Development of sorghum populations for resistance to Striga hermonthica in the Nigerian Sudan Savanna

Abstract

Six elite sorghum varieties, ICSV 111, ICSV 400, KSV 4, Gaya Early, CS 54, and CS 95 were used to improve Striga 
resistance through pedigree breeding. SRN 39 and IS 9830 varieties were confirmed resistant to Striga hermonthica 
(Del.) Benth in field trials. The two Striga resistance lines were crossed with the six elite varieties. Three hundred 
and sixty Striga-free plants from F2s of good agronomic traits were identified, and selfed to produce F3s. The 
number of selections varied from 12 (ICSV 400 x IS 9830) to 59 (ICSV 400 x SRN 39) per F2 population. About 50% 
more plants were selected from the crosses involving SRN 39 as donor parent for Striga resistance than the crosses 
involving IS 9830. In addition, 58 out of the 100 plants selected were from a cross, ICSV 111 and SRN 39. Crosses 
from which Striga free plants were obtained were CS 54 x SRN 39 (12 plants selected), CS 95 x SRN 39 (9), ICSV 400 
x SRN 39 (6), Gaya Early x IS 9830 (6), Gaya early x SRN 39 (5), and KSV 4 x IS 9830 (4). Crop syndrome reaction 
score was higher in 1995 (2.3 - 4.0) than in 1996 (1.0 - 2.7). Our results suggest that SRN 39 is a better donor parent 
for Striga resistance than IS 9830. ICSV 00090 NG, a cross between ICSV 111 and SRN 39 gave the highest grain 
yield of 2.02 t/ha in a replicated trial compared to the two parents, ICSV 111 (1.11 t/ha) and SRN 39 (0.86 t/ha). This 
variety combines potential for high yield and resistance to Striga. Our data indicates that the elite varieties can be 
improved for Striga resistance using pedigree breeding. A large F2 population (500 to 1000 plants per cross) is 
recommended for the selection of transgressive segregants. Further efforts are required to back cross-promising 
segregants with established Striga resistant variety in order to develop durable Striga resistant varieties with 
acceptable agronomic traits.