Screening for pre- and post-anthesis drought responses in selected bread wheat (Triticum aestivum L.) genotypes

ABSTRACT

Wheat genotypes with pre- and post-anthesis drought tolerance offer enhanced yield gains under water-limited environments. This study determined pre- and post-anthesis drought responses of selected bread wheat genotypes in order to identify and select candidate genotypes for breeding. Fifteen genetically differentiated wheat genotypes were evaluated under non-stressed (NS), pre-anthesis drought stress (PrADS) and post-anthesis drought stress (PoADS) in glasshouse (GH) and field (FLD) environments. Data were collected on agronomic and physiological traits including number of days to heading (DTH), days to maturity (DTM), plant height (PH), number of spikelet per spike (NSPS), number of kernels per spike (NKPS), thousand kernel weight (TKW), grain yield (GY) and canopy temperature (CT). Analysis of variance revealed significant effects of genotypes, environments and their interactions for studied traits. Weak and positive correlations were recorded between GY with PH (r?=?0.47 and 0.32), NSPS (r?=?0.37 and 0.52) and TKW (r?=?0.30 and r?=?0.20) under PrADS and PoADS conditions, respectively. Genotypes SMY-006, SMY-008, SMY-016, SMY-042 and SMY-044 were identified with pre- and post-anthesis drought tolerance and high yield potential and suitable yield-component traits. These are useful genetic stocks for breeding or cultivation in water-limited environments to improve yield gains.     

Breeding tepary bean (Phaseolus acutifolius) for drought adaptation: A review

Tepary bean (Phaseolus acutifolius A. Gray) is a relatively higher drought-tolerant crop than common bean (P. vulgaris), serving as genetic resource for food and genetic enhancement of related legumes. Tepary bean production is hampered by cultivation of low yielding and abiotic stress-susceptible cultivars. Targeted selection of agronomic, physiological and biochemical traits that maximizes yield gains using Phaseolus gene pool is useful to develop stress-tolerant and high-performing genotypes. The objective of this review is to provide breeding progress made regarding tepary bean improvement for drought adaptation. Agronomic, physiological and biochemical traits utilized for selection of drought-tolerant genotypes are highlighted. Genetic and genomic resources developed for tepary bean or closely related species such as common bean useful for genetic analysis and breeding are discussed. Opportunities and challenges to facilitate breeding of tepary bean genotypes with improved abiotic stress adaptation are highlighted. This will enable development of drought-tolerant tepary bean genotypes targeting selection of agronomic, physiological and biochemical traits. Use of genetically related and complementary Phaseolus species and marker-assisted selection method is key to developing drought-tolerant genotypes.     

Physiological and molecular evaluation of ten Egyptian barley cultivars under salt stress conditions

Journal of Crop Science and Biotechnology - Ten Egyptian barley cultivars (Giza 129, 132, 123, 127, 2000, 130, 126, 135, 128 and 133) were assessed under 0, 100 and 200 mM NaCl. The...     

Faba bean genomics: current status and future prospects

Faba bean represents a crucial source of protein for food, especially for Mediterranean countries, and local demand for faba bean grains is increasing. The crop is also gaining increased attention as an elite candidate for conservation agriculture. However, the complexity of the faba genome has made progress in breeding programs and molecular studies relatively slow compared with other legume crops. Recent advances in plant genomics have made it feasible to understand complex genomes such as faba bean. With the increase of faba bean consumption in the Middle East region, there is an urgent need to develop elite faba genotypes suitable for arid and semi arid environments, with high yield potential and acceptable nutritional quality. This article highlights the recent advances in legume and faba genomics and its potential to contribute to the above mentioned goal. Emphasis is given on prospects on faba improvements strategies from the Middle East point of view.     

Genetic relationship among selected heat and drought tolerant bread wheat genotypes using SSR markers,agronomic traits and grain protein content

ABSTRACT

Assessing the genetic variation and relationships present in crop germplasm is a pre-requisite for parental selection and breeding. The objective of this study was to determine the genetic relationships present among selected heat and drought tolerant wheat genotypes using simple sequence repeat (SSR) markers, agronomic traits and grain quality parameters to select desirable parents for breeding. Twenty-four agronomically selected wheat genotypes sourced from the International Maize and Wheat Improvement Centre (CIMMYT)’s heat and drought tolerance nursery and four local check varieties were genotyped using 12 selected polymorphic SSR markers. The test genotypes were phenotyped using yield and yield-component traits, and grain protein content (GPC) under non-stressed (NS) and drought-stressed (DS) conditions. Expected heterozygosity mean value of 0.58 indicated moderate genetic diversity for breeding. The studied wheat genotypes were delineated into six genetic groups using cluster analysis. Significant genotypic differences were observed for agronomic traits and GPC under NS and DS conditions. Genetically unrelated breeding parents including LM02, LM13, LM23, LM41, LM44, LM71, LM73 and LM75 were selected for population development and breeding for enhanced grain yield and protein content under heat and drought-stressed environments.     

Genetic variation and genetic advance in cowpea based on yield and yield-related traits

ABSTRACT

The objective of this study was to determine phenotypic variation for yield and yield-related traits among cowpea genotypes and select best candidate genotypes for breeding. Hundred cowpea genotypes were evaluated across two environments using an alpha lattice design with two replications. The pooled data were subjected to analysis of variance, correlation and principal component analyses (PCA). Significant differences were observed among cowpea genotypes for assessed traits. PCA revealed three principal components contributing to 77.75% of the total variation. Grain yield was significantly correlated with most of the traits. The genotypic coefficient of variation was relatively higher, whereas the phenotypic coefficient of variation values were moderate for branch number, seed number per pod, and high for seed number per plant and pod weight per plant. Heritability and genetic advance values respectively ranged from 37.27% to 97.2% and 73.3% to 2242.6% for the studied traits. High direct path coefficient value of 0.71 for pod weight per plant with highly significant correlation with grain yield was observed. The study identified cowpea genotypes such as Glenda RV 465, RV 574, RV 115, RV 28, RV 419, RV 28, RV 419, RV 213, RV 550, RV 470, RV 111, RV 315 and RV 550 with better responses for yield and yield-related traits.     

A novel T177P missense variant in the HSPA8 gene associated with the low tolerance of Awassi sheep to heat stress

Tropical Animal Health and Production - This study was conducted to identify the association of coding variations in the HSPA8 gene with heat stress in two different breeds of sheep. All the coding...