Genetic analysis of yield-related traits in F₂ diallel cross in durum wheat (Triticum durum Desf.)

Abstract

The study evaluated the combining ability of four durum wheat cultivars—Achouri, Waha, Beni Mestina, and Mohamed 
Ben Bachir—through a 4×4 half-diallel cross design, generating six F₂ hybrid combinations. Parents and their progeny 
were assessed during the 2023–2024 growing season under rainfed conditions in Setif, Algeria, for eight morpho
agronomic traits including plant height (cm), spike length (cm), spike weight (g plant⁻1), number of spikes plant−1, number 
of grains spike⁻1, thousand kernel weight (g), grain yield (g plant⁻1), and aboveground biomass (g plant⁻1). Analysis 
of variance revealed significant genetic variation for all traits. Both general (gca) and specific (sca) combining ability 
significantly influenced trait expression, indicating additive and non-additive gene actions. Additive effects controlled 
plant height, spike length, spikes plant−1, and grains per spike, while non-additive effects prevailed for spike weight, 
kernel weight, grain yield, and biomass. Beni-Mestina exhibited strong positive gca estimates for multiple yield traits 
including spike weight (0.40), spikes plant−1 (0.39), kernel weight (2.31), and grain yield (0.28), alongside a desirable 
reduction in plant height (–3.77). Achouri contributed positively to plant height (7.10), spike length (0.63), grains spike⁻1 
(4.14), and biomass (0.72). Hybrids Achouri × Mohamed Ben Bachir and Waha × Mohamed Ben Bachir showed 
favorable sca effects for kernel weight (11.54 and 6.47, respectively) and grain yield (1.45 and 1.83, respectively), with 
the later also improving spike weight (0.49). Superior crosses were not always derived from high-gca parents. These 
findings support strategic parent selection and generation-targeted phenotyping—early selection for additive traits and 
delayed selection (F₃–F₄) for non-additive traits, along with bi-parental mating within promising sca crosses