MSc

An experiment was carried out at the College of Horticulture, Kerala
Agricultural University, Vellanikkara during August 2002-July 2003 to study the
efficacy of three levels ofbioregulators viz., PCPA (25,50 and 75 ppm), NAA (10,
20 and 30 ppm), CCC (25, 50 and 75 ppm) and 2,4-D (0.5, 1.0 and 2.0 pp m) on
growth, fruit set, yield and quality in tomato. The bioregulators were sprayed at
three different stages of the crop growth viz., 15, 30 and 45 DAT. The bacterial
wilt resistant variety Sakthi was used for the study. The experiment was laid out in
Randomized Block Design with two replications. \
All the bioregulators significantly influenced the vegetative characters
like height of the plant and number of branches. While the treatments with NAA
increased the height of t le plant, CCC reduced the same. Treatment of plants with
CCC at all concentrations increased the number of branches. The bioregulators
PCPA and 2,4-D had a negative influence on the plant height and number of
branches as they recorded a lower height and number of branches than control. The
growth parameters like RGR, NAR, LAI, CGR and LAD were positively
influenced by CCC and NAA while the PCPA and 2,4-D treatments reduced the
same, except NAR and CGR.
Earliness was influenced by the bioregulators during summer. The
plants treated with PCPA flowered earlier (5-10 days than- control) and produced
early yield (10-15 days than control). NAA was found to be effective in inducing
earliness during rabi.
All the bioregulators were effective in increasing the per cent fruit set,
number of fruits and fruit yield. The bioregulator CCC during both the seasons,
NAA during rabi and PCP A during summer were effective in increasing per cent
fruit set. The treatments with CCC increased the per cent fruit set, number of fruits
and yield per plant by 57.67, 42.74 and 61.53 per cent respectively. Treating the
plants with CCC 75 ppm was found to be effective in increasing the productivity of
the crop during both rabi and summer with 17.54 and 5.63 tonnes per hectare
respectively, while control recorded 13.07 and 1.17 tonnes per hectare during rabi

and summer respectively. The increase in the yield over control was 34.20 per cent
during rabi and 381.19 per cent during summer.
Plants treated with PCPA resulted in severe vegetative malformations,
up to an extent of 90 per cent. The malformations noticed were upward cupping of
leaves and thickening of lamina. Fruit malformations were noticed in 2,4-D and
CCC treated plants. The biochemical characters like TSS and ascorbic acid were
not highly influenced by the bioregulators. Cercospora leaf spot incidence was
reduced by the bioregulator treatments with PCPA recording 75 per cent less
incidence of the disease than control.