ABSTRACT
A field experiment was carried out at Agriculture Farm, Palli Siksha Bhavana, Visva-Bharati, Sriniketan, West Bengal, India during kharif season of 2015 to compare rice cultivation in conventional transplanting (CT) and system of rice intensification (SRI) in terms of energy use, energy input output relationship and green house gas emission. Results showed that regardless of cultivars, conventional transplanting consumed 62.39% higher energy over SRI. Maximum energy input was associated with non renewable and indirect sources. Higher dose of nitrogenous fertilizer had contributed to 32.35% and 26.26% to the total input energy in CT and SRI respectively. Energy use efficiency (13.22), energy productivity (6.94 kg MJ-1), energy profitability (12.22) and energy intensity (4.60 MJ Rs-1) of hybrid rice varieties were noted higher in SRI. Maximum green house gas emission from rice field was also attributed to fertilizer nitrogen followed by diesel in both the system. Total green house gas emission in CT was estimated to 834.85 (kg CO2ha-1) i.e. 1.8 times of SRI. Engirdling different energy indices, total input energy and green house gas emission, the system of rice intensification was emerged as the most energy efficient and sustainable rice production system in resource stricken areas (Red Lateritic Zone).
ABSTRACT
Field experiments were conducted using 68 hybrids, 17 parents and four checks across two different agroclimatic zones of Andhra Pradesh, South India during Kharif, 2008 and rabi-2008-09 to estimate the genetic variability parameters for yield and yield contributing characters. Pooled analysis over the environments, genotype and environment interactions were significant for traits like panicle weight, flag leaf length, flag leaf width, productive tillers per plant, filled grains per panicle, 1000 grain weight and grain yield per plant, implies differential behavior of genotypes under the four environments for these characters. The estimates of phenotypic coefficient of variation (PCV) were slightly higher than those of genotypic coefficient of variation (GCV) for all the traits studied across the seasons. Slight differences were observed for all the characters with regard to variability coefficients, heritability and genetic advance % of mean in different environments. Panicle weight, flag leaf length, flag leaf width, grains per panicle, yield per plant, 1000 grain weight and productivity per day were recorded moderate to high GCV, PCV, heritability, genetic advance % of mean, characters could be transmitted to the progeny and phenotypic based selection would be effective.
ABSTRACT
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.
ABSTRACT
Rice (Oryza sativa L.) breeding seeking to combine high productivity and cold tolerance for the temperate Latin America region is an important challenge. We estimated some useful parameters which can be used to investigate the genetic control of agronomic characters in crosses combining cold tolerance and productivity. A partial diallel design was used in crosses between six tropical indica rice cold susceptible genotypes (group 1) and seven japonica or indica/japonica cold tolerant rice genotypes (group 2). Parents and crosses were evaluated for agronomic characters under field conditions in two different experiments in 2005. The results showed significant mid-parent heterosis for all characters (plant height, tiller number, days to 50 percent flowering, panicle length, grains per panicle, sterility, and one-hundred grain weight). The predominant direction of dominance effects was negative for days to 50 percent flowering, and positive for all the other characters. General combining ability (GCA) and specific combining ability (SCA) were significant for all characters, although the GCA effects of the two groups were more important than the SCA effects.