Gamma ray induced positive alterations in morphogenetic and yield attributing traits of finger millet (Eleusine coracana (L.) Gaertn.) in M2 generation

Induced mutagenesis by gamma rays plays a potent promising technology to be applied for crop improvement through breeding methods, especially in tiny florets possessing self- pollinated plants such as cereals. Finger millet (Eleusine coracana (L.) Gaertn.) which always ensured for valuable nutrients, as well as famine tolerant crop to supply food for global population throughout the year. The present study was performed to assess the spectrum and frequency of macro mutants induced by gamma radiations in M2 generation finger millet. The chlorophyll mutants viz., albina, xantha, chlorina and viridis and morphological mutants such as tall, dwarf, bushy, brittle stalk and broad leaf were recorded in different doses. Among the mutagen doses 600 Gy dose induced maximum increase in mean values and phenotypic and genotypic coefficients of variation for the plant height (cm), number of leaves per plant, leaf length (cm), number of tillers per plant, number of panicles per plant, panicle length, days to 50% flowering, and 1000 seeds weight. Except for panicle number/plant and 1000 seed weight, all traits showed high heritability in all doses. The results revealed a progressive decrease in mean values of quantitative traits with the increase in doses. The present study provides an idea about the optimum dose of gamma rays from a pool of doses that could be employed in future breeding programmes

Performance evaluation of induced mutant lines of black gram (Vigna mungo (L.) Hepper)

Article Details: Received: 2020-01-12      |      Accepted: 2020-03-02      |      Available online: 2020-06-30https://doi.org/10.15414/afz.2020.23.02.70-77 Present investigation was carried out to explore the possibility of inducing genetic variability for yield and yield contributing traits in well-adapted variety PU-19 of black gram (Vigna mungo (L.) Hepper) following mutagenesis with methyl methane sulfonate (MMS), sodium azide (SA) and hydrazine hydrate (HZ). A considerable increase in mean values for fertile branches per plant, pods per plant and total plant yield was noticed among the mutant lines in M4 and M5 generations. Estimates of genotypic coefficient of variation, heritability and genetic advance for yield and yield components were also recorded to be higher compared to control. MMS followed by SA and HZ showed highest mutagenic potential for improving total plant yield of black gram var. PU-19. Treatment concentration 0.3% was found to be most effective in generating significant increase in total plant yield of black gram var. PU-19. The increased genetic variability for yield and yield components indicates the ample scope of selection for superior mutants in subsequent generations due to preponderance of additive gene action.Keywords: black gram, mutagenesis, chemical mutagens, genetic variability, yield componentsReferences AHLOOWALIA, B., MALUSZYNSKI, M. and NICHTERLEIN, K.(2004). Global impacts of mutation derived varieties. Euphytica, 135, 187. ANNUAL REPORT (2016–2017). In: Government of India, Ministry of Agriculture and Farmers Welfare, Department of Agriculture, Cooperation and Farmers Welfare, Directorate of Pulses Development, Vindhyachal Bhavan, India. AUTI, S. G. (2012). Induced morphological and quantitative mutants in mungbean. Biorem. Biodiv. Bioavail., 6 (Special Issue), 27-39. BHATIA, C. R. and SWAMINATHAN, M. S. (1962). 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Grasslands Development for Ecotourism: Aesthetic Perspectives

Grasslands (also known as savanna, prairie, steppe, and pampas) are natural or seminatural areas encompassing vegetation belonging to the family Poaceae as the most dominant vegetation, while, sedges and rushes may also constitute a minor proportion. These provide numerous natural products such as food feed medicinal raw material, and honey along with nonproduct-based ecosystem services. Grasslands in lowlands and mountains either in natural form or developed landscape can provide an added value in terms of ecotourism opportunities owing to having huge esthetic and recreational potential compared to uniform agricultural areas. Grasslands characterized by high species and habitat diversity-based ecotourism are nature-based tourism whereby people visit natural or developed areas for recreation, sight-seeing, permitted and controlled hunting, on-site purchase of organic products, etc., and are usually managed by adopting sustainable practices. Ecotourism generates multifaceted economic advantages for local communities such as direct sale of products to tourists. However, ecotourism may also have a variety of negative impacts when the tourists’ number multiplies which leads to overuse of resources. The most pronounced challenges confronted to the development of grasslands for ecotourism include lack of community cooperation, careless herders, need of hefty investment, and absence of trained human capital along with climate change and loss of biodiversity

Conventional and new-breeding technologies for improving disease resistance in lentil (Lens culinaris Medik)

Lentil, an important cool season food legume, is a rich source of easily digestible protein, folic acid, bio-available iron, and zinc nutrients. Lentil grows mainly as a sole crop in the winter after harvesting rice in South Asia. However, the annual productivity is low due to its slow growth during the early phase, competitive weed infestation, and disease outbreaks during the crop growth period. Disease resistance breeding has been practiced for a long time to enhance resistance to various diseases. Often the sources of resistance are available in wild crop relatives. Thus, wide hybridization and the ovule rescue technique have helped to introgress the resistance trait into cultivated lentils. Besides hybridization, induced mutagenesis contributed immensely in creating variability for disease tolerance, and several disease-resistant mutant lines have been developed. However, to overcome the limitations of traditional breeding approaches, advancement in molecular marker technologies, and genomics has helped to develop disease-resistant and climate-resilient lentil varieties with more precision and efficiency. This review describes types of diseases, disease screening methods, the role of conventional and new breeding technologies in alleviating disease-incurred damage and progress toward making lentil varieties more resilient to disease outbreaks under the shadow of climate change

Mechanisms of Genome Maintenance in Plants: Playing It Safe With Breaks and Bumps

Maintenance of genomic integrity is critical for the perpetuation of all forms of life including humans. Living organisms are constantly exposed to stress from internal metabolic processes and external environmental sources causing damage to the DNA, thereby promoting genomic instability. To counter the deleterious effects of genomic instability, organisms have evolved general and specific DNA damage repair (DDR) pathways that act either independently or mutually to repair the DNA damage. The mechanisms by which various DNA repair pathways are activated have been fairly investigated in model organisms including bacteria, fungi, and mammals; however, very little is known regarding how plants sense and repair DNA damage. Plants being sessile are innately exposed to a wide range of DNA-damaging agents both from biotic and abiotic sources such as ultraviolet rays or metabolic by-products. To escape their harmful effects, plants also harbor highly conserved DDR pathways that share several components with the DDR machinery of other organisms. Maintenance of genomic integrity is key for plant survival due to lack of reserve germline as the derivation of the new plant occurs from the meristem. Untowardly, the accumulation of mutations in the meristem will result in a wide range of genetic abnormalities in new plants affecting plant growth development and crop yield. In this review, we will discuss various DNA repair pathways in plants and describe how the deficiency of each repair pathway affects plant growth and development

Mutagenic effect of gamma rays on induced mutation and principal component analysis of yield characters on green gram in M2 generation

The present study was aimed to evaluate the effect of gamma irradiation on green gram through chlorophyll mutation frequency, leaf mutation frequency, mutagenic effectiveness and efficiency and principal component analysis. Eight different types of chlorophyll mutants, namely albino, aurea, striata, tigrina, xantha, chlorina, viridis, xanthaviridis and variegated were observed at different doses of gamma irradiation in M2 generation. Albino showed the highest frequency percentage (0.229) followed by Viridis (0.163) and Xantha (0.131) and the highest frequency was noted at 500 Gray (Gy). Though, chlorophyll mutants can be lethal in nature, they increase genetic variability and induce new traits. Leaf mutant is another key indicator for induced mutations that induce leaf morphology changes and the highest frequency was noted in 500 Gy. Among the mutagenic treatments, the mutagenic effectiveness shows the maximum at 100 Gy and efficiency shows at 500 Gy. This indicated that low to moderate doses are more effective for induced mutation. This was also confirmed by Principal Component Analysis (PCA) results, which specified that gamma irradiation of 500 Gy indicated that the first five principal components were attributed to 70.82% total variability of traits studied. From this, the experimental finding evidently showed that 500 Gy of gamma irradiation, an optimum dose, resulted in considerable variation in all the parameters analyzed

Improving French bean yield potential through induced mutagenesis using EMS and SA

IntroductionFrench bean (Phaseolus vulgaris L.) holds global significance as one of the most consumed legumes, with commercial value surpassing that of all other legume crops combined. In India, the consumption of French beans has grown steadily, especially in the North Eastern region, driven by heightened consumer interest in its nutritional benefits. Considering these factors, we initiated an induced mutagenesis program to enhance the genetic diversity of locally grown French bean genotypes, traditionally cultivated for their superior adaptability.MethodsTo achieve this, we initiated an induced mutagenesis program. Seeds from the village seed stock were subjected to treatments with varying doses of ethyl methane sulfonate (EMS) ranging from 0.1% to 0.4% and sodium azide (SA) from 0.1% to 0.4%. The objective was to increase yield potential and enhance genetic diversity.ResultsThe treatment with EMS and SA led to a non-specific, dosage-independent reduction in biophysiological characteristics in French bean mutants. Notably, the 0.4% SA treatment significantly inhibited germination and fertility, causing a decrease in chlorophyll (10.02 mg. g-1 FW) and carotenoid (1.57 mg. g-1 FW) levels. This suggests a disruption in genes associated with chlorophyll and carotenoid synthesis. However, in the M2 generation, the mutagenic treatments substantially improved yield and associated traits. The highest pod yield per plant was recorded at 79.50 gm for the 0.2% EMS treatment. A character association study revealed strong correlations (0.217 to 0.995) between pod yield and other agronomic traits.DiscussionThe results indicate that selecting mutants based on these traits in populations treated with EMS and SA can significantly increase crop yield. The 0.2% SA and 0.2% EMS M2 mutant populations exhibited the highest induced variability, making them ideal for selecting higher-yielding mutant lines for further breeding generations. The increased yields in these mutant lines, derived from a local cultivar, show promise for meeting the growing demand for French bean production through their widespread cultivation

Effect of TiB2 on the Mechanical and Tribological Properties of Marine Grade Aluminum Alloy 5052: An Experimental Investigation

Aluminum Alloy 5052 is one of the excellent corrosion resistant alloys among the Aluminum 5000 series alloys. Despite the favourable corrosion resistance, it exhibits low resistance to wear and perform poorly in various tribological applications.This study attempts to investigate the impact of TiB2 reinforcement on the mechanical and tribological properties of Aluminum Alloy 5052 matrix alloy, fabricated using the stir casting technique. Composites with varying weight percentages (0, 2.5, 5 and 7.5 wt. %)of TiB2 were prepared. Vicker's hardness testing was conducted to assess the effect of TiB2 content on composite hardness.Hardness of composites increased from 65.5 to 85.16 HV in tandem with the TiB2 content depicting a rise of about 30 %. Tribological properties were studied through dry sliding wear tests using a pin-on-disc tribometer, with varying loads (10 N and 50 N)and sliding speeds (1 m/s and 3 m/s). The results demonstrate that the addition of TiB2 significantly improves the wear resistance of the composites,being optimum in composite with 5 wt. % of TiB2. A maximum increase of about 36 % in wear resistance was observed at high load and high-speed conditions corresponding to 5 wt. % TiB2 concentration. FESEM analysis revealed distinct wear modes and the role of TiB2 in changing the wear mechanism from abrasion to delamination. This study underscores the pivotal role of TiB2 in enhancing the mechanical and tribological properties of Aluminum Alloy5052, expanding its application scope, particularly in lightweight engineering applications in general and marine in particular