Modelling the influence of seed set on fruit shape in apple

SummaryThe influence of seed set on fruit shape was examined in lopsided ‘Granny Smith’ apple (Malus domestica Borkh.). Variability in seed weight reflected the dynamics of seed development while asymmetrically distributed seed resulted in asymmetrical fruit. A three-order model was developed which predicted the influence of seed weight on fruit sector weight. The growth of a particular sector was principally influenced by the seeds within its locule (first order), less by the seeds in the two flanking locules (second order) and not by the seeds in the two most distant locules of the fruit (third order). The growth behaviour appears to be modular where each carpel exerts a somewhat autonomous effect on fruit growth and, at least partially, develops as a unit. A weakening seed influence with increasing distance from the sector indicates that seeds principally govern fruit development.