Graduate Thesis Or Dissertation

 

The inheritance of ten quantitative characteristics in sweet corn (Zea mays L.) Public Deposited

Downloadable Content

Download PDF
https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/x633f3483

Descriptions

Attribute NameValues
Creator
Abstract
  • The inheritance of ten characteristics of sweet corn was studied by quantitative genetic analysis. Characters studied were tassel date, silk date, plant height, ear height, shank length, husk extension, tip blanking, number of kernel rows, ear length, and weight of the first ear. Diallel crosses were made between seven inbred parents. The ten characters were measured on the seven parents and 21 F₁ crosses in two years and on the 21 reciprocal F₁ crosses and 21 F₂ families in one year. A fixed model of the diallel analysis was used to partition genetic variation into general combining ability (GCA) and specific combining ability (SCA). F₁ data were combined over years to evaluate genotype by year interactions. Regressions of progeny on parents were calculated to compare the results of covariance among relatives with results based on variance components. Combining ability effects and genotypic correlations between characters were also estimated. Both GCA and SCA were involved in the inheritance of all ten characters. This was consistent for the F₁ crosses in both years and for the F₂ families. Variance components were extracted from expectations of mean squares and expressed as ratios of V subscript [SCA]/V subscript [GCA] to compare the relative importance of GCA and SCA. SCA was more important than GCA for ear length and weight of the first ear in the F₁. Ratios for these characters were slightly larger than 1.0. GCA was more important than SCA for all other characters in the F₁. Ratios ranged from .047 for number of kernel rows to .566 for plant height. Variance ratios for most characters decreased in the F₂. The failure of some ratios to decrease in the F₂ was attributed to either differential interactions of GCA and SCA with the environment or inadequate sampling of the F₂ families. Analyses of heterosis and inbreeding depression were in general agreement with variance component ratios. Genotype by year interactions influenced the expression of most characters. A greater portion of the genotype by year interaction was contained in estimates of SCA than in estimates of GCA. Heritability estimates from parent-progeny regression and from variance components were generally in close agreement, although those from regression were generally larger than those from variance components. This supports the use of the combining ability analyses in this study. Large positive genotypic correlations were found between tassel date and silk date, plant height and ear length, ear height and shank length, ear height and tip blanking, ear height and ear length, number of kernel rows and ear weight, and ear length and ear weight. Large negative genotypic correlations were found between plant height and husk extension, ear length and husk extension, and ear weight and husk extension. Characters with large genotypic correlations also had large phenotypic correlations. Reciprocal F₁ crosses differed for all characters except weight of the first ear. These differences were large enough in some crosses to have important breeding implications. The cause of these reciprocal differences could not be definitely established in this study.
Resource Type
Date Available
Date Issued
Degree Level
Degree Name
Degree Field
Degree Grantor
Commencement Year
Advisor
Committee Member
Academic Affiliation
Non-Academic Affiliation
Subject
Rights Statement
Publisher
Peer Reviewed
Language
Digitization Specifications
  • File scanned at 300 ppi (Monochrome) using Scamax Scan+ V.1.0.32.10766 on a Scanmax 412CD by InoTec inPDF format. LuraDocument PDF Compressor V.5.8.71.50 used for pdf compression and textual OCR.
Replaces

Relationships

Parents:

This work has no parents.

In Collection:

Items