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Value of Selection for Osmotic Potential in Tropical Maize
Author(s) -
Bolaños J.,
Edmeades G. O.
Publication year - 1991
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1991.00021962008300060006x
Subject(s) - agronomy , turgor pressure , biology , drought tolerance , osmotic pressure , population , heritability , trait , hybrid , horticulture , botany , demography , genetics , sociology , computer science , programming language
Osmotic adjustment, the lowering of osmotic potential (Ψ S ) under drought, is considered a desirable component of drought tolerance since it has been shown to maintain turgor, growth, and photosynthesis at lower water potentials. This study attemped to determine the relative merits of selecting for osmotic adjustment and low Ψ S under drought in lowland tropical maize ( Zea mays L.). During 3 yr of trials in Mexico that examined 204 maize landacres, elite open pollinated populations (OPPs), experimental synthetics (ESs), and hybrids, osmotic adjustment averaged 0.10 MPa and ranged from 0.54 to −0.23 MPa. Only 7% of genotypes showed a capacity to adjust by more than 0.40 MPa, a level considered minimum for them to serve as sources for the trait. Variation for Ψ S , under drought for 222 to 225 S 1 progeny of three maize populations ranged from −1.04 to −1.79 MPa. Divergent selection within each population for high and low Ψ S under drought resulted in the formation of ESs which differed in Ψ S by an average of 0.17 MPa when grown under a line source moisture gradient. Realized heritability for Ψ S averaged 0.46. The ESs selected for high and low Ψ S did not yield differently from the cycle bulk, suggesting little adaptive value for Ψ S Correlations between several traits indicative of performance under drought and osmotic adjustment or Ψ S under drought generally were weak, inconsistent, and non‐significant. These studies suggest that selecting for increased capacity to adjust osmotically or low Ψ S under drought does not appear advantageous in lowland tropical maize.