SCREENING OF SOME SORGHUM GENOTYPES FOR RESISTANCE TO SORGHUM MIDGE, Stenodiplosis= (Contarinia) sorghicola Coqillet (Diptera: Cecidomyiidae) UNDER GEDARIF RAINFED CONDITIONS

Preliminary experiments were conducted at Northern area, Gedarif State during seasons of 2002-03, 2006-07. Where as advanced trials during 2008/2009 to 2012/2013 at northern and Southern areas. The objective was to evaluate selected sorghum genotypes for sorghum midge resistance. 3000 accessions were obtained from Gene Bank Resources. Resistant genotype, DJ 6514 (Resistant Check already released in 2007) was obtained from International Crops Research Institute for the Semi-Arid Tropics (ICRISAT). Data on midge damage rating was significantly different among genotypes. The midge damage rating scores ranged between, 1.3- 8.6; 1.1- 9.2; 1.4- 9.0; 1.1 – 9.4; and 1.2- 9.2 for all seasons (2008/09; 2009/10; 2010/11; 2011/12 and 2012/13). However, the lowest midge damage rating was recorded by DJ 6514 (Resistant check), followed by P₁ 570162 (Hag Abbakar); GBM 30 (Early Feterita); Wad Baco; and Safra (1.4; 1.5; 1.5, 1.6 and 1.7), respectively. Genotypes, P₁ 570162 (Hag Abbakar); GBM 30 (Early Feterita); Wad Baco; Safra and Harerai showed lowest % yield loss and performed similar to the resistant check (14.2; 14.5; 14.5; 17.0 and 17.3%), respectively. The combined analysis showed that a significant difference was observed between genotypes. The genotypes were significantly different in panicle types, compact and semi-compact headed genotypes showed lower % glumes coverage (1.3- 4.5%), while semi-compact headed genotypes ranged between 5.5 – 7.8%. Genotypes, Wad Baco; P₁ 570162 (Hag Abbakar); GBM 30 (Early Feterita); Safra; Wad Ahmed; Harerai and Wad Akar showed the shortest glumes coverage (1.3; 1.3; 1.5; 1.5; 1.6; 1.7 and 1.8 %). Compact headed genotypes recorded lowest midge density (6.5 adults/ 5 heads), while the semi-compact headed genotypes were recorded 15.7 adults/ 5 heads compared with others types of heads.