Inter - plant variability in maize crops grown under contrasting N X stand density combinations links between development, growth and kernel set

Genotypic differences in the response of maize kernel number per plant to ear growth rate around silking, caused by contrasting N availability, have been attributed to the effects of this element on reproductive efficiency [i.e. kernel set per unit of ear growth rate]. The objective of current resea...

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Autor principal: Rossini, María de los Angeles
Otros Autores: Maddonni, Gustavo Angel, Otegui, María Elena
Formato: Artículo
Lenguaje:Inglés
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Acceso en línea:http://ri.agro.uba.ar/files/intranet/articulo/2012Rossini.pdf
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Sumario:Genotypic differences in the response of maize kernel number per plant to ear growth rate around silking, caused by contrasting N availability, have been attributed to the effects of this element on reproductive efficiency [i.e. kernel set per unit of ear growth rate]. The objective of current research was to assess if reduced reproductive efficiency of some genotypes under N stress is due to the effect of this nutrient on the number of completely developed florets per ear, the number of exposed silks per ear, and/or abortion of pollinated florets. Two field experiments were conducted with two hybrids previously characterized by their contrasting reproductive efficiency [high for AX820 and low for AX877] under N stress, two stand densities [9 and 12plm-2] and two levels of added N [0 and 200kgNha-1]. We established links among plant and ear growth rates, reproductive traits and kernel number per plant. Reduced reproductive efficiency [quantified as kernel number per plant per unit of spikelet growth rate around silking] of both hybrids under N deficiency was mainly due to an enhanced abortion of pollinated florets of the most suppressed plants of the stand [dominated individuals]. This response did not appear to be the result of low spikelet growth rate around silking, but a direct control of N on sink capacity of fertilized ovaries for assimilates allocation.
ISSN:0378-4290