Selection of some morphological traits of bread wheat that enhance the competitiveness against wild oat (Avena fatua L.).

摘要

Using more competitive cultivars can be an important integrated weed management tools, used both in large and small-scale farming systems. In order to breed for strongly competitive wheat cultivars, identifying morphological traits that are important in enhancing competing ability will be beneficial. The objective of this experiment was to examine some morphological traits associated with the competitiveness of bread wheat against wild oat (Avena fatua L.). Seven bread wheat genotypes were grown with and without competition from wild oat for three growing seasons. Pot experiment was also conducted in the green house to study the growth behavior of bread wheat and wild oat in pure stand using one plant per pot. Due to the observed sporadic emergence of the wild oat, Avena sativum L. was used as the weedy competitor. There was distinct variation among genotypes in number of tillers per plant, leaf length, leaf width, leaf area, plant height, height growth rate, biomass yield, grain yield, HI, number of seeds per spike and kernel weight. Competition from Avena sativa significantly reduced these parameters expect plant height. However, genotypes had similar response to weed competition for these traits except to the number of tillers per plant. On the other hand, correlation studies indicated that plant height, height growth rate and leaf area were critically important in enhancing the reduction of Avena seed production and panicle length. Avena sativa had the highest RGR at early growth stages while bread wheat had relatively the highest at latter growth stages. Season x genotype interaction was significant for all morphological traits and yield component indicating that the competitive ability of the genotypes were confounded with effects of season and the ranking of the current bread wheat genotypes was inconsistent among seasons. This study suggests that if breeder utilizes genotypes with more productive tillers, taller plant, leaf area and fast height growth rate as selection criteria, the competitiveness of the cultivars against grass weeds would be improved.