Aflatoxin contaminated groundnut can cause serious health effects to both humans and livestock. Twenty nine prebreeding genotypes derived from A, B and K genomes of groundnut along with their ...parents, susceptible, resistant checks, released cutlivars and advanced breeding lines were evaluated under field for various productivity parameters in addition to screening for resistance against aflatoxin in the artificial condition. Among the pre-breeding genotypes only two genotypes (ICGIL 17101 and ICGIL 17124) showed resistance to A flavus with colonization severity of 1 and very less incidence percentage (< 7%) and considered as resistant compared to known resistant check, ICG 02207 which had colonization severity of 3 with 95 % incidence. Three pre breeding genotypes, ICGIL 17107, ICGIL 17114, and ICGIL 17128 showed colonization severity of 2 and considered as moderately resistant. The late leaf spot and rust resistant released variety, GPBD 4 showed colonization severity of 3 and classified as susceptible indicating different resistant mechanism operating against different pathogens. The genotype ICGIL 17124 in addition to having resistance to A flavus, also had higher pod yield per plant and hence could be tested widely for its consistent performance before releasing as a variety.
Precipitation is predicted to become more variable in the western United States, meaning years of above and below average precipitation will become more common. Periods of extreme precipitation are ...major drivers of interannual variability in ecosystem functioning in water limited communities, but how ecosystems respond to these extremes over the long-term may shift with precipitation means and variances. Long-term changes in ecosystem functional response could reflect compensatory changes in species composition or species reaching physiological thresholds at extreme precipitation levels.
We conducted a five year precipitation manipulation experiment in a sagebrush steppe ecosystem in Idaho, United States. We used drought and irrigation treatments (approximately 50% decrease/increase) to investigate whether ecosystem functional response remains consistent under sustained high or low precipitation. We recorded data on aboveground net primary productivity (ANPP), species abundance, and soil moisture. We fit a generalized linear mixed effects model to determine if the relationship between ANPP and soil moisture differed among treatments. We used nonmetric multidimensional scaling to quantify community composition over the five years.
Ecosystem functional response, defined as the relationship between soil moisture and ANPP, was similar among irrigation and control treatments, but the drought treatment had a greater slope than the control treatment. However, all estimates for the effect of soil moisture on ANPP overlapped zero, indicating the relationship is weak and uncertain regardless of treatment. There was also large spatial variation in ANPP within-years, which contributes to the uncertainty of the soil moisture effect. Plant community composition was remarkably stable over the course of the experiment and did not differ among treatments.
Despite some evidence that ecosystem functional response became more sensitive under sustained drought conditions, the response of ANPP to soil moisture was consistently weak and community composition was stable. The similarity of ecosystem functional responses across treatments was not related to compensatory shifts at the plant community level, but instead may reflect the insensitivity of the dominant species to soil moisture. These species may be successful precisely because they have evolved life history strategies that buffer them against precipitation variability.
This volume is devoted to the derivation and application of simplified bioclimatic boundary conditions at vegetated land surfaces using natural selection of vegetation characteristics driven by ...productivity maximization. It investigates the internal control of forest growth by the vertical fluxes of light, CO2, water vapor, and heat within the canopy, as well as the external control offered by the balances of thermal energy and water. Through these means it seeks to determine how the physical characteristics and productivity of forest communities are related to the climates and soils in which they are found. Ecohydrology bridges the fields of hydrology and ecology and proposes new unifying principles derived from the concept of natural selection. It also has potential application in determining the response of vegetation to slow variations in climate and will provide fascinating reading for graduate-level students and research scientists working in ecohydrology, hydroclimatology, forest ecology, and surface water hydrology.
The growth experiences of 6 major OECD countries are examined over the period 1965-1988, particularly how different rates of capital accumulation in physical and R&D capital and the rate of technical ...change contributed to the rate of growth of output and the narrowing of the productivity gap among the members of the catch-up club. Based on the structural estimates of the model, disembodied technical change is found to be the most important source of output and labor productivity growth in all countries.
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