Journal of Agricultural Science 141(2): 149-154 (Sept 2003)
Earliness per se and its dependence upon temperature in diploid wheat lines differing in the major gene Eps-Am1 alleles.
M. L. Appendino, G. A. Slafer
Departamento de Biología Aplicada y Alimentos,
Facultad de Agronomía, Universidad de Buenos Aires, Av. San Martín
4453, (1417) Buenos Aires, Argentina.

Abstract:
Differences in development among wheat cultivars are not only restricted to photoperiod and vernalization responses. When both requirements are fully satisfied differences may still arise due to earliness per se. It is not clear at present to what extent this trait is ‘intrinsically’ expressed (a constitutive trait) independently of the environmental conditions so that it might be selected under any thermal condition or if it may be altered to the extent of showing a crossover interaction with temperature in which the ranking of wheat genotypes may be altered. The present study assessed the influence of temperature on the intrinsic earliness for lines of diploid wheat characterized for their differences in a major gene for intrinsic earliness, but also possibly differing in their genetic background for other factors controlling this polygenic trait. To do so the lines were grown individually in two temperature regimes (16 and 23°C) under long days having previously been fully vernalized. Multiple comparisons analyses were carried out among lines of the same allelic group for the Eps-Am1 gene. Results indicated that within each group there were lines that did not differ in their earliness per se, others differed but without exhibiting any line temperature interaction and finally different types of interaction were shown, including cases where the ranking of lines was altered depending on the growing temperature. It is thus possible that the selection of a genotype based on its earliness per se in an environment might not represent the same performance in another location where temperature varied significantly.

Vernalized lines were grown individually under two temperature regimes (16 and 23°C) and long days. Multiple comparison analyses were carried out among the lines of the same allelic group for the Eps-Am1 gene. Within each group, there were lines that did not differ in their earliness per se, whereas others differed but without exhibiting any line x temperature interaction. The various types of interaction were evident, including cases where the ranking of lines was altered depending on the growing temperature. It is, thus, possible that the selection of a genotype based on its earliness per se in an environment might not represent the same performance in another location where the temperature varied significantly.

Intrinsic Earliness Bibliography