Hybrid Vigor (F1) and Inbreeding Depression (F2) for Some Economic Traits in
Crosses Between Glandless and Glanded Cotton

A.R. Soomro and A.D. Kalhoro

Central Cotton Research Institute, Sakrand Sindh, Pakistan

Abstract: Eight parents in eight cross combinations were studied for heterosis in F1 a nd inbreeding depression in
F2 populations for seedcotton yield, number of bolls per plant, ginning outturn percent and staple length.
Seedcotton yield and number of bolls expressed considerable amount of heterosis, however, hybrids showing
higher magnitudes of heterosis were generally associated with higher amount of inbreeding depression suggesting
dominant genes functioning for these traits. Small amount of heterosis, lower magnitude of inbreeding depression
for lint percent and staple length indicated that additive genes were responsible for the expressions of these traits.
Hybrid vigor recorded in F1 in respect of seedcotton yield per plant ranged from 14.9 to 88.7%, whereas in bolls
per plant, ginning outturn and staple length, the range was 13.5 to 91.6, -0.57 to 4.29 and -5.92 to 5.23%
respectively.

Key words: Inbreeding depression, heterosis, dominant genes, additive genes

Introduction

Crosses