52 research outputs found
Employment, Income and Labour Supply Decision of Rural Households : An Economic Analysis of MGNREGS in Tamil Nadu
In India, Mahatma Gandhi National Rural Employment Guarantee Scheme (MGMGNREGS) is one of the major rural development programmes. It provides guaranteed employment to the rural households for 100 days in a year. This paper has attempted to find out the employment status, income and labour supply decision of the participants and non-participants of MGNREGS in Tamil Nadu. It has also studied the household nutritional security of these households. The study has revealed that the number of migrants in the family, number of livestock units owned, and number of person-days employed in agriculture, nonagriculture and MGNREGS are significantly influenced by the household income of the participants and non-participants of MGNREGS. The analysis of household food-security has shown that the expenditure for all commodities, viz. leisure, cereals, pulses, oils, fruits & vegetables, milk, chicken and fish are positive and significant in the case of MGNREGS participants, whereas the expenditure variable is significant only for two commodities, viz. cereals and oils in case of MGNREGS non-participants. It shows that the MGNREGS participants consume more high-value commodities like milk, chicken and fish, as compared to MGNREGS non-participants. The labour supply decision of sample respondents has shown that the elasticity of labour supply with respect to wage rate is more than one in both participants and non-participants of MGNREGS, indicating that an one per cent increase in wage rate increases labour supply by 1.92 per cent and 2.36 per cent, respectively. In addition, as the number of dependents increases, the household increases labour supply to derive additional income to meet the increased household expenditures. An interesting and encouraging observation is that the scheme has reduced the migration of people from rural to urban areas.MGNREGS, employment, income, labour supply, Agricultural and Food Policy, J21, J22, H23, I31,
Transpiration difference under high evaporative demand in chickpea ( Cicer arietinum L.) may be explained by differences in the water transport pathway in the root cylinder
Terminal drought substantially reduces chickpea yield. Reducing water use at vegetative
stage by reducing transpiration under high vapor pressure deficit (VPD), i.e. under dry/
hot conditions, contributes to drought adaptation. We hypothesized that this trait could
relate to differences in a genotypeâs dependence on root water transport pathways and
hydraulics.
âą Transpiration rate responses in conservative and profligate chickpea genotypes were
evaluated under increasing VPD in the presence/absence of apoplastic and cell-to-cell
transport inhibitors.
âą Conservative genotypes ICC 4958 and ICC 8058 restricted transpiration under high
VPD compared to the profligate genotypes ICC 14799 and ICC 867. Profligate genotypes
were more affected by aquaporin inhibition of the cell-to-cell pathway than conservative
genotypes, as measured by the root hydraulic conductance and transpiration
under high VPD. Aquaporin inhibitor treatment also led to a larger reduction in root
hydraulic conductivity in profligate than in conservative genotypes. In contrast, blockage
of the apoplastic pathway in roots decreased transpiration more in conservative
than in profligate genotypes. Interestingly, conservative genotypes had high early vigour,
whereas profligate genotypes had low early vigour.
âą In conclusion, profligate genotypes depend more on the cell-to-cell pathway, which
might explain their higher root hydraulic conductivity, whereas water-saving by
restricting transpiration led to higher dependence on the apoplastic pathway. This
opens the possibility to screen for conservative or profligate chickpea phenotypes using
inhibitors, itself opening to the search of the genetic basis of these differences
Plant vigour QTLs co-map with an earlier reported QTL hotspot for drought tolerance while water saving QTLs map in other regions of the chickpea genome
Background
Terminal drought stress leads to substantial annual yield losses in chickpea (Cicer arietinum L.). Adaptation to water limitation is a matter of matching water supply to water demand by the crop. Therefore, harnessing the genetics of traits contributing to plant water use, i.e. transpiration rate and canopy development dynamics, is important to design crop ideotypes suited to a varying range of water limited environments. With an aim of identifying genomic regions for plant vigour (growth and canopy size) and canopy conductance traits, 232 recombinant inbred lines derived from a cross between ICC 4958 and ICC 1882, were phenotyped at vegetative stage under well-watered conditions using a high throughput phenotyping platform (LeasyScan).
Results
Twenty one major quantitative trait loci (M-QTLs) were identified for plant vigour and canopy conductance traits using an ultra-high density bin map. Plant vigour traits had 13 M-QTLs on CaLG04, with favourable alleles from high vigour parent ICC 4958. Most of them co-mapped with a previously fine mapped major drought tolerance âQTL-hotspotâ region on CaLG04. One M-QTL was found for canopy conductance on CaLG03 with the ultra-high density bin map. Comparative analysis of the QTLs found across different density genetic maps revealed that QTL size reduced considerably and % of phenotypic variation increased as marker density increased.
Conclusion
Earlier reported drought tolerance hotspot is a vigour locus. The fact that canopy conductance traits, i.e. the other important determinant of plant water use, mapped on CaLG03 provides an opportunity to manipulate these loci to tailor recombinants having low/high transpiration rate and plant vigour, fitted to specific drought stress scenarios in chickpea
Chickpea Genotypes Contrasting for Vigor and Canopy Conductance Also Differ in Their Dependence on Different Water Transport Pathways
Lower plant transpiration rate (TR) under high vapor pressure deficit (VPD) conditions and early plant vigor are proposed as major traits influencing the rate of crop water use and possibly the fitness of chickpea lines to specific terminal drought conditionsâthis being the major constraint limiting chickpea productivity. The physiological mechanisms underlying difference in TR under high VPD and vigor are still unresolved, and so is the link between vigor and TR. Lower TR is hypothesized to relate to hydraulic conductance differences. Experiments were conducted in both soil (Vertisol) and hydroponic culture. The assessment of the TR response to increasing VPD showed that high vigor genotypes had TR restriction under high VPD, and this was confirmed in the early vigor parent and progeny genotype (ICC 4958 and RIL 211) having lower TR than the late vigor parent and progeny genotype (ICC 1882 and RIL 022). Inhibition of water transport pathways [apoplast and symplast (aquaporins)] in intact plants led to a lower transpiration inhibition in the early vigor/low TR genotypes than in the late vigor/high TR genotypes. De-rooted shoot treatment with an aquaporin inhibitor led to a lower transpiration inhibition in the early vigor/low TR genotypes than in the late vigor/high TR genotypes. Early vigor genotypes had lower root hydraulic conductivity than late vigor/high TR genotypes. Under inhibited conditions (apoplast, symplast), root hydraulic conductivity was reduced more in the late vigor/high TR genotypes than in the early vigor/low TR genotypes. We interpret that early vigor/low TR genotypes have a lower involvement of aquaporins in water transport pathways and may also have a smaller apoplastic pathway than high TR genotypes, which could explain the transpiration restriction under high VPD and would be helpful to conserve soil water under high evaporative demand. These findings open an opportunity for breeding to tailor genotypes with different âdosageâ of these traits toward adaptation to varying drought-prone environments
Lessons from Innovative Institutions in the Marketing of Fish and Fishery Products in India §
Abstract This study has been conducted with the objective of understanding the process of innovative marketing models in the fisheries sector and to draw lessons from the success stories to upscale and replicate in a similar socio-politico-economic scenario in other parts of the country. It has been conducted to provide a better understanding of fish marketing by self-help groups (SHGs), producer associations, fisheries development corporations, fisherman cooperatives and private institutions in the southern states of India, namely Tamil Nadu, Kerala, Karnataka and Andhra Pradesh with the hypothesis that the institutional arrangements in the marketing of fish and fishery products reduce the transaction cost and improve the market access and its efficiency. The study has reported the primary activities of those institutions in the efficient fish marketing, such as inbound logistics, operations, outbound logistics, marketing and sales promotion and support activities like infrastructural facilities, technological backstopping, price information and procurement. Through these advantages, the fishermen have been found to achieve economies of scale, technological innovations, capacity development, linkage among activities, degree of vertical integration, timing of market entry, product differentiation, market access, credit access, etc. The study has suggested replication of such successful innovative institutions in marketing the fish and fishery products through appropriate policies and programmes. It has also suggested to promote institutions like SHGs, producer / fishermen associations, cooperatives, etc. and allow the entry of private agencies with appropriate regulatory mechanism to improve the efficiency of fish marketing in the country
Phenotypic and genetic dissection of water stress adaptations in pearl millet (Pennisetum glaucum)
Pearl millet is an important staple food for farming communities
across semi-arid tropical systems of South Asia and
Sub-Saharan Africa where production suffers uncertain precipitation.
This work is undertaken under the premise that maximizing
grain yield under water-limited conditions depends
on both maximizing water use and ensuring water availability
for the grain filling period. Here we discuss the phenotyping
methods targeting the variability in plant water use strategies
which determine the crop production success in water-limited
environments. A fine-mapping population of pearl millet,
segregating within the previously identified drought tolerance
quantitative trait locus (QTL) on chromosome 2 (LG02), was
tested across different experimental environments (pot culture,
high-throughput phenotyping platform (LeasyScan), Lysimeter,
and Field). Recombinants were then analyzed for traits
at different levels of plant organization, ranging from water-use
traits (transpiration rate, leaf area, plant organ dry weights,
etc.) to crop production and agronomic traits (grain yield, tiller
number, harvest index, etc.) The linkages between traits
across the experimental systems were analyzed, using principal
component analysis (PCA) and QTL co-localization approach.
The functional relevance of the phenotyping systems was traced
by PCA analysis. Furthermore, we found four regions within the
LG02-QTL underlying substantial co-mapping of water-use related
and agronomic traits. These regions were identified across
the experimental systems and justified linkages between water-
use traits were phenotyped at lower level of plant organization
to the agronomic traits assessed in the field. Therefore, the
phenotyping systems at ICRISAT are validated and well set to
accelerate crop breeding for drought adaptations
Molecular cloning and expression analysis of Aquaporin genes in pearl millet [ Pennisetum glaucum (L) R. Br.] genotypes contrasting in their transpiration response to high vapour pressure deficits
Pearl millet is a crop of the semi-arid tropics having high degree of genetic diversity and variable tolerance to drought stress. To investigate drought tolerance mechanism that possibly accounts for differences in drought tolerance, four recombinant inbred lines from a high resolution cross (HRC) were selected for variability in their transpiration rate (Tr) response to vapour pressure deficit (VPD) conditions. The differential Tr response of the genotypes to increased VPD conditions was used to classify the genotypes as sensitive or insensitive to high VPD. Aquaporin (AQP) genes PgPIP1;1, PgPIP1;2, PgPIP2;1, PgPIP2;3, PgPIP2;6, PgTIP1;1 and PgTIP2;2 were cloned. Phylogenetic analysis revealed that the cloned PgAQPs were evolutionarily closer to maize AQPs than to rice. PgAQP genes, including PgPIP1;1 and PgPIP2;6 in root tissue showed a significant expression pattern with higher expression in VPD-insensitive genotypes than VPD-sensitive genotypes under low VPD conditions (1.2 kPa) i.e when there is no high evaporative demand from the atmosphere. PgAQP genes (PgPIP2;1 in leaf and root tissues; PgPIP1;2 and PgTIP2;2 in leaf and PgPIP2;6 in root) followed a diurnal rhythm in leaves and roots that have either higher or lower expression levels at different time intervals. Under high VPD conditions (4.21 kPa), PgPIP2;3 showed higher transcript abundance in VPD-insensitive genotypes, and PgPIP2;1 in VPD-sensitive genotypes, while rest of the PgAQPs showed differential expression. Our current hypothesis is that these differences in the expression of AQP genes under different VPDs suggests a role of the AQPs in tuning the water transport pathways with variation between genotypes
Quantitative trait loci (QTLs) for water use and crop production traits co-locate with major QTL for tolerance to water deficit in a fine-mapping population of pearl millet (Pennisetum glaucum L. R.Br.)
Key message
Four genetic regions associated with water use traits, measured at different levels of plant organization, and with agronomic traits were identified within a previously reported region for terminal water deficit adaptation on linkage group 2. Close linkages between these traits showed the value of phenotyping both for agronomic and secondary traits to better understand plant productive processes.
Abstract
Water saving traits are critical for water stress adaptation of pearl millet, whereas maximizing water use is key to the absence of stress. This research aimed at demonstrating the close relationship between traits measured at different levels of plant organization, some putatively involved in water stress adaptation, and those responsible for agronomic performance. A fine-mapping population of pearl millet, segregating for a previously identified quantitative trait locus (QTL) for adaptation to terminal drought stress on LG02, was phenotyped for traits at different levels of plant organization in different experimental environments (pot culture, high-throughput phenotyping platform, lysimeters, and field). The linkages among traits across the experimental systems were analysed using principal component analysis and QTL co-localization approach. Four regions within the LG02-QTL were found and revealed substantial co-mapping of water use and agronomic traits. These regions, identified across experimental systems, provided genetic evidence of the tight linkages between traits phenotyped at a lower level of plant organization and agronomic traits assessed in the field, therefore deepening our understanding of complex traits and then benefiting both geneticists and breeders. In short: (1) under no/mild stress conditions, increasing biomass and tiller production increased water use and eventually yield; (2) under severe stress conditions, water savings at vegetative stage, from lower plant vigour and fewer tillers in that population, led to more water available during grain filling, expression of stay-green phenotypes, and higher yield
Component traits of plant water use are modulated by vapour pressure deficit in pearl millet (Pennisetum glaucum (L.) R.Br.)
Traits influencing plant water use eventually define the fitness of genotypes for specific rainfall environments. We assessed the response of several water use traits to vapour pressure deficit (VPD) in pearl millet (Pennisetum glaucum (L.) R.Br.) genotypes known to differ in drought adaptation mechanisms: PRLT 2/89â33 (terminal drought-adapted parent), H 77/833â2 (terminal drought-sensitive parent) and four near-isogenic lines introgressed with a terminal drought tolerance quantitative trait locus (QTL) from PRLT 2/89â33 (ICMR01029, ICMR01031, ICMR02042, and ICMR02044). Plant water use traits at various levels of plant organisation were evaluated in seven experiments in plants exposed either transiently or over the long term to different VPD regimes: biomass components, transpiration (water usage per time unit) and transpiration rate (TR) upon transient VPD increase (gâH2Oâcmâ2âhâ1)), transpiration efficiency (g dry biomass per kg H2O transpired), leaf expansion rate (cm per thermal time unit) and root anatomy (endodermis dimensions)). High VPD decreased biomass accumulation by reducing tillering, the leaf expansion rate and the duration of leaf expansion; decreased root endodermis cell size; and increased TR and the rate of TR increase upon gradual short-term VPD increases. Such changes may allow plants to increase their water transport capacity in a high VPD environment and are genotype-specific. Some variation in water use components was associated with terminal drought adaptation QTL. Knowledge of water use traitsâ plasticity in growth environments that varied in evaporative demand, and on their genetic determinacy, is necessary to develop trait-based breeding approaches to complex constraints
Modelling the effect of plant water use traits on yield and stay-green expression in sorghum
Post-rainy sorghum (Sorghum bicolor (L.) Moench) production underpins the livelihood of millions in the semiarid tropics, where the crop is affected by drought. Drought scenarios have been classified and quantified using crop simulation. In this report, variation in traits that hypothetically contribute to drought adaptation (plant growth dynamics, canopy and root water conducting capacity, drought stress responses) were virtually introgressed into the most common post-rainy sorghum genotype, and the influence of these traits on plant growth, development, and grain and stover yield were simulated across different scenarios. Limited transpiration rates under high vapour pressure deficit had the highest positive effect on production, especially combined with enhanced water extraction capacity at the root level. Variability in leaf development (smaller canopy size, later plant vigour or increased leaf appearance rate) also increased grain yield under severe drought, although it caused a stover yield trade-off under milder stress. Although the leaf development response to soil drying varied, this trait had only a modest benefit on crop production across all stress scenarios. Closer dissection of the model outputs showed that under water limitation, grain yield was largely determined by the amount of water availability after anthesis, and this relationship became closer with stress severity. All traits investigated increased water availability after anthesis and caused a delay in leaf senescence and led to a âstay-greenâ phenotype. In conclusion, we showed that breeding success remained highly probabilistic; maximum resilience and economic benefits depended on drought frequency. Maximum potential could be explored by specific combinations of traits
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