RESISTANCE OF HS-2 HYBRID MAIZE SEEDS TO AXIAL COMPRESSION

Abstract

Axial compression resistance influences seed production stages, such as parent selection, seed conditioning and storage, and design of machinery and operations. In this study, conducted in 2013 at the Materials Laboratory of Universidad Autónoma Chapingo, State of Mexico, the strength and deformation at points of proportional limit (LL), biocedence (Y) and rupture (R) were determined in seeds of HS-2 hybrid maize (Zea mays L.). Seeds were subjected to axial compression at the apical, middle and basal ear strata at 10 and 23 % moisture content. Seeds were compressed between two flat and polished plates by using a universal testing machine. Seeds from the middle stratum at 10 % moisture content were more resistant to axial load (LL = 301 N, Y = 434 N and R = 344 N) than those from the apical and basal strata (LL = 258 and 238 N, Y = 345 and 341 N, and R = 248 and 246 N, respectively). Seeds at 23 % moisture content had higher compression resistance than seeds at 10 % moisture content (LL = 429 vs. 301 N, Y = 598 vs. 434 N, and R = 568 vs. 344 N, respectively), as well as higher elasticity (LL = 0.827 vs. 0.215 mm) and displacement in general (Y = 1.165 vs. 0.303 mm, and R = 1.215 vs. 0.341 mm, respectively).