Effect of Seed Priming and Soil Application of Humic Acid on Growth and Yield of Roselle (Hibiscus sabdariffa L.)

A factorial field experiment based on a randomized complete block design with three replications was conducted to investigate the effect of seed priming and soil application of humic acid on the growth and yield of Roselle (Hibiscus sabdariffa L.). The research was carried out in Farm Research of Shirvan Faculty of Agriculture in 2020. Experimental factors included seed priming with three levels of humic acid (0 (P-1), 2.5g/l (P-2) and 5g/l (P-3)) and two levels of humic acid soil application (0 (S-1) and 6 liters per hectare humic acid (S-2)). The results of the statistics analysis showed that the application of humic acid (both seed priming and soil application) significantly increased the growth traits and yield of Roselle plants compared to non-humic acid-treated plants (P1S1). Plants treated with P3S2 significantly had the highest plant height (167.3 cm), number of branches per plant (9.8), number of leaves per plant (81), leaf dry weight (34 g/m(2)), leaf area index (5.2), calyx yield ( 53.3 g/m(2)), number of seeds per plant (882), seed yield (1281 kg/ha) and biological yield (4230 kg/ha). However, non-humic acid-treated plants (P1S1) had the lowest plant height (133.5cm), number of branches per plant (6.7), number of leaves per plant (46), leaf dry weight (18.7 g/m(2)), leaf area index (2.9), calyx yield (37.3 g/m(2)), number of seeds per plant (554), seed yield (977 kg/ ha) and biological yield (2900 kg/ha). The results also showed that soil application of humic acid had a more positive effect on the growth traits of Roselle plants than seed priming. However, leaf chlorophyll content and weight of thousand seeds (g) were not affected by both seed priming and soil application of humic acid.