Comparative study on three nuclei seeds of Giza 90 cotton cultivar and the corresponding farmer's seed in general use [electronic resource].

Includes references.

Three successive pure nuclei of Giza 90 cotton cultivar (N) and their corresponding farmer's seeds (F) were used in this study to evaluate and follow the changes that might occur in yield, yield components and fiber properties after using the seeds in general cultivation by the farmers. The field experiments were carried out in Sohag governorate (Upper Egypt) through . two successive growing seasons (2011 and 2012).Genotypes mean squares were significant and highly significant for seed index in combined analysis and lint index in the first season, respectively. Among nuclei seeds (N) no significant differences were detected for all studied traits, while among farmer's seeds (F) the differences were significant for boll weight in the first season and lint index in both two seasons and highly significant for seed index in second season. The genotypes by years interactions were detected to be significant and highly significant for seed index and lint index in combined analy~is, respectively. The interactions of nuclei seeds (N) by years '~¥ere highly significant for boll weight and lint index in combined analysis, while the interactions of farmer's seeds (F) by years were not significant for all studied traits. With respect to the mean performances, The results indicated that there were no significant differences overall genotypes for all yield and its components traits except seed index in combined analysis and lint index in the first season were significant and highly significant respectively. The results also showed that the second season was higher in the mean performance than those of the first season for all studied characters of all genotypes. These results may be indicated that the second season was optimum to evaluate these strains of_Giza 90 cotton variety for all studied traits. Concerning the fiber properties, the nuclei seeds of Giza 90/2009 gave the best mean value for fiber length, fiber strength and uniformity ratio in the first season compared with the other nucleus strains, also Giza 90/2010 farmer's strain gave the best performance for yarn strength in the tow seasons,. Moreover, Giza 90/2008 farmer's strain (the oldest strain) gave the lowest mean performances for most fiber traits in both seasons exhibiting some deterioration in this strain and, suggesting the need of replacing of a new strain in the general cultivation and must be advice to short duration strain age by increasing the propagation index for it.

Summary in Arabic.

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