Wheat Yield Loss in a Two Species Competition with Emex australis and Emex spinosa

Abstract

-Emex australis and E. spinosa are significant weed species in wheat and other crops. Information on the extent of competition of the Emex species will be helpful to access yield losses in wheat. Field experiments were conducted to quantify the interference of tested weed densities each as single or mixture of both at 1:1 on their growth and yield, wheat yield components and wheat grain yield losses in two consecutive years. Dry weight of both weed species increased from 3-6 g m -2 with every additional plant of weed, whereas seed number and weight per plant decreased with increasing density of either weed. Both weed species caused considerable decrease in yield components like spike bearing tillers, number of grains per spike, 1000-grain weight of wheat with increasing density population of the weeds. Based on non-linear hyperbolic regression model equation, maximum yield loss at asymptotic weed density was estimated to be 44 and 62% with E. australis, 56 and 70% with E. spinosa and 63 and 72% with mixture of both species at 1:1 during both year of study, respectively. It was concluded that E. spinosa has more competition effects on wheat crop as compared to E. australis. Keywords

Estimation of economic threshold for Lathyrus aphaca L. in wheat

“…Our findings are parallel with the results ofMorales-Payan (2000), who stated 63% reduction in tomatoes yield with increasing 0-12 parthenium plants m -2 Bridges et al (1992). also reported 4 to 54% reduction in peanut yield as density of Euphorbia heterophylla increased from 1-32 plants in 5 m long row Javaid et al (2016). who affirmed that weeds competed with wheat and significantly decreased yield.…”

“…Saeed et al (2012) also reported sever yield reduction in maize by increasing weed density. Similarly, Javaid et al (2016) reported that E. spinosa and E. australis significantly decreased biological yield of yield. Armin and Asghripour (2011) described that wild oat at high density decreased grain yield of wheat by decreasing number of spike bearing tiller per plant and number of spike per unit area.…”

“…Similarly, Javaid et al (2016) illustrated that weeds densities significantly dropped off harvest index in wheat crop. Safdar et al (2015) also stated harvest index of maize plants decreased when parthenium weed density level was above 5 plants m -2 .…”

“…Armin and Asghripour (2011) described that wild oat at high density decreased grain yield of wheat by decreasing number of spike bearing tiller per plant and number of spike per unit area. Javaid et al (2016) reported that wheat produced lower yield due to presence of weeds. Similarly, Siddiqui and Subhan (2004) reported lower wheat grain yield with the increase in weeds densities.…”

Challenges and prospects for weed management in Pakistan: A review

“…Being a botanical pest, weeds share similar trophic level as that of crop plants, and weed-crop competition results in a substantial crop yield loss (Ali et al, 2015b;Javaid et al, 2016;Ramesh et al, 2017). The cost incurred in M A N U S C R I P T…”