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Abstract
Visual symptoms of N, P, K, Ca, Mg, Mn, Fe and B deficiencies were induced in Caladium × hortulanum Birdsey ‘Candidum’. Characteristic symptoms were photographed and described and a key summarizing these symptoms follows:
a. Chlorosis or necrosis not expressed;
b. Petioles brittle and/or leaves orbicular.........................................................................................................................B
bb. Plants grow slowly, but have no other symptoms......................................................................................................P
bbb. Rust colored spots on underside of leaf near petiole, spots may become “windows” (only the cuticle and epidermal layer remain)................................................................................................................................................. Ca
aa. Chlorosis and/or necrosis expressed;
b. Chlorosis primary symptom.
c. Interveinal and veinal chlorosis
d. Chlorosis evident as leaves unfurl............................................................................................................... Mn
dd. Chlorosis not evident as leaves unfurl, older leaf blades and veins may turn bright yellow as they abscise................................................................................................................................................................... N
cc. Interveinal chlorosis...................................................................................................................................................Fe
bb. Both chlorosis and necrosis expressed.
c. Interveinal chlorosis developing into necrotic spots, leaves turn bright yellow (except basal veins remain green) as they abscise............................................................................................................................................. Mg
cc. Necrotic specks (@ 1 mm) near veins, general chlorosis............................................................................... Mn
bbb. Necrosis primary symptom.
c. Necrotic lesions (2–5 cm) on leaf apex and distal m argin.................................................................................K
cc. Marginal necrosis.
d. Necrosis spreads toward the center of the leaf, margins dry but the leaf blade around petiole remains intact.......................................................................................................................................................................K
dd. Interveinal rust colored, blotchy areas.........................................................................................................Ca
×hortulanum for fancy-leaved caladium. Little information is available in the literature about the parentage of fancy-leaved caladium cultivars that were produced in other countries or those produced in Florida before 1976. The species that contributed to the
Gibberellic acid (GA 3 ) stimulates flowering in Caladium hortulanum Birdsey HortScience 14 72 73 Henny, R.J. 1982 Inheritance of foliar variegation in two Dieffenbachia cultivars J. Hered. 73 384 Henny, R.J. 1992 Inheritance of the foliar variegation
The ornamental value of caladium (Caladium ×hortulanum Birdsey) depends primarily on leaf characteristics, including leaf shape and main vein color. Caladium leaf shapes are closely associated with plant growth habit, stress tolerance, and tuber yield; leaf main vein colors are often used for cultivar identification. Thirty-eight crosses were made among 10 cultivars and two breeding lines; their progeny were analyzed to understand the inheritance of leaf shape and main vein color and to determine if there is a genetic linkage between these two traits. Results showed that a single locus with three alleles determined the main vein color in caladium. The locus was designated as V, with alleles V r, V w, and V g for red, white, and green main veins, respectively. The white vein allele was dominant over the green vein allele, but it was recessive to the red vein allele, which was dominant over both white and green vein alleles; thus the dominance order of the alleles is V r > V w > V g. Segregation data indicated that four major red-veined cultivars were heterozygous with the genotype Vr V g, and that one white-veined cultivar was homozygous and one other white-veined cultivar and one breeding line were heterozygous. The observed segregation data confirmed that the three leaf shapes in caladium were controlled by two co-dominant alleles at one locus, designated as F and f, for fancy and strap leaves, respectively. The skewedness of leaf shape segregation in some of the crosses implied the existence of other factors that might contribute to the formation of leaf shape. Contingency chi-square tests for independence revealed that caladium leaf shape and main vein color were inherited independently. The chi-square tests for goodness-of-fit indicated that the five observed segregation patterns for leaf shape and main vein color fit well to the expected ratio assuming that two co-dominant and three dominant/recessive alleles control leaf shape and main vein color and they are inherited independently.