HighlightsEarly-morning flowering (EMF) helps rice plants to escape heat stress damage under field conditions.EMF traits and spikelet sterility were estimated from indica cultivars originating from 13 tropical and 20 subtropical countries.None of the tested 289 cultivars had the EMF trait.EMF trait introgressed into popular rice cultivar showed high environmental stability.

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For optimizing the structural parameters for optimum performance of seeder or planter depends on seed size and its uniformity. Selected important physical and mechanical properties of black gram variety VBN-3 and green gram variety CO-6 were studied and its importance in inclined seed metering mechanism development discussed. The digital vernier caliper was used to measure the major axis and minor axis of black gram and green gram seeds. Standard procedures were employed for measuring bulk density and angle of repose. The major axis and minor axis of the selected varieties of black gram and green gram seeds were 3.97, 4.25, 3.60 and 3.92 mm, respectively, were considered in the design of cells on the metering plate of pulse planter. The average 1000 seed weight and bulk density of black gram and green gram varied between 51 to 56 g, 46 to 51 g, 1389.68 to 1494.43 kg m-3, 626.56 to 984.29 kg m-3 respectively. The mean angle of repose and coefficient of friction over the surfaces of plywood, galvanized steel, mild steel and rubber was 28.64°and 0.605, 35.55°and 0.746, 24.26° and 0.592 and 39.57° and 0.706 respectively, were recorded for black gram and 26.3°and 0.676, 32.6°and 0.823, 26.8° and 0.486 and 38.5°and 0.865 respectively were recorded for green gram.

For achieving desired seed placement index for black gram variety VBN-3, a laboratory test rig was developed with the following independent variables. Cell geometry (S) -3 levels -Maximumseed dimension -4.25 mm, 10 per cent more than maximum seed dimension -4.67 mm and 25 per cent more than maximum seed dimension -5.31 mm. Inclination of seed metering disc (θ θ θ θ) -4 levels -30°°°°, 35°°°°, 40°°°° and 45°°°°. Peripheral speed of seed metering disc (V) -4 levels -0. 1 ms-1, 0.15 ms-1, 0.2 ms-1 and 0.25 ms-1 0.20 ms-1 peripheral velocity of seed metering disc, the cell geometry 4.67 mm (10 per cent more than the maximum seed dimension) yielded higher SPI than the cell geometry of 4.25 mm and 5.31 mm. . From the experiments, it was inferred that the cell geometry with 10 percent maximum seed dimension registered maximum seed placement index. The angle of inclination of the seed metering disc had no profound effect on SPI for all levels of combination. At