106 research outputs found
Genome-wide SNP identification, linkage map construction and QTL mapping for seed mineral concentrations and contents in pea (Pisum sativum L.)
Linkage map. This file contains the details of the linkage map. (XLSX 38 kb
Concentration and localization of zinc during seed development and germination in wheat
In a field experiment, the effect of foliar Zn applications on the concentration of Zn in seeds of a bread wheat cultivar (Triticum aestivum L. cv. Balatilla) was studied during different stages of seed development. In addition, a staining method using dithizone (DTZ: diphenyl thiocarbazone) was applied to (1) study the localization of Zn in seeds, (2) follow the remobilization of Zn during germination, and (3) develop a rapid visual Zn screening method for seed and flour samples. In all seed development stages, foliar Zn treatments were effective in increasing seed Zn concentration. The highest Zn concentration in the seeds was found in the first stage of seed development (around the early milk stage); after this, seed Zn concentration gradually decreased until maturity. When reacting with Zn, DTZ forms a redcolored complex. The DTZ staining of seed samples revealed that Zn is predominantly located in the embryo and aleurone parts of the seeds. After 36 h of germination, the coleoptile and roots that emerged from seeds showed very intensive red color formation and had Zn concentrations up to 200 mg kg1, indicating a substantial remobilization of Zn from seed pools into the developing roots (radicle) and coleoptile. The DTZ staining method seems to be useful in ranking flour samples for their Zn concentrations. There was a close relationship between the seed Zn concentrations and spectral absorbance of the methanol extracts of the flour samples stained with DTZ. The results suggest that (1) accumulation of Zn in seeds is particularly high during early seed development, (2) Zn is concentrated in the embryo and aleurone parts, and (3) the DTZ staining method can be used as a rapid, semiquantitative method to estimate Zn concentrations of flour and seed samples and to screen genotypes for their Zn concentrations in seeds
Quantitative trait loci conferring grain mineral nutrient concentrations in durum wheat 3 wild emmer wheat RIL population
Mineral nutrient malnutrition, and particularly
deficiency in zinc and iron, afflicts over 3 billion people
worldwide. Wild emmer wheat, Triticum turgidum ssp.
dicoccoides, genepool harbors a rich allelic repertoire for
mineral nutrients in the grain. The genetic and physiological
basis of grain protein, micronutrients (zinc, iron,
copper and manganese) and macronutrients (calcium,
magnesium, potassium, phosphorus and sulfur) concentration
was studied in tetraploid wheat population of 152
recombinant inbred lines (RILs), derived from a cross
between durum wheat (cv. Langdon) and wild emmer
(accession G18-16). Wide genetic variation was found
among the RILs for all grain minerals, with considerable
transgressive effect. A total of 82 QTLs were mapped for
10 minerals with LOD score range of 3.2–16.7. Most QTLs
were in favor of the wild allele (50 QTLs). Fourteen pairs
of QTLs for the same trait were mapped to seemingly
homoeologous positions, reflecting synteny between the A
and B genomes. Significant positive correlation was found
between grain protein concentration (GPC), Zn, Fe and Cu,
which was supported by significant overlap between the
respective QTLs, suggesting common physiological and/or
genetic factors controlling the concentrations of these
mineral nutrients. Few genomic regions (chromosomes 2A,
5A, 6B and 7A) were found to harbor clusters of QTLs for
GPC and other nutrients. These identified QTLs may
facilitate the use of wild alleles for improving grain
nutritional quality of elite wheat cultivars, especially in
terms of protein, Zn and Fe
Advances in genetics and molecular breeding of three legume crops of semi-arid tropics using next-generation sequencing and high-throughput genotyping technologies
Molecular markers are the most powerful genomic tools to increase the efficiency and precision of breeding practices
for crop improvement. Progress in the development of genomic resources in the leading legume crops of the semi-arid
tropics (SAT), namely, chickpea (Cicer arietinum), pigeonpea (Cajanus cajan) and groundnut (Arachis hypogaea), as
compared to other crop species like cereals, has been very slow. With the advances in next-generation sequencing
(NGS) and high-throughput (HTP) genotyping methods, there is a shift in development of genomic resources
including molecular markers in these crops. For instance, 2,000 to 3,000 novel simple sequence repeats (SSR)
markers have been developed each for chickpea, pigeonpea and groundnut. Based on Sanger, 454/FLX and
Illumina transcript reads, transcriptome assemblies have been developed for chickpea (44,845 transcript
assembly contigs, or TACs) and pigeonpea (21,434 TACs). Illumina sequencing of some parental genotypes
of mapping populations has resulted in the development of 120 million reads for chickpea and 128.9 million
reads for pigeonpea. Alignment of these Illumina reads with respective transcriptome assemblies have
provided >10,000 SNPs each in chickpea and pigeonpea. A variety of SNP genotyping platforms including
GoldenGate, VeraCode and Competitive Allele Specific PCR (KASPar) assays have been developed in
chickpea and pigeonpea. By using above resources, the first-generation or comprehensive genetic maps have
been developed in the three legume speciesmentioned above. Analysis of phenotyping data together with genotyping data
has provided candidate markers for drought-tolerance-related root traits in chickpea, resistance to foliar diseases in
groundnut and sterility mosaic disease (SMD) and fertility restoration in pigeonpea. Together with these traitassociated
markers along with those already available, molecular breeding programmes have been initiated for
enhancing drought tolerance, resistance to fusarium wilt and ascochyta blight in chickpea and resistance to
foliar diseases in groundnut. These trait-associated robust markers along with other genomic resources including
genetic maps and genomic resources will certainly accelerate crop improvement programmes in the SAT legum
Nutritionally Enhanced Staple Food Crops
Crop biofortification is a sustainable and cost-effective strategy to address
malnutrition in developing countries. This review synthesizes the progress
toward developing seed micronutrient-dense cereals and legumes cultivars by
exploiting natural genetic variation using conventional breeding and/or transgenic
technology, and discusses the associated issues to strengthen crop biofortification
research and development. Some major QTL for seed iron and zinc,
seed phosphorus, and seed phytate in common bean, rice,J;md wheat have been
mapped. An iron reductase QTL associated with seed-iron ~QTL is found in common bean where the genes coding for candidate enzymes involved in phytic
acid synthesis have also been mapped. Candidate genes for Ipa co segregate with
mutant phenotypes identified in rice and soybean. The Gpe-B1 locus in wild
emmer wheat accelerates senescence and increases nutrient remobilization
from leaves to developing seeds, and another gene named TtNAM-B1 affecting
these traits has been cloned. Seed iron-dense common bean and rice in Latin
America; seed iron-dense common bean in eastern and southern Africa;....
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