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

Petrology and physical conditions of metamorphism of calcsilicate rocks from low- to high-grade transition area, Dharmapuri District, Tamil Nadu

Calc-silicate rocks comprising quartz, plagioclase, diopside, sphene, scapolite, grossularite-andradite and wollastonite occur as lensoid enclaves within the greasy migmatitic and charnockitic gneisses of the Archaean amphibolite- to granulite-facies transition zone in Dharmapuri district, Tamil Nadu. The calc-silicate rocks are characterized by the absence of K-feldspar and primary calcite, presence of large modal quartz and plagioclase and formation of secondary garnet and zoisite rims around scapolite and wollastonite. The mineral distributions suggest compositional layering. The chemical composition and mineralogy of the calc-silicate rocks indicate that they were derived from impure silica-rich calcareous sediments whose composition is similar to that of pelite-limestone mixtures. From the mineral assemblages the temperature, pressure and fluid composition during metamorphism were estimated. The observed mineral reaction sequences require a range of X sub CO2 values demonstrating that an initially CO2-rich metamorphic fluid evolved with time towards considerably more H2O-rich compositions. These variations in fluid composition suggest that there were sources of water-rich fluids external to the calc-silicate rocks and that mixing of these fluids with those of calc-silicate rocks was important in controlling fluid composition in calc-silicate rocks and some adjacent rock types as well

Elastic and structural instability of cubic Sn3N4 and C3N4 under pressure

We use in-situ high pressure angle dispersive x-ray diffraction measurements to determine the equation of state of cubic tin nitride Sn3N4 under pressure up to about 26 GPa. While we find no evidence for any structural phase transition, our estimate of the bulk modulus (B) is 145 GPa, much lower than the earlier theoretical estimates and that of other group IV-nitrides. We corroborate and understand these results with complementary first-principles analysis of structural, elastic and vibrational properties of group IV-nitrides, and predict a structural transition of Sn3N4 at a higher pressure of 88 GPa compared to earlier predictions of 40 GPa. Our comparative analysis of cubic nitrides shows that bulk modulus of cubic C3N4 is the highest (379 GPa) while it is structurally unstable and should not exist at ambient conditions.Comment: 5 pages, 4 figure

The Indian Mackerel; VI Exploitation

The types of fishing craft and gear commonly used in the fishery have been evolved to suit the local requirement depending upon the physical characteristics of the coastline, surf conditions as well as habits of fish. Descriptive accounts of the types of these craft and gear, used both on the west and east coasts of India, are given by Hornell (1910a and 1938), Chopra (1951), Anon. (1941 and 1943), and Zeiner and Rasmussen (1958). Later Jones and Rosa (1965 and 1967) have listed the important types of fishing craft and gear commonly employed in the mackerel fishery. Similarly Rao (1969) has shown, among other things, the most common types of fishing boats and nets used in the Indian waters for this fishery

Food of the Indian mackerel, Rastrelliger kanagurta (Cuvier) taken by drift-nets in the Arabian sea off Vizhingam, South Kerala

Being one of the most important neritic pelagic specie:., the Indian mackerel, RastrelUger kanagurta (Cuvier), has been, the object of investigations by many fishery biologists. On the West Coast of India, while this species supports a rich commercial fishery, its distribution on the East Coast is only of biological interest. Most of the earlier works (Devanesan and John, 1940; Devanesan, 1942; John and Menon, 1942 and Chidambaram, 1944) are of brief notes dealing with the nature of food of the mackerel on the West Coast of India. In recent years, Chidambaram et al. (1952) have studied in detail the fat variations, sizo composition, maturity and food habits of the mackerel. Bhimachar and George (1952) have given a detailed account of the seasonal fluctuations in the food of this species from Calicut. Mention should be made of the comprehensive works of Pradhan (1956) and Sekharan (1958) on the fishery and certain biological aspscts of the mackerel from the Konkan Coast. Our knowledge on the biology of this species from the East Coast of India is confined to the recent works of Kuthalingam (1956) from Madras, Rao and Rao (1957) and Rao (1962) from Waltair