INVESTIGADORES
OTEGUI Maria Elena
congresos y reuniones científicas
Título:
Heat stress in temperate and tropical maize hybrids: kernel weight determination.
Autor/es:
RATTALINO EDREIRA, J.I.; OTEGUI, M.E.
Lugar:
Bento Goncalves
Reunión:
Congreso; VI International Crop Science Congress; 2012
Institución organizadora:
International Crop Science Society
Resumen:
Heat stress affects kernel growth as it influences both rate and duration of grain filling. The former
has been linked with potential kernel weight and may be affected by heating around flowering. The
latter depends on assimilate availability per kernel during effective grain filling (i.e. postflowering
source-sink ratio), and may be affected by heating during this period. The magnitude of these
effects has not been documented for heat stress. In this work we evaluated mentioned traits in ?eld
experiments (Exp1 and Exp2), including (i) two temperature regimes, control and heated during
daytime hours (ca. 33-40 °C at ear level), (ii) three 15-d periods (GS1: presilking; GS2: from silking
onwards: GS3: active grain filling), and (iii) three hybrids (Te: temperate; Tr: tropical; TeTr: Te×Tr)
with contrasting tolerance to heat stress. We also assessed the dynamic of water-soluble
carbohydrates (WSC) in stem. Heat stress reduced final kernel weight (KW) in most of heated plots,
but the magnitude of this effect was larger for (i) the Te (-20%) hybrid than the TeTr (-11%) and Tr
(-9%) hybrids, and (ii) GS3 (-22%) than GS1 (-6%) and GS2 (-11%). Negative effect of heating on
final KW was mostly related to changes in the duration of grain filling (r2= 0.49; P