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|Title:||Variation and Inheritance of Hardseededness in Soybeans (Glycine Max (L.) Merr.)|
|Department / Program:||Agronomy|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Abstract:||A series of experiments dealing with variation as well as inheritance of hardseededness in soybeans was conducted from July 1977 to July 1979. Field and greenhouse plantings were made at Isabela Experiment Station, Puerto Rico and the Department of Agronomy, University of Illinois, respectively.
Three regression models (linear, second degree polynomial, and exponential) were employed to explain the relationship between days after putting seeds in a germinator and hard seed percentage in two soybean varieties, Barchet and PI 326578. The exponential regression model was the best in explaining the relationship using field data whereas the second degree polynomial model was the best using greenhouse data. All models fitted the data better when first day observations were excluded.
Two determinate varieties (Barchet and PI 326578) and two indeterminate varieties (PI 307865 and PI 323566) were grown in the field to study relationships between positions of seeds on a plant and hard seed percentages. Relationships were detected between hard seed percentages and nodal positions on the main stems of Barchet and PI 307865 and on the primary branches of PI 323566. No relationship was found between hard seed percentages and seed positions in a pod.
When field grown seeds from Barchet and PI 326578 were planted in the greenhouse, the resulting plants grown from normal seeds yielded hard seed percentages similar to those from plants grown from hard seeds. No correlation was found in proportion of hard seeds from a plant grown in a different environment. Percentages of hard seeds were much higher on greenhouse grown than on field grown plants. Genotype by environment interaction of this trait was also observed.
Inheritance studies using crosses between low and high hard seed percentage varieties (Barchet x Hardee, Barchet x SJ 2, Hardee x PI 326578, and SJ 2 x PI 326578) indicated that two to four loci of major genes controlled the observed variation in hard seed percentages. Genes for normal seeds were dominant. Modifiers seemed to involve in variation of this trait in the cross between low and medium hard seed percentage varieties (Barchet x PI 323566), as well as in the cross between high hard seed percentage varieties (Barchet x 326578), however, the former cross displayed a heterotic effect in the progenies whereas the latter showed only minor (modifier) genes with additive effects.
A linkage probably exists between one major gene locus for hardseededness and the i locus which is involved in seed and coat color.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1980.
|Date Available in IDEALS:||2014-12-14|