Progress in Modeling Very Low Mass Stars, Brown Dwarfs, and Planetary Mass Objects

We review recent advancements in modeling the stellar to substellar transition. The revised molecular opacities, solar oxygen abundances and cloud models allow to reproduce the photometric and spectroscopic properties of this transition to a degree never achieved before, but problems remain in the important M-L transition characteristic of the effective temperature range of characterizable exoplanets. We discuss of the validity of these classical models. We also present new preliminary global Radiation HydroDynamical M dwarfs simulations.Comment: Submitted to Mem. S. A. It. Supp

Genetic Variability, Diversity and Interrelationship for Twelve Grain Minerals in 122 Commercial Pearl Millet Cultivars in India

Pearl millet contributes to the major source of dietary calories and essential micronutrients intake among rural populations in certain regions of India as its grains are more nutritious than other cereals. The aims of this investigation were to profile cultivar nutrition, diversity and interrelationship for grain minerals (Ca, K, Mg, Na, P, S, Cu, Fe, Mn, Zn, Mo and Ni) among 122 pearl millet hybrids and open-pollinated varieties in India. Trials were evaluated in randomized complete block design with three replications at two locations (Patancheru and Mandor) representing two major cultivation zones. The grain minerals in cultivars exhibited two- to- four-fold variation. Positive and significant correlations were noted among different minerals. A higher magnitude of positive and significant association between Fe and Zn (r = 0.71, P\0.01) and with other minerals suggested the existence of greater genetic potential for the concurrent improvement of Fe and Zn without lowering the other grain minerals in pearl millet. The first two principal components accounted for 49% of variation. Euclidian distancebased cluster analysis grouped the 122 cultivars into seven clusters. Cluster I had higher mean for Fe (56 mg kg-1) and Zn (49 mg kg-1), in which ICTP 8203, Ajeet 38, Sanjivani 222,PAC 903 and 86 M86 were identified as rich sources of iron, zinc and calcium with considerable levels of other nutrients. About 65% of cultivars for iron and 100% of cultivars for zinc have met the minimum standards set forth by the Indian Council of Agricultural Research. This indicates the feasibility of breeding nutrient-rich hybrids with competitive yields through mainstreaming in future

Exploring the short-term variability of Hα\alpha and Hβ\beta emissions in a sample of M dwarfs

The time scales of variability in active M dwarfs can be related to their various physical parameters. Thus, it is important to understand such variability to decipher the physics of these objects. In this study, we have performed the low resolution ($\sim$5.7\AA) spectroscopic monitoring of 83 M dwarfs (M0-M6.5) to study the variability of H$\alpha$ / H$\beta$ emissions; over the time scales from $\sim$0.7 to 2.3 hours with a cadence of $\sim$3-10 minutes. Data of a sample of another 43 late-type M dwarfs (M3.5-M8.5) from the literature are also included to explore the entire spectral sequence. 53 of the objects in our sample ($\sim$64\%) show statistically significant short-term variability in H$\alpha$. We show that this variability in 38 of them are most likely to be related to the flaring events. We find that the early M dwarfs are less variable despite showing higher activity strengths (L$_{H\alpha}$/L$_{bol}$ \& L$_{H\beta}$/L$_{bol}$), which saturates around $\sim$10$^{-3.8}$ for M0-M4 types. Using archival photometric light curves from TESS and Kepler/K2 missions, the derived chromospheric emission (\ha and \hb emission) variability is then explored for any plausible systematics with respect to their rotation phase. The variability indicators clearly show higher variability in late-type M dwarfs (M5-M8.5) with shorter rotation periods ($<$2 days). For 44 sources, their age has been estimated using StarHorse project and possible correlations with variability have been explored. The possible causes and implications for these behaviors are discussed.Comment: There are 35 pages including 18 pages of supplementary material. The manuscript is accepted for publication in MNRA

Pearl Millet Crop Management and Seed Production Manual

Pearl millet is a major warm season coarse grain cereal grown on 26 million ha in some of the harshest semi-arid tropical environments of Asia and Africa. India has the largest area (9–10 million ha) under this crop, ranking it third along with sorghum. It is cultivated in the most sandy, infertile soils and droughty environments (eg, arid Rajasthan) where no other cereal crop can survive. Even under these conditions, pearl millet yields 300–400 kg ha-1 of grain. Pearl millet hybrids maturing in 80–85 days, when cultivated as an irrigated summer season crop in parts of Rajasthan, Gujarat and Uttar Pradesh states of India, have been reported to give as high as 4000–5000 kg ha-1 of grain yield. Pearl millet grains have high protein content, balanced amino acid profile, and high levels of iron, zinc, and insoluble dietary fiber. Eggs produced from layers fed on a diet of pearl millet have much lower levels of LDL (the bad cholesterol) than those fed on a maize-based diet. These adaptive and nutritional features combined with high yield potential make pearl millet an important cereal crop that can effectively address the emerging challenges of global warming, water shortages, land degradation and food-related health issues. Farmers cultivating pearl millet continue to be plagued by uncertain and low economic returns when production falls and also when production increases (due to low prices). This serves as a deterrent for farmers to invest in improved crop management, although the latter can play an effective dual role in increasing productivity and enhancing production stability. The demand for pearl millet grain is likely to increase with its increasing use as poultry and animal feed. This demand can further increase if pearl millet enters the commercial convenience foods channel, thereby increasing grain price. In turn, this will lead to greater investment in crop management and consequently productivity enhancement. The International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) and National Agricultural Research System (NARS) in India have played a pioneering role in developing a diverse range of improved breeding lines and parental lines of potential hybrids. These lines have been used extensively by breeding programs in both the public and private sectors to develop and commercialize a large number of hybrids (more than 70 were under cultivation in 2006). These hybrids are cultivated on 50% of the total pearl millet area, leading to 65% increase in grain yield during the past 20 years. Since its inception in 1974, the All India Coordinated Pearl Millet Improvement Project (AICPMIP) has developed production-protection technologies specific to agro-ecoregions of different states. Their application holds the promise of further enhancing the productivity of improved cultivars to commercial farming scales, and hence increasing the profitability of their cultivation, similar to the one witnessed in the seed production sector. This lucid and comprehensive manual on pearl millet crop management and seed production by AICPMIP and ICRISAT scientists delves into pearl millet biology, its distribution and climatic requirements; and various aspects of crop management and seed production. Though written primarily in the context of agriculture in India, its contents have a wider application for students, teaching and training personnel, extension workers and farmers interested in development, crop management and seed production and marketing of pearl millet

SOPHIE velocimetry of Kepler transit candidates XVII. The physical properties of giant exoplanets within 400 days of period

While giant extrasolar planets have been studied for more than two decades now, there are still some open questions such as their dominant formation and migration process, as well as their atmospheric evolution in different stellar environments. In this paper, we study a sample of giant transiting exoplanets detected by the Kepler telescope with orbital periods up to 400 days. We first defined a sample of 129 giant-planet candidates that we followed up with the SOPHIE spectrograph (OHP, France) in a 6-year radial velocity campaign. This allow us to unveil the nature of these candidates and to measure a false-positive rate of 54.6 +/- 6.5 % for giant-planet candidates orbiting within 400 days of period. Based on a sample of confirmed or likely planets, we then derive the occurrence rates of giant planets in different ranges of orbital periods. The overall occurrence rate of giant planets within 400 days is 4.6 +/- 0.6 %. We recover, for the first time in the Kepler data, the different populations of giant planets reported by radial velocity surveys. Comparing these rates with other yields, we find that the occurrence rate of giant planets is lower only for hot jupiters but not for the longer period planets. We also derive a first measurement on the occurrence rate of brown dwarfs in the brown-dwarf desert with a value of 0.29 +/- 0.17 %. Finally, we discuss the physical properties of the giant planets in our sample. We confirm that giant planets receiving a moderate irradiation are not inflated but we find that they are in average smaller than predicted by formation and evolution models. In this regime of low-irradiated giant planets, we find a possible correlation between their bulk density and the Iron abundance of the host star, which needs more detections to be confirmed.Comment: To appear in Astronomy and Astrophysic

Improving pearl millet for drought tolerance – Retrospect and prospects

Drought stress is the most important production constraint of pearl millet (Pennisetum glaucum) in sub-Sahara Africa and south Asia where it is the staple diet and cheaper source of nutritious food for more than 90 million people. A much greater necessity therefore exists for improving pearl millet for drought-prone areas to attain food security in resourcelimited and fragile ecosystems. An attempt is made here to review the progress made in understanding the adaptation mechanism of pearl millet to drought situation and then to appraise how this knowledge has been used in improving drought-tolerance of pearl millet. A good amount of work has been accomplished in understanding the response of pearl millet to drought imposed at different growth stages of crop in order to understand its adaptation to drought stress. The foremost issues that have been addressed in breeding for enhanced drought tolerance in pearl millet are nature of base germplasm used, selection criterion, and representation of target environment during development, testing and evaluation of cultivars. Recent advancement in development and application of genomic tools in pearl millet is expected to improve the efficiency of breeding for improved drought tolerance. The major achievements in developing pearl millet specifically for drought conditions include identifying genetic material with built-in tolerance, developing early maturing cultivars, assigning importance to both grain and stover yields while releasing the cultivars, and identification of quantitative trait loci associated with drought tolerance. Prospects of further improvement of pearl millet for drought-prone areas are also discussed in this review

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..

Pearl millet (Pennisetum glaucum) restorer lines for breeding dual-purpose hybrids adapted to arid environments

The adoption of pearl millet hybrids in the north-western arid zone has been very limited in contrast to their widespread coverage in relatively more favourable areas. This research was conducted to assess the combining ability of progenies derived from a composite, called Mandor Restorer Composite (MRC) that was synthesized using 12 lines with inbuilt combination of characters that are useful for arid environments. Testcross hybrids of 43 MRC progenies made on five diverse male-sterile lines were evaluated for their performance in four environments over three years (2005–07) under rainfed conditions of arid zone. There existed significant and exploitable differences among restorer (R) lines in their combining ability for biomass, grain yield, stover yield, harvest index and panicle harvest index under receding moisture conditions. General combining ability (GCA) for early flowering was consistently and positively related to GCA for grain yield. GCA for harvest index was positively and significantly related to GCA for grain yield, but was variably negatively related to stover yield. Neither GCA for HI nor GCA for time to flowering had as large an effect on GCA for grain and stover yields as did GCA for biomass. The results suggested that GCA for earliness, biomass and HI are not necessarily mutually antagonistic characteristics under arid zone conditions indicating that there are good prospects of identifying lines to produce hybrids with enhanced grain and stover yields without compromising crop duration. This study also identified a few progenies that had significant GCA for grain and stover yield in early-maturity backgroun

Identifying Mega-Environments and Essential Test Locations for Pearl Millet Cultivar Selection in India

Pearl millet [Pennisetum glaucum (L.) R. Br.] is grown under a wide range of environmental conditions in India. The All India Coordinated Pearl Millet Improvement Project (AICPMIP) has the responsibility of testing and releasing pearl millet cultivars adapted to such conditions. As a part of this process, AICPMIP has divided the entire pearl millet growing regions into three different zones (A1, A, and B) based on the rainfall pattern and local adaptation of the crop. This study was conducted to define the presently used test locations into possible mega-environments and to identify essential test locations for cost-effective evaluation of pearl millet cultivars. Grain yield data of different sets of 34 to 45 medium-maturity pearl millet hybrids tested at 29 to 34 locations during 2006 to 2008 were analyzed using genotype main effects and genotype × environment interaction biplot method. Two distinct pearl millet mega-environments with consistent grouping of locations across the years and corresponding to AICPMIP’s designated A and B zones were identified. No such consistent grouping of locations corresponding to AICPMIP’s designated A1 zone was, however, observed. Based on the discriminating ability, uniqueness, and research resources, 13 locations were identified as essential test locations for evaluation across the two mega-environments. Testing at these locations appeared to provide good coverage of the whole pearl millet growing areas of India. Based on these findings, it is suggested to conduct initial yield trials at identified 13 locations across all the pearl millet growing zones represented by two mega-environments followed by testing of selected hybrids with specific adaptation in their respective adaptation zones

Breeding pearl millet cultivars for high iron density with zinc density as an associated trait

Pearl millet, as a species, has higher levels of iron (Fe) and zinc (Zn) densities than other major cereal crops. However, this study showed the existence of about twofold variability for Fe density (31–61 ppm) and zinc density (32–54 ppm) among 122 commercial and pipeline hybrids developed in India. Thus, there is a need to increase the cultivation of hybrids having higher Fe and Zn levels and enhance their consumption to better address various health problems associated with the deficiencies of these micronutrients. High-yielding openpollinated varieties (OPVs) and hybrids with higher levels of Fe and Zn densities than those found in most of the commercial cultivars otherwise not bred for these micronutrients as target traits have been developed and are available for commercialization. Breeding lines and germplasm with still higher levels of Fe and Zn densities have been identified. Their utilization in breeding has the potential to enable development of hybrids with >75 ppm Fe density and >55 ppm Zn density. The primary focus of pearl millet biofortification is on improving Fe density with Zn density as an associated trait. Depending on the genotypic composition of the trials, moderate to high correlations between Fe and Zn densities have been observed, indicating good prospects of simultaneous genetic improvement for both traits, but perhaps also the need to make conscious selection for Zn density along with Fe density. Lack of association of Fe and Zn densities with grain size showed that both micronutrients can be improved without compromising on seed size. The association of Fe and Zn densities with grain yield was weak and negative, but not always significant, indicating that both micronutrients can be improved without significantly compromising grain yield by using large segregating populations. This, however, is one area that merits further research