Estrategias para la fijación de granos en híbridos de maíz liberados en diferentes décadas

CIANCIO, NICOLÁS; GIMÉNEZ, VICTOR DAVID; INCOGNITO, SALVADOR JUAN PABLO; MADDONNI, GUSTAVO ÁNGEL

Rosario

Congreso; Congreso Nacional de maíz; 2014

AIANBA

Maize (Zea mays L.) hybrids differ in their response to high plant density because breeding has improved the tolerance to abiotic stresses. A greater tolerance to crowding is associated with increased kernel setting at low plant growth rates during the critical period (PGRCP). Underlying processes of this fact may be a greater biomass partitioning to ears during this period and / or a higher set of kernels per unit of ear growth rate (EGRCP). The aim of the present study was to analyse the relationships between kernel number (KN) per plant (KNP), PGRCP and EGRCP of four maize hybrids released in different decades. The experiment was conducted in the experimental field of FAUBA during 2013-2014. Four argentine hybrids representative of the 70´, 90 ´, 00´ and 10´ decades were grown at three plant population densities (4, 8 and 12 plants m-2) in a split plot design with three replicates. At each plot 10 plants were measured by a non destructive method to estimate: PGRCP, EGRCP of the apical (EGR1CP) and the sub-apical ear (EGR2CP). The ratios between these traits were obtained to estimate biomass partitioning to reproductive organs (EGR1CP/PGRCP and EGR2CP/PGRCP) and reproductive efficiency of both ears (KN/EGR1CP and KN/EGR2CP). At each plant density KNP of the oldest hybrid (DK-3F22) was lower than those of the modern (DK-7210) one. Mentioned differences in KNP among hybrids were not determined by PGRCP, because all hybrids attained similar values of this trait. Similarly, EGR1CP/PGRCP and EGR2CP/PGRC did not present significantly differences among hybrids. Hence, differences in kernel setting were related to KN/EGR1CP and KN/EGR2CP.