A single gene controls leaf background color in caladium (Araceae) and is tightly linked to genes for leaf main vein color, spotting and rugosity

Zhe Cao,Zhanao Deng,Qian Yang,Shunzhao Sui

doi:10.1038/hortres.2016.67

Zhe Cao, Zhanao Deng + Show 2 more

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https://doi.org/10.1038/hortres.2016.67

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Abstract

Modern cultivated caladiums (Caladium×hortulanum) are grown for their long-lasting and colorful leaves. Understanding the mode of inheritance for caladium leaf characteristics is critical for plant breeders to select appropriate parents, predict progeny performance, estimate breeding population sizes needed, and increase breeding efficiencies. This study was conducted to determine the mode of inheritance of two leaf background colors (lemon and green) in caladium and to understand their relationships with four other important leaf characteristics including leaf shape, main vein color, spotting, and rugosity. Seven caladium cultivars and three breeding lines were used as parents in 19 crosses, and their progeny were phenotyped for segregation of leaf traits. Results showed that the two leaf background colors are controlled by a single nuclear locus, with two alleles, LEM and lem, which control the dominant lemon and the recessive green leaf background color, respectively. The lemon-colored cultivar ‘Miss Muffet’ and breeding lines UF-52 and UF-53 have a heterozygous genotype LEMlem. Chi-square tests showed that the leaf background color locus LEM is independent from the leaf shape locus F, but is tightly linked to three loci (S, V and RLF) controlling leaf spotting, main vein color, and rugosity in caladium. A linkage map that consists of four loci controlling major caladium leaf characteristics and extends ~15 cM was developed based on the observed recombination frequencies. This is the first report on the mode of inheritance of leaf background colors in caladium and in the Araceae family. The information gained in this study will be very useful for caladium breeding and study of the inheritance of leaf colors in other ornamental aroids, an important group of ornamental plants in the world.

Highlights

Caladiums are often grown in containers, hanging baskets, and landscapes for their long-lasting and colorful leaves
When ‘Miss Muffet’ was selfed (Table 2; cross no. 1), progeny segregated in a ratio of 3: 1 (P = 0.521). This segregation ratio suggests that the leaf background color is controlled by a single nuclear locus with a dominant allele for the lemon background color and a recessive allele for the green background color, and that ‘Miss Muffet’ should be heterozygous at this locus
A better understanding of the mode of inheritance for caladium leaf characteristics is of tremendous value to caladium breeding

Summary

Introduction

Caladiums are often grown in containers, hanging baskets, and landscapes for their long-lasting and colorful leaves. Understanding the mode of inheritance of important leaf characteristics is very critical to caladium breeding and genetic improvement. Such knowledge can enable breeders to select appropriate parents for breeding, estimate population sizes required to achieve particular breeding goals, predict the likely segregation patterns of traits in progeny, and improve breeding and selection efficiency. It has been reported that leaf shapes in caladium are controlled by a single locus with two co-dominant alleles F and f, resulting in three genotypes (FF, Ff and ff) that control the fancy, lance, and strap-shaped leaves, respectively.. Caladium main vein colors are regulated by a single nuclear locus V with three alleles [V r (for red veins)4Vw (for white veins)4Vg (for green veins)].3. It has been reported that leaf shapes in caladium are controlled by a single locus with two co-dominant alleles F and f, resulting in three genotypes (FF, Ff and ff) that control the fancy, lance, and strap-shaped leaves, respectively. Caladium main vein colors are regulated by a single nuclear locus V with three alleles [V r (for red veins)4Vw (for white veins)4Vg (for green veins)].3 Leaf spotting in caladium is controlled by a single nuclear locus with a dominant allele S for spotting and a recessive allele s for non-spotting.

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