Articles
Identification of below-ground phenotypic markers for early flowering (cycle 1) Gladiolus hybridus: daughter corm and cormel production, cormel types
Article number
1435_29
Pages
217 – 226
Language
English
Abstract
Gladiolus hybridus (Iridaceae) is an important herbaceous perennial and cut flower crop.
As a geophyte, it produces corms and cormels for perennial survival and cloning.
The life cycle of gladiolus (seed to flower) is typically 3-5 years, which slows the rate of breeding progress.
We have developed rapid generation cycling (RGC) lines that flower in <1 year from sowing (Cycle 1). After the first-year cycle ends, it is impossible to phenotypically distinguish Cycle 1 RGCs from seedlings flowering in years 2-5 (Cycles 2-5) using above-ground traits.
The objective of this phenomics study was to screen below-ground structures to determine if unique phenotypic traits(s) could be found for Cycle 1s.
Two experiments were conducted (2021; 2022): Pilot study, Expt. 1, screened traits across Cycles 1-5 genotypes (varying numbers of clones/genotypes); Expt. 2 had balanced replications/genotype (n=5). Expt. 1 had n=123 genotypes whereas Expt. 2 tested n=92. In both experiments, genotypes were categorized as wild species; Cycle 1s-hybrids (documented); Cycle 1s-cultivars (theorized): ‘Manhattan’, ‘Fordhook’, ‘White Prosperity’; Cycles 2-5: hybrids, cultivars.
Gladioli were field-grown and harvested post-flowering in late fall of each year.
Traits examined in Expt. 1 included: no. daughter corms, no. cormels/quadrant (Q1-Q4)/corm, no. cormels, no.
UCT (unbranched cormel type), no.
BsCT (branched, simple cormel type), no.
BfCT (branched, fasciated cormel type). Cormel production/quadrant/corm was not significantly different among cycle categories and was eliminated in Expt. 2. From these experiments, three below-ground traits had significantly higher mean counts for Cycle 1 genotypes than Cycles 2-5: no. daughter corms (DC)/basal plate, total cormel counts, and UCT. These three markers are selectable, diagnostic markers for Cycle 1 gladioli to identify their ramets in the second and successive years of growth.
All other traits overlapped among categories and are neither diagnostic nor selectable for Cycle 1s.
Future research will focus on identifying molecular markers linked with one or more of these traits.
As a geophyte, it produces corms and cormels for perennial survival and cloning.
The life cycle of gladiolus (seed to flower) is typically 3-5 years, which slows the rate of breeding progress.
We have developed rapid generation cycling (RGC) lines that flower in <1 year from sowing (Cycle 1). After the first-year cycle ends, it is impossible to phenotypically distinguish Cycle 1 RGCs from seedlings flowering in years 2-5 (Cycles 2-5) using above-ground traits.
The objective of this phenomics study was to screen below-ground structures to determine if unique phenotypic traits(s) could be found for Cycle 1s.
Two experiments were conducted (2021; 2022): Pilot study, Expt. 1, screened traits across Cycles 1-5 genotypes (varying numbers of clones/genotypes); Expt. 2 had balanced replications/genotype (n=5). Expt. 1 had n=123 genotypes whereas Expt. 2 tested n=92. In both experiments, genotypes were categorized as wild species; Cycle 1s-hybrids (documented); Cycle 1s-cultivars (theorized): ‘Manhattan’, ‘Fordhook’, ‘White Prosperity’; Cycles 2-5: hybrids, cultivars.
Gladioli were field-grown and harvested post-flowering in late fall of each year.
Traits examined in Expt. 1 included: no. daughter corms, no. cormels/quadrant (Q1-Q4)/corm, no. cormels, no.
UCT (unbranched cormel type), no.
BsCT (branched, simple cormel type), no.
BfCT (branched, fasciated cormel type). Cormel production/quadrant/corm was not significantly different among cycle categories and was eliminated in Expt. 2. From these experiments, three below-ground traits had significantly higher mean counts for Cycle 1 genotypes than Cycles 2-5: no. daughter corms (DC)/basal plate, total cormel counts, and UCT. These three markers are selectable, diagnostic markers for Cycle 1 gladioli to identify their ramets in the second and successive years of growth.
All other traits overlapped among categories and are neither diagnostic nor selectable for Cycle 1s.
Future research will focus on identifying molecular markers linked with one or more of these traits.
Authors
N.O. Anderson
Keywords
gladiolus, geophyte, corms, cormels, phenotyping, phenomics
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