•More salt-tolerant than any other vegetable crops.•Can produce enough biomass under moderate salinity stress which other vegetable crops cannot.•Salinity stressed plants signify increased bioactive ...compounds for economical use.•Those bioactive components which in turn probably can be harnessed for human health benefits.
Dry matter (DM), total phenolics, flavonoids, carotenoid contents, and antioxidant activity of 12 purslane accessions were investigated against five levels of salinity (0, 8, 16, 24 and 32dSm−1). In untreated plants, the DM contents ranged between 8.0–23.4g/pot; total phenolics contents (TPC) between 0.96–9.12mgGAEg−1DW; total flavonoid contents (TFC) between 0.15–1.44mgREg−1DW; and total carotenoid contents (TCC) between 0.52BCEg−1DW. While FRAP activity ranged from 8.64–104.21mgTEg−1DW (about 12-fold) and DPPH activity between 2.50–3.30mgmL−1 IC50 value. Different levels of salinity treatment resulted in 8–35% increases in TPC; about 35% increase in TFC; and 18–35% increases in FRAP activity. Purslane accessions Ac4, Ac5, Ac6 and Ac8 possessed potentials for salinity-induced augmented production of bioactive compounds which in turn can be harnessed for possible human health benefits.
Submergence or flood is one of the major harmful abiotic stresses in the low-lying countries and crop losses due to waterlogging are considerably high. Plant breeding techniques, conventional or ...genetic engineering, might be an effective and economic way of developing crops to grow successfully in waterlogged condition. Marker assisted selection (MAS) is a new and more effective approach which can identify genomic regions of crops under stress, which could not be done previously. The discovery of comprehensive molecular linkage maps enables us to do the pyramiding of desirable traits to improve in submergence tolerance through MAS. However, because of genetic and environmental interaction, too many genes encoding a trait, and using undesirable populations the mapping of QTL was hampered to ensure proper growth and yield under waterlogged conditions Steady advances in the field of genomics and proteomics over the years will be helpful to increase the breeding programs which will help to accomplish a significant progress in the field crop variety development and also improvement in near future. Waterlogging response of soybean and major cereal crops, as rice, wheat, barley, and maize and discovery of QTL related with tolerance of waterlogging, development of resistant variety, and, in addition, future prospects have also been discussed.
The response of twelve rice varieties against six salinity levels (0, 4, 8, 12, 16 and 20 dS m super(-1)) were studied at germination and early seedling stages. Data were analyzed using SAS and means ...were separated by LSD for final germination percentage (FGP), speed of germination (SG), germination energy percentage (GE%), plumule and radical length and plumule and radical dry weight. Based on dry matter yield reduction, rice varieties were classified as tolerant (T), moderately tolerant (MT), moderately susceptible (MS) or susceptible (S). Germination was completely arrested at 20 dS m super(-1) salt concentration. Salinity decreased FGP, SG, GE % and led to reduction in shoot and root length and dry weight in all varieties and the magnitude of reduction increased with increasing salinity stress. Rice varieties MR211, IR20, BR40 and MR232 showed greater salt tolerance during germination (germinated at 12 dS m super(-1) salinity). However, MR211, MR232 and IR20 performed better based on dry matter yield reduction. The result suggested that MR211, MR232 and IR20 might be used for further study of salinity effect on growth processes and physiological consequences at advanced stage of growth, since salt tolerance of a crop at germination and early seedling stage may not correspond to that at advanced stage.
Critical Period of Weed Control in Aerobic Rice Anwar, M. P.; Juraimi, A. S.; Samedani, B. ...
The scientific world journal/TheScientificWorldjournal,
01/2012, Letnik:
2012
Journal Article
Recenzirano
Odprti dostop
Critical period of weed control is the foundation of integrated weed management and, hence, can be considered the first step to design weed control strategy. To determine critical period of weed ...control of aerobic rice, field trials were conducted during 2010/2011 at Universiti Putra Malaysia. A quantitative series of treatments comprising two components, (a) increasing duration of weed interference and (b) increasing length of weed-free period, were imposed. Critical period was determined through Logistic and Gompertz equations. Critical period varied between seasons; in main season, it started earlier and lasted longer, as compared to off-season. The onset of the critical period was found relatively stable between seasons, while the end was more variable. Critical period was determined as 7–49 days after seeding in off-season and 7–53 days in main season to achieve 95% of weed-free yield, and 23–40 days in off-season and 21–43 days in main season to achieve 90% of weed-free yield. Since 5% yield loss level is not practical from economic view point, a 10% yield loss may be considered excellent from economic view point. Therefore, aerobic rice should be kept weed-free during 21–43 days for better yield and higher economic return.
Till now, herbicide seems to be a cost effective tool from an agronomic view point to control weeds. But long term efficacy and sustainability issues are the driving forces behind the reconsideration ...of herbicide dependent weed management strategy in rice. This demands reappearance of physical and cultural management options combined with judicious herbicide application in a more comprehensive and integrated way. Keeping those in mind, some agronomic tools along with different manual weeding and herbicides combinations were evaluated for their weed control efficacy in rice under aerobic soil conditions. Combination of competitive variety, higher seeding rate, and seed priming resulted in more competitive cropping system in favor of rice, which was reflected in lower weed pressure, higher weed control efficiency, and better yield. Most of the herbicides exhibited excellent weed control efficiency. Treatments comprising only herbicides required less cost involvement but produced higher net benefit. On the contrary, treatments comprising both herbicide and manual weeding required high cost involvement and thus produced lower net benefit. Therefore, adoption of competitive rice variety, higher seed rate, and seed priming along with spraying different early-postemergence herbicides in rotation at 10 days after seeding (DAS) followed by a manual weeding at 30 DAS may be recommended from sustainability view point.
Aerobic rice system, the most promising irrigation water saving rice production technology, is highly impeded by severe weed pressure. Weed control through the use of same herbicide causes ...development of herbicide resistant weed biotypes and serious problem in weed management. This study was aimed at finding out herbicides with different mode of actions to suggest effective weed control herbicide technology in aerobic rice system. This study was conducted at Malaysian Agricultural Research and Development Institute (MARDI), Seberang Perai Station, Penang, Malaysia during off season 2008 (April - July 2008) and main season 2008-2009 (November 2008 - February 2009) to evaluate fourteen and eight combinations of different locally available herbicides, in the off season and main seasons, respectively. A weed free control and a weedy check treatment were also included in the both trials. The trial used a RCB design with three replications in the off season and four replications in the main season, respectively. Twenty one (21) weed species were found in the aerobic rice field but two species (Eleusine indica and Digitaria ascendens) appeared as dominant. Based on the weed control efficiency, weed index values and net benefit from economic analysis, it appeared that the herbicide combinations such as Propanil/Benthiocarb fb Bentazone/MCPA or Cyhalofop-butyl+Bensulfuron fb Bentazone/MCPA or Pendimethalin fb Cyhalofopbutyl+ Bensulfuron fb Bentazone/MCPA or Pretilachlor+Pendimethalin fb Bentazone/MCPA could be the possible alternative options for effective and economic weed control in rice under aerobic system towards avoiding development of herbicide resistance in weed. Manual weeding is not at all cost-effective. The selected herbicide combinations could be used in rotation for sustainable weed management and to run the aerobic rice system as a profitable business venture.
Aim : Rice (Oryza sativa L.) is the second most important food crop in Malaysia, and weedy rice is the severe constraint in the Malaysian rice field. An experiment was conducted in Shadehouse at ...Field 2, Universiti Putra Malaysia to assess the performance of Agroplus BioDcomposer as a bioherbicide to control weedy rice and to select appropriate dosage of Agroplus BioDcomposer for effective control of weedy rice in the rice field. Methodology: Ten treatments of herbicides were applied in the experiment viz., control (0 ml), Agroplus BioDcomposer® (150 ml 201-1 water, 300 ml 201-1 water and 450 ml 201-1 water), Paraquat (125 ml 201-1 water, 250 ml 201-1 water and 375 ml 201-1 water) and the combination of Agroplus BioDcomposer® with Paraquat@150 ml 201-1 water+@125 ml 201-1 water, 300 ml 201-1 water+ 250 ml 201-1 waterand 450 ml 2011 water+375 ml 201-1 water). Data on the percentage of weedy rice killed three days after treatments and percentage of weedy rice emergence 7 and 14 days after soil application of treatments were recorded to evaluate the efficacyofdifferent treatments. Results : The results revealed significant differences among treatments in the percentage of weedy rice killed, weedy rice emergenceaftertreatments application and the ultimateyield ofrice. Paraquat, @ 375 ml 201-1 water and a combination of Agroplus BioDcomposer® and Paraquat (300 ml 201-1 water + 250 ml 201-1 water) performed better over other treatments to kill the weedy rice, to control the emergence of weedy rice from the seed bankand produced the highest rice yield. Interpretation : The overall result revealed that the recommended rate of Agroplus BioDcomposer® + Paraquat (300 ml 20 l-1 water + 250 ml 20 l-1 water) is more appropriate and suitable for environmental friendly control ofweedy rice in Malaysia.
This study investigated the allelopathic effect of Axonopus compressus litter on Asystasia gangetica and Pennisetum polystachion. In experiment 1 the bioassays with 0, 10, 30, and 50 g L−1 of aqueous ...A. compressus litter leachate were conducted. Experiment 2 was carried out by incorporating 0, 10, 20, 30, 40, and 50 g L−1 of A. compressus litter leachate into soil. In experiment 3, the fate of A. compressus litter leachate phenolics in the soil was investigated. A. compressus leachates did not affect the germination percentage of A. gangetica and P. polystachion, but delayed germination of A. gangetica seeds and decreased seed germination time of P. polystachion. A. compressus litter leachates affected weeds hypocotyl length. Hypocotyl length reductions of 18 and 31% were observed at the highest concentration (50 g L−1) compared to the control in A. gangetica and P. polystachion, respectively. When concentration of A. compressus litter leachate-amended soil increased A. gangetica and P. polystachion seedling shoot length, root length, seedling weight and chlorophyll concentration were not affected. The 5-week decomposition study of A. compressus showed that the phenolic compounds in A. compressus litter abruptly decreased about 52% after two weeks and remained steady until the end of the incubation.
Irrigation seawater of different salinity levels (0, 24, 48 and 72 dSm super(-1)) were applied to experimental plants grown in a plastic pots filled with a mixture of sand and peat (9:1). The results ...were analyzed using SAS and treatment means were compared using LSD Test. The results indicated that Paspalum vaginatum (seashore paspalum) (SP), Zoysia matrella (manilagrass) (MG), Pasplaum vaginatum local (SPL), Cynodon dactylon (common bermuda) (CB), Cynodon dactylon (bermuda greenless park) (GLP), Eremochloa ophiuroides (centipede) (CP), Axonopus compressus (cow grass) (CG) and Axonopus affinis (narrowleaf carpet grass) (NCG) experienced a 50% shoot growth reduction at the EC of 39.8, 36.5, 26.1, 25.9, 21.7, 22.4, 17.0 and 18.3 dSm super(-1), respectively, and a 50% root growth reduction at the EC of 49.4, 42.1, 29.9, 29.7, 26.0 24.8, 18.8 and 20.0 dSm super(-1), respectively. The ranking for salinity tolerance of selected grasses was SP>MG>SPL>CB>GLP>CP>NCG>CG. The results indicate the importance of the selection of turfgrass varieties according to the soil salinity and seawater salinity levels to be used for irrigation.
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