Utilization of different methods for earliness measurements on some Egyptian cotton genotypes [electronic resource].

Includes bibliographical references.

The performances of three Egyptian cotton genotypes (Giza 90, Giza 90 x Aust. and [G.83 x (G.75 x5844)] x G.80) were evaluated for earliness using seven methods of measurements during 2013 and 2014 seasons. Date of flowering was estimated daily, and the average number of flowers for 10 plants per week was calculated to construct curves for weekly flowering. Moreover, this study included six measurements of earliness, i.e., position of first sympodial node (PFN), days to first flower (DFF), days to first open boll (DFB), earliness percentage (Er %), mean maturity date (MMD) and production rate index (PRJ). Rate of weekly flowering followed a normal distribution curve. The genotype (Giza 90 x Aust.) produced the highest total number of flowers compared to other tested genotypes. The maximum average rate of flowering was found at fifteen week after planting ( 1317-19/7). The total number of flowers was significantly different between genotypes. Also, the data showed significant differences in most flowering weeks. Measurements of earliness (PFN, DFF, DFB, Er %, MMD and PRI) indicated that (Giza 90 x Aust.) was the earliest compared to other genotypes. Significant differences existed between the genotypes in (DFF, DFB, Er % and MMD). While, the differences between genotypes were not significant for (PFN and PRI). The results obtained clarify that (Giza 90 x Aust.) was the earliest compared to other genotypes.

Summary in Arabic.

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