Effect of NPK combinations on some growth and yield indicators of two varieties of roselle plant (Hibiscus sabdariffa L.)

Abstract

A field experiment was carried out during the 2022 agricultural season in one of the experimental fields affiliated with Ibn Al-Bitar Vocational Preparatory School, located in Karbala Governorate, to study the effect of NPK combinations on the growth and yield traits of two varieties of Roselle plant. The experiment was carried out in with three replicates, according to a randomized complete block design (RCBD) with two factors. The first factor included combinations of NPK fertilizers and according to the as follows: C0= 0  NPK kg ha-1, C1= 50,25,25  NPK kg ha-1, C2 = 75,50,50 NPK  kg ha-1, C3 =100,75,75  NPK  kg  ha-1, C4 = 125,100,100  NPK  kg ha-1, C5 = 150,125,125  NPK  kg  ha-1, C6 = 175,150,150 NPK kg ha-1. The second factor was two varieties of Roselle plants: white (W) and red (R). The results showed that the red variety excelled in most of the studied traits, such as growth traits, plant height 173.27 cm, leaves number 295.65 leaf plant-1, leaf area 3.48 m2,total chlorophyll content in leaves 6.61 mg g-1, fresh weight 2188.57 g plant-1, yield characteristics, number of nuts 137.65 nut plant-1, total nut yield 6298. 44 kg ha-1 and total yield of calyx leaves 1558.01 kg ha-1. C5 and C6 combinations were superior in plant height (189.05 and 195.05 cm), leaves number (331.0 and 348.0 leaf plant-1), chlorophyll a ( 6.10 and 6.45 mg g-1), chlorophyll b( 4.23, and 4.72 mg g-1 , Total chlorophyll(10.36 and 10.96 mg g-1), number of nuts (141.90 and 143.30 nut plant-1),  total nut yield (6815.82 and 7090.42 kg ha-1), total yield of calyx leaves(1769.68 and 1967.81 kg ha-1 and fresh weight (2845and 2969 g plant-1) respectively. The C6 treatment was significantly superior to the C5 treatment in the characteristics of chlorophyll b, total chlorophyll, fresh weight, total nut yield, and total yield of calyx leaves.