Sajjad Ahmad, Muhammad Sayyar Khan, Muhammad Siraj Swati, Gul Sanat Shah and Iftikhar Hussain Khalil

pp. 1 - 8

Abstract

The experiment was conducted at NWFP Agricultural University, Peshawar to study heterosis and
inbreeding depression in 7×7 half diallel crosses of sunflower. The planted materials consisted of parental
inbred lines, their F₁ hybrids and F₂ populations using randomized complete block design with three
replications. Data were recorded on yield and other important agronomic characters. Significant genetic
differences were observed among the parents, their F₁ hybrids and F₂ populations for all the characters under
study. Yield and leaf area showed highly significant heterosis in F₁ hybrids ranging from 102 to 309% and
46.3 to 163.9%, respectively, while inbreeding depression in the F₂ population ranged from 17-71% and
-9.7-43%, respectively. Leaves per plant showed low level of heterosis in F1 hybrids (-0.9 to 39.7%), whereas
the effect of inbreeding depression in F₂ population was comparatively high (1.1 to 22.2%) for this character.
The parent RHA-822 proved itself to be a good general combiner by making higher contribution towards
heterosis both in F₁ hybrids and in F₂ populations.

Keywords

• heterosis
• inbreeding depression
• F₁ hybrids
• F₂ population
• sunflower