Improving Drought Tolerance in Wheat with Physiological and Molecular Tools
Improving Drought Tolerance in Wheat with Physiological and Molecular Tools

Author: Surya Laxmi Shrestha

Publisher:

Published: 2014

Total Pages:

ISBN-13:

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Drought is a limiting factor for wheat (Triticum aestivum L.) production in the low precipitation regions of the Pacific Northwest (PNW). To improve wheat performance in drought, this study focused on three main objectives. Our first objective was to determine water use efficiency (WUE) in the PNW wheat lines through carbon isotope discrimination (CID) technique. Genotypic variation of CID was found in soft spring and hard winter wheat lines. Low CID or high WUE was found important for increasing yield of soft spring wheat lines in drought and semi-drought environments but not in other wheat types. The second objective of this study was to determine important physiological traits associated with yield. Fifteen spring wheat, 140 Alpowa/Express (AE) recombinant inbred lines (RILs) and 165 Hollis/Drysdale (HD) RILs, were evaluated in replicated field trials in two moisture environments, rainfed and irrigated, in different years. The wheat materials were screened for physiological (CT, CID, FLS: Flag leaf senescence), agronomic and phenological traits. The low canopy temperature (CT) was consistently associated with high yield in all wheat lines. The study found that CT was the main driver of wheat adaptation in drought in studied environmental conditions. Our third objective was to identify genomic regions associated with the studied traits through quantitative trait loci (QTL) mapping. In the AE population, yield and test weight QTL were identified on chromosome 1B in the irrigated environments but none of the QTL for physiological traits was found in this chromosomal region. The major QTL associated with yield and CT (at milking), which explained 15 and 22% of the phenotypic variation, were found on chromosome 3B in terminal drought environment. In the HD population, two QTL associated with yield were identified on chromosomes 2A and 4A in averaged rainfed environments in which yield QTL on chromosome 4A explained 35% of the phenotypic variation. These QTL for yield were associated with later FLS. Through the genetic dissection of yield into component traits, this study may help to incorporate quantitative traits into wheat drought breeding programs through marker-assisted selection.

Wheat Blast
Wheat Blast

Author: Sudheer Kumar

Publisher: CRC Press

Published: 2020-04-09

Total Pages: 157

ISBN-13: 0429894074

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Wheat Blast provides systematic and practical information on wheat blast pathology, summarises research progress and discusses future perspectives based on current understanding of the existing issues. The book explores advance technologies that may help in deciding the path for future research and development for better strategies and techniques to manage the wheat blast disease. It equips readers with basic and applied understanding on the identification of disease, its distribution and chances of further spread in new areas, its potential to cause yield losses to wheat, the conditions that favour disease development, disease prediction modelling, resistance breeding methods and management strategies against wheat blast. Features: Provides comprehensive information on wheat blast pathogen and its management under a single umbrella Covers disease identification and diagnostics which will be helpful to check introduction in new areas Discusses methods and protocol to study the different aspects of the disease such as diagnostics, variability, resistance screening, epiphytotic creation etc. Gives deep insight on the past, present and future outlook of wheat blast research progress This book’s chapters are contributed by experts and pioneers in their respective fields and it provides comprehensive insight with updated findings on wheat blast research. It serves as a valuable reference for researchers, policy makers, students, teachers, farmers, seed growers, traders, and other stakeholders dealing with wheat.

The Effects of Drought and High Temperature Stress on Reproduction, Physiology, and Yield of Spring and Winter Wheat
The Effects of Drought and High Temperature Stress on Reproduction, Physiology, and Yield of Spring and Winter Wheat

Author: Kyle J. Shroyer

Publisher:

Published: 2016

Total Pages:

ISBN-13:

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Drought and high temperature are major detriments to global wheat production. Wheat varies in its susceptibility to drought and high temperature stress. Three experiments were performed to address the challenges of drought and high temperature stress in wheat. The first experiment consisted of 256 genotypes of spring wheat and 301 genotypes of winter wheat, field screened for yield traits related to drought tolerance, in irrigated and dryland experiments. The experimental designs for the first experiment were both augmented incomplete block designs with one-way or row-column blocking. This experiment was performed at the Ashland Bottom Research Farm, south of Manhattan, KS, between 2011-2013. From this experiment, three conclusions were made: wheat genotypes vary widely in their responses between dryland and irrigated treatments and this variation can be used in future experiments or breeding tolerant genotypes. The number of seeds per unit of area, total biomass per unit area, and the average weight of one thousand seeds, were the best yield traits for predicting yield in both irrigated and dryland environments. Twenty genotypes were selected for future research based on their susceptibility or tolerance to drought. The second experiment was performed in the greenhouse facilities to observe the source-sink relationship of spring wheat genotype Seri 82 under drought and defoliation. The experiment was a randomized complete block design with a split-plot treatment arrangement. Post-anthesis cessation of watering and defoliation were the treatments. Both water stress and defoliation affected seed yield and total biomass. The major effect of post-anthesis water stress was a decrease in single seed weight. Defoliation affected the source-sink relationship by reducing the source strength of the leaves. This caused the stem to contribute more to overall yield. The defoliation also caused the remaining leaves to compensate for the removed leaves. The final experiment evaluated the changes in seed-filling rate and duration of three winter wheat genotypes during high temperature stress. High temperature stress reduced the duration of seed fill and increased the rate, differently in each genotype. Higher yields in the winter wheat growing regions, susceptible to post-anthesis high temperature stress, may be possible through selection of cultivars with faster seed-filling rates and/or duration of seed filling.