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Laboratory-scale research had shown the potential of using cotton burr/stem (CBS) as fiber filler in thermoplastic composites. This study evaluates the potential of using waste materials from cotton harvesting/ginning operations, CBS and cotton module wraps (CMWs), as a filler and substrate in thermoplastic composites at commercial scale. The study also compares the effect of scale-up from laboratory to commercial scale on the properties of the thermoplastic composite materials. Two separate commercial trials were conducted to manufacture thermoplastic composite boards with (a) 0, 12.5, 25 and 37.5% by weight of CBS and (b) up to 30% by weight of CMW. Testing of these samples showed that commercial-scale samples with 12.5% CBS had all properties comparable to those made with wood filler. At higher substitution rates, CBS tended to increase water absorption and coefficient of thermal expansion, and increase nail-holding capacity (NHC) and hardness in commercial-scale samples. This study also showed that CMW can be substituted by up to 30% by weight without deterioration of properties in comparison with a commercially available product. Scaling of the process had significant influence on all properties tested, expect NHC. In general, all commercial-scale samples exhibited physicomechanical properties within the range of properties reported for commercially available wood–plastic composite decking materials. [ABSTRACT FROM AUTHOR]

Cottonseed remains a low-value by-product of lint production mainly due to the presence of toxic gossypol that makes it unfit for monogastrics. Ultra-low gossypol cottonseed (ULGCS) lines were developed using RNAi knockdown of δ-cadinene synthase gene(s) in Gossypium hirsutum. The purpose of the current study was to assess the stability and specificity of the ULGCS trait and evaluate the agronomic performance of the transgenic lines. Trials conducted over a period of 3 years show that the ULGCS trait was stable under field conditions and the foliage/floral organs of transgenic lines contained wild-type levels of gossypol and related terpenoids. Although it was a relatively small-scale study, we did not observe any negative effects on either the yield or quality of the fibre and seed in the transgenic lines compared with the nontransgenic parental plants. Compositional analysis was performed on the seeds obtained from plants grown in the field during 2009. As expected, the major difference between the ULGCS and wild-type cottonseeds was in terms of their gossypol levels. With the exception of oil content, the composition of ULGCS was similar to that of nontransgenic cottonseeds. Interestingly, the ULGCS had significantly higher (4%-8%) oil content compared with the seeds from the nontransgenic parent. Field trial results confirmed the stability and specificity of the ULGCS trait suggesting that this RNAi-based product has the potential to be commercially viable. Thus, it may be possible to enhance and expand the nutritional utility of the annual cottonseed output to fulfil the ever-increasing needs of humanity. [ABSTRACT FROM AUTHOR]

Summary Cottonseed, containing 22.5% protein, remains an under-utilized and under-valued resource because of the presence of toxic gossypol. RNAi-knockdown of δ-cadinene synthase gene(s) was used to engineer plants that produced ultra-low gossypol cottonseed (ULGCS). In the original study, we observed that RNAi plants, a month or older, maintain normal complement of gossypol and related terpenoids in the roots, foliage, floral organs, and young bolls. However, the terpenoid levels and profile of the RNAi lines during the early stages of germination, under normal conditions and in response to pathogen exposure, had not been examined. Results obtained in this study show that during the early stages of seed germination/seedling growth, in both non-transgenic and RNAi lines, the tissues derived directly from bulk of the seed kernel (cotyledon and hypocotyl) synthesize little, if any new terpenoids. However, the growing root tissue and the emerging true leaves of RNAi seedlings showed normal, wild-type terpenoid levels. Biochemical and molecular analyses showed that pathogen-challenged parts of RNAi seedlings are capable of launching a terpenoid-based defence response. Nine different RNAi lines were monitored for five generations. The results show that, unlike the unstable nature of antisense-mediated low seed-gossypol phenotype, the RNAi-mediated ULGCS trait exhibited multi-generational stability. [ABSTRACT FROM AUTHOR]