EVALUATION OF TRAP CROPS AND INTEGRATED STRIGA MANAGEMENT IN THE CONTROL OF WITCH WEED (Striga hermonthica (Del.) Benth) IN SORGHUM (Sorghum bicolor L. Moench)
ABSTRACT
Field trials were conducted in 2012 and 2013 cropping seasons on a naturally heavily striga infested field at the research farm of Federal University of Technology, Gidan kwano campus Minna to evaluate the effect of seed treatment, sowing date and trap crop in the management of Striga hermonthica. The experiment consisted of two varieties of sorghum (resistant ICSV1002 and susceptible Gwari local varieties), three different concentration of Parkia pulp powder (0, 66 and 100 g/l) and one trap crop (soyabean variety TGX 1448-2E). Two sowing date (JUNE 15 and JULY 21) Were used in both years 2012 and 2013; the experiment was laid out in a randomized complete block design with three replications. The screen house experiment, evaluated the variability of ten soyabean, cowpea and groundnut varieties each, with respect to their ability to induce suicidal germination of Striga hermonthica seeds. The experiment was 3x10x2 factorial laid out in completely randomized design with five replications. Factor A consisted of Striga seeds at three levels of inoculation (0, 2.5 and 5g) mixed with 20g of sterilized soil respectively. Factor B was 10 varieties of either soyabeans, cowpea or groundnut as trap crops. Factor C consisted of resistance (ICSV1002) and susceptible (local) sorghum varieties. In the laboratory assay, the ten soyabeans, cowpea and groundnut varieties each were screened for ability to stimulate the Striga seed germination in vitro, using cut root technirque .The experimental design was completely randomized design (CRD) with four replications. In the field trial sorghum seeds soaked with 66g/l Parkia pulp concentration significantly (p < 0.05) reduced Striga attack and produced higher yield in 2012 and 2013 compared to those primed with 100 and 0g/l (control) .The sorghum seed planted in July significantly (p>0.05) had fewer Striga shoots and produced higher grain yield compared with those planted in June in 2012 and 2013. Intercropping sorghum with soyabeans significantly (p<0.05) reduced Striga attack per plot in both study years compared to sole sorghum. Among the ten soyabeans, cowpea and groundnut varieties screened , soyabeans variety TGX 1448 -2E , cowpea variety ITO4K -217-5 and groundnut variety RMP-91 had fewer Striga shoot and produced higher grain yields compared to other varieties in the laboratory assay. The test crop (soyabeans, cowpea and groundnut) varieties screened showed significant differences in stimulant production in their ability to induce suicidal seed germination in Striga hermonthica. Soyabeans variety TGX 1448-2E, cowpea variety ITO4K-217-5 and groundnut variety RMP-91 gave the highest germination percentage compared to other varieties.