Studies on drought tolerance in maize inbred lines using morphological and molecular approaches

A set of hundred homozygous maize inbred lines were analyzed for drought toleranceby studying twenty-four traits related to maturity, morphological, physiological, yield, quality and few root traits. Evaluation confirmed a wide range of variability revealing significant response of main effects (lines, irrigations and years and their respective digenic and trigenic interactions). These lines were subjected to different stress regimes over years leading to identification of fifteen elite lines which performed well under droughtstress showing inbuilt drought tolerance. A set of 32 SSR markers, having genome-wide coverage, were chosen for genotyping the inbred lines. These markers generated a total of 239 polymorphic alleles with an average of 7.47 alleles per locus. The minimum and maximum PIC value was 0.886 and 0.608 with a mean of 0.782. The coefficient of genetic dissimilarity ranged from 0.215 to 0.148. DARwin derived cluster analysis grouped 15 elite maize lines in three major clusters with five lines each in cluster-III and II and four lines in cluster-I with KDM-361A as root. Molecular diversity however, confirmed diverse genetic nature of six lines (KDM-372, KDM-343A, KDM-331, KDM-961, KDM-1051 and KDM-1156) showing drought tolerance. Exploitation of identified elite lines in a crossing program involving all possible combinations would help to develop hybrids with inbuilt mechanism to drought tolerance. Markers viz., umc -1766, umc-1478 and phi-061 recorded PIC >8 and alleles per locus more than 9 and therefore, discriminated the set of lines more efficiently. Genotyping data complemented by morpho- hysiological parameters were used to identify a number of pair-wise combinations for the development of mapping population segregating for drought tolerance and potential heterotic pairs for the development of drought tolerant hybrids.

Breeding strategies for improving growth and yield under waterlogging conditions in maize: A review

Waterlogging, caused by flooding, excessive rains and poor drainage is a serious abiotic stress determining crop productivity worldwide. Maize (Zea mays L) is a basic food grain in many areas and several cultures and is culti- vated under much diverse agro-climatic zones extending from subtropical to cooler temperate regions. Therefore, the crop remains open to varied types of biotic as well as abiotic stresses. Among various abiotic stresses, water- logging is one of the most important constraints for maize production and productivity. Breeding for improved wa- terlogging tolerance includes modification of plant morphology, use of tolerant secondary traits and development of resistant varieties through conventional breeding and biotechnological approaches. A successful programme in conventional breeding should involve the integration of several criteria into one selection index and also successful breeding programmes for improved tolerance to submergence stress frequently combine two or more breeding strategies. Marker assisted selection (MAS) is an effective approach to identify genomic regions of crops under stress and construction of molecular linkage maps enable carry out pyramiding of desirable traits to improve sub- mergence tolerance through MAS

Breeding Maize for Food and Nutritional Security

Maize occupies an important position in the world economy, and serves as an important source of food and feed. Together with rice and wheat, it provides at least 30 percent of the food calories to more than 4.5 billion people in 94 developing countries. Maize production is constrained by a wide range of biotic and abiotic stresses that keep afflicting maize production and productivity causing serious yield losses which bring yield levels below the potential levels. New innovations and trends in the areas of genomics, bioinformatics, and phenomics are enabling breeders with innovative tools, resources and technologies to breed superior resilient cultivars having the ability to resist the vagaries of climate and insect pest attacks. Maize has high nutritional value but is deficient in two amino acids viz. Lysine and Tryptophan. The various micronutrients present in maize are not sufficient to meet the nutritive demands of consumers, however the development of maize hybrids and composites with modifying nutritive value have proven to be good to meet the demands of consumers. Quality protein maize (QPM) developed by breeders have higher concentrations of lysine and tryptophan as compared to normal maize. Genetic level improvement has resulted in significant genetic gain, leading to increase in maize yield mainly on farmer’s fields. Molecular tools when collaborated with conventional and traditional methodologies help in accelerating these improvement programs and are expected to enhance genetic gains and impact on marginal farmer’s field. Genomic tools enable genetic dissections of complex QTL traits and promote an understanding of the physiological basis of key agronomic and stress adaptive and resistance traits. Marker-aided selection and genome-wide selection schemes are being implemented to accelerate genetic gain relating to yield, resilience, and nutritional quality. Efforts are being done worldwide by plant breeders to develop hybrids and composites of maize with high nutritive value to feed the people in future

Reactive Oxygen Species, Oxidative Damage and Their Production, Detection in Common Bean (<em>Phaseolus vulgaris</em> L.) under Water Stress Conditions

Reactive oxygen species (ROS) being small and highly reactive oxygen containing molecules play significant role in intracellular signaling and regulation. Various environmental stresses lead to excessive production of ROS causing progressive oxidative damage and ultimately cell death. This increased ROS production is, however, tightly controlled by a versatile and cooperative antioxidant system that modulates intracellular ROS concentration and controls the cell’s redox status. Furthermore, ROS enhancement under stress serves as an alarm signal, triggering acclimatory/defense responses via specific signal transduction pathways involving H2O2 as a secondary messenger. Nevertheless, if water stress is prolonged over to a certain extent, ROS production will overwhelm the scavenging action of the anti-oxidant system resulting in extensive cellular damage and death. DAB (3,3′-diaminobenzidine) test serves as an effective assessment of oxidative damage under stress. It clearly differentiates the lines on the basis of darker staining of leaves under water stress. The lines showing greater per cent reduction in yield parameters show greater staining in DAB assay underlining the reliability of using this assay as a reliable supplement to phenotyping protocols for characterizing large germplasm sets

Quantitative response of wheat to sowing dates and irrigation regimes using ceres-wheat model

An experiment was conducted at Punjab Agricultural University, Ludhiana during 2014–15 and 2015–16, keeping four sowing dates {25th Oct (D1), 10th Nov (D2), 25th Nov (D3) and 10th Dec (D4)} in main plots and five irrigation schedules {irrigation at 15 (FC15), 25 (FC25), 35 (FC35) and 45 (FC45) % depletion of soil moisture from field capacity (FC) and a conventional practice} in sub plots. The objective of the study was to evaluate the performance of CERES-Wheat model for simulating yield and water use under varying planting and soil moisture regimes. The simulated and observed grain yield was higher in D1, with irrigation applied at FC15 as compared to all other sowing date and irrigation regime combinations. Simulated grain yield decreased by 19% with delay in sowing from 25th October to 10th December because of 8% reduction in simulated crop evapotranspiration. Simulated evapotranspiration decreased by 16%, wheat grain yield by 23% and water productivity by 15% in drip irrigation at 45% depletion from field capacity as compared to drip irrigation at 15% of field capacity. It was further revealed that the model performed well in simulating the phenology, water use and yield of wheat

Anesthesia and sedation in pediatric gastrointestinal endoscopic procedures: A review

Gastrointestinal (GI) endoscopic procedure has become an essential modality for evaluation and treatment of GI diseases. Intravenous (IV) sedation and General Anesthesia (GA) have both been employed to minimize discomfort and provide amnesia. Both these procedures require, at the very least, monitoring of the level of consciousness, pulmonary ventilation, oxygenation and hemodynamics. Although GI endoscopy is considered safe, the procedure has a potential for complications. Increased awareness of the complications associated with sedation during GI endoscopy in children, and involving the anesthesiologists in caring for these children, may be optimal for safety. Belonging to a younger age group, having a higher ASA class and undergoing IV sedation were identified as risk factors for developing complications. Reported adverse events included inadequate sedation, low oxygen saturation, airway obstruction, apnea needing bag mask ventilation, excitement and agitation, hemorrhage and perforation. A complication rate of 1.2% was associated with procedures performed under GA, as compared to 3.7% of complications associated with IV sedation. IV sedation was seen to be independently associated with a cardiopulmonary complication rate 5.3% times higher when compared to GA. GA can therefore be considered safer and more effective in providing comfort and amnesia

Isolation, molecular characterization and prevalence of Clostridium perfringens in sheep and goats of Kashmir Himalayas, India

Aim: The study was conducted to report the occurrence of the Clostridium perfringens in sheep and goats of the Kashmir valley for the 1st time and to characterize them molecularly with respect to toxin genes to determine the prevalence of the various toxinotypes. Materials and Methods: A total of 177 samples (152 from sheep and 25 from goats) collected from healthy, diarrheic animals, and morbid material of animals suspected to have died of enterotoxaemia were screened for C. perfringens toxinotypes. The presumptive positive isolates were confirmed using 16S rRNA gene-based polymerase chain reaction (PCR). All the confirmed isolates were screened for six toxin genes, namely; cpa, cpb, etx, cpi, cpb2, and cpe using a multiplex PCR. Results: The PCR amplification of 16S rRNA gene revealed that out of 177 samples collected, 125 (70.62%) were found positive for C. perfringens, of which 110 (72.36%) were from sheep and 15 (60%) were from goats. The highest prevalence of C. perfringens toxinotype D was observed in lambs (56.16%) and kids (46.16%) followed by 3.84% in adult sheep while it was absent in samples obtained from adult goats. The multiplex PCR revealed that 67 (60.90%) isolates from sheep and 8 (53.33%) isolates from goats belonged to toxinotype A, while 43 (39.09%) isolates from sheep and 7 (46.66%) isolates from goats were detected as toxinotype D. None of the isolates was found to be toxinotype B, C, or E. All the C. perfringens toxinotype A isolates from sheep were negative for both cpb2 and cpe genes, however, 27.90% toxinotype D isolates from sheep carried cpb2 gene, and 6.97% possessed cpe gene. In contrast, 12.50% C. perfringens toxinotype A isolates from goats harbored cpb2 and cpe genes while 14.28% isolates belonging to toxinotype D carried cpb2 and cpe genes, respectively. Conclusion: The high prevalence of C. perfringens was observed, even in day-old lambs. The toxinotypes A and D are prevalent in both sheep and goats. The severity of disease and mortality may be associated with the presence of minor toxins in both the detected toxinotypes

Evaluation of antioxidant activity of crocin, podophyllotoxin and kaempferol by chemical, biochemical and electrochemical assays

The present study was designed to evaluate the antioxidant potential of three natural origin drugs, namely crocin, kaempferol and podophyllotoxin by chemical, biochemical and electrochemical assays. The chemical assay was carried out by DPPH and reducing power assays while the biochemical assay evaluated the lipid peroxidation inhibition capacity, using brain cells as models; the electrochemical characterization was performed by cyclic voltammetry and differential pulse voltammetry using multi-walled carbon nanotube paste electrode (MWCNTPE) in 0.02 M acetate buffer (pH 4.5). The superoxide radical scavenging activity was performed at dropping mercury electrode (DME) in 0.1 M KCl. All the species proved to have antioxidant activity, and particularly, by the electrochemical techniques, it has been shown that these drugs showed scavenging ability on superoxide anion produced by electrochemical reduction of oxygen. The highest scavenging property of crocin may be due to the hydroxyl and glucose moieties that could provide the necessary component as a radical scavenger

Sustainable Fruit Growing: An Analysis of Differences in Apple Productivity in the Indian State of Jammu and Kashmir

Apple is considered as an important fruit crop in temperate regions of the world including India. It is one of the major fruit crops, with a considerable area under cultivation throughout the world and a large associated population. Despite this, the productivity of this important fruit is not up to the expected standard. To gain a practical understanding of the low productivity of apple fruit and its probable causes, a study was undertaken to analyze productivity differentials and their determinants to enable sustainable cultivation. A multistage sampling procedure was adopted to select districts, horticultural zones, and villages, and data were collected from randomly selected apple growers (300). The collected data were empirically analyzed with simple descriptive statistics, logistic regression, polynomial plots, and inferential statistics such as t-tests. The results indicated that apple yields followed a sigmoidal pattern, with the average yield per hectare for the current season as 9.43 t/ha, which depends on experience, education, annual income, and the adoption rate of apple growers. This yield average was significantly lower than the yield of the previous season at a probability level of 1%. To determine the root cause of low productivity, different constraints were studied, creating yield disparities in different quarters; hence, their percentage and value contributions (socioeconomic 11.1%, credit 4.2%, pests and diseases 0.05%, technology 0.9%, extension 2.0%, and market 3.5%) were also established in the study. The study will be of great interest to the relevant authorities in the study area, and the areas globally having similar congenial agro-climatic conditions, who are seeking to address the issues raised in this study through sustainable policy decisions. The different constraints that were the fundamental reasons for low productivity and that prevented the apple growers from adopting innovative techniques/improved practices to increase their yields need to be addressed as a matter of urgency