Predicting the effect of temperature on leaf appearance in seven spring bread wheat genotypes

ABSTRACT: Field experiments were conducted at the Faculty of Agriculture, Cairo University, Agriculture Experiment and Research Station, during two successive seasons starting with 2010/2011 in Giza, Egypt. The study aimed to determine the effect of temperature (by sowing dates) on leaf appearance and growth of seven spring bread wheat genotypes. Linear response was found between rate of leaf appearance and thermal time. Phyllochron ranged between 108oC d and 122oC d. Mean final leaf number on the main stem ranged from 8.5 to 11.5 and it was highly correlated with thermal time (r=0.99**). Genetic constitution of genotypes had larger effect on number of leaves per main-stem than temperature. These results suggests that, to model leaf appearance and canopy development in wheat, genotypic coefficients of phyllochron need to be determined in relation to growing environment temperature.