Laboratory tests were conducted to characterize the chemical composition
on seed samples from the three extra long stable G4S, G70 and G88 and the six long
stable cultivars G80, G83, G8S, G86, G89 and G90 which represent all the nine
cultivated Egyptian cotton varieties during 2002 planting season. Each variety was
represented with two seed classes. In addition to the determination of total proteins,
carbohydrates and oil percentages, the seed storage proteins were separated
according to their molecular weight using sodium dodecyl sulphate gelelectrophoresis
(SOS- PAGE) method. The free fatty acids also were estimated as an index of seed
quality. It was apparent that there were significant differences between varieties as
well as between seed classes of the same varieties.