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|Title:||Inheritance and Genetic Correlations of Certain Traits in Modified Endosperm Texture Opaque-2 Maize (Zea Mays L.)|
|Author(s):||Beaver, Linda Wessel|
|Department / Program:||Agronomy|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Abstract:||Modified endosperm texture may be useful in improving agronomic characteristics in opaque-2 (o2) maize (Zea mays L.). Five methods of quantifying endosperm modification were compared. Visual estimates of endosperm modification were found to be reliable and efficient means of rating modification. Using these estimates cytoplasmic effects on endosperm modification were studied in crosses of four o2 and six modified o2 lines, and xenia effects, genetic variance components, and genetic correlations were determined in a modified population Synthetic Disease Oil o2o2. Variance components were estimated from analyses of S(,1) and S(,2)/S(,1) families and S(,1) progeny means. Plant height, 100 kernel weight, kernel volume, kernel density, percent oil, percent lysine, percent protein, and lysine per 100 grams protein were determined in addition to endosperm modification.
Few cytoplasmic differences were found in the 24 reciprocal crosses of o2 by modified o2 lines. Only B37o2 cytoplasm appeared to have an effect on modification levels. Xenia was observed to be of a magnitude that would necessitate controlled pollinations in a breeding program. Endosperm modification, 100 kernal weight, volume, and density were found to be influenced by xenia when the same families in open and self pollinated blocks were compared.
Significant genetic variability was observed for all traits in modified Synthetic Disease Oil o2o2. Family mean basis heritabilities were high for all traits except density. Additive genetic variance was important for percent lysine, percent protein, percent oil, L/P, and plant height. Dominance variance was important for endosperm modification, volume, 100 kernel weight, and density. Dominance variance will bias predicted response to selection for the traits in which it is an important component of variance. Modification was negatively correlated with percent lysine and L/P in S(,1) families but not in S(,2) families. Modification was positively correlated with density but not correlated with 100 kernel weight and volume. Increased modification by recurrent S(,1) family selection should be possible in modified Synthetic Disease Oil o2o2. It should be possible to maintain present lysine levels while improving modification by applying some selection pressure.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1981.
|Date Available in IDEALS:||2014-12-14|