Crop yield is very sensitive to climatic conditions such as increasing temperature. This study was conducted to evaluate the role of allelopathy in improving terminal heat stress during reproductive stages (booting and anthesis) of wheat. Seeds of two wheat cultivars (Mairaj-2008 and Faisalabad -2008) were primed with allelopathic water extracts of sorg hum, sunflower, moringa and brassica (each at 3% either alone or in combination) for 12 h, keeping seed:water ratio of 1:5 . Seeds of wheat cultivars were sown in 10 kg soil filled pots on November 21, 2013 . The heat stress was imposed separately at booting and anthesis by placing pots in gla ss canopies with temperature of 4 -5°C above than the ambient until maturity. Controlled pots were maintained under well-watered conditions at ambient temperature. Heat stress negatively impeded the performance of both wheat cultivars by enhancing the leaf malondialdehyde contents and reducing the membrane stability, which drastically reduced the grain weight and yield. However, seed priming with all the allelopathic crop water extracts, eithe r used alone or in combination, significantly improved plant height, spike length, 100 -grain weight, biological yield, grain yield, harvest index, chlorophyll a, chlorophyll b, free leaf proline, total soluble ph enolics, leaf glycinebetaine membrane stability, and reduced the leaf malondialdehyde contents under terminal heat stress conditions. Seed priming with combined sorghum and moringa water extract s was more beneficial than other allelopathic water extracts in this regard. Among wheat c ultivars, the performance of wheat cultivar Mairaj-2008 was better than Faisalabad-2008.
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