Agronomic and molecular evaluation of maize inbred lines for drought tolerance (original) (raw)
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Genetic studies for drought related traits in temperate maize
Electronic Journal of Plant Breeding, 2016
Under the INSA Fellowship Programme (2015), thirty genotypes of Maize which included twenty eight inbred lines and two checks maintained at D(K)ARS, SKUAST-K were used for a "Comprehensive Assessment of Drought Tolerance" in the Department of Crop Physiology, University of Agricultural Sciences, GKVK Bangalore. In this programme the genetic variability for Roots, Water Use Efficiency and Photosynthesis related traits studied to identify contrasts for trait based introgression for drought tolerance. Maize accessions revealed a significant genetic variability for roots, WUE (∆13C). Further significant genetic variability in WUE at single level was also observed. Significant genetic variability in drought tolerance traits was revealed among the maize germplasm lines. The promising lines identified like KDM-932A for root length, KDM-1095 for root volume, KDM-918A for root weight, KDM-954 for epicuticular wax content and KDM-944A for WUE can be used as trait donor lines to transfer specific traits into a recipient genotype.
Frontiers in Plant Science, 2021
Current climate change models predict an increased frequency and intensity of drought for much of the developing world within the next 30 years. These events will negatively affect maize yields, potentially leading to economic and social instability in many smallholder farming communities. Knowledge about the genetic resources available for traits related to drought tolerance has great importance in developing breeding program strategies. The aim of this research was to study a maize landrace introgression panel to identify chromosomal regions associated with a drought tolerance index. For that, we performed Genome-Wide Association Study (GWAS) on 1326 landrace progenies developed by the CIMMYT Genetic Resources Program, originating from 20 landraces populations collected in arid regions. Phenotypic data were obtained from early testcross trials conducted in three sites and two contrasting irrigation environments, full irrigation (well-watered) and reduced irrigation (drought). The ...
Genetic Analysis of Performance of Maize Inbred Lines Under Drought Stress
Journal of Crop Improvement, 2011
The majority of farmers in sub-Saharan Africa (SSA) depend on maize (Zea mays L.), which is mostly grown in drought-prone areas. Understanding the inheritance of drought tolerance would help in developing drought-tolerant maize hybrids that would help increase maize production under erratic rainfalls. Twenty-four maize inbred lines were subjected to NC design II to generate 96 single-cross hybrids. The 24 inbred lines and their 96 hybrids were evaluated under managed drought-stress conditions between 2002 and 2005 at Ikenne, Nigeria. The objectives of this study were to determine the effects of drought-susceptible and drought-tolerant inbred lines on performance of their hybrids, investigate mode of inheritance of drought tolerance, and determine the relationship between parental lines and their hybrids. Most crosses with at least one drought-tolerant parent produced tolerant hybrids, and the crosses between susceptible inbred lines produced susceptible hybrids. General combining ability (GCA) accounted for 55% to 87% of total variation among hybrids for most of the traits. Additive genetic effects influenced grain yield under drought stress. Correlation coefficient between grain yield of the inbred lines and their hybrids was positive and highly significant (r = 0.46***) under severe drought stress and relatively low (r = 0.30**) under mild drought stress and well-watered (r = 0.34**) regimes. Grain yield of inbred lines represented >20% of hybrid yield under severe stress. KU1409, 1824, 9006, 9432, and TZMI501xKU1414x501 had positive GCA effects for yield under drought stress and could be used for developing drought-tolerant hybrids.
Assessment of Gene Action to Develop Drought Tolerance Maize Inbred Lines
2015
2 Abstract: Drought is one of the most significant environmental pressures around the world. The climate changes and increasing population pose serious factor to crop improvement. It is one of the most serious production restraints for world agriculture and is estimated to get worse with anticipated climate change. It is thought that understanding of how plants reply to drought at the molecular level are useful for developing improved genotypes which would accomplish well under drought. Maize (Zea mays L.), one of the most important food crops in the world, is very sensitive to drought, especially during flowering, pollination and embryo enlargement. Inter-disciplinary scientists have been trying to understand and dismember the mechanisms of plant tolerance to drought stress using a variety of tactics; however, success has been inadequate. Recent genomics and genetic approaches coupled with developments in particular phenotyping and breeding methodologies are expected to be more eff...
Genetic analysis of drought tolerance in maize by molecular markersI. Yield components
Theoretical and Applied Genetics, 1999
Grain yield is a complex trait, strongly influenced by the environment: severe losses can be caused by drought, a stress common in most maize-growing areas, including temperate climatic zones. Accordingly, drought tolerance is one of the main components of yield stability, and its improvement is a major challenge to breeders. The aim of the present work was the identification, in maize genotypes adapted to temperate areas, of genomic segments responsible for the expression of drought tolerance of yield components: ear length, ear weight, kernel weight, kernel number and 50-kernel weight. A linkage analysis between the expression of these traits and molecular markers was performed on a recombinant inbred population of 142 families, obtained by repeated selfing of the F1 between lines B73 and H99. The population, genotyped at 173 loci (RFLPs, microsatellites and AFLPs), was evaluated in well-watered and water-stressed conditions. A drought tolerance index was calculated as the ratio between the mean value of the trait in the two environments. For the traits measured, a highly positive correlation was found over the two water regimes, and more than 50% of the quantitative trait loci (QTLs) detected were the same in both; moreover, the direction of the allelic contribution was always consistent, the allele increasing the trait value being mostly from line B73. Several QTLs were common to two or more traits. For the tolerance index, however, most of the QTLs were specific for a single component and different from those controlling the basic traits; in addition, a large proportion of the alleles increasing tolerance were provided by line H99. The data suggest that drought tolerance for yield components is largely associated with genetic and physiological factors independent from those determining the traits per se. The implications of these results for developing an efficient strategy of marker-assisted selection for drought tolerance are discussed.
Numerical Classification of Western Balkan Drought Tolerant Maize (Zea mays L.) Landraces
Journal of Agricultural Science and Technology
Global warming and predictions of climatic changes additionally put breeding for drought tolerance in the focus of breeding programmes for maize. Extensive studies on the existing gene bank collection of the Maize Research Institute "Zemun Polje" have been performed with the aim to identify and form initial sources for the development of maize inbreds more tolerant to drought. All accessions (about 6,000) were exposed to controlled drought stress in Egypt. Out of this number, approximately 8% of the tested genotypes were selected. In this study attention was given to 321 selected Western Balkan maize landraces, adapted to temperate climate growing conditions and the day length. Data derived from morphological characterization according to CIMMYT/IBPGR descriptors for maize, along with the application of numerical classification methods, were used to define homogeneous landraces groups based on morphological similarities. Results obtained from hierarchical and non-hierarchical analyses revealed the formation of 11 divergent groups. According to the obtained grain yield and visually scored stalk lodging and stay green, approximately 15% of the accessions from each of 11 groups were selected. Further investigations are towards defining their heterotic patterns and their possible utilization in developing and improving synthetic populations.
Agronomy
As a most significant cereal crop, maize provides vital nutritional components to humans and livestock. Drought stress curtails maize growth and yield by impairing several morphological, physiological, and biochemical functions. The rising threats of drought stress significantly affect global food security and increase the ratio of hunger and starvation. The use of molecular breeding techniques has enabled maize researchers to deeply examine the genetic control of drought tolerance and the genetic differences between genotypes to drought stress. Despite the significant progress in molecular genetics, the drought tolerance mechanism is still not fully understood. With the advancements in molecular research, researchers have identified several molecular factors associated with maize tolerance to drought stress. Quantitative trait loci (QTL) mapping and genome-wide association study (GWAS) analysis have led to identifying QTL, and genes linked to drought tolerance in maize that can be ...
Euphytica, 2014
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