Effect of Summer Crops Producing Allelopathic Compounds, Plant Density and Varieties of Faba Bean on Incidence of Broomrape

Abstract

Allelopathy is a natural which may prove to be a unique tool for weed control treatments and thereby increase some crop yields. Two experiments were conducted in naturally infested fields with broomrape (Orobanche crenata Forsk.) at Shandaweel Research Station, Sohag Governorate during 2013/14 and 2014/15 winter seasons. The aim of this work was to study the effect of crop sequences for producing allelopathic (cotton, sorghum and maize), two faba bean varieties (Giza-843 and Giza-40) and two plant densities (one side of the ridge and two sides of the ridge) in a split split-plot design were used to study the control of broomrape in faba bean. Results showed that sowing of maize before faba bean decreased significantly numbers and weight of broomrape spikes by 32.0 & 18.5% in the first season and by 37.7 & 37.5% in second season and lead to increase in number of days to broomrape emergence above soil surface by 18.5 & 16.6% in both seasons, respectively, compared to cotton and sorghum. Faba bean seed yield and components were increased by sowing faba bean after maize compared with faba bean after cotton and sorghum. While, faba bean after maize increased the seed yield of faba bean by 13.8 and 13.6 % in both seasons, respectively. Sowing of cotton before faba bean increased significantly the plant height, weight of pods/plant, weight of seeds/plant, 100-seed weight and seed yield (ardab/fed) by 3.9, 5.2, 4.9, 4.8 and 5.8% in 1 st season, respectively, and by 9.1, 2.0, 3.5, 4.7 and 5.5% in 2 nd season, receptively, compared with sowing of sorghum before faba bean. Number, weight and days emergence of broomrape above the soil surface were significantly affected with varieties of faba bean. Superiority of Giza 843 over Giza 40 was by 30.7 and 16.8% in the first season and by 39.7 and 37.5% in the second season. Late-onset broomrape above the surface of the soil with the cultivation of Giza 843 was by 16.8 and 22.5% in the first and second seasons, respectively. Varieties of (vicia faba) were significantly increased on yield ( plant height, weight of pods/plant, weight of seeds/plant, 100seed weight and seed yield/fed) in both seasons. Seed yield of faba bean was increased at cultivation of Giza 843 by 39.7 and 37.5% in the respective 1 st and 2 nd seasons, respectively, compared with Giza 40. Plant density showed significant effect on the number and weight of broomrape and days of number emergence of broomrape above the soil surface. Increasing plant density from 13 to 26 plants/m 2 increased the number and dry weight of broomrape/m 2 by (25.5 and 36.7%) and (29.3 and 28.6%) in both seasons, respectively. Faba plant height, weight of pods/plant, weight of seeds/plant, 100-seed weight and seed yield (ardab/fed) significantly affected was plant density in both seasons. The seed yield of faba bean cultivation was increased at the rate of 26 plants/m 2 by 5.58 and 4.91% in both seasons, respectively, compared to faba density of 13 plants/m 2 . The interaction between crop sequences for producing allelopathic, faba variet...