Thermoinhibition, or failure of seeds to germinate at warm temperatures, is common in lettuce (Lactuca sativa) cultivars. Using a recombinant inbred line population developed from a lettuce cultivar (Salinas) and thermotolerant Lactuca serriola accession UC96US23 (UC), we previously mapped a quantitative trait locus associated with thermoinhibition of germination to a genomic region containing a gene encoding a key regulated enzyme in abscisic acid (ABA) biosynthesis, 9-cis-EPOXYCAROTENOID DIOXYGENASE4 (NCED4). NCED4 from either Salinas or UC complements seeds of the Arabidopsis thaliana nced6-1 nced9-1 double mutant by restoring germination thermosensitivity, indicating that both NCED4 genes encode functional proteins. Transgenic expression of Salinas NCED4 in UC seeds resulted in thermoinhibition, whereas silencing of NCED4 in Salinas seeds led to loss of thermoinhibition. Mutations in NCED4 also alleviated thermoinhibition. NCED4 expression was elevated during late seed development but was not required for seed maturation. Heat but not water stress elevated NCED4 expression in leaves, while NCED2 and NCED3 exhibited the opposite responses. Silencing of NCED4 altered the expression of genes involved in ABA, gibberellin, and ethylene biosynthesis and signaling pathways. Together, these data demonstrate that NCED4 expression is required for thermoinhibition of lettuce seeds and that it may play additional roles in plant responses to elevated temperature.
Desiccant drying prior to hermetic storage extends viability and reduces bruchid (Callosobruchus chinensis L.) infestation of mung bean (Vigna radiata (L.
Purpose
The purpose of this paper is to analyze the potential returns to value chain actors from employing desiccant bead drying and hermetic storage technology.
Design/methodology/approach
Information was collected from 175 different onion (Allium cepa L.) seed value chain actors in Nepal. Four different business models for the introduction of new bead drying and hermetic storage technology were compared to current practices through use of partial budgeting.
Findings
The increase in net income throughout the chain was quite similar in all four models, ranging from US$28.86 to 29.61 per kg of onion seed, making it difficult to say that any single model is best for all situations. However, there are differences in sharing of positive net income and negative net income for different actors in different models. Moreover, about US$5.85 million incremental return could be earned per year in Nepal from improved preservation of onion seed alone.
Research limitations/implications
This research assesses how to introduce a new technology, the dry chain concept to maintain seed quality, into the existing marketplace.
Originality/value
This paper focuses on the economics of a novel technology and compares different business models and scenarios.
Background: Even as increasing populations put pressure on food supplies, about one-third of the total food produced for human consumption is wasted, with the majority of loss in developing countries occurring between harvest and the consumer. Controlling product dryness is the most critical factor for maintaining quality in stored non-perishable foods. The high relative humidity prevalent in humid climates elevates the moisture content of dried commodities stored in porous woven bags, enabling fungal and insect infestations. Mycotoxins (e.g., aflatoxin) produced by fungi in insufficiently dried food commodities affect 4.5 billion people worldwide. Scope and approach: We introduce the term "dry chain" to describe initial dehydration of durable commodities to levels preventing fungal growth followed by storage in moisture-proof containers. This is analogous to the "cold chain" in which continuous refrigeration is used to preserve quality in the fresh produce industry. However, in the case of the dry chain, no further equipment or energy input is required to maintain product quality after initial drying as long as the integrity of the storage container is preserved. In some locations/seasons, only packaging is required to implement a "climate smart" dry chain, while in humid conditions, additional drying is required and desiccant-based drying methods have unique advantages. Key findings and conclusions: We propose both climate-based and drying-based approaches to implement the dry chain to minimize mycotoxin accumulation and insect infestations in dry products, reduce food loss, improve food quality, safety and security, and protect public health.
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