Full Length Research Paper

Genetic control of flag leaf area in wheat (Triticum aestivum) crosses

Muhammad Irfaq Khan*, Gul Sanat Shah Khattak, Abdul Jabbar Khan, Fazle Subhan, Tila Mohammad and Akhtar Ali

Plant Breeding and Genetics Division, Nuclear Institute for Food and Agriculture (NIFA), P.O Box. 446,

G.T. Road, Peshawar, Pakistan.

Accepted 21 May, 2012

*Corresponding author. E-mail: irfaq@live.com.

 Abstract

Mixed inheritance analysis for flag leaf area (FLA) was carried out using joint segregation analysis of six basic generations (P₁, P₂, F₁, F₂, B₁ and B₂) in two wheat crosses in 2006 to 2007 and 2008 to 2009. The results indicated that the trait was mostly under control of one major gene in combination with polygenes (model D-2) for the two crosses during the first year. However, it was controlled by mixed epistasis of two major genes plus polygenes (model E-1) in cross 2 during the second year. Transgressive segregate on both upper and lower extremity of the trait in B_1, B₂ and F₂ indicated the presence of both favorable and reversed genes in the parents. Higher major gene heritability (9.6 to 71.0) for the trait was recorded than the polygenes heritability (4.8 to 38.9) in the segregating generations (B₁, B₂ and F₂). Moderate to high environmental variations (14.4 to 85.0) in the trait for segregating generations revealed that FLA is influenced by the environmental fluctuations. Predominant additive effect over all other types of genetic effects suggests the delay in selection for FLA until maximum favorable genes are accumulated in the individuals.

Key words: Flag leaf area, major genes plus polygenes inheritance, Triticum aestivum L.