Grain yield of maize (Zea mays L.) in Africa is greatly constrained by the parasitic weed Striga hermonthoica (Del.) Benth. The weed infests maize on an estimated 20 million ha, making it a major cause of maize yield reduction from near the world average of about 4.2 t/ha a few decades ago, to the present level of 1.3 t/ha. Doubling yields from 1.0 t/ha would produce enough food for 400 million people in Africa. One way to increase maize productivity and production that would have immediate impact in sub-Saharan Africa is to control the weed. CIMMYT and its partners have developed a unique technology for Striga control in maize. The technology combines low doses of imazapyr (<30 g/ha) herbicide applied as a seed coating to nontransgenic imidazolinone resistant (IR) maize seed to effect early Striga control before or during attachment to the maize roots. The technology has no adverse effects on intercropped legumes if sown more than 12-cm from the treated maize seed, and it costs only 4 USD/ha, in addition to about 8% increase in seed costs. CIMMYT has developed and tested IR early and late OPVs adapted to the midaltitude ecology of western Kenya. Twenty-two early IR OPVs were evaluated across 7 sites under both Striga-free and Striga- infested conditions in Western Kenya. Five cultivars out yielded the best commercial Striga tolerant check (KSTP94) under both Striga- free (5.7 vs. 5.1 t/ha for the check) and Striga-infested (3.4 vs. 1.7 t/ha for the check) conditions. The number of Striga plants was three times lower under IR OPVs compared to the check. This technology and germplasm could increase maize production in sub-Saharan Africa.

Conservation Agriculture Program|Socioeconomics Program|Global Maize Program

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INT2512|INT2460|INT2340