Flowering in Pisum: effect of the parental environment

The parental photoperiod appears to have no effect on the flowering node of the progeny, provided the progeny seed is selected to be of the same weight. However, the parental photoperiod does influence the mean seed weight and seed weight is shown to cause significant alterations in the flowering node and time as well as causing alterations in vegetative characters like the internode length and the rate of leaf expansion and node formation. The effect of seed weight on flowering is thought to result from the alterations in the growth rate. On the other hand, vernalization of the parents does appear to cause a small, but significant effect on the flowering node of the progeny (i.e. it could be transmitted through a meiotic division). This effect disappears in the next generation and the possible nature of this effect is discussed.