To maximize profitability, cotton (Gossypium hirsutum L.) producand As. Elms et al. (1997) reported that yield in an ers must attempt to control the quality of the crop while maximizing irrigated cotton field in Texas displayed spatial correlayield. The objective of this research was to measure the intrinsic variability present in cotton fiber yield and quality. The 0.5-ha experi-tion. These authors also noted that production of fruitmental site was located in a producer's field (Norfolk-Coxville soil ing sites and fruit retention was spatially correlated. association) in Florence, SC, for 2 yr (1996 and 1997). Soil (0-20 cm) Micronaire exhibited a moderate degree of spatial variand fiber samples (1-m row) were collected from a regular grid (129.2 ability, and strength showed the lowest degree of variby 45.6 m, 7.6-m interval). Soil properties determined included soil ability.

Volatile emissions from residues of the winter cover legumes, Berseem clover (Trifolium alexandrinum L.), hairy vetch [Vicia hirsuta (L.) S.F. Gray], and crimson clover (Trifolium incarnatum L.), inhibited germination and seedling development of onion, carrot, and tomato. Using GC-MS, 31 C2-C10 hydrocarbons, alcohols, aldehydes, ketones, esters, furans, and monoterpenes were identified in these residue emission mixtures. Mixtures of similar compounds were found in the volatiles released by herbicide-treated aerial and root residues of purple nutsedge (Cyperus rotundus L.) and the late-season woody stems and roots of cotton (Gossypium hirsutum L.). Vapor-phase onion, carrot, and tomato seed germination bioassays were used to determine the time- and concentration-dependent inhibition potential of 33 compounds that were either identified in the plant residue emissions or were structurally similar to identified compounds. Cumulative results of the bioassays showed that (E)-2-hexenal was the most inhibitory volatile tested, followed by nonanal, 3-methylbutanal, and ethyl 2-methylbutyrate. All the volatile mixtures examined contained at least one compound that greatly inhibited seed germination.

the southeast USA, Porter et al. (1996) reported higher fiber strength, greater elongation, and lower micronaire Normal-and late-planted cotton (Gossypium hirsutum L.) often for late-planted cotton. They found no effect of planting differ in fiber properties, especially those properties related to fiber date on fiber length. Cathey and Meredith (1988) found secondary wall characteristics. This field study was conducted to (i) determine the effect of planting date on fiber properties of bolls at that late planting reduced micronaire but did not affect two flowering times, and (ii) determine the relationship between fiber fiber length, strength, or elongation. Bauer et al. (1998) properties and canopy photosynthesis during development of those found that cotton planted in late May had fiber with bolls. Cotton ('Stoneville 453') was planted on 3 May and 3 June in higher yarn strength, greater elongation, and greater 1995 and 3 May and 31 May in 1996. Canopy photosynthesis was fiber length, but lower micronaire and fiber maturity measured 10 to 12 times on sunny days from initial flowering through than fiber produced from cotton planted in late April. the end of the season. Fiber properties were determined on first Recent evidence suggests that carbohydrate supply sympodial position bolls that bloomed during the first and fourthcan affect fiber properties of cotton. Pettigrew (1995) week of flowering (WOF). Maximum canopy photosynthesis was 21% evaluated the effects of irradiance on cotton fiber prophigher in 1996 than in 1995 and lint yield was 22% greater in 1996 erties. He found that higher irradiance, which would than in 1995. Within each year, average maximum canopy photosynthesis did not differ between planting dates, although yield was approx-increase carbohydrate supply through higher photosynimately 30% lower for the late planting date each year. Bolls from thetic rates, increased micronaire and fiber strength. the first WOF generally had lower lint percent, higher short fiber Jones et al. (1996) indirectly measured carbohydratecontent, lower elongation, and lower whiteness index than bolls from supply effect on fiber properties by removing flowers, the fourth WOF. Micronaire, immature fiber fraction, and fiber crosswhich reduced competition for carbohydrate among the sectional area were linearly related to the amount of canopy photosynremaining developing bolls. Flower removal resulted in thesis that occurred from 15 to 45 d after flowering. Our results are higher boll weight and micronaire of the remaining bolls consistent with the hypothesis that assimilate supply influences cotton in that study. fiber properties associated with secondary wall characteristics.Canopy photosynthesis of cotton increases until 80 to 90 d after planting as plants develop leaf area, then decreases as leaves in the canopy age (

No abstract

No abstract

No abstract

Worldwide round-testing and calibration of the nep-counting and fiber-length modules of the Zellweger Uster advanced fiber information system (AFIS) are well advanced. Lack of appropriate quantitative calibration standards for fiber maturity has limited similar development of the prototypic AFIS fineness and maturity (F&M) module. A combination of calcium x-ray fluorescence Spectroscopy (Ca-XRF) and AFIS-F&M mapping of fiber quality from twenty-one days post anthesis (DPA) to boll opening (56 DPA) permits direct comparisons of AFIS-determined fiber physical maturity (as micronAFIS, circularity, and cross-sectional area) with fiber chronological maturity (as DPA) and physiochemical maturity (as Ca-XRF). The AFIS-F&M module is a powerful tool that makes possible quantitative comparisons of fiber maturity across time (during fiber development and in different crop years), across space (different boll and locule positions and different growing areas), within single bolls and locules, and between cotton varieties and species.In the U.S., price, marketability, and utility value of cotton lint are determined during cotton classing [ 14]. The high volume instrumentation (HVI) system used in U.S. classing offices provides quantitations of fiber parameters, i.e., micronaire, fineness, length and length uniformity index, short fiber content, strength and elongation, and maturity, as well as instrumental readings of color, trash, and sugar content [3,9,11 ]. Standard HVt fiber shape and size measurements require a minimum of 3.0 to 3.3 grams of randomly collected, ginned fibers subjected before testing to defined pretreatment or conditioning [ 1 ]. The HVI sample weight requirement significantly exceeds single-boll fiber weight, thus precluding examination of fiber quality levels and uniformity at the boll, locule, or seed level. Since the major component of fiber quality variance is at the seed level [2], rapid, reproducible, statistically valid, small-sample quantitations of fiber quality are essential if fiber quality levels and uniformity are to be improved.The sample size for fiber quality determinations with the Zellweger-Uster advanced fiber information system (AFIS)L equipped with the prototypic 5neness and maturity (FdtM) module can theoretically be set between 1 and 10,000 fibers, depending on available fiber sample size. However, a practical AHS-PAM sampk-size lower limit has been set empirically at > 500 fibers or 100 mg fiber [ 13]. This small-sample capability of AF1S-FdcM is particularly valuabk in research situations where fiber quality (size andshape) measurements must be made on a per seed, locule, or boll basis.The .Zellweger-Uster (Knoxvilk, TN) AHS-P&M is an airflow, etectro-opticai particle sizer that rapidly and reproducibly quantifies fiber circularity (0 or degree of fiber wall thickening) and cross-sectional area by number A(n) by analyzing the light scattered at a 40° angle 1 Trade names are necessary to report factually on available data. The USDA neither guarantees nor warrants the standard of th...

No abstract