Effect of some Egyptian cotton varieties and grades on fibers and yarn mechanical properties

Abstract EN

This investigation was carried out at Plant Production Department, Faculty of Agriculture (Saba-Basha), Alexandria University, Egypt and at Cotton Research Institute, ARC, Giza, Egypt, to study the effect of cotton variety and lint grade on fiber and yarn mechanical properties during 2018 season.

Two commercial Egyptian cotton varieties, G.

barbadense namely: Giza 87 and Giza 96 as Extra-long staple (ELS) were used.

Three lint cotton grades i.e., Good to Fully Good (G/FG), Good (G) and Fully Good Fair to Good (FGF/G) were used for each variety.

Fibers were processed to combed yarns Ne 80.

The H.V.I.

classing 1000, Pressely, Stelometer and Cotton Classifying System (CCS) instruments were used to determine the physical and mechanical fiber properties.

The grading system in Egypt depends upon the experience of the classer to determine grade and quality of the raw cotton according to the official grade standard of each cotton variety.

The results indicated that classer's was highly significant correlated with all instrumentally measured traits (positively or negatively).

The Extralong cotton varieties had a highly significant effect for fiber properties The highest mean value of micronaire reading (3.51), maturity index (87%) , fiber length (UHML) (35.80 mm) , fiber strength (44.1 g/tex), fiber elongation(5.4 %), spinning constant index (222), reflectance degree (75.7) and trash count (112) were recorded for the Egyptian cotton variety Giza 96 .As for the lint cotton grades effect , it could be concluded that the highest lint cotton grade Good to Fully Good (G/FG) recorded the best of all fiber properties which as high value of micronaire reading , maturity index , fiber length(UHML), uniformity index, fiber strength, spinning constant index and less of short fiber index , yellowness degree and trash count vice versa.

Cotton varieties (V) had highly significant differed for mechanical cotton properties measured by three instruments( HVI , Stelometer and Pressley) i.e.

fiber strength and fiber elongation the highest mean values of the fiber strength ( 44.4 g / tex) , was attained by the cotton variety Giza 96.

Whereas the lowest mean values (43.2 g/tex) and (4.8 %) of the fiber elongation.

The conventional methods are biased toward the long, strong fibers in cotton, whereas the high speed instruments use less accurate, indirect methods to measure bundle mass and produce a force measurement that is confounded by differences in fiber crimp.

When we compared single instrument testing (Pressley and Stelometer) with the HVI technology for evaluation of fiber properties is faster and coast less per measurement.

The disadvantage of HVI for genetic modification for fiber properties may be reduced accuracy and ability to separate small differences.

The HVI instrument had a highly significant effect on all studied fiber properties i.e.

the micronaire reading , maturity index , fiber length , uniformity index , fiber strength , short fiber index, reflectance degree and yellowness degree .The highest mean value were (3.18), (85%) , (35.7mm), (86.4 %) , (47.6g/tex) , (5.7 %) , (76.0) and (9.4),respectively.

of the maturity index, while the CCS instrument possessed the lowest mean of these traits.

HVI measurements were calibrated across instruments using USDA cotton calibration standards making it possible to compare results from different instruments over a long period of time.

In addition, cotton testing laboratories use cottons of known values throughout the day to check for a possible drift in measurements over time.