Genetics And Interrelationship of Yield and Yield Related Attributes in Some Genotypes of Safflower (Carthamus Tinctorius L.) Under Rainfed Conditions

In order to estimate variability, heritability, genetic advance and relationship of grain yield with other yield related attributes, the experiments were carried out in field research Area of Barani Agricultural Research Institute, Chakwal, Pakistan during two rabi growing seasons 2011-12 and 2012-13. The experimental materials were comprised of 40 genotypes of safflower and were sown in randomized complete block design with three replications each year. The analysis of variance showed that all the safflower genotypes were significantly different for all the traits studied except days to physiological maturity. Among the attributes studied the estimates of phenotypic coefficient of variation (PCV) were generally higher than the genetic coefficient of variation (GCV).  Highest GCV was found in grain filing rate plant-1 (49.34 & 48.25) followed by seed yield plant-1 (49.09 & 48.18) during 2011-12 & 2012-13 respectively. Grain filing rate plant-1 showed maximum PCV (49.78 & 48.96) followed by seed yield plant-1 (49.64 & 49.44) during both years (2011-12 & 2012-13) respectively. The high heritability coupled with high genetic advance was measured in biological yield plant-1, harvest index (%), number of heads plant-1, and seed yield plant-1. These results revealed that high estimates of heritability and genetic advance for these traits would be helpful for the plant breeders to select the suitable combination and to achieve the enviable level of seed yield potential in safflower under arid environment conditions. The correlation results of two year studies revealed that seed yield plant-1 had significant and positive relationship with days to maturity, plant height, biological yield plant-1, number of seeds head-1, 1000-grain weight, grain filing rate plant-1, effective head weight, number of primary branches  plant-1 and plant height. On the other hand, days to 50% flowering, days to physiological maturity, number of seeds head-1, seed weight head-1 and 1000- grain weight showed low heritability with low genetic advance. Key words: Safflower, Rainfed, Variability, Heritability, Genetic Advance, Correlatio

Insights into Drought Stress Signaling in Plants and the Molecular Genetic Basis of Cotton Drought Tolerance

Drought stress restricts plant growth and development by altering metabolic activity and biological functions. However, plants have evolved several cellular and molecular mechanisms to overcome drought stress. Drought tolerance is a multiplex trait involving the activation of signaling mechanisms and differentially expressed molecular responses. Broadly, drought tolerance comprises two steps: stress sensing/signaling and activation of various parallel stress responses (including physiological, molecular, and biochemical mechanisms) in plants. At the cellular level, drought induces oxidative stress by overproduction of reactive oxygen species (ROS), ultimately causing the cell membrane to rupture and stimulating various stress signaling pathways (ROS, mitogen-activated-protein-kinase, Ca2+, and hormone-mediated signaling). Drought-induced transcription factors activation and abscisic acid concentration co-ordinate the stress signaling and responses in cotton. The key responses against drought stress, are root development, stomatal closure, photosynthesis, hormone production, and ROS scavenging. The genetic basis, quantitative trait loci and genes of cotton drought tolerance are presented as examples of genetic resources in plants. Sustainable genetic improvements could be achieved through functional genomic approaches and genome modification techniques such as the CRISPR/Cas9 system aid the characterization of genes, sorted out from stress-related candidate single nucleotide polymorphisms, quantitative trait loci, and genes. Exploration of the genetic basis for superior candidate genes linked to stress physiology can be facilitated by integrated functional genomic approaches. We propose a third-generation sequencing approach coupled with genome-wide studies and functional genomic tools, including a comparative sequenced data (transcriptomics, proteomics, and epigenomic) analysis, which offer a platform to identify and characterize novel genes. This will provide information for better understanding the complex stress cellular biology of plants

Genetic characterization of flowering and phytochrome genes in peanut (Arachis hypogaea L.) for early maturity

Peanut (Arachis hypogaea L.) production and cropping pattern is highly influenced by the climatic factors including temperature and rain pattern fluctuations. It is one of the most important cash crop in the rain fed areas of Pakistan and its production, under changing climatic conditions, that can be improved by developing short duration varieties. The present study was based on the molecular characterization of the maturity associated gene families in the peanut under two light conditions. Genomic analysis based on the in silico study of important gene families for early maturity associated attributes like flowering time, their pattern, duration and photoperiodism was done for a comprehensive mapping of maturity related genes. Phytochromes genes Phy A, Phy B and Phy E and flowering genes FT2a, Ft5a and COL2 were selected for in silico characterization for protein based analysis including Multiple Sequence Alignment (MSA), and Neighbor Joining (NJ) tree. MSA and NJ trees of the peanut with Arabidopsis thaliana and Glycine max showed a clear picture of the phylogenetic relationship on the basis of selected gene proteins. Expression profile of phytochrome and flowering genes revealed that photoperiod conditions i.e. short and long days, have great influence on the Phy A, Phy B and Phy E, Ft2a, FT5a and COL2 gene expression pattern. In current study, the relative expression of all studied genes was found higher in short day light condition at flower initiation stage of the plants than in the long light day condition with exception of COL2 gene protein. The molecular characterization based on the in silico study of the particular genes and qPCR based gene expression profiling of the selected genes provided an evidence of the role of these genes and their comparative analysis under two photoperiodic conditions

Induction and identification of colchicine induced polyploidy in Gladiolus grandiflorus ‘White Prosperity’

Gladiolus is one of the most important lucrative cut flower crops that is commercially cultivated worldwide due to its various spike forms, size, and shape and color combinations. In order to further increase the commercial and horticultural value by improving the ornamental traits of gladiolus ‘White Prosperity’, polyploidy was induced by soaking gladiolus corms in different colchicine concentrations (0.1%, 0.2% and 0.3%) for 24 h. Different colchicine concentrations had a little effect on sprouting and survival percentage but it significantly delayed the emergence of sprouts. About one third decreases in plant height along with reduction in number of leaves per plant, leaf area, length and width, chlorophyll content, diameter and number of cormlets per corm was observed in treated plants. Colchicine at 0.1% concentration improved the ornamental value of gladiolus by increasing vase life whereas colchicine at 0.3% was effective in increasing floret diameter. However, the colchicine treated plants exhibited delayed and reduced percentage of flowering corms. Pollen and stomatal study was done for the identification of polyploidy and it showed that both pollen and stomata size were increased while stomatal density and pollen fertility was significantly reduced in polyploid plants. Induction of polyploidy (mixoploids + octoploids) was achieved in all concentrations, however 0.2% and 0.3% concentrations of colchicine were effective for producing large number of polyploid plants. But at 0.1% concentration of colchicine, majority of plants did not show any change in their original ploidy level (tetraploid). These putative polyploids may be helpful for further improvement in ornamental and horticultural value of gladiolus

Response of Olive Shoots to Salinity Stress Suggests the Involvement of Sulfur Metabolism

Global warming has two dangerous global consequences for agriculture: drought, due to water scarcity, and salinization, due to the prolonged use of water containing high concentrations of salts. Since the global climate is projected to continue to change over this century and beyond, choosing salt-tolerant plants could represent a potential paramount last resort for exploiting the secondary saline soils. Olive is considered moderately resistant to soil salinity as compared to other fruit trees, and in the present study, we investigated the influence of NaCl solutions (ranging from 0 to 200 mM) in a salt-tolerant (cv Canino) and two of its transgenic lines (Canino AT17-1 and Canino AT17-2), overexpressing tobacco osmotin gene, and in a salt-sensitive (Sirole) olive cultivar. After four weeks, most of the shoots of both Canino and Sirole plants showed stunted growth and ultimate leaf drop by exposure to salt-enriched media, contrary to transgenic lines, that did not show injuries and exhibited a normal growth rate. Malondialdehyde (MDA) content was also measured as an indicator of the lipid peroxidation level. To evaluate the role of the S assimilatory pathway in alleviating the adverse effects of salt stress, thiols levels as well as extractable activities of ATP sulfurylase (ATPS) and O-acetyl serine(thiol)lyase (OASTL), the first and the last enzyme of the S assimilation pathway, respectively, have been estimated. The results have clearly depicted that both transgenic lines overexpressing osmotin gene coped with increasing levels of NaCl by the induction of S metabolism, and particularly increase in OASTL activity closely paralleled changes of NaCl concentration. Linear correlation between salt stress and OASTL activity provides evidence that the S assimilation pathway plays a key role in adaptive response of olive plants under salt stress conditions