The influence of fertilizer nitrogen application on development and number of reproductive primordia in field grown two- and six-rowed barleys.

ARISNABARRETA Y MIRALLES

AUSTRALIAN JOURNAL OF AGRICULTURAL RESEARCH

CSIRO

Lugar: Melbourne Australia; Año: 2004 vol. 1 p. 357 - 366

0004-9409

A field experiment using different two- and six-rowed barley cultivars grown at two fertilizer nitrogen application rates (40 and 150 kgN ha-1) without water restrictions was carried out to explore how the number of leaf primordia and the rate of leaf emergence interact to modify the duration of different pre-heading phenological phases, and to analyze the dynamics of initiation and mortality of different sub-components of grain number per unit area, in response to different fertilizer nitrogen regimes. The lower nitrogen supply (40 kgN ha-1) delayed heading time as a consequence of higher phyllochron without any effect on the final number of leaves initiated in the apex. The different fertilizer nitrogen rates only altered the co-ordination between tiller appearance and leaf emergence in two of the six-rowed cultivars, whereas for the rest of the cultivars co-ordination between leaf emergence and primary tillers appearance was not altered by fertilizer nitrogen rate. The lower nitrogen supply resulted in less fertile florets per ear due to a reduction in floret primordia survival without any effect on the maximum number of spikelet primordia initiated in the apex. The higher floret abortion observed in six-rowed with respect to two-rowed cultivars could be associated with the fact that lateral floret primordia, in those apical and basal positions within the ear in six-rowed cultivars, are poorly developed with respect to the central spikelets.