Effect on fruit yield of bending ('kinking') the peduncles of tomato inflorescences

The effect on fruit yield of bending or 'kinking' the peduncles of inflorescences of tomato (Lycopersicon esculentum Mill. cv. Counter) was tested in two experiments in which the peduncle of the first truss of control plants was supported while in treated plants, the peduncle of this truss was bent either to a large radius bend or to a more severe, small radius bend. Within each of the two latter treatments, the peduncle was bent at one of three different stages of fruit development, viz. when at least one fruit of the truss was either 10, 20 or 30 mm in diameter, In all treatments, the second and third trusses were neither treated nor supported and the plants were decapitated above the third truss. Bending the peduncle of the first truss significantly reduced the fresh and dry weight yield of fruit from that truss and the reduction was greater when the bending was more severe, indicating that kinking of the peduncle did create a barrier to the translocation of assimilate to the fruit of that truss. In general, also, the distal fruit of the treated truss were more adversely affected than the first, proximal fruit. If the peduncle was bent when the fruit were small, i.e., 10 mm or less in diameter, the effect was less than when the fruit were larger, suggesting that the ability to translocate assimilate was recovered when kinking occurred early in fruit development. Some of the assimilate that was 'lost' from the first truss was partitioned to the second truss and especially to the proximal fruit of the second truss. (C) 1998 Elsevier Science B.V.