Inheritance and allelism of morphological traits in eastern redbud (Cercis canadensis L.)

Abstract

Inheritance of purple, gold, and variegated foliage types, weeping architecture, and double flower was explored in F₁, F₂, and backcross families resulting from controlled hybridization of eastern redbud (Cercis canadensis L.). Potential allelic relationships were explored when possible. Inheritance analysis in families derived from controlled hybridization of ‘Covey’ (green leaf) and ‘Forest Pansy’ (purple leaf) suggest that purple leaf color and weeping architecture are both controlled by single recessive genes, for which the symbols pl1 and wp1 are proposed, respectively. Inheritance of gold leaf was explored in families of ‘Covey’ (green leaf) × ‘Hearts of Gold’ (gold leaf). Interpretation of inheritance of gold leaf in these families was confounded by the recovery of a leaf color phenotype in the F₂ family unlike either parent. However, data suggested the action of a single locus controlling gold leaf color in ‘Hearts of Gold’, and that instability of gold leaf expression may be based on transposable element activity. Segregation of gold leaf in the F₂ families of ‘Texas White’ [green leaf (C. canadensis var. texensis)] × ‘JN2’ [gold leaf (The Rising Sun)] did not fit a Mendelian ratio. Analysis of progeny of ‘Silver Cloud’ and ‘Floating Clouds’ (both showing white/green leaf variegation) with non-variegated cultivars demonstrated that variegation in ‘Silver Cloud’ is controlled by a single recessive nuclear gene, while variegation in ‘Floating Clouds’ is controlled by cytoplasmic factors. The symbol var1 is proposed for the gene controlling variegation in ‘Silver Cloud’. Double flower in progeny derived from ‘Flame’ (double flower) suggested that double flower is dominant to single flower, and that ‘Flame’ is heterozygous at the double-flower locus, for which the symbol Df1 is proposed. Allelism studies showed that the gene controlling purple leaf in ‘Forest Pansy’ is allelic to the purple leaf gene in ‘Greswan’ and that the gene controlling weeping phenotype in ‘Traveller’ (C. canadensis var. texensis) is non-allelic to the weeping gene found in ‘Covey’. Allelism of the gold leaf trait in ‘Hearts of Gold’ and ‘JN2’ was investigated, but no clear conclusions regarding allelism could be made due to recovery of leaf color phenotypes unlike either parent.

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