FECHA DE SIEMBRA Y CICLO DEL HÍBRIDO PARA EL CULTIVO DE MAÍZ EN BALCARCE: I ? RESPUESTA A CAMPO DEL RENDIMIENTO Y SUS COMPONENTES

BONELLI, L.; MONZON, J.P.; CERRUDO, A.; RIZZALLI, R.

Rosario

Congreso; X Congreso Nacional de Maíz; 2014

AIANBA

Delaying sowing date of maize (Zea mays L.) at Balcarce (Buenos Aires, Argentina) shortens the crop growing season and places the reproductive period under deteriorated environmental conditions for crop growth. Under such conditions, short season hybrids would be better adapted than long or mid-season hybrids. The main objective of this work was to quantify the effect of hybrid cycle modification depending on the sowing date on grain yield and its ecophysiological and numerical components. A field experiment with three contrasting maturity hybrids (relative maturity: 92, 102 and 119) was sown at four sowing dates (4-Oct, 14-Nov, 15-Dec and 4-Jan) during 2011-12 growing season. The experiment was carried out under non-limiting availability of water and nutrients. Grain yields for early sowings were positively related to the hybrid cycle length. Contrarily an inverse relationship was observed for the late sowing. Grain yields differences among hybrids were related to the number of kernels m-2 and to the weight per kernel for early sowings and late sowings, respectively. The numerical grain yield components were closely linked with the source-sink relationships during the effective grain filling period. The delay in sowing date and the increment of hybrid cycle length resulted in a progressive decrease of the sourcesink relationship and in an increased apparent remobilization of reserves, which were associated with a lower final weight per kernel. Based on the result of this work, short season hybrids are more appropriates for late sowings of maize at Balcarce because they have a better coupling to the available growing season and show similar or higher grain yields compared with their long or mid-season counterparts.