competitive ability and tolerance of 18 wheat (triticum aestivum l.) cultivars to wild mustard (sinapis arvensis l.)

introduction: weeds causing 15 % or more damage to crops, annually. the amount of these damages depends upon different factors such as cultivar type and weeds species. wild mustard is a cosmopolitan and most serious broad leaf weed in wheat fields which has widespread through world including iran. rapid emergence of wild mustard under cold condition and fast growth early in the spring are reasons that make its competitive capability along growing season with wheat. in the more global regions, soil seed bank persistence, height competitive ability, vast fecundity and herbicides resistance are chief problems in wild mustard control. nonetheless, one of the weeds control strategies in integrated weed management systems is utilization of height competitive ability cultivars. materials and methods: in order to examine competitiveness of various wheat cultivars on wild mustard and evaluation of presence of this weed species yield and its components in wheat, an outdoor pot experiment was conducted at agricultural research greenhouse, college of agriculture, mohaghegh-e ardabili university, during 2013-2014. treatments comprising of 18 wheat cultivars namely: [var1: karkheh, var2: alborz, var3: azadi, var4: shahpasand, var5: sepahan, var6: flat, var7: ghods, var8: roshan, var9: sorkh tokhm, var10: moghan3, var11: alvand, var12: ms-81-14, var13: yarvarus, var14: shahriyar, var15: golestan, var16: bam, var17: niknajad, var18:karaj3]. all mentioned cultivars were laid in the weed free (no wild mustard present) and interference condition (wild mustard present) pots and were arranged in a factorial experiment based on completely randomized design with three replications. wild mustard seeds, were used as weed seeds source that previously have collected in agronomic department laboratory of mohagheghe ardabili university. each pot was filled with almost 5 kg mixtures of (sand, farm soil and farm yard manure). also in each pot 15 wheat seeds along with several wild mustard seeds in regular pattern had been sown. first irrigation was done immediately after sowing on the pots. in the spring after wheat seedling were established pots were thinning and 6 seedlings in each pots and only one established wild mustard was remaining. at the end of growing season, yield, yield components and weeds losses dry weight were estimated. competitive index (ci) and weed interference tolerance index (witi) were assessed. all gathered data and trials that involving yield such as (spike number, seeds number per spike and thousand seeds weight), at ripening stage of all wheat in the pots were measured and weighted. numeric observations which ascribing to wheat cultivars based on squared euclidean clustering analysis procedure for all cultivars categorize were used. data were subjected to anova, and means were separated using fisher’s protected lsd test at 0.05 probability (p ≤ 0.05). results and discussion: wild mustard dry matter weight was influenced by means of different wheat cultivars (p ≤ 0.01). this effects resulting reduction of wild mustard dry matter weight ranged 14.4 -67.4% based on cultivar types, so that bam, alvand and ms-81-14 cultivars in this aspect was superior cultivars. also, collected information represented that between cultivars there are significant difference in the spike production in each pot (p ≤ 0.01). whereas, numbers of spike in each pot varied between 22 to 43, but golstan cultivar had maximum spike in each pots and minimum spike belonged to sepahan and roshan cultivars. spike numbers also had a significantly positive correlation with decreased weed dry matter percentage. there was difference between wheat cultivars in the seed per spikes (p ≤ 0.01). there was negative correlation between seed numbers and spike numbers (p ≤ 0.01), but positive association was between this character with wild mustard dry matter percentage decline (p ≤ 0.05). numbers of fertile spikes were important factor in grain yield (15). there are significant differences in wheat yield between eighteen cultivars (p ≤ 0.01), so that bam, ms-81-14 and yarvarus have highest yield and roshan has lowest from the rest cultivars. yield data was influenced under wheat cultivars and wild mustard interference effects and inter-act of two mentioned factors (p ≤ 0.05). conclusion: although, large numbers of study in overall world focus on cultivar’s merits and competitor cultivars study well documented, but we credence is that cultivars election and recommendations for each specific local must be documented in repeated and long-terms studies (in time and site). but results originated of this study, well documented cultivars selections in view of more effective weed interference tolerance index (witi) for alvand, bam, ms-81-14, and yarvarus cultivars for weed suppress such wild mustardin ardabil conditions,and yield productionalso bam, ms-81-14 and yarvarus were superior cultivars from others cultivars in ardabil regions, which appear to be implemented in integrated weed managements design options. finally, authors must be mentioned that this conclusion merely is primarily information in cultivars selections and other works must extended and carry out in ardabil field conditions.