Assessing the Genotypic Differences for Seed Set and Seed Abortion in Tomato Genotypes

Tomato (_Lycopersicon esculentum_ Mill.) is one of the most popular fruit vegetable around the world. Seed abortion where in only a small proportion of ovules in an ovary develops into matured seeds, is a wide spread phenomenon in multi-ovulated species. In agriculturally important crops such as chickpea, groundnut, Brassica, pigeon pea and field bean seed abortion substantially reduces their productivity. Tomato genotypes exhibited seed abortion where in only some proportion of ovules developed into matured seeds. Seed abortion in tomato cultivars would increase the cost of hybrid seed production. In this study, we have analyzed 19 genotypes for number of ovules, seed set and seed abortion. Tomato genotypes differed significantly for number of ovules per ovary, seed set per fruit and per cent seed abortion. The ovules, matured seeds and seed abortion ranged from 52 to 412 per ovary; 50.90 to 240.76 per fruit and 6.06 to 24.44 per cent respectively. Strong positive correlation was observed in genotypes with higher number of ovules showed higher percentage of seed abortion

Love games that insects play: the evolution of sexual behaviours in insects

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The Cosmic Ballet: spinning in the web

All the celestial objects, from small asteroids and planets to large galaxies and even the long filaments of the cosmic web are rotating. The origin of rotation is yet to be fully understood, especially in the context of galaxies and their dark matter haloes. In the young Universe, as matter began to clump together, the resulting anisotropic distribution of matter torqued up proto-galaxies. Simultaneously, the matter overdensities collapsed to form the large-scale filaments, clusters, walls and voids of the cosmic web that we see today. As a result, we expect a correlation between galaxy spin and the cosmic web. In this thesis, we uncover the role of the cosmic web environment in establishing the rotation of haloes and galaxies using large cosmological simulations. We show that haloes in filaments are in general spinning faster than in other web components. We have studied the correlations between the spin-axis of haloes/galaxies with the orientation of the cosmic filaments that they are growing in. The thesis explores in detail the spin transition from parallel to perpendicular as a function of the halo or galaxy mass with respect to the spine of the host filament. We show how these trends evolve with cosmic time and filament properties using the MMF/Nexus and Bisous formalisms for cosmic web detection. The results from this thesis are important for various reasons. They not only hold information on how structure in the Universe emerged but also the notion of spin-transition mass promises to be a potential tool to probe the Universe

Are plants with anti-cancer activity resistant to crown gall? : A test of hypothesis

The Crown gall tumour assay (CGTA) is one of several bench top bioassays recommended for the rapid screening of plants with anti-cancer activity. The rationale for the use of the bioassay is that the tumorogenic mechanism initiated in plant tissues by _Agrobacterium tumefaciens_ is in many ways similar to that of animals. Several plant species with anti-cancer activity have already been discovered using this bioassay. However till date no explicit test of an association between anti-cancer activity of plants and their resistance to crown gall formation has been demonstrated. Demonstration of an association could have exploratory potential when searching for plants with anti-cancer activity. In this paper, we determined whether or not a statistically significant association between crown gall resistance and anti-cancer activity exists in plants found in existing published data sets. Our results indicate that plants with anti-cancer activity have a higher proportion of their species resistant to crown gall formation compared to a random selection of plants. We discuss the implications of our results especially when prospecting for newer sources of anti-cancer activity in plants

Large-scale density and velocity field reconstructions with neural networks

We assess a neural network (NN) method for reconstructing 3D cosmological density and velocity fields (target) from discrete and incomplete galaxy distributions (input). We employ second-order Lagrangian Perturbation Theory to generate a large ensemble of mock data to train an autoencoder (AE) architecture with a Mean Squared Error (MSE) loss function. The AE successfully captures nonlinear features arising from gravitational dynamics {and} the discreteness of the galaxy distribution. In comparison, the traditional Wiener filter (WF) reconstruction exhibits a stronger suppression of the power on smaller scales and contains regions of unphysical negative densities. In the density reconstruction, the reduction of the AE MSE relative to the WF is $\sim 15 \%$, whereas for the velocity reconstruction a relative reduction of up to a factor of two can be achieved. The AE is particularly superior to the WF towards the tails of the density and velocity distributions. In fact, trained with an MSE loss, any NN estimate approaches the unbiased mean of the underlying target given the input. This implies a slope of unity in the linear regression of the true on the NN-reconstructed field. Only for the special case of Gaussian fields, the NN and WF estimates are equivalent. Nonetheless, we also recover a linear regression slope of unity for the WF with non-Gaussian fields.Comment: 17 pages, 13 figures. Submitted to MNRAS. Comments are welcom

The Thalakaadu phenomenon: a miracle or an ecological disaster?

The Thalakaadu curse has established itself in the folklore as a miracle since the early part of 16th century because of two strange events visible even to date: (i) Thalakaadu, an historically vibrant city, is now being submerged under sand dunes several meters deep, and (ii) the Mysore royal family have faced problem in having a rightful heir to the throne since 1600s. Both these events linked to an apparent curse by a pious lady have defied logic. Based on the data from diverse sources and field studies, I have reconstructed the possible chronology of events of this acclaimed miracle. I argue that the Thalakaadu phenomenon represents an ecological disaster unintentionally wrought on to a vibrant civilization at this place and in this sense the curse per se is an intelligently inserted story as an overlay. Using this example I discuss the possible process through which the miracles or myths of this kind survive in a society

In pursuit of a universal barcode of plants: peril of followers?

In May 2007, during the early days of the DNA bar coding project in India, we published an article, ‘DNA barcoding: an exercise in futility or utility’1. As the title reflects, we were literally at crossroads, caught between the cross-fire of traditional taxonomists (we think it is disrespectful to call them traditional; they are as much modern as are archaeologists and molecular biologists) and molecular systematists and not knowing which way to go forward. After a reasonable amount of brain-storming that took us through well-trodden criticisms of the DNA barcoding initiative, we concluded that while debates can go on, the tool itself can be effectively used in complementing conventional taxonomic studies and in securing Intellectual Property Rights (IPRs) for important taxa. We also felt at that time that it would be important for the country to develop skills and infrastructure to undertake barcoding of at least some of the important taxa, both for conservation and commerce

Does forest type classification reflect spatial dynamics of vegetation? Analysis using GIS techniques

The existing methods of classification of forest vegetation rely more on the structure and composition of tree vegetation with little information derived from other layers. We suggest that any classificatory process of forest vegetation should consider the spatial dynamics of all the three layers namely, tree, shrub and herb. In this paper we have attempted to offer an objective method of classifying the vegetation at all the three layers utilizing GIS and multivariate statistical tools. Unlike the existing techniques, our method views the forest as a continuously changing mosaic of vegetation and not as an assemblage of discrete patches. Our study suggests that understanding the spatial dynamics of vegetation at one layer may not reflect that at others. Further, as an alternate to the existing methods, we also develop a continuum map of biodiversity of the forest that offers the conservation value of each patch, an element that is not conveyed in the existing classificatory processes. Discover the world's researc

Floral resources of Karnataka: a geographic perspective

We compiled the data on the floral resources of Karnataka from diverse published sources and analysed the geographic patterns of distribution of floral diversity. Our database shows that Karnataka harbours 4758 species from 1408 genera and 178 families and accounts for about 27 per cent of the country's floral diversity. We computed the 'endemicity value' of different districts based on the number of endemic species (those restricted to a maximum of five districts) harboured by them and found that the most species-rich districts (viz. Uttara Kannada, Dakshina Kannada, Mysore, Hassan, Udupi and Kodagu) were also characterized by high values of endemicity while the species-poor districts had low values of endemicity. However, the relation between the species richness and endemicity of the districts was not linear; the species richness increases abruptly at lower levels of endemicity but plateaus off later at high levels of endemicity. Based on the number of species packed into the families, all the 27 districts segregated distinctly into three clusters that geographically correspond with the three major agro-climatic zones of the state. Our analysis showed that though the districts along the Western Ghats are florally rich, those along the dry tracts also harbour certain unique elements of the flora; thus these dry zone districts appear to be as important as those along the Western Ghats in conserving the floral resources

An unscientific way to bury astrology

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