Sorghum seed storage in Purdue Improved Crop Storage (PICS) bags and improvised containers

doi:10.1016/j.jspr.2017.04.004

Journal of Stored Products Research

Volume 72, May 2017, Pages 138-142

https://doi.org/10.1016/j.jspr.2017.04.004 Get rights and content

Highlights

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Sorghum was stored in PICS and woven bags and tested for quality after 6 months.
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Plastic soda bottles were also tested as storage containers.
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Storage in hermetic containers had no effect of metrics of grain quality.
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Sorghum can be safely stored in hermetic containers.

Abstract

Seed storage is a major challenge for smallholder farmers in developing nations. Purdue Improved Crop Storage (PICS) bags effectively control the postharvest insect pests of cowpea and other crops. Farmers, encouraged by this success, have begun to expand the use of PICS bags for storing other crops. Little is known about how sorghum seed, one of these important crops, fares when stored under hermetic conditions. Accordingly, we stored sorghum seed for six months in either airtight containers (PICS bags or sealed plastic bottles) or open ones (woven polypropylene bags and open plastic bottles). Overall, sorghum seed stored in PICS bags and in sealed plastic bottles maintained its initial moisture level, germination rate and seed weight. Porous polypropylene bags and open plastic bottles lost moisture over six months. We conclude that sorghum seed can be safely stored in hermetic containers without any loss of quality for extended periods of time.

Introduction

Sorghum (Sorghum bicolor), native to Africa where more than 36% of the global supply is produced (FAOSTAT, 2015), is an important crop worldwide. Sorghum produces a small, pearl-like grain that ranges in color from white to red to brown and that typically weighs around 25–30 mg. Much of the recent increase in world sorghum production has been for animal feed, though it still remains a staple food source for many dry and semi-arid regions (Curtis, 1967).

Smallholder farmers typically store sorghum seed in small quantities, either threshed or unthreshed (Sorghum and Millets- FAO, 1995). Losses during storage are caused by a combination of biotic (insects and molds) and physical forces. Insects and molds can reduce seed weight and can destroy the nutritional quality of the seed. Aside from such organisms, sorghum grain stored in sealed, airtight containers has been observed to decline in quality under high temperature and humidity (Sorghum and Millets-FAO, 1995).

Options to control pest insects in developing nations are limited. Synthetic pesticides are expensive and hard to obtain (Jones et al., 2011, Njoroge et al., 2014). Even if applied appropriately, several applications may be needed to prevent damage. Repeated treatments are not only more expensive and laborious, they also increase the chance for human or environmental toxicity (Meikle et al., 2002, Addo et al., 2002). Synthetic pesticides are not a preferred option for most farmers seeking to control grain pests.

Hermetic storage for grain has been used for pest control in one form or another since ancient times (De Lima, 1990, Njoroge et al., 2014). More recently, this storage method has increased in popularity thanks in part to the dissemination of Purdue Improved Crop Storage (PICS) bags throughout Africa. The PICS bag consists of two polyethylene liners and one outer layer of woven polypropylene. Together, the three layers severely restricts oxygen flow into the grain from the surrounding airspace. Respiration of insects, grain and other organisms changes the composition of the air within the bag, decreasing oxygen levels and increasing carbon dioxide. These conditions are inhospitable for most grain pests. Population growth is arrested and many of the insects die (Baoua et al., 2012). PICS bags have become widely available throughout West Africa, where almost 50% of cowpea kept on farm is stored in some sort of hermetic container (Baributsa, 2014, Moussa et al., 2014, Ibro et al., 2014). Farmers, noting the success of PICS with cowpea, have already begun to store other crops such as maize and sorghum, in PICS bags.

Only a few studies have investigated the storage of sorghum seed under hermetic conditions (Ellis and Hong, 2007). With farmers already storing sorghum in PICS bags, it is essential that we collect evidence to determine if sorghum seed can be safely stored under these conditions. This would lay the scientific foundation for encouraging further adoption and use of the technology for seed storage. Accordingly, we investigated the performance of sealed hermetic bags as well as plastic bottles for storing sorghum seed to determine if these containers maintain seed quality as well or better than unsealed containers. Since our focus was mainly on seed viability and germination, care was taken to ensure that no insects were present in the sorghum grain kept in the test containers.

Section snippets

Trial set-up

Red sorghum seed (Channel Seed #A1005963) was purchased from Channel Seed, (Kentland, IN) and stored for a period of 6 months between September 2014 and March 2015. This seed had been frozen for five days prior to setting up the experiment to kill any insects present and then stored in hermetically-sealed buckets until used. A total of 200 kg of sorghum seed was stored as 20 kg units in ten storage bags, each with a 50 kg storage capacity. Five bags were the PICS, hermetically-sealed triple bag

Absence of insects

Over the six month period, no insects were observed in the storage containers or inside the seeds removed at each sampling period. Neither were there signs of feeding damage to seeds observed in either treatment group, confirming that there was no contamination by insects during the study.

Temperature and humidity

Bag temperature correlated with environmental temperatures, regardless of treatment type (Sealed: Pearson's correlation- P = 0.84; Porous: Pearson's correlation- P = 0.86) (Fig. 1a). Stored sorghum seed

Discussion

Storage of sorghum seed under hermetic conditions does not reduce germination or affect other aspects of seed quality. While poor storage conditions can lead to deterioration of the seed and loss of vigor even in the absence of insect pests or molds (Ekechukwua and Norton, 1999), but our study shows that proper storage of sorghum seed can preserves germination well for at least six months.

The modest decline in oxygen in the storage bags and bottles suggests a low level of biological activity

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Performance of triple bagging hermetic technology for postharvest storage of cowpea grain in Niger
J. Stored Prod. Res.
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D. Baributsa
Market building for post-harvest technology through large-scale extension efforts
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Adoption of cowpea hermetic storage by women in Nigeria, Niger, and Burkina Faso
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B. Moussa et al.
Adoption of on-farm hermetic storage for cowpea in west and central Africa in 2012
J. Stored Prod. Res.
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A.W. Njoroge et al.
Triple bag hermetic storage delivers a lethal punch to Prostephanus truncatus (Horn) (Coleoptera: bostrichidae) in stored maize
J. Stored Prod. Res.
(2014)
M.I. Vales et al.
Effective and economic storage of pigeonpea seed in triple layer plastic bags
J. Stored Prod. Res.
(2014)
S.B. Williams et al.
Assessing Purdue Improved Crop Storage (PICS) bags to mitigate fungal growth and aflatoxin contamination
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Effect of seed storage temperature and relative humidity on maize (Zea mays L.) seed viability and vigour
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(1999)
S. Addo et al.
Ten years after the arrival in Ghana of Larger Grain Borer: farmers' responses and adoption of IPM strategies
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(November, 1928)

There are more references available in the full text version of this article.

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Citation Excerpt :
Nganga et al. (2016) reported that PICS bags achieved a relatively stable modified environment, as High-density polyethylene (HDPE) liners capable of trapping aerobic breathing items from inside the bag. Our research did not produce a low concentration of oxygen; unlike other studies (Murdock et al., 2012; Cheng et al., 2012; Hell et al., 2014; Williams et al., 2017; Yeole et al., 2018; Baoua et al., 2013) report on the trends of oxygen and carbon dioxide progression. Carvalho et al. (2019) found that the amount of oxygen fell between 2 and 4% and carob dioxide raised to 11–15%.
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Citation Excerpt :
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Journal of Stored Products Research

Highlights

Abstract

Introduction

Section snippets

Trial set-up

Absence of insects

Temperature and humidity

Discussion

References (20)

Performance of triple bagging hermetic technology for postharvest storage of cowpea grain in Niger

J. Stored Prod. Res.

Market building for post-harvest technology through large-scale extension efforts

J. Stored Prod. Res.

Adoption of cowpea hermetic storage by women in Nigeria, Niger, and Burkina Faso

J. Stored Prod. Res.

Adoption of on-farm hermetic storage for cowpea in west and central Africa in 2012

J. Stored Prod. Res.

Triple bag hermetic storage delivers a lethal punch to Prostephanus truncatus (Horn) (Coleoptera: bostrichidae) in stored maize

J. Stored Prod. Res.

Effective and economic storage of pigeonpea seed in triple layer plastic bags

J. Stored Prod. Res.

Assessing Purdue Improved Crop Storage (PICS) bags to mitigate fungal growth and aflatoxin contamination

J. Stored Prod. Res.

Effect of seed storage temperature and relative humidity on maize (Zea mays L.) seed viability and vigour

Seed Sci. Technol.

Ten years after the arrival in Ghana of Larger Grain Borer: farmers' responses and adoption of IPM strategies

Int. J. Pest Manag.

U.S. Department of Agriculture. Respiration of Sorghum Grains

Cited by (19)

Physicochemical stability, microbial growth and sensory quality of refined wheat flour as affected by packaging materials during storage

Effects of hot air-assisted radio frequency stabilization of brown millet and millet bran: Enzyme inactivation, microstructure, nutritional quality, and storage stability

Physicochemical stability, microbial growth, and sensory quality of teff flour as affected by packaging materials during storage

Effects of storage bags type and storage duration on seed quality and proximate composition of emmer wheat (Triticum dicoccum L.) in Ethiopia

Evaluating of hermetic bags for long-term storage of turmeric (Curcuma longa L.) rhizomes

Effects of storage temperature and packaging material on physico-chemical, microbial and sensory properties and shelf life of extruded composite baby food flour