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Khazaie H.,University of Helsinki | Mohammady S.,Shahrekord University | Monneveux P.,Generation Challenge programme | Stoddard F.,University of Helsinki
Australian Journal of Crop Science

The study was conducted on 20 wheat genotypes including four einkorn wheat (T. monococcum subsp. monococcum), eight durum wheat (T. turgidum subsp. durum), six hexaploid landraces and two developed modern varieties including Rooshan and Azar 2 to identify direct effects of stomatal characteristics, water use efficiency (WUE) and δ on grain yield and also to discover the effects of stomatal characteristics on the character through affecting δ and water use efficiency using sequential path analysis. The variations observed among the genotypes were highly significant for all the characters under study. Stomatal frequency indicated negative relationship with grain yield. While stomatal frequency on the either sides of leaves had negative association with grain yield (GY), stomatal area on the both sides indicated close positive correlations with GY. The only significant direct effect on GY was belonging to WUE and surprisingly neither stomatal characteristics nor δ had significant direct effects on grain yield. The least significant direct effect was belonging to stomatal area on abaxial surface followed by stomatal area on adaxial one. Regarding to indirect effects, stomatal frequency on both sides of leaves had positive significant indirect effects on GY via WUE. In addition, stomatal frequency on the abaxial surface had a negative significant indirect effect on GY via δ. A positive significant indirect effect on GY was also observed from stomatal area through carbon isotope discrimination. Source

Khazaei H.,University of Helsinki | Monneveux P.,Generation Challenge programme | Hongbo S.,CAS Institute of Soil and Water Conservation | Hongbo S.,Chinese Academy of Sciences | And 2 more authors.
Genetic Resources and Crop Evolution

Wheat is one of the most important crops in the world. Its study has involved anatomy, ecology, physiology, molecular biology, biotechnology, and cultivation. Knowledge of the relationship of diploid, tetraploid and hexaploid wheat with stomatal characteristics and water-use efficiency is spare and is subject to argument. The present study was aimed to examine different characteristics of stomata in 28 Iranian landraces belonging to the species Triticum monococcum (2n = 2x = 14), Triticum durum (2n = 4x = 28) and Triticum aestivum (2n = 6x = 42), respectively and investigated a possible relationship between these characteristics and water use efficiency by pot cultivation experiments. The results revealed large variation among landraces as well as between the different species for stomatal frequency and size. The diploid wheat species had the highest stomatal frequency and the lowest stomatal length and width. The hexaploid species had a lower stomatal frequency than the tetraploid species. A highly significant relationship was noted between the value of those traits on the adaxial and abaxial surfaces of the leaf. The ratio of adaxial to abaxial values appeared to be constant for a given species. Both stomatal frequency and size were associated with ploidy level, but also with the nature of the constituting genomes of the species. A highly significant negative association was found among accessions between stomatal frequency and size. As a consequence, the variation for stomatal area per unit leaf area was less than for the other traits. Diploid and hexaploid wheat have significantly higher water use efficiency, compared to tetraploid wheat. No clear association was found, however, between water use efficiency and stomatal characteristics. © Springer Science+Business Media B.V. 2009. Source

Pariasca-Tanaka J.,Japan International Research Center for Agricultural science | Lorieux M.,International Institute Of Tropical Agriculture | He C.,Generation Challenge programme | McCouch S.,Cornell University | And 2 more authors.

Oryza glaberrima accessions harbor genes for tolerance to abiotic stresses such as mineral deficiency in problem soils. This genetic potential could be exploited in interspecific crosses with Oryza sativa, as in the case of the ‘New Rice for Africa’ (NERICA) varieties; however, to attain this goal it would be desirable to develop a high-throughput marker system to specifically detect O. glaberrima introgressions in an O. sativa background. Therefore, a single nucleotide polymorphism (SNP) genotyping analysis of an O. glaberrima accession (CG14) with two O. sativa lines (WAB56-104 and WAB181-18) was performed on a genome-wide basis. Comparison of CG14 and the WAB lines resulted in a set of 9,523 polymorphic SNPs which would be suitable to detect O. glaberrima introgressions in upland NERICAs. In addition, a set of 1,540 polymorphic SNPs between O. glaberrima versus O. sativa was identified. A subset of SNPs which were evenly distributed in the genome was then used to design a flexible and cost-effective SNP genotyping panel using the Competitive Allele-Specific PCR technology (KASP). This SNP genotyping panel consists of 2,015 SNPs successfully converted into KASP markers, providing 745 polymorphic SNPs for the parents O. glaberrima CG14/O. sativa WAB56-104 (upland NERICA), and 752 for O. glaberrima TOG5681/O. sativa IR64 (lowland NERICA). KASP markers were successfully validated by mapping O. glaberrima introgressions in NERICA-derived breeding lines. This new SNP genotyping panel will be useful in modern breeding applications such as QTL mapping and/or marker-assisted selection. © 2014, Springer Science+Business Media Dordrecht. Source

Akhter J.,Nuclear Institute for Agriculture and Biology NIAB | Monneveux P.,Generation Challenge programme | Sabir S.A.,Nuclear Institute for Agriculture and Biology NIAB | Ashraf M.Y.,Nuclear Institute for Agriculture and Biology NIAB | And 2 more authors.
Pakistan Journal of Botany

Carbon isotope discrimination (Δ) has been suggested as an indirect tool for selecting plants having higher water use efficiency (WUE) and yield potential. Enhancing WUE is an important breeding objective as water scarcity is increasing with every passing day. This study was undertaken to assess the genotypic variation and relationship between leaf, straw, grain Δ, grain yield and WUE in eight aromatic rice cultivars grown in lysimeters under three water regimes, in absence of drainage and runoff. Highly significant positive correlations were found between aboveground biomass and WUEB, and grain yield and WUEG, due to the low variation in water consumed by different cultivars. Leaf, straw and grain Δ showed a consistent variation across treatments and cultivars. Under water stress conditions, both leaf and straw Δ were positively correlated to grain yield and WUEG. In all the water treatments, WUEG was positively correlated to harvest index and negatively to plant height. All the mutants from Basmati 385 had significantly higher Δ values as compared to the mutants from Basmati 370. It was concluded that the new cultivar, Basmati 385, represents a better genetic source for Δ improvement than the old cultivar, Basmati 370. Source

Van Damme V.,Carrera 115 No. 6 28 | Gomez-Paniagua H.,Generation Challenge programme | de Vicente M.C.,Generation Challenge programme
Molecular Breeding

Crop genetic resources carry variation useful for overcoming the challenges of modern agriculture. Molecular markers can facilitate the selection of agronomically important traits. The pervasiveness of genomics research has led to an overwhelming number of publications and databases, which are, nevertheless, scattered and hence often difficult for plant breeders to access, particularly those in developing countries. This situation separates them from developed countries, which have better endowed programs for developing varieties. To close this growing knowledge gap, we conducted an intensive literature review and consulted with more than 150 crop experts on the use of molecular markers in the breeding program of 19 food security crops. The result was a list of effectively used and highly reproducible sequence tagged site (STS), simple sequence repeat (SSR), single nucleotide polymorphism (SNP), and sequence characterized amplified region (SCAR) markers. However, only 12 food crops had molecular markers suitable for improvement. That is, marker-assisted selection is not yet used for Musa spp., coconut, lentils, millets, pigeonpea, sweet potato, and yam. For the other 12 crops, 214 molecular markers were found to be effectively used in association with 74 different traits. Results were compiled as the GCP Molecular Marker Toolkit, a free online tool that aims to promote the adoption of molecular approaches in breeding activities. © 2010 The Author(s). Source

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