR-3116 which is an improved one), two levels of sowing methods (broadcast and row) and four levels of seed rate (125, 150, 175 and 200 kg/ha) arranged in RCBD with three replications. Samples of harvested seed from those treatment combinations were subjected to seed quality analysis according to procedures described by ISTA 2003. The result of Seed quality analysis showed that physical purity, standard germination, the speed of germination, vigor index-I and II, and field emergence index were significantly affected by treatment effects. All these parameters were higher in Digelu than in Molgo at the lowest seed rate (125 kg/ha) studied in row except the mean value of speed of germination which was higher for Molgo at a seed rate of 150 kg/ha. Six fungi and one bacterium species were associated with the seed samples studied. The results indicated that good quality seed was produced when both varieties were sown in row at a seed rate of 125 kg/ha. Moreover, variety Digelu was better in terms of seed quality than variety Molgo at all seed rates and both sowing methods.

Evaluating the Impact of Variable Seed Rates on Growth, Productivity and Yield attributes of different Wheat (Triticum aestivum L.) Genotypes of Barani Areas

“…He also reported that seed with good size had more vigor and produced more shoot, root and coleoptile length with excellent utilization of seed reserves. Similar results were reported by (Geleta, 2017) who also reported maximum seedling root length at seeding density of 125 kg ha -1 whereas the shortest root length was observed at 200 kg ha -1 planting density. These findings show a similar trend that an optimal increase in seed rate results in enhanced root length however, an excessive planting density can negatively affect root length.…”

“…Contrarily, planting density of 100 kg ha -1 (8.70 cm, 10.71 cm, 8.52 cm) revealed more shoot length than higher planting density of 140 kg ha -1 (8.70 cm, 8.20 cm, 9.53 cm) although lesser than 120 kg ha -1 altogether (Table 5). Parallel conclusions were found by (Geleta, 2017) who also reported greater shoot length at an optimum seed rate of 125 kg ha -1 while the minimum shoot length was revealed at higher seeding density of 200 kg ha -1 . This disparity among shoot length may be due to lesser plant population at lower seed rate with minimum competition for nutrients, space, and sunlight.…”

“…Conversely, Dharabi-11 showed lowest germination percentage (75%) proving that varying seed rates had a prominent effect on germination percentage (Table 4). The analyzed data clearly represents that germination percentage decreased with an increment in seeding density of 80, 100, 120 and 140 kg ha -1 as elucidated by (Geleta, 2017). He also found the highest mean value for germination percentage at the seeding density of 125 kg ha -1 whilst lowest mean value was observed at a higher seed rate of 200 kg ha -1 .…”

“…Thousand grain weight is a significant yield determining feature that is said to be impacted by genetic constitution of a plant therefore less affected by environmental factors (Geleta, 2017). Different seed rate had significantly affected thousand grain weight in all genotypes.…”

Effect of seed vigor and sowing densities on the yield and physiological potential of wheat seeds

“…Different sowing densities can modify not only yield but also the physiological potential of the seeds produced. For the wheat crop, Geleta (2017) found that an increase in plant density negatively affected the physiological potential of the seeds produced, which exhibited reduction in speed of germination and an increase in the number of abnormal plants they developed.…”