Ahmad Aljuoma(1) and Jamila Dirbas*(1)
(1). Cotton Research Administration–Syria
(*Corrsponding author: Jamila Dirbas..Email: email@example.com)
Received: 04/03/2019 Accepted: 07/04/2019
The experiment was conducted at Hama Agricultural Research Center during 2016, 2017 and 2018 seasons to study the heterosis according to the best parent and inbreeding depression in F1 and F2 of the resulted hybrids from top cross program among ten parents of upland cotton. Analysis of variance indicated high significant differences among the genotypes for all characters except sympodial brunch number in F2. Estimation of heterosis showed significant positive values in some F1 hybrids that reached 20.18% sympodial brunch number, (44. 74%, 44.30%, 47.06%, 65.00%) opened bolls number and (39.07%, 44.18%) seed cotton yield which may refers to variance of parents in genetic factors that control these traits. Heterosis in F2 excelled F1 which indicated to the transgressive segregation. Heterosis accompanied with positive inbreeding depression values indicating to dominance effect. Also, negative values of inbreeding depression were noticed in some hybrids because of F2 excellence to F1. To confirm the superiority in these hybrids, it is recommended to be tested in large-scale trials.
Keyword: Cotton, Heterosis, Inbreeding depression, F1, F2.
Full paper in Arabic: PDF