Proteína, triptófano y componentes estructurales del grano en híbridos de maíz (Zea mays L.) producidos bajo fertirrigación

In order to determine how kernel composition can be modified through agronomic practices, the N and P effect on protein quantity, Trp present in proteins, and structural kernel components in hybrids of simple crosses of maize (Zea mays L.), adapted to the region of the Central High Valleys of México, was evaluated. Sixty treatments resulting from the combination of 10 hybrids, three doses of N (150, 225, and 300 kg ha^-1) and two of P (60 and 120 kg ha^-1) in a randomized complete block design, were assessed at Montecillo, state of México, during the springsummer cycle of 2002. Fertilizer application through drip irrigation was carried out daily There were no important changes in any of the variables evaluated in response to P application. Kernel protein varied between 9.5 and 11.5 %, and Trp in protein between 0.5 and 0.6 %. Nitrogen increased protein content in grain by 4 % on an average, compared to the control (150-60-80), 7 % in CS10*4 and CS6*10 with 300 kg N ha^-1, and 9 % in CS6*4 with 225 kg N ha^-1 without significantly affecting the Trp content in protein. Floury endosperm diminished as well by 16.9 % on average, and corneous endosperm increased proportionally: 33.8 % in CS3*9 with 225 kg N ha^-1, and between 21 and 25 % in CS3*4, CS10*3, and CS4*9 with 300 kg N ha^-1.