DOI: https://doi.org/10.21276/AATCCReview.2025.13.02.347

Abstract

The tomato is highly sensitive to very hot, humid and cold conditions and it is directly or
indirectly affecting the production and productivity of tomato. Due to increase in temperature
there is more incidence of viral diseases as well as problem in pollination and fertilization
This experiment was laid out in Randomized Block Design (RBD) having seven treatments
and three replications. Treatments consist of different levels of NAA (T 1 @10 ppm, T 2 @ 20
ppm, and T 3 @30 ppm), GA 3 (T 4 @50 ppm, T 5 @100 ppm, and T 6 @150 ppm) along with
control (T 7 @ sprayed only with distilled water). These different concentrations of NAA and
GA 3 were sprayed on the crop at 25, 50, and 75 days after transplanting to study the different
parameters at all successive stages of crop growth. The result revealed that the morphological
parameters were greatly affected by the different levels of NAA and GA 3 at all the successive
growth stages except 25 days after transplanting. Treatment T 3 (NAA@30 ppm) produced
maximum plant height, number of branches per plant, and number of leaves per plant which
were at par with treatment T 5 (GA 3 @100 ppm) at 50 and 75 days after transplanting
respectively. All the flowering, physiological and yield-attributing parameters were also
greatly influenced by the application of growth regulators (NAA and GA 3 ). It may be
concluded that in the subtropical climate, farmers face flower and fruit drop problems due to
high temperatures in the Kharif and late Kharif season. To overcome this problem, plant
growth regulator GA 3 @100ppm can be used to increase the flowering, fruit set, and fruit size
and control the fruit drop.

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