Study of Radiophotoluminescence of Eu Doped CaSO4 Phosphor for Gamma Dosimetric Applications

CaSO4:Eu phosphor is synthesised by acid distillation method with varying synthesis parameters for studying its Radiophotoluminescence (RPL) properties for gamma absorbed dose measurements. Five phosphor samples are prepared by varying quantity of solvent, distillation temperature and reaction time. XRD, SEM, particle size analysis and photoluminescence studies are carried out. The characterisation study shows polycrystalline luminescent particles of average size varying from 35 μm to 55 μm. Characteristic emission of Eu3+ is observed around 590, 615 and 620 nm at 242 nm excitation. Gamma dose response of maximum Eu3+ PL intensity sample is studied in the range 10 cGy to 1000 cGy using Co-60 source. Gamma radiation exposure induces conversion of Eu3+ to Eu2+ giving luminescence at 385 nm with 320 nm excitation. Repetitive measurements of gamma exposed samples are carried out and no significant fading is observed within one week of post-irradiation. The phosphor has the potential to be used for gamma dosimetry

Strategy for downy mildew resistance breeding in pearl millet in India

Downy mildew (DM) caused by Sclerospora graminicola is a widespread and economically most important disease of pearl millet causing substantial annual yield losses, particularly in single-cross F1 hybrids in India. Currently, in India about 50% of the 9 million ha under pearl millet cultivation is grown with more than 70 hybrids in which DM incidence has been highly variable, with some hybrids showing more than 90% incidence in farmers' fields. With increasing area under hybrid cultivation since the 1970s the disease has become more severe due to evolution of new virulent pathotypes in response to new hybrid genotypes. At ICRISAT, breeding for DM resistance using conventional pedigree breeding and more recently marker-assisted backcross breeding has been successful, and a large number of disease resistant hybrids have been developed and deployed. This has, to a large extent, helped in arresting the occurrence of widespread DM epidemics since the 1990s. In view of the increasing severity of the disease and evolution of new more virulent pathotypes, there is a need to develop a long-term DM resistance breeding strategy in India. In this paper, we discuss various aspects of the pearl millet-DM pathosystem, factors that influence disease resistance breeding and suggest short-, medium- and long-term strategies for DM resistance breeding

Genetic Gains in Pearl Millet in India: Insights Into Historic Breeding Strategies and Future Perspective

Pearl millet (Pennisetum glaucum R. Br.) is an important staple and nutritious food crop in the semiarid and arid ecologies of South Asia (SA) and Sub-Saharan Africa (SSA). In view of climate change, depleting water resources, and widespread malnutrition, there is a need to accelerate the rate of genetic gains in pearl millet productivity. This review discusses past strategies and future approaches to accelerate genetic gains to meet future demand. Pearlmillet breeding in India has historically evolved very comprehensively from open-pollinated varieties development to hybrid breeding. Availability of stable cytoplasmic male sterility system with adequate restorers and strategic use of genetic resources from India and SSA laid the strong foundation of hybrid breeding. Genetic and cytoplasmic diversification of hybrid parental lines, periodic replacement of hybrids, and breeding disease-resistant and stress-tolerant cultivars have been areas of very high priority. As a result, an annual yield increase of 4% has been realized in the last three decades. There is considerable scope to further accelerate the efforts on hybrid breeding for drought-prone areas in SA and SSA. Heterotic grouping of hybrid parental lines is essential to sustain long-term genetic gains. Time is now ripe for mainstreaming of the nutritional traits improvement in pearl millet breeding programs. New opportunities are emerging to improve the efficiency and precision of breeding. Development and application of high-throughput genomic tools, speed breeding, and precision phenotyping protocols need to be intensified to exploit a huge wealth of native genetic variation available in pearl millet to accelerate the genetic gains

Emerging research priorities in pearl millet

Pearl millet (Pennisetum glaucum) is grown on more than 27 million ha in some of the most marginal environments of Africa (17 million ha) and Asia (10 million ha) with India having the largest area (9 million ha). Based on the rainfall patterns and the latitude, pearl millet area in India is divided into three agroclimatic zones: the arid zone (A1 zone) in northwestern India, which includes parts of Rajasthan, Gujarat and Haryana, receiving <400 mm of the annual rainfall; the A zone, which includes the remainder of northern and western India; and B zone in peninsular India, receiving >400 mm annual rainfall (Yadav et al. 2011). Farmers in these three zones have varied plant and grain trait preferences, which change over time in response to changes in the farming systems, consumer needs and environmental factors. This calls for periodic reprioritization of plant and grain traits

Harnessing wild relatives of pearl millet for germplasm enhancement: Challenges and opportunities

Pearl millet [Pennisetum glaucum (L.) R. Br.] is one of the world’s hardiest warmseason cereal crop and is cultivated mainly in the semi-arid tropics of Asia and Africa for food, feed, fodder, and brewing. It is mainly cultivated for its gluten-free grains with high content and better quality of nutrients. Pearl millet is a resilient crop that can produce grain and biomass under harsh conditions like low fertility, erratic rainfall, acidic and saline soils, and the hottest climates. However, biotic stresses such as downy mildew and blast diseases and abiotic stresses, especially drought and seedling- and flowering-stage heat stress, pose constant threat to the realization of yield potential of this crop. To make further improvement in threshold level of abiotic and biotic stress tolerance, breeders are looking for novel genes in diverse germplasm sources. Crop wild relatives (CWRs) could be a source of novel genes that are important for diversification of the genetic base of pearl millet. A stage-gate process is proposed for the efficient management of prebreeding programs using CWRs as a source of germplasm diversity and improvement. This article explains the various strategies for capturing and using alleles for climate resilience traits improvement. This article covers breeders’ perspectives on importance of using CWRs as germplasm source for crop improvement. This article also describes the availability of CWRs, characterization of new traits and the strategies to be applied for the identification and introduction of genes of interest in elite breeding lines and commercial varieties and hybrids of pearl millet

Pearl Millet Seed Production and Processing

Seed is the vital input and driver in crop production, as seed quality determines the return on investment made on other inputs like fertilizer, irrigation, pesticide, labour etc. A poor seed quality will result in poor return despite best investment on other farm inputs, which, implies that utmost attention must be given to the use of quality seed in crop production. Therefore, every country needs a robust seed production and supply chain system as one of the key components of sustainable growth in agricultural production. A robust seed production programme is central to providing high quality seeds of improved hybrids, pure-line cultivars and open-pollinated varieties (OPVs) for agricultural development, and food security. High quality in case of seed refers to high genetic purity (true to type), high physical purity (freedom from objectionable weeds, other crops’ seeds, inert matter etc.) and high seed vigour and germination in addition to freedom from seed-borne diseases..

Downy Mildew of Pearl Millet and its Management

Pearl millet (Pennisetum glaucum [L.] R. Br.) is the third most important rainfed cereal crop of India grown over 9 million hectares with an annual production of 9.5 million tonnes (Yadav and Rai, 2013). Globally, it is the sixth most important cereal grain cultivated on more than 30 million hectares which accounts for approximately 50% of world’s millet production. Though the most of the crop area is in Asia (>10 m ha) and Africa (about 18 m ha), pearl millet cultivation is being expanded in some of the non-traditional areas, with Brazil having the largest area (about 2 m ha). It is also being experimented as a grain and forage crop in the USA, Canada, Mexico, the West Asia and North Africa (WANA), and Central Asia. Pearl millet, being a C4 plant, has a very high photosynthetic efficiency and dry matter production capacity. It is usually grown under the most adverse agro-climatic conditions where other crops like sorghum and maize fail to produce economic yields. Besides, pearl millet has a remarkable ability to respond to favourable environments because of its short developmental stages and capacity for high growth rate, thus making it an excellent crop for short growing seasons under improved crop management..

Use of wild Pennisetum species for improving biotic and abiotic stress tolerance in pearl millet

Pearl millet [Pennisetum glaucum (L.) R. Br.] is one of the world’s hardiest warmseason cereal crop cultivated for food and animal feed in the semi-arid tropics of Asia and Africa. This crop faces terminal drought during rainy and flowering-stage heat stress during summer seasons. Blast is emerging as a serious threat affecting its production and productivity in India. Using wild P. violaceum (Lam) Rich. and pearl millet cultivars, prebreeding populations were developed following backcross method. These populations were evaluated in target ecologies in India at three locations during the 2018 summer season for flowering-stage heat stress and at two locations during the 2018 rainy season for terminal drought stress.Atotal 18 introgression lines (ILs) from Population (Pop) 3 exhibited improved seed set under high heat stress vs. the cultivated parent, whereas no IL was better than the cultivated parent in Pop 4. Under rainfed conditions at Hisar and Bawal, India, 19 ILs from Pop 3 and 16 ILs from Pop 4 showed significantly higher dry fodder yield than the cultivated parents. Further, screening of ILs for five diverse pathotype isolates—Pg 45, Pg 138, Pg 186, Pg 204, and Pg 232—of blast resulted in the identification of resistant ILs. Use of these promising ILs in breeding programs will assist in developing new varieties and hybrids with improved tolerance to biotic and abiotic stresses. The study indicated the genetic differences between the parents involved in crossing and also highlighted the importance of precise phenotyping of wild species for target trait prior to use in prebreeding work

Genetic enhancement for flowering period heat tolerance in peart millet (Pennisetum glaucum L.(R.) Br.)

Pearl millet, basically a rainfed crop worldwide, is increasingly being cultivated in summer season in north western parts of India where air temperatures during flowering time often exceed 42 degree Celsius..