Kernel weight responses to the photothermal environment in maize dent × flint and flint × flint hybrids

HISSE, IGNACIO R.; DANDREA, KARINA E.; OTEGUI, MARÍA E.

CROP SCIENCE

CROP SCIENCE SOC AMER

Año: 2021 vol. 61 p. 1996 - 2011

0011-183X

Maize (Zea mays L.) grain yield is assumed to be source limited during the flowering period but sink limited during grain growth; however, environmental restrictions during active grain filling may strongly affect final kernel weight (KW). In this study, we evaluated the effect of natural changes in photothermal conditions during lag phase (LP) and effective grain-filling period (EGFP) on KW, its physiological determinants, and the post-flowering source–sink relationships of flint and semident germplasm. F1 hybrids of flint × flint and dent × flint background were tested during four seasons (Y1, Y2, Y3, and Y4). Across years, the highest KW (286 mg) was obtained under the maximum photothermal quotients during LP (PTQLP = 1.18 MJ m−2 °C−1) and EGFP (PTQEGFP = 1.07 MJ m−2 °C−1) of Y2, whereas the smallest KW (252 mg) and source–sink ratio during grain filling was obtained under the lowest PTQEGFP (.79 MJ m−2 °C−1) of Y3. Supra-optimum temperatures during LP of Y3 negatively affected potential KW determination, and hence kernel growth rate (P