Wheat Special Issue 2013
From Agronomy to Biotechnology


Edited by: Aakash Goyal
Co-edited by: Ardashir Kharabian

Special issue 2013 [7(4) 2013]

Table of Contents
Review article

An integrated physical map of simple sequence repeats in bread wheat

Sachin Kumar1, Aakash Goyal2, Amita Mohan3, Harindra S. Balyan1, Pushpendra K. Gupta1*

Molecular Biology Laboratory, Department of Genetics and Plant Breeding, Ch. Charan Singh University, Meerut - 250 004, India
2Canadian Wheat Breeder, Bayer Crop Science, Lab 10, 410 Downey Road, Saskatoon, SK S7N 4N1, Canada
3Department of Crop and Soil Sciences, Washington State University, Pullman, USA

Physical mapping of DNA-based markers in wheat has been greatly facilitated due to the availability of deletion stocks, which constitute an ideal material for mapping these markers to specific chromosomal regions or bins to create physical landmarks. In the present study, the available physical maps for wheat SSRs were enriched by addition of 128 new SSR loci that belonged to wheat gSSRs and brachypodium gSSRs and EST-SSRs. This led to the development of an integrated physical map of 2,031 wheat SSR loci. A maximum of 765 loci (37.67%) were mapped on sub-genome B followed by the 651 loci (32.05%) on sub-genome D and 615 loci (30.28%) on sub-genome A, thus giving a mean resolution of 7.8 Mb between any two SSR loci. Relative to genomic SSRs (gSSRs), the EST-SSRs of brachypodium showed greater transferability in cv. Chinese Spring. Using 704 SSR loci which were mapped genetically as well as physically, a comparison was made between genetic and physical maps to determine the distribution of recombination frequencies (cM/Mb) in different regions of the wheat genome. Recombination frequencies within the individual bins ranged from 0.01 cM/Mb (low recombination) to 13.16 cM/Mb (high recombination), suggesting an uneven distribution along the chromosomes or chromosome arms. Hopefully, the integrated physical map presented in this communication may prove useful in the currently on-going whole genome sequencing of wheat genome through alignment of BAC contigs. A comparison of integrated physical map with genetic linkage map will also facilitate on-going and future genomics research.

Pages 460-468 | Full Text PDF | Supplementary data

Review article

Biotechnological approaches for grain quality improvement in wheat: Present status and future possibilities

Umesh Goutam1,2,3 *, Sarvjeet Kukreja1 ,  Ratan Tiwari2, Ashok Chaudhury3, R. K. Gupta2, B.B. Dholakia4 and Rakesh Yadav3

1Lovely Professional University, Phagwara-144411, Punjab, India
2Directorate of Wheat Research, Karnal-132 001, Haryana, India
3Department of Bio & Nano Technology, Guru Jambheshwar University of Science & Technology, Hisar-125001, Haryana, India
4Division of Biochemical Sciences, National Chemical Laboratory, Pune- 411008, India

Among cereals, wheat is a unique gift of nature to the mankind. Once wheat grain is converted into dough, it can be moulded into innumerable products of the choice, depending upon its suitability for making various end products. The criteria of assessing wheat grain quality traits are as varied as their different uses. Moreover, these quality traits and their parameters are very complex, often polygenic and still not well defined. However, the effects of some major genes for grain hardness, storage-protein encoding genes etc. have been well established. With the advent of molecular biology, it has become possible to develop DNA-based markers for traits of interest. These markers are now gaining the attention of the breeders, since PCR-based functional markers developed from gene sequences provide accurate and high throughput data for determination of allelic compositions in breeding materials.  Thus, DNA markers complement conventional methods of breeding for developing novel cultivars with desirable attributes in less time. The present review describes the recent advancement in molecular markers and their utilization in breeding programs especially to improve traits relating to wheat grain.

Pages 469-483 | Full Text PDF
Review article

Silicon priming: a potential source to impart abiotic stress tolerance in wheat:
A review

Mukhtar Ahmed1, Atif Kamran2, Muhammad Asif2, Ummara Qadeer1, Zammurad Iqbal Ahmed1, Aakash Goyal3*

Department of Agronomy, PMAS, Arid Agriculture University, Pakistan
2Agricultural, Food and Nutritional Science, 4-10 Agriculture/Forestry Centre, Univ. of Alberta, Edmonton, AB T6G 2P5, Canada
3Bayer Crop Science, Saskatoon, Saskatchewan, S7N4N1, Canada

Water deficiency adversely affects a number of physiological and metabolic mechanisms in plants and probably, is a major yield limiting factor. This often put into perspectives, the challenge to produce higher crop yields than ever by conserving and efficiently using the depleting underground water and bringing the marginal water deficit lands under cultivation. A possible potential solution is to induce drought tolerance to mitigate this challenge. The drought resistance recently has drawn the future research focus mainly due to exhausting water table and distribution. Silicon priming is known to enhance crop tolerance against various environmental stresses by tailoring the plant water uptake and transport. Drought tolerance could be induced by modified physio-morphic features such as: adjustment for leaf water potential, stomatal frequency, stomatal size, osmotic adjustments. Silicon priming potentially can induce anatomical changes in cell wall with deposition of silica in the form of polymerized silicon dioxide (SiO2) solid particles, alleviating the oxidative damage of functional molecules and improving anti-oxidative defense abilities. Silicon, actually, induces dehydration tolerance at tissue or cellular levels by improving the water status and hence, facilitates the plant to access photosynthates and this modified adaptability mechanism varies among species. In this review, we discuss the plant drought tolerance adjustments and role of silicon priming to withstand drought stress.

Pages 484-491 | Full Text PDF
Research article

Mapping main effect QTL and epistatic interactions for leaf rust and yellow rust using high density ITMI linkage map

Ajay Kumar1,2, Parveen Chhuneja3, Shalu Jain2, Satinder Kaur3, H. S. Balyan1, P. K. Gupta1,*

Molecular Biology Laboratory, Department of Genetics & Plant Breeding, Ch. Charan Singh University, Meerut-250004, India
2Department of Plant Sciences, North Dakota State University, Fargo, ND-58108, USA
3School of Agricultural Biotechnology, Punjab Agricultural University, Ludhiana-141004, India

The present study was undertaken to identify QTL for leaf rust (LR) and stripe or yellow rust (YR) using ITMI-mapping population under Indian environmental conditions. A high density framework linkage map consisting of 1,345 markers was used to conduct single and two locus QTL analyses using QTLCartographer and QTLNetwork. A total of 14 main-effect QTL (M-QTL) for LR and 12 M-QTL for YR were detected. Among all these M-QTL, 7 for LR and 4 for YR were novel, and have not been reported in earlier studies using same population. Eight significant QQ interactions for each trait were also identified, which involved 16 epistatic-QTL (E-QTL) for LR and 14 E-QTL (including 2 M-QTL) for YR. Four genomic regions had QTL for both LR and YR. The phenotypic variation explained (PVE) ranged from 2.16% - 29.07% for M-QTLLR and from 0.80%-7.05% for E-QTL. Epistasis contributed a significant portion of the PVE (26.01% for LR and 31.51% YR) for the two traits. Minor environment interactions were observed for YR.

Pages 492-499 | Full Text PDF
Review article

Detection of seed borne pathogens in wheat: recent trends

Dipali Majumder*, Thangaswamy Rajesh, E. G. Suting, Ajit Debbarma

School of Crop Protection, College of Post Graduate Studies, Central Agricultural University, Umiam, Meghalaya -793 103, India

Infected wheat seeds are the carrier of pathogens for long-distance dissemination. Major impact of seed borne diseases in wheat is not only the yield reduction but also deteriorate marketable quality of grains. Early detection of pathogens is a crucial step in diagnosis and management programmes in wheat. The failure to adequately identify and detect plant pathogens using conventional, culture based morphological techniques has led to the development of nucleic acid-based molecular approaches. Polymerase chain reaction (PCR) revolutionised pathogen detection and identification, but these methods have not yet entirely replaced traditional cultural and phenotypic tests practiced for detection of major wheat seed borne pathogens e.g. NaOH seed soak method for detection of Tilletia indica causing Karnal bunt of wheat. Methods for detection of seed borne microorganisms in wheat are ranged from simple visual observation to spectroscopic and imaging techniques. Immuno-diagnostic tools can also be successfully employed for differential diagnosis, disease surveillance of seed borne pathogens of quarantine importance and determination of teliospore load in wheat seeds. PCR-based methods result in high level of sensitivity, specificity is used for species-specific detection of Tilletia spp and Fusarium spp. The present paper highlights the brief outlines of traditional detection methods and discusses recent PCR-based and spectroscopic and imaging techniques being employed in detection of seed borne pathogens in wheat

Pages 500-507 | Full Text PDF
Research article

Development and molecular characterization of wheat- Aegilops longissima derivatives with high grain micronutrients

Kumari Neelam1, Nidhi Rawat2, Vijay K. Tiwari2*, Nikita Ghandhi3, Patokar Chetan Arun4, Sundip Kumar4, Sangharsh K. Tripathi5, Gursharn S. Randhawa3, Ramasre Prasad3 and Harcharan S. Dhaliwal6

1School of Agricultural Biotechnology, Punjab Agricultural University, Ludhiana-141004, Punjab, India
2Department of Plant Pathology, Kansas State University, Manhattan-66506, Kansas, USA
3Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee-247667, Uttarakhand, India
4Department of Molecular Biology and Genetic Engineering, GB Pant University of Agriculture and Technology, Pantnagar-249196 , Uttarakhand, India 
5Department of Water Resources Development and Management, Indian Institute of Technology Roorkee, Roorkee-247667, Uttarakhand, India
6Eternal University, Baru Sahib Via Rajgarh, Distt. Sirmour, Himachal Pradesh-173101, India

Developing food crops with enhanced mineral concentrations is one of the most sustainable and cost effective approaches for alleviation of micronutrient. This article aims at development and molecular characterization of wheat- Aegilops longissima derivatives with high grain micronutrients (iron, zinc, copper, manganese, calcium, magnesium and potassium). Aegilops longissima (2n=14, SlSl) accession 3506 with high grain micronutrients was used for transferring these traits to elite wheat (Triticum aestivum) cultivars through wide hybridization. The fertile HD2687/L3506//WL711 BC1F3 derivatives were developed through selfing and selection for chromosome constitution, meiotic stability and micronutrient concentrations was done at each generation. Sixteen derivatives were finally selected and characterized. The selected backcross derivatives showed enhanced grain iron, zinc, copper, manganese, calcium, magnesium and, potassium concentrations over the parental wheat cultivars by up to 183.6%, 243.6%, 135.18%, 160.42%, 223.29%, 43.90% and 35.05%, respectively. Introgression of chromosomes 2, 7 and 1 from Ae. longissima
, confirmed by plant waxiness,GISH, anchored wheat SSR markers and HMW glutenin subunit profiling and was found to be associated with enhanced micronutrients in the derivatives.

Pages 508-514 | Full Text PDF
Review article

Growing wheat on saline lands: Can a dream come true?

Armghan Shahzad1, Muhammad Iqbal1, Muhammad Asif2*, Arvind H. Hirani3, Aakash Goyal4 

1Plant Biotechnology Program, National Agricultural Research Center, Park Road 45500 Islamabad, Pakistan
2Agricultural, Food and Nutritional Science, 4-10 Agriculture/Forestry Centre, Univ. of Alberta, Edmonton, AB T6G 2P5, Canada

3Department of Plant Science, University of Manitoba, Winnipeg, Canada
4Bayer Crop Science, Saskatoon, Saskatchewan, S7N4N1, Canada

Wheat is the third largest cereal produced in the world and it supplies over 20% of calories in human food around the globe. Wheat production and productivity directly influence human survival in developing countries and quality of life in industrial countries. World population is growing at a very rapid pace. It is one of the biggest concerns for current and future food supply due to limitations in the availability of land for agricultural production. The land available for cultivation is also affected by progressive salinization. Food security can only be mitigated by continuous increase in production and productivity of major crops like wheat. Utilization of saline land for wheat production is one of the important strategies to enhance production. Wheat and its wild relatives possess ample diversity for abiotic stresses, especially salt tolerance, however, limited research has been conducted to explore salt tolerance mechanism and its utilization in current and future wheat production. Current review has focused mainly on progressive salinity issues in agricultural land, salt tolerance mechanism in wheat and existence of genetic diversity in wild relatives of wheat and its utilization in breeding for salt tolerance. In addition, this review has highlighted different conventional, molecular and advance genomic strategies to enhance salt tolerance in wheat. Current status of available molecular markers, marker assisted selection/breeding and transgenic approaches for salt tolerance in wheat is discussed along with challenges and future research direction that could be directly employed in wheat breeding programs globally to enhance wheat production.

Pages 515-524 | Full Text PDF
Research article

Interdependence of cultivar and environment on fiber composition in wheat bran

K. Hossain1, C. Ulven2, K. Glover3 F. Ghavami4, S. Simsek4, M.S. Alamri5, A. Kumar4 and M. Mergoum4,*

1Mayville State University, Mayville, ND, USA
2Department of Mechanical Engineering, North Dakota State University, Fargo, ND, USA
3Plant Science Department, South Dakota State University, Brookings, SD, USA
4Dept. of Plant Sciences, North Dakota State University, Fargo, ND, USA
5Nutrition and Food Sciences Department College of Food and Agricultural Sciences; King Saud University, P.O. Box 2460, Riyadh 11451, Saudi Arabia

Starch and cellulose are among the best known renewable reinforcing components. Scientists are continuously looking for various renewable sources such as flax, hemp, jute, and corn hulls with polymer matrixes to form composite materials and make structural biocomposites a reality. Wheat is a major cereal grain in the US and the world. During wheat milling, a large amount of wheat bran, a by-product, is disposed off as waste. The high percentage of water-insoluble fiber in wheat bran could be advantageous for reinforcing industrial material. However, the utilization of cellulosic fibers derived from wheat by-product has not been explored in processing of biocomposites. Therefore, the objectives of this study were to characterize wheat bran fiber compositions including dry matter (DM), ash, crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), cellulose (Cell), hemicellulose (Hemi), calcium (Ca), fat, starch, and acid detergent lignin (ADL); identify the interrelationship between the fiber composition traits and the influence of the environment and genotype on these traits. The experiment included six diverse and popular hard red spring wheat (HRSW) cultivars commonly grown in spring wheat region of the Northern Plains of the USA. The experiment was installed in three different environments in North and South, USA. Results from this study showed that the DM, ash, Ca, Cell, starch, and ADL contents were influenced mainly by environment. However, CP along with fat, ash and Ca contents were influenced by genotypes in addition to environment. All bran components were influenced by the genotype x environment (G x E) interactions. We observed significant negative correlation of Cell with CP and ADL, which make wheat bran a suitable reinforcing industrial material. However surface treatment of bran fiber would make it even more efficient. These preliminary results indicate the potential use of wheat bran components as biocomposite, but further studies to elucidate more these finding are warranted.

Pages 525-531 | Full Text PDF

Southern Cross Publishing Group©2013

Australian Journal of Crop Science (AJCS)