Heterosis, inbreeding depression, potence ratio and some genetic parameters in two intraspecific cross of Egyptian cotton [electronic resource].

Includes references.

This research was carried out at Experimental Farm of Faculty of Agriculture (Saba Basha), Alexandria University, during the successive seasons of 1993, 1994 and 1995 on two intraspecific crosses belong to Gossypium barbadense, L. These crosses were cross I (Giza 76 x Giza 70) and cross II (Giza 70 x Giza 75). The main objective of the present research was to estimate heterosis, inbreeding depression, potence ratio and some genetic parameters, i.e" gene action, genetic advance upon selection and heritability in both broad and narrow senses. The six population P1, P2, F1, F2, BC1 and BC2 were grown during 1995 season in randomized complete block design for yield and its components. The results could be summarized as follow : (1) Cross I (Giza 76 x Giza 70) revealed a significant or highly signif~cant heterosis relative to mid-parent or better parent for all traits except lint percentage and seed index. Cross II showed also significant heterosis for (Giza 70 x Giza 75) number of seeds/boll and number of vegetative branches/plant, (2) Inbreeding depression value recorded significant or highly significant values in six traits for cross I whereas did not differ significantly in three traits, i.e., lint percentage, number of fruiting and vegetative branches/plant for cross II, (3) Potence ratio values showed that over dominance control for these number of harvested bolls/plant, number of fruiting and vegetative branches/plant in cross I. Also, this over dominance was observed in cross II for all studied characters except number of vegetative branches/plant, ( 4) Scaling test parameters differed significantly for all traits in cross I and II except lint percentage in cross I, B parameters deviated than zero in cross I for three traits, lint percentage, number of vegetative branches/plant and number of seeds/boll.

Summary in Arabic.

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