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Drought resistance indices for screening of potato (Solanum tuberosum L.) genotypes
2019
Beyene, Z.K. | Mekbib, Firew | Abebe, T. | Asfaw, A.
In breeding for drought tolerance, availability of precise, cheap and easy to apply selection tool is critical. The aim of the present study was to identify potential screening tools that are useful for selection of drought tolerant genotypes in potato and select drought resistant potato genotypes. The study assessed sixty clones arranged in a 10×6 alpha lattice design with two replicates in a managed stress experiment. Two irrigation treatments were applied: fully watered non-stress and terminal drought, where the irrigation water supply to the crop was withheld after 50 % flowering to induce post-flowering stress. Stress indices were calculated based on tuber yield of genotypes in both stressed and non-stressed conditions. Identification of drought tolerant genotypes based on a single index was less informative as different indices identified different genotypes as drought tolerant. Hence, to determine the most desirable drought tolerant clones rank sum of indices, correlation, and bi-plot display of the principal component analysis was employed. The indices modified stress tolerance index based on non-stressed yield, Men productivity, Geometric mean productivity, Stress tolerance index, Harmonic mean, modified stress tolerance index based on stressed yield and Yield index exhibited strong association with both yield under stressed and non-stressed yield. These indices discriminated drought tolerant genotypes with higher tuber yielding potential both under stress and non-stress conditions. Genotypes CIP-398180.612, CIP-397069.5, and CIP-304371.67 were identified as drought tolerant. These genotypes could be potentially grown both under drought prone and potential environments and these selection attributes could help to develop climate resilient potato varieties.
Show more [+] Less [-]Major Sorghum Production Constraints and Coping Mechanisms: The Case of Anthracnose (Colletotrichum sublineolum)
2021
Kebede Dessalegn Lemu | Peter Ogbonna | Christian Agbo | Dagnachew Lule
This paper attempts to review the major sorghum production constraints, the progress and perspective on sorghum anthracnose (Colletotrichum sublineolum) resistance breeding. The importance of anthracnose in sorghum production and breeding for resistance status and progress were also primly discovered. Sorghum is an ancient environment resilient crop and believed to be a future crop due to its important merits like tolerant to stresses, wide adaptability and low input requirement. Insects and disease are major biotic impediments to realizing the yield potential of the crop. Anthracnose disease caused by Colletotrichum sublineolum is the most important disease that severely affecting the crop in all sorghum producing regions of the world. Research results revealed that anthracnose resulted in 30-50% or greater yield losses. Several management strategies such as, cultural, chemical and using resistance varieties have been developed. Employing host-plant resistance is the most economical and environmentally friendly approach which can successfully control the disease. Breeding assisted with molecular markers plays a great role in resistance breeding programme as it makes easy to screen large number of genotypes at once. Recent advancement of molecular breeding and bio-informatics tools are playing a significant role in efficiencies and precisions of resistance breeding. QTLs or genomic area for resistance were identified using traditional molecular markers and recent research results revealed discoveries of specific gene and locus using high throughput markers like SNPs using GWAS approach. The discovery of genes/QTL associated with the resistance trait, using the high through put molecular markers like SNPs, facilitates the easiest way for gene pyramiding from different individual genotypes to a single variety, introgression into adapted elite cultivar through marker assisted and editing genes for elite landraces to develop durable resistance varieties. Transgenic approach is now a day becoming a powerful tool to utilize novel alien genes for crop improvement including anthracnose resistance breeding in sorghum.
Show more [+] Less [-]Effects Of Drought Stress on Germination in Fourteen Provenances of Pinus Brutia Ten. Seeds in Turkey
2015
Hakan Şevik | Nihat Ertürk
Pinus brutia Ten., Red pine, known to be tough drought resistant pine specie, could effectively be used for afforestation of disturbed areas. It is of great interest for the afforestation in arid zones. Appropriate seed sources for the specific areas guarantees reforestation success. Away from its native areas Pinus brutia Ten. is planted for its ornamental value and timber production purposes. Selection of drought resistant provenances can very well increase the survival success. In this study, the effects of water potential on germination were studied in fourteen provenances of Pinus brutia Ten. from Turkey. Water potentials between 0 and -8 bars were obtained using polyethylene glycol 6000 (PEG-6000) solutions. Seeds were kept for 35 day at 20 ± 0.5°C. A decrease in water potential produced a marked reduction in germination percentage and germination value. As a result, significant variations between the provenances were found. It was determined that, under a -8 bar water stress, Isparta-Bucak and Mersin-Silifke, respectively corresponding to 58% and 57% of the control group, were the least water stress affected provenances.
Show more [+] Less [-]Genome wide analysis of stress responsive WRKY transcription factors in Arabidopsis thaliana
2016
Shaiq Sultan | Muhammad Amjid Ali | Rana Muhammad Atif | Farrukh Azeem | Habibullah Nadeem | M. Hussnain Siddique | Ertuğrul Filiz | Khadim Hussain | Amjad Abbas
WRKY transcription factors are a class of DNA-binding proteins that bind with a specific sequence C/TTGACT/C known as W-Box found in promoters of genes which are regulated by these WRKYs. From previous studies, 43 different stress responsive WRKY transcription factors in Arabidopsis thaliana, identified and then categorized in three groups viz., abiotic, biotic and both of these stresses. A comprehensive genome wide analysis including chromosomal localization, gene structure analysis, multiple sequence alignment, phylogenetic analysis and promoter analysis of these WRKY genes was carried out in this study to determine the functional homology in Arabidopsis. This analysis led to the classification of these WRKY family members into 3 major groups and subgroups and showed evolutionary relationship among these groups on the base of their functional WRKY domain, chromosomal localization and intron/exon structure. The proposed groups of these stress responsive WRKY genes and annotation based on their position on chromosomes can also be explored to determine their functional homology in other plant species in relation to different stresses. The result of the present study provides indispensable genomic information for the stress responsive WRKY transcription factors in Arabidopsis and will pave the way to explain the precise role of various AtWRKYs in plant growth and development under stressed conditions.
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