Transgenic sugar beet tolerant to glyphosate

Phenology (i.e. the influence of environment on ontogeny) is the most important single factor influencing crop adaptation. The timing of flowering is particularly important since it largely determines when annual cereal, pulse and oilseed crops will subsequently be ripe for harvest. Two environmental factors are of overriding importance in the induction of flowering – photoperiod (daylength) and temperature. In seeking to predict times from sowing to flowering, f, it has proved profitable to analyse photothermal responses in terms of the rate of progress from sowing to flowering, 1/f. This paper summarises the advantages of a model based on rates rather than the traditional approach based on f. Over a wide range of photothermal regimes, the model involves just six coefficients, all of which (and their derivatives) have clearly defined biological meaning. Of paramount importance too is that the coefficients are not affected by the environment; they are genetic characters which determine phenotypic responses to the environment in a quantitative and predictable way.