Management Practices and Maize Quality for Beer Industry.

The quality of maize grain for beer production is related to kernel hardness and particle size after grinding, two attributes related to flint character of maize (i.e., vitreousness). Knowing the best combination between management practices and “flint” hybrids may help to maize producer to a better meeting of specific demand from beer industry. The objective of this study was to quantify the impact of changes in both plant population density and planting date on mechanical and shape-size kernel parameters of the two most demanded flint maize hybrids for beer industry in the Northeast of Argentina. A two year experiment was carried out at Corrientes, Argentina (27° 28’ S; 58° 47' W; elevation 50 m) during 2006/7 and 2007/8 growing seasons. Two flint maize hybrids (AVANT and P3041) were sown at September (early=E) and December (late=L) under two plant population densities (5.8 and 7.5 plants m^-2). Reproductive growth was estimated by growth analysis and maize kernels were analyzed by floating test (FL), test weight (WE) and kernel weight (KW). Hybrids presented comparable WE and KW and strongly differed for FL (2.25 vs. 6.81 for P3041 and AVANT, respectively). Sowing date and plant population density differentially altered FL of two hybrids. While both hybrids had comparable floating test when sown late (FL=3%), FL showed a three fold increasing for AVANT (FL=10.5) and two fold decreasing for P3041 (FL=1.5) when sown early. In respect to plant population density, while P3041 showed increasing of 100% for FL, AVANT increased it around 65% as plant population density decreased. For both hybrids, FL was negatively correlated (r=-0.72, p<0.0001) with KW. Lower stability of FL seems to be associated with greater sensibility to source-sink ratio during the grain filling period.