Effort to increase off-season production and fruit quality of Siam orange (Citrus nobilis var. microcarva L.) through application of mycorrhizal inoculants and auxin

Abstract

Abstract The study was conducted in Belancan Village, Kintamani, Bangli, Bali, from February to October 2018 with the aim to study the effect of application of mycorrhizal inoculants and auxin to increase off-season production and fruit quality of Siam orange. This experiment used a randomized block design with 2 factors. The first factor mycorrhizal inoculant dosages (0, 50, and 100 g/tree), while the second factor auxin concentrations (0, 50, 100 and 150 ppm/tree), and repeated 3 times. The results showed that the interaction of mycorrhizal inoculant dose and auxin concentration did not significantly effect to all of observed variables. The dose of mycorrhizal inoculant 100 g/tree increased off-season fruit production and quality of fruits, which was reflected by increase number of fruits per tree (142.17 fruits), weight per fruit (96.00 g), weight of fruit per tree (13.53 kg), and total dissolved solids (14.10 %Brix), or an increase of 44.21%; 11.89%; 57.87% and 21.03% compared to without mycorrhizal inoculant (108.58 pieces; 88.80 g; 10.57 kg and 11.65 %brix). Concentration of auxin 100 ppm/tree increased off-season production and quality of fruits, reflected by the higher number of fruits/trees (155.22 fruits), fruit weight per tree (15.03 kg), weight per fruit (96.50 g) and total dissolved solids (14.43% brix), compared to without auxin i.e. 112.11 pieces; 10.44 kg; 84.66 g; and 11.15% brix. The significant result of this research was mycorrhizal inoculant dose of 100 g/tree and auxin in the form of IBA 100 ppm/tree proven fruit drop, increased off-season fruit production and quality of fruits of Siam orange.