Demand-Driven Technologies for Sustainable Maize ... - IITA

were signifi cant for all traits under infested and non-infested conditions.Only ear aspect was not signifi cant for location × variety interactionunder infested conditions. The year × location × variety interactionwas not signifi cant for grain yield, plant height, and ear aspect underboth environments. However, signifi cant year × location × varietyinteractions were detected for days to silking, Striga damage ratingat 10 WAP and EPP under artifi cial Striga infestation. 2000 Syn EE-W and 99 Syn EE-W were the outstanding varieties in terms of grainyield under both Striga-infested and non-infested conditions, as well asand Striga damage scores under Striga infestation.The most promising variety, 2000 Syn EE-W outyielded the localcheck, TZEE-W SR BC5 by 63% under Striga-free conditions and69% under Striga infestation. 98 TZEE-W STR had the lowest Strigadamage score but this was not translated into high grain yield since itwas among the lowest yielding varieties. The Striga emergence countswere generally high, ranging from 161 plants for Sine TZEE-W STRto 251 plants for 99 TZEE-Y STR. This indicates that the varietiesstudied have tolerance to Striga. It is encouraging to note that 2000Syn EE-W has been released in Bénin following several years of testingboth on-station and on-farm. The variety is also undergoing on-farmtesting in northern Nigeria. There is, however, the need for nationalmaize programs in the subregion to test 2000 Syn EE-W and otherpromising Striga resistant varieties more extensively in on-farm trialsfor promotion and adoption by farmers.In the second study, 36 advanced extra-early maturing Strigaresistant inbred lines were evaluated under Striga-infested and Strigafreeconditions at Mokwa and Abuja in 2004 to determine the usefulnessof the inbreds as parents of open-pollinated synthetic varieties, as wellas sources of resistance for the national maize breeding programs.The 36 inbred lines were derived from the broad-based Striga andmaize streak virus (MSV) resistant populations, TZEE-W Pop STR C 0and the crosses, TZEE-W SR BC 5× 1368 STR and TZEF-Y SR BC 1×9450 STR (Table 3). A 6 × 6 lattice design with two replications wasused for the trial. There were two rows per plot and a row of each plotwas infested artifi cially with about 5000 germinable S. hermonthicaseeds/hole at planting following the protocol and statistical analysesdescribed earlier for the RSVT-Extra-early. Data for fi ve out of the 36extra-early maturing inbred lines were not usable and were thereforenot included in the results.Results of the second study showed signifi cant differences amongthe inbred lines in grain yield and all other traits except ASI underStriga-infested and Striga-free conditions (Table 3). However, thelocation × inbred interaction was not signifi cant for the traits except31