8th INTERNATIONAL WHEAT CONFERENCE

NITRogeN AVAILABILITy IN PRe ANd PoST ANTheSIS ANd
ITS effeCT oN gRAIN yIeLd ANd quALITy IN CoNTRAST-
INg BReAd WheAT CuLTIVARS
Ignacio Alzueta, Gabriela L Abeledo
and Daniel J. Miralles
Departamento Producción Vegetal, IFEVA, Facultad Agronomía, Universidad de Buenos
Aires, CONICET
Av. San Martin 4453 (C1417 DSE), Buenos Aires, Argentina
E-mail Address of presenting author: ialzueta@agro.uba.ar
Wheat is the main winter crop in Argentina, sustaining its importance in the yields and
quality that make it suitable for the bread-making industry. The nitrogen (N) fertilization
management plays a major role to increase and/or stabilize grain yield as well as to optimize
the quality for industrial uses. However, the negative relationship between yield and
grain protein content (i.e. dilution effect) and the genotype x environment interaction
establish a conflict between the concepts of high levels of production and high industrial
quality, and thereby, the knowledge of the response of the crop to fertilizer application
will become more important in the future. The recent introduction of wheat genotypes
of high yield potential has determined the necessity of intensifies the use of fertilizers to
avoid low grain protein concentration (GPC). In the near future will be essential in Argentina
to consolidate a system of wheat quality segregation for satisfying the demand of
the customers in terms of quality. In this way, the National Seeds Commission of Argentina
(CONASE) has proposed a system to segregate grains. The genotypes are separated
in three groups of quality, associated with dough properties along different environments
of production. The aims of the present work were (i) to identify the main ecophysiological
mechanisms that regulate the response of grain yield and grain quality to N availability in
wheat and (ii) establish genotypic differences in the accumulation of N in the grains considering
the genotype by environment (GxE) interaction. Three experiments were carried
out under field conditions (2006, 2007 and 2008) in the Experimental Field of the Faculty
of Agronomy of the University of Buenos Aires (34º 35’ S, 58º 29’ W), combining 3 different
genotypes of wheat quality (Buck 75 Aniversario, B75, G1 high quality; Baguette
13 Premium, Bg13, G2 medium quality; and Klein Chajá, Kcha, G3, low quality), 2 levels
of N at sowing “low” (ca. 60-90-70 kgN ha -1 ) and “high” (ca. 150-190-170 kgN ha -1 ) for
2006, 2007 and 2008 respectively and 2 levels of N applied at flowering, 0 kgN ha -1 , and 40
kgN ha -1 , half as foliar fertilizer (100 liters ha-1 Foliarsol U) and the other half in the soil
as Urea (20 kgN ha-1) (Nf40). Grain yield and grain quality variables were measured at
maturity. The yield ranged from 175 to 780 g m -2 due to the effects of the years, cultivars,
and N availability. Yield (g m -2 ) showed significant differences among genotypes (p