Response of Sorghum to Striga hermonthica as Influenced by Genotype and Seed Bank Size

Abstract

An experiment was conducted in a greenhouse at the College of Agriculture Studies at Shambat, Khartoum North in season 2014 to study the effects of S. hermonthica seed bank size on performance of three sorghum genotypes Wad-Ahmed (Striga tolerant), Tetron (Striga resistance) and Hakika (Striga resistant). The experiment was conducted in soil artificially infested with Striga hermonthica where the seed bank was adjusted to 0-32 mg/pot. Treatments were arranged in a Randomized Complete block Design (RCBD) with four replicates. Data collected encompassed Striga emergence and dry weight, sorghum height; relative leaf chlorophyll contents (RLCC) and shoot dry weight. Irrespective of sorghum genotype, Striga emergence was minimal (0.5-2.0 plants/pot) and maximal (12.5-23.0 plants/pot) at the lowest and highest seed bank size, respectively. Striga dry weight followed a similar trend. Among genotypes Wad-Ahmed sustained the highest Striga emergence (6.9-13.9 plants/pot) followed in descending order by Tetron (4.3- 6.4 plants /pot) and Hakika (1.9 -2.9 plants/pot). Likewise Wad-Ahmed supported the highest Striga dry weight (6.4 g/pot) followed by Tetron (5.2 g/pot) and Hakika (2.8 g/pot). Among sorghum genotypes Wad-Ahmed displayed the highest reductions in height, RLCC and dry weight, while Hakika showed the lowest. The study showed that though the genotypes vary in their response to the parasite they succumb at high infestation levels. Further, the results enunciate the crucial role of Striga seed bank and articulate the importance of integrated control measures to reduce spatiotemporal variability in performance.