Light Interception and Yield Potential of Short-Season Maize (Zea mays L.) Hybrids in the Midsouth

The midsouthern USA typically has a mid- to late-summer drought that limits the productivity of nonirrigated maize (Zea mays L.) production. We hypothesized that by increasing seeded population and narrowing row spacing, short-season maize hybrids in the Midsouth would have similar yield but require less irrigation compared with hybrids currently grown. Irrigated experiments were conducted at Fayetteville, AR, in 2001, 2002, and 2003 and at Keiser, AR, in 2002 and 2003. Factors evaluated included maize maturity (75- to 110-d maize hybrids) and maize seeded population (5 to 20 seed m-2) sown in 50cm rows. Between emergence and black layer, short-season maize hybrids required 30 to 50% less irrigation than did their full-season counterparts. Yield of short-season maize at high plant populations (~19 plants m-2) was equal to that of fullseason hybrids, which reached maximum yield at lower plant populations (~8 plants m-2). Maize biomass at maturity had a linear relationship with cumulative intercepted photosynthetically active radiation (CIPAR) from emergence to maturity, but maize yield had an asymptotic relationship with CIPAR with little increase in yield for CIPAR above 555 MJ m-2. This research indicates that increasing plant population for short-season maize hybrids increased CIPAR, which compensated for a short growing season to achieve similar potential yield to full-season hybrids in the Midsouth with substantially less irrigation.