Open AccessInheritance and Phenocopy of a Red Beet Gibberellic Acid-deficient Dwarf Mutant
Author(s) -
Irwin L. Goldman,
Jeffery Watson
Publication year - 1997
Publication title -
journal of the american society for horticultural science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.408
H-Index - 80
eISSN - 2327-9788
pISSN - 0003-1062
DOI - 10.21273/jashs.122.3.315
Subject(s) - biology , gibberellic acid , backcrossing , mutant , phenocopy , botany , main stem , tiller (botany) , meristem , horticulture , genetics , gene , shoot , germination
A severe dwarf mutant affecting vegetative and reproductive growth arose spontaneously in our red beet ( Beta vulgaris L. subsp. vulgaris ) breeding nursery and was used in crosses with inbred lines to characterize its inheritance. Segregation data in backcross and F 2 generations were collected. Chi-square goodness-of-fit tests did not deviate significantly from the expected ratios for a monogenic character for each genetic background-generation combination. We propose the symbol dw to describe the genetic control of this dwarf phenotype. Greenhouse experiments were conducted to determine whether the mutant was sensitive to exogenous application of gibberellic acid (GA). GA 3 and GA 4/7 in concentrations of 0 to 1000 ppm were applied to apical meristems during flower stem development in vernalized dwarf plants. Data on flower stem length and leaf length were collected over a 6-week period during reproductive growth. Recovery of wild-type flower stem length was obtained with application of both types of GA. A 30-fold increase in flower stem length over untreated plants was accomplished by GA application. Results of these phenocopy experiments suggest the mutant gene is involved in GA synthesis.