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Kernel weight responses to the photothermal environment in maize dent × flint and flint × flint hybrids
Author(s) -
Hisse Ignacio R.,
D’Andrea Karina E.,
Otegui María E.
Publication year - 2021
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.1002/csc2.20481
Subject(s) - germplasm , sink (geography) , zoology , grain yield , grain size , hybrid , horticulture , biology , photothermal therapy , grain growth , agronomy , materials science , botany , composite material , nanotechnology , cartography , geography
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. F 1 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 (PTQ LP = 1.18 MJ m −2 °C −1 ) and EGFP (PTQ EGFP = 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 PTQ EGFP (.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 < .001) as a result of reduced assimilate availability per kernel. Hybrids dent × flint exhibited higher grain yield, kernel number, and plant growth around flowering than flint × flint throughout evaluated seasons but had reduced source–sink relationship during grain filling ( P < .05) and increased KW sensitivity ( P < .001) to changes in the photothermal conditions. Results emphasized the importance of the photothermal environment during grain filling on KW determination (particularly for seasons with great photothermal imbalance between filling subphases) as well as the dependency of KW responses on the genetic background.