Seed quality viability

Seed qirality is a term which encompasses a nttmber of important criteria, in particitlar genetic pirrity, seed physical qirality, viability, the presence of weed seeds, pests or diseases, and moisture content. The following section describes the various factors which can impact upon seed quality and their nomenclature. 

The production of high-quality hybrid seeds does not only depend on the use of parental lines of superior class, but also on the degree of isolation of the cultivation field from other sunflower plantations, including wild varieties. The isolation conditions cannot be accurately established, in view of the role of insects as pollination agent, and the long viability period of pollen yet, recommendations have been made. 

Media for the production phase are usually richer in nutrient content than the seed train medium in order to maintain viability and productivity of the cells for a minimum of 1-2 weeks. For facilitating recovery and purification of the product and for cost reduction, serum is not used for the production phase. The attachment of cells to the surface of the rollerbottle wiU not be compromised by such a modification in the medium. However, gentle handling is required or the sheets of cells will detach. Upon incubation of the confluent cells with the enriched, serum-free medium, the secreted product will be harvested, leaving the adherent cells inside the bottle. Sometimes, a refeeding with fresh medium for a second production cycle is possible, on the condition that the product of the first and the second harvest will be similar in composition and quality. Since a standard 2-L rollerbottle will contain about 300 mb of medium for harvest, 1000 roUer-bottles will provide from 300 L to 600 L of supernatant. Over a one-year period, a manufacturing process based on this schedule will deliver 15 000-30000 L of... 

In addition to health hazards, several mycotoxins have phytotoxic impacts on host plants and may cause loss of viability and reduced quality of plant seed (Nishiuchi, 2013). Several mycotoxins have antimicrobial activity and thus may also influence the behaviour of other microbes present in the same surrounding. Mycotoxins may have adverse effects on animal health if they are transmitted to sidestreams used as animal feed. Consumption of contaminated batches at farms can lead to reduced livestock productivity and to serious illness or even death (Murphy et al., 2006). Some of the most common mycotoxins associated with foods and beverages are presented in Table 6.2. 

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