New tools now are available, or are under construction, that will spur cotton improvement in the next few years.

As the U.S. Cotton Industry suffers through a period of historically low profitability, the University of Georgia Cotton Breeding Program is looking to the future to develop germplasm that enhances the profitability and sustainability of cotton production for Georgia growers.

In this article, we will discuss the current status of cotton improvement in light of these new tools.

With the technological evolution of yarn manufacturing — from ring spinning to rotor spinning and potentially air-jet systems in the near future — comes the need for fiber property profiles to better exploit the increased productivity of these spinning systems.

Today, fiber property profiles that meet requirements of older ring spinning technologies often fail to satisfy the newer yarn manufacturing systems.

The challenge to breeders is to address the needs of fiber producers and consumers, a difficult task because the simultaneous enhancement of fiber quality and yield has been elusive. For example, increasing fiber strength and yield has long been a goal of most breeding programs but has been difficult to achieve because of a general negative association between yield and strength in breeding populations.

Our approach to enhancing yield and fiber quality is to re-examine certain basic fiber properties for their influence on yield and quality and design breeding strategies thereof.

One strategy under way is to examine effects on yield and fiber quality of enhancing overall fiber length uniformity. Breeding for enhanced fiber length properties has traditionally focused on lengthening staple or upper half mean fiber length as measured by High Volume Instrumentation.

Both staple and upper half mean fiber length are measures of the longest fibers in a sample of cotton fiber. But in nearly any sample of cotton fiber, there exists a range of fiber lengths from less that one half inch on up to fibers that exceed the staple or upper half mean fiber length. This inherent length variability reduces the strength and durability of cotton yarns spun with rotor or air-jet technologies.

Measuring only the length of the longest fibers in a sample does not indicate overall fiber length uniformity, but it has not been possible to assess length variability in fiber samples until the recent development of the Zellweger Uster Advanced Fiber Information System or AFIS®, an instrument capable of measuring certain properties of fiber on every fiber in the sample.

This technological breakthrough measures the length and linear density among other properties on all fibers in the sample, allowing both magnitude and variability of a fiber property to be quantified.

The downside of the AFIS is its relatively slow speed and high cost per measurement, currently $15 to $25 per sample at commercial fiber testing laboratories. Such expense precludes using AFIS as a research tool in most breeding programs.

Instead, National Textiles, Mountain City, Tenn., graciously donated several hundred AFIS measurements to our cotton-breeding program to test the hypothesis that overall fiber length variability differs among candidates for selection in a breeding population.

Look for updates on the progress of this research in future issues of 100% COTTON NEWS.

Another tool to spur cotton improvement is the micro-ginning facility on the Tifton campus, slated for completion in the fall of 2002. Historically, breeders have relied on small-scale laboratory gins to prepare fiber samples from hand-picked boll samples for determination of fiber quality and lint fraction (lint fraction is analogous to gin turnout).

While laboratory gins are adept at separating fiber and seed they lack seed-cotton and lint cleaning abilities common to commercial gins.

Consequently, the lack of fiber preparation with lab gins commensurate with that accomplished by commercial gins has limited our ability to ameliorate short fiber content and investigate plant traits that influence fiber contamination after ginning. With the micro-gin, we will be able to impose treatments (genetics, crop management, irrigation) on plots of reasonable size to allow for experimental control, yet the fiber will substantially mimic that from commercial gins.

This gin facility opens the door for expanded research to enhance fiber quality, because we can now develop sufficient fiber to assess yarn and textile product performance that could not be done with laboratory gins.

Additionally, in succeeding years look for expanded information from the University of Georgia Cultivar Trials. The micro-gin will allow gin turnout and more complete classing data to be reported on cultivars as an aide to growers in selecting cultivars.