Document Type

Thesis - Open Access

Award Date

2018

Degree Name

Master of Science (MS)

Department / School

Agronomy, Horticulture, and Plant Science

First Advisor

Xingyou Gu

Abstract

Soybean production in most of the Northern Great Plain area has been challenged by iron deficiency chlorosis (IDC), which is a physiological problem with a plant grown in high pH, calcareous soil. Developing IDC-resistant cultivars is the best approach to meet this challenge. Currently, this approach is limited by lack of knowledge about genetic resources and mechanisms for resistance to IDC. The objectives of this research were to validate quantitative trait loci (QTL) associated with IDC and to evaluate the effect of IDC on yield in soybean cultivars. To validate the QTL, a population of 201 recombinant inbred lines, which was developed from a cross between a cultivated (Glycine max) and a wild (G. soja) soybean line, was grown in a field with calcareous soil (pH 8.5) using a randomized complete block design with four replicates. Phenotypes of IDC were visually scored for individual lines at three-time points during the vegetative growth period starting from the V3 stage. Heritability estimates for IDC scores ranged from 0.26 to 0.71. A linkage map was constructed using 164 SSR markers and covers 2156 cM of the soybean genome a total of 11 QTL for Fe efficiency were detected, with six detected in more than one time points. One of the 11 QTL has the allele from the wild parent enhancing the resistance to IDC. Seven of the QTL were involved in digenic epistasis. Two of the QTL were involved in G-by-E interactions. The epistatic and G-by-E interactions demonstrate the importance of evaluating IDC responses in multiple environments. The validated QTL may contain useful genes for breeding IDC-resistant varieties by pyramiding of the Fe-efficiency alleles. Furthermore, to evaluate the effect of IDC on yield potential, twenty-three soybean cultivars were examined. The results showed the further need for improvement toward better resistance to IDC. The one-year yield test of five cultivars, bearing different levels of resistance to IDC, confirmed the effect of this stress on yield leading to a high yield of resistant cultivars under chlorotic soil and lower when grown on the non-chlorotic soil.

Library of Congress Subject Headings

Soybean -- Diseases and pests.
Chlorosis (Plants)
Plants -- Effect of iron on.
Soybean -- Genome mapping.
Iron deficiency diseases in plants.
Soybean -- Disease and pest resistance.

Description

Includes bibliographical references

Format

application/pdf

Number of Pages

105

Publisher

South Dakota State University

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Rights Statement

In Copyright