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Altering Source‐Sink Relationships in Prolific Maize Hybrids: Consequences for Nitrogen Uptake and Remobilization
Author(s) -
Pan W. L.,
Camberato J. J.,
Moll R. H.,
Kamprath E. J.,
Jackson W. A.
Publication year - 1995
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 - 10.2135/cropsci1995.0011183x003500030034x
Subject(s) - biology , anthesis , hybrid , pollination , limiting , agronomy , competition (biology) , poaceae , sink (geography) , crop , horticulture , botany , cultivar , pollen , mechanical engineering , ecology , cartography , geography , engineering
Competition between grain and roots for photoassimilates may reduce post‐anthesis N uptake (N a ), thereby limiting grain production of prolific maize ( Zea mays L.). Field experiments were conducted to determine if this competition was minimized during the selection for new high‐yielding prolific lines, providing a plausible physiological explanation for the improved grain yields. The dry matter (DM) and N accumulation and partitioning of two high‐yielding and three low‐yielding prolifics were compared under full pollination, limited pollination of the apical ear, or no pollination. The following year, one high‐yielding and one low‐yielding hybrid were grown at 34 000 and 45 000 plants ha −1 . Fully pollinated, high‐yielding hybrids averaged 74% more grain weight (G w ) than low‐yielding hybrids. A highyielding hybrid produced 71% more G w under full pollination than with apical ears only pollinated, while limiting pollination had little effect on low‐yielding hybrids. Greater contributions of subapical ears in new prolifics were attributed to greater kernel weight and number, which were positively correlated with post‐anthesis DM accumulation (T wa ). The DM partitioning to vegetative tissue [T wa − G w ] is indicator of photosynthate availability for plant functions during grain‐filling. Greater [T wa − G w ] occurred at the low plant density and with limited pollination, and this was positively related to N a while inversely related to N r . The high‐yielding hybrids maintained T a and Na during multiple ear development. These results suggest N a is regulated by the ear sink size relative to photosynthate supply.