Genetic analysis of apical lethality in Triticum aestivum L.

Abstract

Investigations were carried out to determine the nature and number of genes governing apical lethality (apical death) in a number of intervarietal crosses of wheat. Genetic analysis of data in segregating generations of the cross WR95/HW2041 and its reciprocal cross revealed that WR95 carries a recessive gene that leads to the death of certain individuals when combined with another recessive gene derived from HW2041. The phenomenon, which is denoted here as “apical lethality”, is controlled by two complementary recessive genes coming together from two different parents in certain F₂ individuals. The gene symbols apd ₁ in WR95 and apd ₂ in HW2041 are proposed for these genes of apical lethality, respectively. Uniculms observed in the F₂ generation are heterozygous (apd ₁ apd ₁ Apd ₂ apd ₂) and, therefore, the uniculmness trait does not breed true. Of the wheat genotypes tested, the gene apd ₂ was found to be present in CL983, CL1019, Lok-1, HW2041, HD2329, HW2011, WH147, HW2042, HW2047, WR196, WR544, WR798 and WR936, while the remaining genotypes, including some of the exotics such as Atila, carried both Apd ₁ and Apd ₂ in the homozygous condition.