EFFECT OF HUMIC ACID AND SOME MICRO NUTRIENTS ON GROWTH, SEED YIELD AND OIL CONTENT OF BORAGO OFFICINALIS L. PLANT

Borage (Borago officinalis L.) is a yearly herbaceous plant belonging to the Boraginaceae family and known as the bee plant or bee bread. Borage is a significant medicinal plant indigenous to the Mediterranean region and has become widespread in many other countries. A factorial experiment was executed to assess the impact of humic acid and micro nutrients on the growth characteristics, chemical composition, and oil production of borage plants. It was carried out at the Experimental Farm of the Horticulture Department, Faculty of Agriculture, Moshtohor, Benha University, through the two consecutive growing seasons of 2020/2021 and 2021/2022. This trial comprised 16 treatments which were the outcome of the combination between soil addition with humic acid at 0 (control), 2, 3 and 4 kg/fed, and foliar spray with water (control), Zn, Fe or Mn at 100 ppm for each one. Results indicated that the treatment of humic acid at 4 kg/fed + Fe at 100 ppm was significantly improved the growth characters including number of branches, fresh and dry weight of herb. The treatment of humic acid at 4 kg/fed + Fe at 100 ppm also produced the greatest values of total nitrogen, phosphorus, potassium and carbohydrate in both seasons. Meanwhile, the treatment of humic acid at 4 kg/fed + Zn at 100 ppm significantly improved the characters including plant height, fresh and dry weights of inflorescences, and seed yield in both seasons. The treatment of humic acid at 4 kg/fed + Zn at 100 ppm gave the highest fixed oil percentage followed by humic acid at 4 kg/fed + Fe at 100 ppm. Exactly 68 compounds were identified and accounted in the components of Borago officinalis fixed-seed oil samples of the second season when analyzed by GC-MS. Where the sample resulted from the treatment of humic acid (4 kg/fed) + Fe (100 ppm) recorded 33 compounds. Conversely, the sample resulted from the control treatment recorded 14 compounds.