No satisfactory technology has emerged for routine rapid measurement of fiber linear density at commercial speed for the cotton industry. This paper introduces the CottonscanTM instrument, a new technology designed to undertake this task. An inter-laboratory trial of the Cottonscan TM system to ascertain the performance of the technology is described. Overall, the 95% confidence limit for a single measurement was estimated to be ±10.4 mtex. Further, spinning trial results have confirmed that unlike the Micronaire value, average fiber linear density obtained from the CottonscanTM correlate well with measured yarn properties. These data indicate that the CottonscanTM instrument can be usefully employed to determine average fiber linear density, an important fiber quality parameter which can be a useful additional tool for the spinner in predicting yarn properties.

Various source–sink perturbations were employed to alter partitioning to orange flesh melon (Cucumis melo L. reticulatus group) and thus to influence fruit biomass and soluble sugar content (indexed as total soluble solids of fruit juice, % TSS), with attention given to the timing of treatment application. A strong relationship existed between harvest index and fruit mass (r2 = 0.88) in control plants, whereas the correlation with fruit TSS was poor (r2 = 0.11). Augmentation of assimilate supply to fruit early in fruit development (before approx. 21 days before harvest, DBH) resulted in more fruit set and increased fruit biomass, whereas augmentation after 21 DBH resulted in increased fruit TSS. Thus, fruit biomass was increased (1644 cf. 1442 g FW per fruit for control, P = 0.02), but not TSS, on plants in which fruit set was delayed (source biomass increased, harvest index decreased from 59% for control to 38%). Treatment of plants with a cytokinin-based vegetative growth inhibitor at 14 DBH produced fruit with higher TSS (11.3 cf. 10.7% for control). Thinning fruit to leave 1 fruit per plant 1 week before harvest increased the proportion of fruit in a population that exceeded a quality control standard of 10% TSS from 20 to 80%. Variations in plant response with timing of treatment application are interpreted in terms of fruit development (cell division, cell expansion, and sugar accumulation phases). Although a detriment to yield (15 cf. 31 t/ha for control), the fruit thinning treatment was recommended for commercial use and a simple model was developed to calculate the required farm-gate price of fruit to make thinning economically viable.

Cotton fibers are single-celled trichomes that develop from the epidermis cells on the outer integument of cotton seeds (ovules). Initiation of fiber growth occurs at about anthesis (flowering), following which fiber initials spherically expand above the epidermal surface. Growth of the cotton fiber is continuous and extends for 40 to 60 days postanthesis (dpa) in a series of overlapping phases [1], including a cell elongation phase until 20 to 30 dpa, and a secondary cell wall thickening phase which dominates fiber growth until fruit maturation [2][3][4][5][6]. This secondary cell wall development consists of the deposition of cellulose in a series of Abstract Cotton fibers are trichome cells composed primarily of cellulose. Mature fibers have more cellulose and a greater degree of cell wall thickening, and perform better than less mature fibers during textile processing. An automated polarized light microscope instrument called SiroMat that measures cotton fiber cell wall thickening was employed to assess the maturity of developing fibers from single cotton fruit. Fruit were taken from the first fruiting branch and position on glasshouse grown Gossypium hirsutum L. (Upland) and G. barbadense L. (Pima) plants, sequentially harvested from 24 days postanthesis (dpa) at approximately four-day intervals up until approximately 50 dpa. The instrument assessed an average of 13,000 fiber snippets per fruit. Upland fibers matured at a slower rate than Pima fibers up to 35 dpa. However, after 45 dpa Upland fibers had achieved a higher average maturity (i.e. 0.99 birefringence maturity index (BMI), cf. 0.79 for Pima). For both species the uniformity of fiber maturity increased as fibers matured up until 35 dpa for Upland and 29 dpa for Pima (i.e. the BMI coefficient of variation decreased as BMI increased during fruit development). It is envisaged that SiroMat will be a useful tool in helping to understand and manage fiber maturity by characterizing the maturation dynamics of cultivars with different inherent fiber properties, and for cultivars subjected to different environmental and agronomic conditions.

Immature cotton (Gossypium hirsutum L.) fi bers and neps in ginned cotton will aff ect textile quality and thus can aff ect overall industry reputations. Th is study conducted three fi eld studies that systematically varied the timing of harvest aid application to generate diff erences in the amount of immature fi ber and levels of neps in crops at harvest. Th e aim was to ascertain what crop conditions (percent open bolls, number of immature bolls, percent immature bolls, and percent immature lint mass) at the time of application contribute to these diff erences, and assess whether these outcomes are infl uenced by 0, 1, 2 lint cleaning passes. Earlier harvest aid treatments increased neps and the level of neps was best related to fi ber linear density (r 2 = 0.78). All measurements of crop condition at harvest aid application explained changes in yield and fi ber properties well, although the percent immature bolls (r 2 > 0.67) can be applied when crops are nonuniform in their maturity, and when they contain fruiting gaps. Relationships between lint cleaning passes and crop condition at harvest aid application showed an interaction between earlier harvest treatments and lint cleaning passes. One lint cleaning pass contributed between 95 and 141 count g −1 more neps, while a second pass added between 101 and 181 count g −1 more neps. Th is information will be valuable in refi ning strategies that aim to optimize both yield and fi ber quality (including less neps). Th is study also supported the current recommendation of applying harvest aids at 60% open bolls.