Seaweed extract and indoleacetic acid foliar application in relation to the growth performance of sweet pepper grown under net house conditions

Abstract EN

Sweet pepper plants (Capsicum annuum L.) grown worldwide in various distinct colours and shapes, and favors for consumers, especially those grown under protected houses.

The attention of growers is directed toward enhancing or improving the growth, yield and quality of their fruits via safe agricultural practices using seaweed extract (SWE) as a biostimulant and plant growth regulators as the auxin IAA as safe alternatives for inorganic fertilization and their negative impacts.

Therefore, two field experiments were carried out during two successive seasons of 2017 and 2018, to determine their influences on both vegetative and reproductive growth of sweet bell red pepper cv.

'Strick F1' grown under net house conditions.

Treatments were consisted of two independent variables as foliar applicants such as seaweed extract (SWE) [Cytokan-S ] at four concentrations ( control, 500, 1000 and 2000 mg.l-1 ) in combination with five concentrations of indoleacetic acid (IAA) [control, 30, 60, 90 and 120 mg.l-1 ].

Control plants were sprayed with tap water.

Pepper plants were sprayed with the assigned treatments twice, once at 15 days after transplanting, and the second one was 20 days later.

Both conducted experiments were factorial experiments laid out in a randomized complete block design (RCBD), with three replicates.

The obtained results showed that vegetative growth were affected significantly (p 0.05) due to the combination of SWE at either 1000 or 2000 mg/l × IAA at 120 mg/l; as number of leaves/plant, plant fresh and dry weights as compared to control plants.

Respecting yield characters and its components, the interaction between both independent variables, exerted significant (p 0.05) effect on the various studied traits but without clear trends, except for fruit dry weights especially, wherein the interactions between control (SWE) 120 mg/l (IAA), and SWE at 500 mg IAA at 120 mg/l, gave rise to the highest average values during both seasons, in comparison to the interaction between control treatments of both variables; recorded, mostly, the least average values of the given traits.

In terms of nutrient contents of fruits; N, P and K nutrient contents, the foliar application of the combination between SWE and IAA at 2000 and 120 mg/l, each in turn, significantly (p ;brought about the highest average values of nutrient contents of fruits compare to the other tested combinations.

In brief, this investigation suggests that foliar application with combination of both SWE at 2000 mg / l and IAA at 120 mg / l twice after 15 and 20 days later of transplanting, is recommended to achieve the best vegetative and yield and quality of the given cultivar.