Seed Coating with Hydro-Absorbers as Potential Mitigation of Early Season Drought in Sorghum (Sorghum bicolor L. Moench)

Abstract

Climate change poses a threat to sorghum production systems by shifting the onset of the rainy season to a later date, increasing the risk of crop failure during crop establishment. The effects of drought on sorghum during seedling establishment have not been determined. Coating seeds with a water absorbing substance offers a way to buffer the seed against insufficient moisture in the surrounding soil. Seeds of two different sorghum varieties were coated with one of two commercially available hydro-absorbers: Stokosorb® and Geohumus®. These hydro-absorbers have the capacity to store water several times their own weight. The aim of this study was to compare the effects of the cited hydro-absorbers on early seedling growth of two sorghum landraces under different levels of soil water deficit. Seedlings were grown for 12 days under three water availability levels (Field capacity (FC), 50% of FC, and 25% of FC). The seedlings under water limited treatments were subsequently re-watered. Biomass, root length, plant height, leaf area, and leaf extension rate were monitored in two-day intervals for 24 days. Coating strongly affected seedling growth both under fully watered and water deficit conditions. Sorghum varieties differed in their responses to both soil water deficit and coating materials. In general, Stockosorb improved seedling performance under water limited conditions particularly by promoting root growth, whereas Geohumus did not.

Effect of Seed Coating and PEG-Induced Drought on the Germination Capacity of Five Clover Crops

“…The overall average values could have been distorted by the different responses of respective plant species to the coating technology. This is confirmed also by Vymyslický et al [ 34 ] or Gorim and Asch et al [ 33 ], who pointed out the effect of varieties that may influence the response to seed coating within one plant species. On the other hand, seed coating is considered a practice intended rather to improve handling and protection of plants (against mechanical or biological damage) and to a lesser extent also to enhance germination capacity [ 35 ].…”

“…In the submitted study, no positive influence of coating was observed on the overall average values of seed drought resistance at higher PEG concentrations. The coating of seed with hydro-absorbents has been tested over a long time with respect to their influence on the growth of plants after sowing, i.e., their effect on the emergence of plants [ 33 ]. The coating of seed with a substance that is capable of binding water is considered a possibility for mitigating the impact of drought on the emergence of seed stock [ 8 , 33 ].…”

Germination and Growth Performance of Water-Saving and Drought-Resistant Rice Enhanced by Seed Treatment with Wood Vinegar and Biochar under Dry Direct-Seeded System

“…For example, seed coating with super absorbent polymer improved the energy and rate of seed germination, along with promoting seedling growth [21]. A previous study also reported that the dydro-absorber coating increased seedling performance under water-limited conditions, particularly by enhancing root growth [22]. However, the existing materials with seed coating are chemical, and the majority of them have little effect on seed vigor, germination characteristics, and seedling growth.…”