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Gibberellins and Heterosis in Sorghum
Author(s) -
Rood Stewart B.,
Witbeck J. E. Teddy,
Major David J.,
Miller Fred R.
Publication year - 1992
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1992.0011183x003200030027x
Subject(s) - heterosis , sorghum , biology , gibberellin , hybrid , shoot , sweet sorghum , sorghum bicolor , elongation , pisum , agronomy , poaceae , botany , horticulture , materials science , ultimate tensile strength , metallurgy
Two triplet combinatioas of sorghum, [ Sorghum bicolor (L.) Moench], each consisting of two homozygous parental lines and their F 1 hybrid (ATx623 × Hegaria; ATx378 × RTx430), were grown in controlled environment chambers to examine the possible relationship between gibberellins (GAs) and heterosis (hybrid vigor). Heterosis for shoot growth occurred as shoot dry weights and leaf areas were greater in the hybrids than in parental inbreds. The exogenous application of 0.1, 0.5, or 1.0 mg GA 3 by pipetting into the leaf whorl promoted leaf sheath and leaf blade elongation in all genotypes. GA 3 also promoted shoot dry weight and/or leaf area in three of the four inbreds, but hybrids were relatively unaffected. Endogenous GA 1 was measured by gas chromatography‐selected ion monitoring, using [ 2 H 2 ]GA 1 as an internal standard. At one of the two harvests (Day 22 and 29) for each triplet, the hybrid contained significantly higher concentrations of GA 1 than either parent. Endogenous GA 3 was characterized by GC‐SIM in samples, from the second harvest and showed the same pattern as GA 1 . Thus, at some stages, these sorghum inbreds apparently have a partial deficiency of endogenous GA. The response to exogenous GA 3 application suggests that the GA deficiency is a limitation to their growth. Thus, GAs are apparently involved in heterosis for shoot growth in sorghum.