VARIABILITY AND GENETIC PARAMETERS FOR GRAIN YIELD AND ITS COMPONENTS AND KERNEL QUALITY ATTRIBURTES IN CMS BASED RICE HYBRIDS (ORYZA SATIVA L.)
The present investigation was under taken to study the extent of variability and genetic parameters with 16 parents and 48 hybrids for nine yield and its components and twenty five quality characters. The magnitude of difference between PCV and GCV was relatively low for all the traits, indicating less environmental influence. High GCV and PCV were recorded for harvest index, total number of productive tillers per plant and gelatinization temperature in parents and for total number of productive tillers per plant, number of grains per panicle, gelatinization temperature and amylose content in hybrids. High heritability coupled with high genetic advance as per cent of mean were recorded for gelatinization temperature, harvest index, total number of productive tillers per plant, number of grains per panicle, kernel length, kernel L/B ratio and grain yield per plant in case of parents and for gelatinization temperature, amylose content, total number of productive tillers per plant, number of grains per panicle and harvest index in case of hybrids indicating the additive gene effects in the genetic control of these traits and can be improved by simple selection in the present breeding material.
Genetic variability and character association in early maturing rice
Genetic parameter and correlation of 12 quantitative traits including the grain yield were studied in forty four extra early and early maturing rice genotypes. High estimates of genotypic coefficient of variation were recorded for grain yield plant-1, flag leaf area and grain L/B ratio. Estimates of heritability in broad sense were observed to be high for flag leaf area, 1000-grain weight, grain L/B ratio, days to 50 per cent flowering and grains panicle-1. High heritability coupled with high genetic advances as per cent mean were recorded for grain yield plant-1, flag leaf area, grain L/B ratio, spikelets panicle-1 and days to 50 per cent flowering. Grain yield palnt-1 exhibited highly significant and positive correlation with fertile grains panicle-1, grains panicle-1, 1000-grain weight, panicle length, flag leaf area and spikelets panicle-1.
Pneumolabyrinth in perilymphatic fistula: report of three cases.
In three patients with perilymphatic fistula, exploratory tympanotomy revealed air bubbles emerging through the ruptured round window membrane. Review of the literature disclosed three case reports in which air was demonstrated in the labyrinth in association with perilymphatic fistula. Experimental evidence that air could enter the labyrinth through a defect of the round window membrane was described in two articles. In our patients, the perilymphatic fistula was produced by implosive force. When a perilymphatic fistula was produced by implosive force, or in the case of a pre-existing perilymphatic fistula, we assume, air may enter the scala tympani through the defect of the round window membrane if the middle ear pressure rises beyond a certain limit. Sudden onset of deafness and reversibility of hearing in perilymphatic fistula could be attributable to the presence of air bubble in the scala tympani--pneumolabyrinth--which might disturb propagation of the traveling wave of the basilar membrane.