A possible scenario for the end of the 21st century is that the atmospheric CO2 concentration will be in the range of 510 - 760 μl·L-I and that the mean global temperature will be 1.5°C - 4.5&d...A possible scenario for the end of the 21st century is that the atmospheric CO2 concentration will be in the range of 510 - 760 μl·L-I and that the mean global temperature will be 1.5°C - 4.5°C higher than present day. One of the pre-eminent manifestations of climate change is the increase in atmospheric CO2 concentration. Both CO2 and temperature are the key variables of global climate and may cause significant changes in crop productivity. An experiment was conducted inside open top chamber (OTCs) in kharif season 2014 to evaluate the effects of CO2 enrichment and temperature rise with condition OTC1 (ambient condition), OTC2 (25% higher CO2 than ambient), OTC3 (25% higher CO2 + 2°C 】ambient temperature) and OTC4 (2°C 】ambient temperature) on physiological traits and yield of rice genotypes to identify the suitable genotypes for changing climatic conditions. The study revealed that rice genotypes performed better under elevated CO2, with slight changes in development, such as growth and in yield attributing traits, depending on the genotypes. However, the beneficial direct impact of elevated (CO2) on crop yield can be counteract by elevated temperatures. Rice genotype IR83376-B-B-24-2 was highly responsive while IR84895-B-127-CRA-5-1-1 was least responsive toward elevated CO2. Physiological traits like relative water content (RWC %), membrane stability index (MSI %), chlorophyll content, photosynthetic rate and TSS content were improved under elevated CO2. However, responses of these traits were negative with elevated temperature. We point out that studies related to changes in crop physiology and yield as a consequence of global climatic changes should be a priority due to their association with food security.展开更多
Chickpea(Cicer arietinum L.) and pigeonpea [Cajanus cajan L.(Millsp.)] play an important role in mitigating protein malnutrition for millions of poor vegetarians living in regions of the semi-arid tropics. Abiotic str...Chickpea(Cicer arietinum L.) and pigeonpea [Cajanus cajan L.(Millsp.)] play an important role in mitigating protein malnutrition for millions of poor vegetarians living in regions of the semi-arid tropics. Abiotic stresses such as excess and limited soil moisture(water-logging and drought), heat and chilling(high and low temperature stresses), soil salinity, and acidity are major yield constraints, as these two crops are grown mostly under rainfed conditions in risk-prone marginal and degraded lands with few or no inputs. Losses due to such stresses vary from 30% to 100% depending on their severity. The literature abounds in basic information concerning screening techniques, physiological mechanisms, and genetics of traits associated with resistance/tolerance to abiotic stresses in these two crops. However, the final outcome in terms of resistant/tolerant varieties has been far from satisfactory. This situation calls for improving selection efficiency through precise phenotyping and genotyping under high-throughput controlled conditions using modern tools of genomics. In this review, we suggest that an integrated approach combining advances from genetics, physiology, and biotechnology needs to be used for higher precision and efficiency of breeding programs aimed at improving abiotic stress tolerance in both chickpea and pigeonpea.展开更多
The effect of auxins （IAA or IBA at 100, 200, 500 mg.L J） on rooting and sprouting parameters differed significantly （p 〈 0.05）. Rooting and sprouting percentages were higher in some treatments while other parame...The effect of auxins （IAA or IBA at 100, 200, 500 mg.L J） on rooting and sprouting parameters differed significantly （p 〈 0.05）. Rooting and sprouting percentages were higher in some treatments while other parameters were significantly higher in other treatments. The results of the present study revealed that rooting was significantly （p 〈 0.05） affected by the length of cuttings, as well as the position of shoots and type of cuttings. On average, 86.0 per cent rooting was observed in the 30-cm long cuttings com- pared to the other two lengths of cuttings, i.e., 20 and 25 cm, irrespective of any auxin treatment. In a control set, without any auxin treatment, a maximum of 60.0% rooting was recorded in the 30-cm long cuttings and a minimum of 40.0% of the cuttings rooted in the 20-cm long cuttings. Similarly, cuttings collected from the lower and upper portions of shoots resulted in 72.5 and 52.5 per cent rooting respectively, irrespective of auxin treatments. Maximum rooting was observed in the lower portion （40.0%） of cutting com- pared to the upper portion （30.0%） in the control set without auxin treatment. Leafless branches produced maximum （72.0%） rooting compared to the leafy cuttings （35.0%）, irrespective of the auxin treatment. The leafy cuttings produces a minimum of 15.0% sprout- ing and rooting in the control set.展开更多
文摘A possible scenario for the end of the 21st century is that the atmospheric CO2 concentration will be in the range of 510 - 760 μl·L-I and that the mean global temperature will be 1.5°C - 4.5°C higher than present day. One of the pre-eminent manifestations of climate change is the increase in atmospheric CO2 concentration. Both CO2 and temperature are the key variables of global climate and may cause significant changes in crop productivity. An experiment was conducted inside open top chamber (OTCs) in kharif season 2014 to evaluate the effects of CO2 enrichment and temperature rise with condition OTC1 (ambient condition), OTC2 (25% higher CO2 than ambient), OTC3 (25% higher CO2 + 2°C 】ambient temperature) and OTC4 (2°C 】ambient temperature) on physiological traits and yield of rice genotypes to identify the suitable genotypes for changing climatic conditions. The study revealed that rice genotypes performed better under elevated CO2, with slight changes in development, such as growth and in yield attributing traits, depending on the genotypes. However, the beneficial direct impact of elevated (CO2) on crop yield can be counteract by elevated temperatures. Rice genotype IR83376-B-B-24-2 was highly responsive while IR84895-B-127-CRA-5-1-1 was least responsive toward elevated CO2. Physiological traits like relative water content (RWC %), membrane stability index (MSI %), chlorophyll content, photosynthetic rate and TSS content were improved under elevated CO2. However, responses of these traits were negative with elevated temperature. We point out that studies related to changes in crop physiology and yield as a consequence of global climatic changes should be a priority due to their association with food security.
文摘Chickpea(Cicer arietinum L.) and pigeonpea [Cajanus cajan L.(Millsp.)] play an important role in mitigating protein malnutrition for millions of poor vegetarians living in regions of the semi-arid tropics. Abiotic stresses such as excess and limited soil moisture(water-logging and drought), heat and chilling(high and low temperature stresses), soil salinity, and acidity are major yield constraints, as these two crops are grown mostly under rainfed conditions in risk-prone marginal and degraded lands with few or no inputs. Losses due to such stresses vary from 30% to 100% depending on their severity. The literature abounds in basic information concerning screening techniques, physiological mechanisms, and genetics of traits associated with resistance/tolerance to abiotic stresses in these two crops. However, the final outcome in terms of resistant/tolerant varieties has been far from satisfactory. This situation calls for improving selection efficiency through precise phenotyping and genotyping under high-throughput controlled conditions using modern tools of genomics. In this review, we suggest that an integrated approach combining advances from genetics, physiology, and biotechnology needs to be used for higher precision and efficiency of breeding programs aimed at improving abiotic stress tolerance in both chickpea and pigeonpea.
文摘The effect of auxins （IAA or IBA at 100, 200, 500 mg.L J） on rooting and sprouting parameters differed significantly （p 〈 0.05）. Rooting and sprouting percentages were higher in some treatments while other parameters were significantly higher in other treatments. The results of the present study revealed that rooting was significantly （p 〈 0.05） affected by the length of cuttings, as well as the position of shoots and type of cuttings. On average, 86.0 per cent rooting was observed in the 30-cm long cuttings com- pared to the other two lengths of cuttings, i.e., 20 and 25 cm, irrespective of any auxin treatment. In a control set, without any auxin treatment, a maximum of 60.0% rooting was recorded in the 30-cm long cuttings and a minimum of 40.0% of the cuttings rooted in the 20-cm long cuttings. Similarly, cuttings collected from the lower and upper portions of shoots resulted in 72.5 and 52.5 per cent rooting respectively, irrespective of auxin treatments. Maximum rooting was observed in the lower portion （40.0%） of cutting com- pared to the upper portion （30.0%） in the control set without auxin treatment. Leafless branches produced maximum （72.0%） rooting compared to the leafy cuttings （35.0%）, irrespective of the auxin treatment. The leafy cuttings produces a minimum of 15.0% sprout- ing and rooting in the control set.
