Variability in the duration of stem elongation in wheat and barley genotypes

WHITECHURCH, E.M. SLAFER, G.A. AND MIRALLES, D.J.

Journal of Agronomy and Crop Science

Blackwell Verlag

Lugar: Berlin; Año: 2007 vol. 193 p. 138 - 145

0931-2250

The stem elongation phase in wheat (Triticum aestivum, L.) and barley (Hordeum vulgare) is important for yield determination as it is the phase when stems and spikes grow actively. A longer duration of this phase could hypothetically increase assimilate availability, fertile florets at anthesis and final grain number. Argentine commercial wheat and barley cultivars were studied to analyze the range of genetic variability existing in the duration of the stem elongation phase in particular, considering cultivars with similar time to anthesis. It was found that cultivars differing in time to anthesis, not only differed in the length of their early, mostly vegetative phases but also in the stem elongation phase (range 301 to 535 ºC d for wheat and 252 to 404 ºC d for barley ), and that the partitioning of a similar time to anthesis into phases was substantially different between cultivars. Various studies with other cultivars were reanalysed showing that the stem elongation phase did present genetic variability as well. As a preliminary step to identify the genetic causes behind this variability, an approximation to the possible photoperiod and/or vernalization sensitivities of this large group of Argentine cultivars was presented, by comparing behaviour in two contrasting sowing dates. This has proved useful to breeders since there have been no other previous studies including this large number of commercial cultivars. Key Words: barley (Hordeum vulgare), developmental phases, genotypic variability, stem elongation, wheat (Triticum aestivum (L.))