No abstract

This research was to study the genetic divergence evaluation of some cotton collection (Gossypium barbadens L.) to select the most suitable genotypes as well as to investigate the importance of evaluate characters, by using multivariate analysis. Based on these data, the first three factors which accounted for 83% of the total variance are important. Factor I included lint%, lint index, lint cotton yield and fiber fineness and its accounted 43% of the total variance. Only fiber length had negative loading indicates the direction of the relationship between the factor and variable. Factor II included seed index, fiber strength and fiber length accounted 25%. Factor III included boll weight and fiber strength and its accounted 14% of the total variance. The most divergent genotypes were Australian 12 and Giza 45 × Sea Island at genetic distance (23.88%). In contrast, the level of similarity was high (95% and more) between 84% from extra long genotypes and between 88% from long stable genotypes.

Present study was carried out to evaluate 11 cotton varieties under two locations over two growing seasons 2015 and 2016 in Egypt. The results showed that there were significant differences among environment, genotypes, and their interactions for all the studied characters. The variety Giza 94 surpassed all varieties in yield and its components shared with the variety Giza 92 for seed cotton yield. The varieties Giza 94, Giza 92 and Giza 96 recorded highest yield and yield components at Nubariya location. The varieties Giza 87, Giza 88, Giza 92, Giza 93 and Giza 96 recorded highest values at Nubariya location for most fiber characters. Principal component analysis showed that the characters which have relatively high value in the first principal component (PC1) were earliness percentage, seed cotton yield, lint yield, boll weight, lint percentage, and micronaire reading. The second principal component (PC2) was principally affected by earliness percentage, fiber length and fiber strength. At the same time, cluster analysis could efficiently describe the characteristics of group of genotypes in different groups. The eleven cotton genotypes were grouped into five major clusters. The obtained results indicated the presence of genetic diversity among the tested cotton genotypes. Genotypes from divergent clusters can be used for hybridization in order to isolate useful recombinants in the segregating generations. This information might be used in the breeding programs for improvement of Egyptian cotton.

This study was conducted during 2009 and 2010 seasons to evaluate the performance of commercial varieties and new promising lines of cotton in new area under new system of irrigation (drip irrigation). A graphic summary of the data using GGE Biplot was used to characterize the performances of genotypes. Long stable genotypes were surpassed in yield properties meanwhile extra long stable were better in fiber quality except for G84 x Ps6 which was strong competitiveness for long stable genotypes in lint percentage. The results showed that the new promising line 10229xG86 was the better under these conditions for seed cotton yield and lint cotton yield, G86 was better for lint percentage and G77xPs6 was better for fiber length meanwhile each of G88 and G84xPs6 were better for yearn strength . Genotypes were always the most important source of variation which ranged from 65.03 for seed cotton yield to 92.5 for yearn strength.

The new promising cross Giza 77x pima s6 is an extra long extra fine Egyptian cotton promising cross while was produced through artificial hybridization between the parents Giza.77 and Pima S 6 . The new promising cross is characterized with its extra fine, extra long and very strong fiber about 46-5 gram / tex, 36.5-38 mm upper half mean, 3.3 micronaire reading 105 -120 millitex for hair weight and over 3000 yarn strength. Also the lint percentage is about 33-35%. This promising cross is characterized with high yield. This promising cross is characterized by its resistance against Fusarium oxysporum and f. vasinfectum. This promising cross could be the best alternative to Giza 45 and Giza 87.