Low-cost Seed Storage Technologies for Development Impact of Small-scale Seed Saving Entities in Tropical Climates

Q: Why is seed storage difficult in tropical climates?

High heat and humidity accelerate deterioration of orthodox seeds. Fluctuating relative humidity and persistent pest pressure further reduce long-term viability, especially where resources are limited.

Q: What storage technologies were compared in the study?

The study tested vacuum drawn on glass jars using a modified bicycle pump, vacuum drawn on polyethylene bags using an electric vacuum sealing machine, desiccants (calcium oxide powder or zeolite Drying Beads®), and untreated seeds stored in paper bags.

Q: Which treatments best maintained germination under high temperature and humidity?

Vacuum treatments and calcium oxide maintained high germination for okra and velvet bean across locations. Glass containers outperformed polyethylene by better sustaining vacuum and stabilizing seed moisture content.

Jul 2, 2026

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Seeds deteriorate quickly in high heat and humidity, making orthodox seed storage in tropical climates costly and difficult, which can limit agricultural development outcomes. This study evaluates low-cost storage technologies that preserve the viability of already-dried seeds. Okra, sorghum, and velvet bean seeds were held for 12 months in warm, humid conditions at two sites, testing vacuum-based methods, desiccants, and untreated controls. Results show vacuum treatments and calcium oxide sustaining germination, with container choice strongly affecting moisture stability and performance.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages14

Reading Time35 min

Summary

Introduction

Seed deterioration in humid tropics

Community seed banks and storage challenges

Need for low-cost storage technologies

Experimental Agriculture (2022), 1–14 doi:10.1017/S0014479722000023 RESEARCH ARTICLE Low-cost seed storage technologies for development impact of small-scale seed saving entities in tropical climates Patrick Trail 1, Timothy Motis2,*, Stacy Swartz2 and Abram Bicksler 1,3 1ECHO Asia Impact Center, 270/5 Tung Hotel Road, Soi 6, Watgate, Chiang Mai, Thailand 50000, USA, 2ECHO Inc., 17391 Durrance Road, North Fort Myers, Florida 33917, USA and 3Current affiliation: Food and Agriculture Organization of the United Nations (FAO), Vialle delle Terme di Caracalla, Rome, 00153, Italy *Corresponding author. Email: [tmotis@echonet.org](tmotis@echonet.org) (Received 15 September 2021; revised 30 November 2021; accepted 06 January 2022) Summary Seeds can deteriorate rapidly under high heat and humidity, making it challenging and potentially costly to store orthodox seeds effectively in the tropics, thereby affecting agriculture development. This work explores the effectiveness of novel, low-cost technologies for storing seeds in warm, humid, resource-constrained environments, focusing on maintaining the viability of seeds already dry prior to storage. Seeds of okra (Abelmoschusesculentus (L.) Moench), sorghum (Sorghum bicolor (L.) Moench), and velvet bean (Mucunapruriens (L.) DC) were kept for 12 months under roofed, outdoor screened porches. Seed moisture content prior to treatment was 6, 9, and 12% for okra, sorghum, and velvet bean, respectively. Treatments, replicated four times at each of two locations (USA [Florida] and Thailand), were technology suites involving vacuum drawn on glass jars with a modified bicycle pump, vacuum drawn on polyethylene bags with an electric vacuum sealing machine, desiccant (calcium oxide powder or zeolite Drying Beads®at a 2:1 ratio, by weight, of seeds to desiccant) in glass jars, and nontreated seeds in paper bags. Ambient temperature and humidity were variable and high, reaching over 35 °C and 83%, respectively, at both locations. Under these conditions, okra and sorghum germination percentages (across locations) without treatment declined from over 90% initially to 30 and 0%, respectively, by month 12. Both vacuum treatments and calcium oxide maintained high germination of okra (≈ 80%) and velvet bean seeds (nearly 100%) across locations. Glass, however, was superior to polyethylene in maintaining vacuum and stabilizing the moisture content of okra and sorghum seeds. Only zeolite reduced seed moisture below initial values, drying seeds to ultradry levels of <5%. With zeolite, sorghum germination stayed near 70% overtime, while okra and velvet bean germination fell to <40 and <20%, respectively, by month 12, suggesting that, with the beads kept with dry seeds in storage rather than removing the beads after reaching a target level of seed moisture, the 2:1 ratio of seed-to-bead weight was too high for seeds that are sensitive to ultralow moisture. Findings have practical implications for inexpensive household-or community-level seed storage to deliver development impact. Keywords: Seed Saving; Seed Banking; Vacuum Sealing; Desiccants; Zeolite Drying Beads®; Community Seed Banks; Calcium Oxide Introduction Maintaining seed quality and viability of stored orthodox crop seeds over time can be challenging in any location but is especially so in the humid tropics and subtropics of the developing world (Delouche et al., 1973; Ellis, 1991; Rao et al., 2006) . Warm year-round temperatures, high rates of relative humidity, fluctuating relative humidity, and year-round pest pressures are all problematic for long-term storage of seeds. Even where seeds are saved, stored, and planted on short annual © The Author(s), 2022 . Published by Cambridge University Press. Downloaded from [https://www.cambridge.org/core. IP](https://www.cambridge.org/core. IP) address: [1.1.161.198](1.1.161.198), on 09 Feb 2022 at 04:09:06, subject to the Cambridge Core terms of use, available at [https://www.camb

FAQs

Why is seed storage difficult in tropical climates?

High heat and humidity accelerate deterioration of orthodox seeds. Fluctuating relative humidity and persistent pest pressure further reduce long-term viability, especially where resources are limited.

What storage technologies were compared in the study?

The study tested vacuum drawn on glass jars using a modified bicycle pump, vacuum drawn on polyethylene bags using an electric vacuum sealing machine, desiccants (calcium oxide powder or zeolite Drying Beads®), and untreated seeds stored in paper bags.

Which treatments best maintained germination under high temperature and humidity?

Vacuum treatments and calcium oxide maintained high germination for okra and velvet bean across locations. Glass containers outperformed polyethylene by better sustaining vacuum and stabilizing seed moisture content.

Jul 2, 2026

Upload by Patrick