Current Issue http://journals.caass.org.cn/jcr EN-US http://journals.caass.org.cn/jcr/EN/current.shtml http://journals.caass.org.cn/jcr 5 Background The strength of cotton fiber has been extensively studied and significantly improved through selective breeding, but fiber elongation has largely been ignored, even though elongation contributes to determining the energy needed to break fibers. Recent developments to calibrate the high volume instrument (HVI) for elongation has renewed interest in elongation. However, it is not understood how best to utilize yet another fiber property which has the potential to add to the complexity of fiber selection. To explore a practical approach to applying elongation, cotton samples were tested using single fiber methods, the Stelometer, and the HVI. Comparison of strength, elongation, and combined properties such as modulus were explored. Results HVI testing was shown to be sensitive enough to characterize elongation differences but unlike single fiber testing it was unable to capture within-sample variation. Fiber bundle testing, like Stelometer and HVI was shown to reduce bias due to fiber selection. Conclusion The use of secant modulus, an intrinsic material property, allowed for one value to represent both strength and elongation. Secant modulus was shown to contain more useful information than either elongation or work-to-break. Work-to-break was shown to be more influenced by a specific value of breaking force or elongation rather than the intrinsic behavior of the sample being tested. Exploring the influence of genetics and environment on elongation, and its interaction with other fiber properties, requires additional work. Secant modulus, by combining strength and elongation into one value, shows the potential to incorporate elongation values into fiber characterization without increasing the complexity of current fiber selection processes.]]> Background Boron (B) deficiency is an important factor for poor seed cotton yield and fiber quality. However, it is often missing in the plant nutrition program, particularly in developing countries. The current study investigated B's effect on growth, yield, and fiber quality of Bt (CIM-663) and non-Bt (Cyto-124) cotton cultivars. The experimental plan consisted of twelve treatments: Control (CK); B at 1 mg·kg⁻¹ soil application (SB1); 2 mg·kg⁻¹ B (SB2); 3 mg·kg⁻¹ B (SB3); 0.2% B foliar spray (FB1); 0.4% B foliar spray (FB2); 1 mg·kg⁻¹ B + 0.2% B foliar spray (SB1 + FB1); 1 mg·kg⁻¹ B + 0.4% B foliar spray (SB1 + FB2); 2 mg·kg−1 B + 0.2% B foliar spray (SB2 + FB1); 2 mg·kg⁻¹ B + 0.4% B foliar spray (SB2 + FB2); 3 mg·kg⁻¹ B + 0.2% B foliar spray (SB3 + FB1); 3 mg·kg⁻¹ B + 0.4% B foliar spray (SB3 + FB2). Each treatment has three replications, one pot having two plants per replication. Results B nutrition at all levels and methods of application significantly (P ≤ 0.05) affected the growth, physiological, yield, and fiber quality characteristics of both cotton cultivars. However, SB2 either alone or in combination with foliar spray showed superiority over others, particularly in the non-Bt cultivar which responded better to B nutrition. Maximum improvement in monopodial branches (345%), sympodial branches (143%), chlorophyll-a (177%), chlorophyll-b (194%), photosynthesis (169%), and ginning out turn (579%) in the non-Bt cultivar was found with SB2 compared with CK. In Bt cultivar, although no consistent trend was found but integrated use of SB3 with foliar spray performed relatively better for improving cotton growth compared with other treatments. Fiber quality characteristics in both cultivars were improved markedly but variably with different B treatments. Conclusion B nutrition with SB2 either alone or in combination with foliar spray was found optimum for improving cotton's growth and yield characteristics.]]>