Document Type : Research Article
Islamic Azad University, Shoushtar
Introduction: Among crops, wheat is one of the most widely cultivated crops in the world that supply about 60 to 70 percent of the world population's food energy. Among the factors reducing crop production, weeds are particularly important, and they could reduce crop yield through competition for water and food and also by disrupting the harvest. It is important to assessment of weed-crop competition mechanism to get vital resources as well as assessment useful crop features for increasing competition with weeds. One of these methods could be use of cultivars with high-ability competitors against weeds. So in this regard, awareness of weed-crop competition aspects in addition to yield losses due to weed competition, will leading to a reduction in herbicide application.
Materials and Methods: To evaluate the effect of wild mustard competition on morphological characteristics, yield and yield components of wheat, a factorial experiment was conducted based on a randomized complete block design with three replications in Islamic Azad University Shoushtar Branch in 2016. In the experiment, the treatments were type of competition between weed and wheat that was included: a) the shoots competition of weed with wheat cultivars b) the root competition of wild mustard with wheat c) the shoot and root competition of wild mustard with wheat cultivars and d) no weed competition as control and wheat cultivars was included: Chamran, Karim and Vrynak.
Results and Discussion: Analysis of variance showed that all the studied traits were significantly different from each other. Results showed that the maximum height (95 cm) was observed for Chamran cultivar in control treatment and the minimum height (74 cm) was for Vrynak in the shoot and root competition of wild mustard with wheat cultivars. A comparative evaluation of interaction effects showed that the highest root length (13.3 cm), number of fertile tillers (2.1) and spike length (11.6 cm) were obtained in Chamran cultivar in control treatment. The least of these traits was observed in Vrynak cultivar in the both shoot and root competition of wild mustard with wheat cultivars. The results showed the largest decrease in the number of seeds per spike (40.95 percent compared to control) and spike number per m2 (17.62 percent compared to control) was obtained in the treatment of shoot and root competition of wild mustard with Vrynak cultivar. The study showed that the highest 1000-grain weight (40 g) was obtained in Chamran and control treatment and the least was obtained in the treatment of shoot and root competition of wild mustard with Vrynak cultivar. The highest grain yield (497.45 g m-2) and biologic yield (1784.39 g m-2) were obtained in Chamran and control treatment, while, the lowest ones (150.25 g m-2 and 1026.31 g m-2) were obtained in the treatment of shoot and root competition of wild mustard with Vrynak cultivar, respectively. Reduction in wheat yield was occurred due to decreasing the number of spike, number of grains per spike and 1000-grain weight. Assessment the results of biological yield and grain yield in wheat cultivars showed that compared to economic performance of wheat, total dry matter production was less affected by wild mustard interference.
Conclusion: Overall, in this study, the highest amount of morphological traits, yield, and yield components were obtained in combined treatment of Chamran and control. Accordingly, Chamran due to higher economic performance both in weed-free and weed-interference conditions could be as a competitor cultivar in agricultural operations and its properties could be used in breeding.