PHYTOTOXICITY AND EFFECTIVENESS OF SOME HERBICIDES IN WHEAT PLANTATIONS

Weeds are severely competition with wheat crop and it highly reduces crop yield. So, the present study was conducted on wheat cultivations during two seasons 2013/2014 and 2014/2015 to evaluated phytotoxicity effects of some herbicides on wheat (Triticum aestivum). Effectiveness of these herbicides on weed control in wheat crop and yield evaluation and quality of wheat was evaluated as well after treatment by herbicides. The field experiment was carried out in agricultural experimental station of Etay El-barod, El-Beheira Governorate, using randomized complete block design (RCBD) with four replicates for each treatment and unweeded check, having two rates of both herbicide recommended and double recommended rates (R, 2R). Treatments comprised of post-emergence application of pyroxsulam, flumetsulam+ florasulam, tribenuron-methyl, diclofop-methyl and tralkoxydim. The results indicated an increase in wheat plant height with all herbicides used compared to unweeded check. Tribenuron-methyl and flumetsulam + florasulam treatments did not cause any visible phytotoxicity, while pyroxsulam, diclofop-methyl and tralkoxydim treatments recorded a low indexes of phytotoxicity on wheat plants which disappeared completely after 8 weeks from post application, compared to unweeded check. Results also, indicated that all herbicide treatments decreased weed density. Herbicide treatments achieved the highest weed control expressed in lowest fresh weight after 56 days from application for broadleaved, grassy and  total weeds. Herbicide treatments caused an excellent increase in yield attributes (spike length, biological and grain yield) and yield quality (weight of 1000 grains, total carbohydrates and crude protein) compared to unweeded check in both seasons. The maximum grain yield was recorded at two trials by pyroxsulam compared to unweeded check.