Genetic variability for grain yield and water use efficiency in blackgram genotypes

Transpiration efficiency (TE, g biomass kg-1 water transpired) is the preferred measure for examining po- tential genetic variation in crop water use efficiency (WUE). TE was assessed gravimetrically from sowing to grain harvest in fifteen blackgram accessions, two checks and two local varieties under well-watered conditions during kharif season. TEbiomass varied from 2.87 - 5.27 g kg-1 and TEseed varied from 1.10 - 2.03 g kg-1 among genotypes. High coefficient of variability was observed for seed yield and TEseed.Total biomass, TEbiomass, HI and water transpired recorded medium coefficient of variability. High heritability in broad sense was observed for seed yield, TEseed and total biomass. High genetic advance as percent of mean was observed for seed yield, TEseed, total biomass and TEbiomass. High heritability coupled with high genetic advance as per cent of mean was observed for seed yield, total biomass and TEseed.TEseed is significantly positively correlated with TEbiomass (0.883**), seed yield/ plant (0.805**), HI (0.757**) and biomass (0.572*). TEbiomass, seed yield per plant, total biomass and HI were the important components of TEseed as revealed by correlation studies.D2 analysis partitioned the nineteen genotypes in to five clusters. The maximum inter cluster distance was observed between cluster II and V (24.94) and III and IV (22.6). Genotypes IC436665, IC343952 and Local II (Cluster III) had high mean values for TEbiomass and TEseed along with total biomass and seed yield. These genotypes should be useful in future breeding programs for higher water use efficiency

Genetic variability for grain yield and water use efficiency in blackgram genotypes

Transpiration efficiency (TE, g biomass kg-1 water transpired) is the preferred measure for examining po- tential genetic variation in crop water use efficiency (WUE). TE was assessed gravimetrically from sowing to grain harvest in fifteen blackgram accessions, two checks and two local varieties under well-watered conditions during kharif season. TEbiomass varied from 2.87 - 5.27 g kg-1 and TEseed varied from 1.10 - 2.03 g kg-1 among genotypes. High coefficient of variability was observed for seed yield and TEseed.Total biomass, TEbiomass, HI and water transpired recorded medium coefficient of variability. High heritability in broad sense was observed for seed yield, TEseed and total biomass. High genetic advance as percent of mean was observed for seed yield, TEseed, total biomass and TEbiomass. High heritability coupled with high genetic advance as per cent of mean was observed for seed yield, total biomass and TEseed.TEseed is significantly positively correlated with TEbiomass (0.883**), seed yield/ plant (0.805**), HI (0.757**) and biomass (0.572*). TEbiomass, seed yield per plant, total biomass and HI were the important components of TEseed as revealed by correlation studies.D2 analysis partitioned the nineteen genotypes in to five clusters. The maximum inter cluster distance was observed between cluster II and V (24.94) and III and IV (22.6). Genotypes IC436665, IC343952 and Local II (Cluster III) had high mean values for TEbiomass and TEseed along with total biomass and seed yield. These genotypes should be useful in future breeding programs for higher water use efficiency

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Not AvailableA CO₂-responsive maize (Zea mays L.) genotype, Harsha, was selected to assess its response to elevated CO₂ in successive generation. The selfed seeds harvested from elevated CO₂ (eCO₂) raised maize plants were sown in open-top chambers (OTCs) to raise second generation (H-II) plants along with fresh seeds as first generation (H-I) under both ambient (400 ppm) and elevated (550 ppm) CO₂ (eCO₂) conditions. It was observed that second-generation (H-II) plants also showed improved performance under eCO₂ for morphological and physiological parameters. It is pertinent to mention that the H-II plants were more vigorous even under ambient CO₂ (aCO₂) condition as compared to H-I plants. The vigor of H-II plants was higher for majority of the morphological and biomass parameters under both aCO₂ and eCO₂. In H-II, the increased photosynthetic rate (Anet) was 6% and decrease in transpiration rate (Tr) was 49%, which resulted in significant increase (110%) in water use efficiency. This reveals that the elevated CO₂ improved the physiological performance of the maize plant over the generations. These results clearly elucidate that a C₄ crop like maize can respond to elevated CO₂ and higher response in subsequent generations may favor the crop resilience under changed climatic conditionsNot Availabl

Research Article IMPACT OF CO2 ENHANCEMENT ON PHOTOSYNTHESIS AND PROTEIN PROFILE- RESPONSE STUDIES WITH A CO2 RESPONSIVE

ABSTRACT: Black gram (Vigna mungo (L.) Hepper) var. IC-282009- a highly CO2 responsive genotype for biomass and seed yield was grown in Open top chambers (OTCs) under three levels of CO2 i.e. ambient (390 ppm) and two elevated levels 550ppm and 700ppm to assess photosynthetic acclimation to elevated CO2. Net photosynthetic rate (PN), change in leaf soluble protein profile and leaf carbohydrate constituents such as total soluble sugars, reducing sugars and starch content in leaves was quantified at all three CO2 concentrations. Photosynthetic rate was enhanced by 78% and 30 % at flowering stage with 550ppm and 700ppm CO2 as compared with ambient control. It was also observed a higher accumulation of starch, total soluble sugars and reducing sugars in leaves at elevated CO2 levels. However, the leaf protein content recorded a decrease and altered the profile of ploy peptides with enhanced CO2 levels. At elevated CO2 concentrations significant differences were observed in ploy peptide profile at vegetative and flowering stages, the intensity of 260 kDa poly peptide increased at vegetative stage, whereas 72 kDa polypeptide increased at flowering stage, while 52 kDa poly peptide decreased at both stages. Enhanced CO2 concentrations improved the PN though certain polypeptides of leaf protein are down regulated and necessitate further experimentation to confirm their involvement in responsiveness of the selected black gram genotype

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Not AvailableThe response of blackgram (Vigna mungo L. Hepper) to two levels of elevated carbon dioxide (550 and 700 ppm) in terms of growth and yield was investigated and compared with ambient CO2 level (365 ppm) using open-top chambers. The growth parameters viz., length and weight of root and shoot, root:shoot ratio, leaf area and weight significantly increased at 700 ppm CO2 when compared with 550 ppm. The percentage increase in total biomass at 700 and 550 ppm CO2 was 65.4% and 39%, respectively compared to the ambient (chamber) control. The increase in total seed yield at 700 ppm (129%) was due to an increase in number of pods per plant and 100 seed weight, whereas at 550 ppm (88.7%) it was due to an increased number of pods/plant and seeds/pod. The results indicate variable responsive effects at different levels of CO2 emphasizing the pertinence of research on elevated CO2 in various agroecological inhabitations all over the world. The indication of higher responses for root and leaf at initial growth stages at the higher elevated level of CO2 (700 ppm), which leads to better root establishment, achieving early photosynthetic efficiency and also better biomass production, and its improved partitioning can be reckoned as a positive aspect of increasing concentrations of CO2 in atmosphere. The harvest index increased significantly to 35.7 and 38.4% at 550 and 700 ppm, respectively; it is a very important phenomenon in pulses for breaking the yield barrier.AP-Cess, ICA

Elevated temperature and moisture deficit stress impact on phenology, physiology and yield responses of hybrid maize

A field experiment was conducted with maize (Zea mays L.) hybrid DHM-117 under elevated temperature and moisture deficit stress to assess the phenology, physiology, biomass and yield responses. The elevated canopy temperature (ET) was maintained as 3°C above ambient canopy temperature (AT) in Free Air Temperature Elevation (FATE) facility and water deficit stress (WD) was imposed at initiation of tasseling stage in an open plot experiment to assess the impact of these two abiotic stresses. As compared with ambient control, the phenology of flowering with the ET was early as 3 days for anthesis, 1 day for silking and this increased 4 days for anthesis silking interval (ASI), while with WD, anthesis was delayed by 2 days, silking by 3 days and ASI increased by 3 days. It was observed that both ET and WD significantly decreased photosynthetic rate (32%, 24%), stomatal conductance (45%, 28%), transpiration rate (36%, 44%) while increased WUE (6%, 38%). It is interesting to record that there was reduction in total biomass (11%, 13%) especially reproductive biomass (44%, 31%) with both ET and WD while vegetative biomass was improved (27%, 8%) revealing that reproductive components are effected with these abiotic stresses thereby decreased HI (42%, 36%). The impact of ET was more on seed set than seed filling as the reduction in test weight (8%) was higher than at WD (4%).

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Not AvailableGrowth and yield responses of castor bean (Ricinus communis L.) to two elevated CO2 levels (550 and 700 ppm) were evaluated up to the maturity of first order spikes in open top chambers (OTCs). The growth characteristics – root and shoot lengths, root volume, root:shoot ratios, leaf area, dry weights of different plant parts, leaf area duration and crop growth rate increased with 550 and 700 ppm of CO2 levels compared with ambient control. The spike length, pod and seed yield of first order spikes increased under enhanced CO2 levels over ambient control. Elevated CO2 levels significantly increased the total biomass and yield of castor bean, however enhanced CO2 levels per se did not changed the content and quality of the castor oil. A positive response of castor bean to increased CO2 concentrations is a good indication for its future existence in potentially changed climatic conditions.NPCC, ICA

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Not AvailablePigeon pea (Cajanus cajan L. Millsp.) is an important grain legume crop of the semi arid tropics and is a major dietary protein source. The extra short duration cultivar of pigeon pea ICPL 88039 was evaluated at ambient (370 μmol/mol) and twice the ambient (700 μmol/mol) concentrations of CO2 in open top chambers (OTCs). The results showed that the crop recorded a significant positive enhanced response for total biomass, fodder yield, grain yield, number of pods and seeds per plant, test weight and HI at elevated CO2. The ANOVA revealed significant differences in response of the characteristics to CO2 concentrations. Under elevated CO2 the total biomass recorded an improvement of 91.3%, grain yield 150.1%, fodder yield 67.1%. The major contributing components for improved grain yield under elevated CO2 were number of pods, number of seeds and test weight which recorded an increase of 97.9%, 119.5% and 7.2%, respectively. The crop maintained a significant positive increase of harvest index (HI) at elevated CO2 with an increment of 30.7% over ambient values. This increase in HI was due to its improved pod set and seed yield under enhanced CO2 concentration thereby emphasizes this crop for sustained food with nutritional security under climate change scenario.AP-Cess, ICA

Elevated CO2 ameliorate the negative effects of high temperature on groundnut (Arachis hypogaea)- Studies under free-air temperature elevation

Four groundnut (Arachis hypogaea L.) genotypes- Narayani, Dharani, K-6 and K-9 were assessed for growth and yield responses at elevated temperature of 3.0 ± 0.5°C above ambient canopy temperature (eT) and its interaction with elevated CO of 550 ± 50ppm (eT+eCO ) under Free Air 2 2 Temperature Elevation (FATE) facility. The study revealed that eT significantly decreased photosynthetic rate (A ) of all groundnut genotypes whereas eT+eCO condition ameliorated the ill effects of eT. The net 2 impact of eT on A was higher than transpiration rate (Tr) and this reflected in decreased WUE with all net genotypes. WUE improved significantly at eT+eCO with increased A and decreased Tr. Increase in 2 net canopy temperature (eT) resulted decreased relative water content (RWC), cell membrane stability and increased osmotic potential, Malondialdehyde (MDA) content and accumulation of proline. Elevated CO 2 along with eT (eT+eCO ) facilitated these parameters to recover to that of ambient controls, revealing the 2 ameliorative effect of eCO . Similar responses were recorded for biomass and yield parameters. Among 2 the selected groundnut genotypes, superior performance for seed yield at high temperature of >40°C by K-9 was due to ability to maintain better reproductive capacity and Dharani was responsive to elevated CO even at high temperature, indicating the genotypic variability

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Not AvailableFour groundnut (Arachis hypogaea L.) genotypes- Narayani, Dharani, K-6 and K-9 were assessed for growth and yield responses at elevated temperature of 3.0 ± 0.5°C above ambient canopy temperature (eT) and its interaction with elevated CO2 of 550 ± 50ppm (eT+eCO2 ) under Free Air Temperature Elevation (FATE) facility. The study revealed that eT significantly decreased photosynthetic rate (Anet ) of all groundnut genotypes whereas eT+eCO2 condition ameliorated the ill effects of eT. The impact of eT on Anet was higher than transpiration rate (Tr) and this reflected in decreased WUE with all net genotypes. WUE improved significantly at eT+eCO2 with increased Anet and decreased Tr. Increase in canopy temperature (eT) resulted decreased relative water content (RWC), cell membrane stability and increased osmotic potential, Malondialdehyde (MDA) content and accumulation of proline. Elevated CO2 along with eT (eT+eCO2) facilitated these parameters to recover to that of ambient controls, revealing the ameliorative effect of eCO2. Similar responses were recorded for biomass and yield parameters. Among the selected groundnut genotypes, superior performance for seed yield at high temperature of >40°C by K-9 was due to ability to maintain better reproductive capacity and Dharani was responsive to elevated CO2 even at high temperature, indicating the genotypic variability.NICR