Evaluation of different seed dormancy breaking techniques on okra (Abelmoschus esculentus L.) seed germination

Abstract

Okra (Abelmoschus esculentus L.) is one of the horticultural crops commonly grown in Zimbabwe but the productivity of the crop is hampered by poor erratic seed germination due to dormancy. A study was carried out at Bindura University of Science Education to determine the best method and treatment combination of breaking okra seed dormancy. Viability tests and germination tests were conducted first to ascertain that failure of germination was due to dormancy. The study consisted of 3 laboratory experiments arranged as factorial treatment structure laid in a completely randomised design with 3 replications. The 3 experiments consisted of 3 methods of breaking seed dormancy (water soaking, acid scarification and dry heating). Each of the different methods was employed at different exposure duration and at different temperature/concentration levels. Germination was measured for 14 days to determine the total final percentage seed germination. Acid scarified seeds for 3 min at 80% H 2 SO 4 concentration level had the best germination percentage of 96.6% followed by dry heating for 5 minutes at 70°C and soaking for 12 h at 30°C which had 92.2 and 91.3% germination respectively. However, H 2 SO 4 scarification for 5 min at 60% concentration gave the least germination of 44% followed by soaking for 48 h at 30°C and dry heating for 5 min at 80°C which all resulted in 50% germination. Based on the research findings, 80% H 2 SO 4 for 3 min can be used by okra farmers to break dormancy while dry heating for 5 min at 70°C and soaking for 12 h at 30°C are equally good alternatives.

Viability and Dormancy of Rice Seeds after Storage and Pre-Treatment with Dry Heat and Chemical Agents

“…The high germination observed due to the use of H 2 O 2 and HNO 3 may be due to the breaking of the seed coat (Ali et al, 2011) which contains lignin and other compounds that make it impermeable to water and gases. The chemicals used may also leach away some of the growth inhibitors thus encouraging germination (Musara et al, 2015). The degree of scarification varies among cultivars and acid concentration (Kimura & Islam, 2012).…”

“…In the present study, the use of 0.5 M, 1 M, 2 M nitric acid and dry heat at 50 o C completely suppressed germination in both rice varieties. This may be due to seed injury which may occur due to high concentration of the treatment or long durations of exposure (Kimura & Islam, 2012;Musara et al, 2015).…”

Seed dormancy mechanism and dormancy-breaking methods in wild raspberry (Rubus fraxinifolius Poir.)

“…Temperatures of 70 °C cause non-uniformity and damage to parenchyma cells in the seed coat and increase the permeability of the seeds to water (Chaodumrikul et al, 2016;Gbenou et al, 2021). A temperature higher than 70 °C can cause cracks in the seed coat, but the dehydration of the seeds is high, affecting enzyme activation and reducing germination (Musara et al, 2015). Germination substrate and dormancy-breaking methods affect dormancy-intensity is present in Table 5.…”

The effect of different treatments on seed dormancy breaking and germination inducing in Louisiana variety of Okra (Abelmoschus esculentus L.)

“…Seed dormancy and germination are also regulated by growth and environmental conditions [3]. The most common type of dormancy is exogenous dormancy, which occurs when the seed coat becomes pale and impermeable to water.…”