Effect of Spring and Summer Sprays of 2,4, 5-T and Ga on Fruit Set and Physical Characters of Some Sweet Orange Cultivars*

The growth regulator treatments 2, 4, 5-T 10 ppm and 15 ppm increased the fruit set over the control significantly. All the GA concentration increased the fruit set over the control significantly except GA at 10 ppm in Pineapple where its effect was not significant. The length of the fruit was significanily increased by 2, 4, 5-T 15 ppm and 25 ppm in Pineapple. In Valencia Late all the 2, 4, 5-T treatments increased the fruit length significantly. However, in Hamlin the effect was not significant in spring spray. GA at 50 ppm reduced the fruit length significantly over the control. Similar trend was obtained in respect of diameter except in Valencia Late none of the 2, 4, 5-T treatments increased the diameter significantly over the control.

In summer spray 2, 4, 5-T 100 ppm increased the fruit length in Pineapple and 200 ppm in Hamlin and both these concentrations were effective in Valencia Late. GA at 150 ppm and 300 ppm reduced the fruit length significantly in all the three varieties in spring spray. In summer spray in Pineapple 2, 4, 5-T at 100 and 200 ppm increased the diameter significantly. In Hamlin none of the treatments increased fruit diameter over the control. In Valencia Late all the 2, 4, 5-T concentrations increased fruit diameter significantly. In spring spray 2, 4, 5-T at 15 ppm and 25 ppm increased the volume and weight in Pineapple and Valencia Late but in Valencia Late 2, 4, 5-T 15 ppm was not significantly different from control. In summer none of 2, 4, 5-T treatments increased volume but weight was increased by 2, 4, 5-T 100 ppm and 200 ppm in Pineapple. In Hamlin voulme and weight was incresed by 100 ppm and 200 ppm 2, 4, 5-T. However, in Valencia Late the volume was increased with these concentration.