Planting date and cultivar effects on grain yield in dryland corn production
Corn (Zea mays L.) production is gradually spreading into the Sudan savanna zone of West Africa where production is limited by erratic and inadequate rainfall. To increase corn production, production practices should be properly designed to minimize the effects of low precipitation and high temperatures that characterize the zone. A study, to determine the performance of late (120 d), early (90 d), and extra-early maturing (80 d) corn cultivars over a range of planting dates, was performed in the Sudan savannas of northeast Nigeria. Delaying planting generally increased days to flowering and the anthesis-silking interval (ASI) and reduced dry matter production and yield and yield components. In Azir, planting of corn on 13 July reduced grain yield by 42% in 2006 because of a dry spell during crop establishment. Delaying planting to 21 and 28 July also reduced grain yield by 19 and 28.5%, respectively over the 2 yr. Averaged over the 2-yr yield reduction was 29.5 and 42% when corn was planted on 21 and 28 July, respectively in Damboa. There was no interaction between planting date and corn cultivar for days to silking, ASI, and grain yield suggesting that the cultivars responded similarly to planting date. The extra-early maturing cultivar, 95 TZEE-W, produced highest dry matter, harvest index, and grain yield at all planting dates suggesting that this cultivar is the most suitable in both locations. To reduce risk of drought stress, extra-early maturing corn cultivars should be planted in the Sudan savanna between the last week of June and the first week of July.