EFFECT OF FOLIAR APPLICATION OF GIBBERELLIC AND THE ADDITION OF HUMIC ACID ON THE APPLE SEEDLINGS GROWTH

The study was carried out in one of the private nurseries affiliated to Babylon Governorate for the period from 15-04-2021 to 30-10-2021, the present study aimed to determine the effects of gibberellic acid foliar application and humic acid addition to the growth medium on the growth traits of apple (Malus domestica cv. Anna) seedlings, was carried out in 2021 at the Babylon Governorate, Iraq. Four different levels of gibberellin acid (0, 50, 100, and 200 mg.L-1) and humic acid (0, 50, 100, 150 ml.L-1) were used in a randomized complete block design (RCBD) with a factorial arrangement and three replications. Results revealed that foliar application of gibberellin acid (100 mg.L-1) was found significantly superior in significantly enhancing the values of growth traits in apple seedlings i.e., stem length (86.98 cm), branches per seedling (9.45), leaves per seedling (180.25), leaf area (32.83 dm2), dry weight of seedlings (39.25 g), chlorophyll content (44.30 spad), the nitrogen content of the leaves (2.83%), phosphorus content (0.41%), and potassium content (2.34%). Adding humic acid to the growth medium at the level of 150 ml .L-1 significantly excelled and gave the highest average values for the above traits reaching 84.13 cm, 9.68 branches, 175.85 leaves, 32.30 dm2, 41.88 g, 45.55 spad, 2.90%, 0.43%, and 2.39% for the above traits, respectively. The combination of gibberellin acid (100 mg.L-1) and humic acid (150 ml.L-1) provided the highest average values for the above characteristics.