Rice Recovery Research Articles

Analyzing genetic variations for head rice recovery under heat stress in rice (Oryza sativa L.)

High temperature induces yield losses in rice, by affecting pollination, fertilization and also by affecting grain quality. High temperature stress coinciding with the grain filling period affects starch granule compaction thereby leading to reduced head rice recovery (HRR). The broken grains significantly reduce the price of rice by 50% in the market. Hence, the development of rice varieties that exhibit a lower reduction in grain quality coupled with higher head rice recovery under high temperature stress has become a major mandate in rice breeding programs. The present study was undertaken to survey the genetic variation for head rice recovery in rice under both normal (wet season) and high temperature (dry season) conditions. Evaluation of 50 diverse rice germplasm lines across different temperature regimes during grain filling viz. mean temperature of 30.8°C (wet season; May to Sep-Oct) and 35.8°C (Dry season 2017; January to May) and 36.2°C (Dry season 2018; Nov-Dec to May) identified huge genetic variation for HRR in rice. During the wet season, HRR ranged between 20.6 per cent and 90.9 per cent. During summer, rice genotypes exhibited a significant reduction in HRR from 3.6 to 82.7 per cent. Stability analysis revealed that the rice genotypes viz. CO 39, ChiemChanh, CO 18, Guan-Yin-Tsan, IR36, Teqing, ARC 10818 and Cimarron exhibited stable head rice recovery across all seasons. Keywords: Rice, heat stress, stability, head rice recovery

Basmati Rice Quality Enhancement by Zinc Fertilization and Green Manuring on a Sub-tropical Inceptisol in Indo-Gangetic Plains of India

Basmati (aromatic) rice is premier rice grown in north-western India and Pakistan. This rice is preferred for their long and slender kernels which expand 3-4 times in length and remain fluffy and are well known all over the world, especially in the Middle East and South Asia for their long fluffy grains on cooking. Paddy soils are usually deficient in organic matter because of high temperature and moisture, which causes rapid decomposition of organic matter. The importance of leguminous green manure crops in improving soil fertility, and soil physical properties received increasing attention. Also, the zinc (Zn) deficiency in soils is prevalent worldwide, especially in high pH calcareous soils. No reports were available on combining green manuring crops and Zn fertilization on productivity, Zn content and kernel quality of Basmati rice. Therefore, the current investigation was undertaken to quantify the combined effects of summer green manuring crops and zinc fertilization on productivity, Zn content and kernel quality of Basmati rice in summer green manuring-Basmati rice cropping system. A field study was therefore conducted for two years (2009 and 2010) on a sandy clay-loam soil (typic Ustochrept) at the research farm of the ICAR-Indian Agricultural Research Institute, New Delhi, India. The experiments were conducted in split plot design, keeping three green manuring crops viz. Sesbania aculeata (Dhaincha), Crotalaria juncea (Sunhemp), and Vigna unguiculata (Cowpea) and one summer fallow treatment as main-plot treatments and six Zn sources viz. control (no Zn application), ZnSO4∙7H2O (21% Zn), ZnSO4∙H2O (33% Zn), ZnO (82% Zn), ZnSO4∙7H2O + ZnO (50% + 50%) and EDTA-chelated Zn (12% Zn) in sub-plots and was replicated thrice. The experiments in both the years were conducted with a fixed lay-out plan on the same site. The results showed that incorporation of green manures along with zinc (Zn) fertilization increased grain and straw yield, enhanced Zn concentrations and improved the kernel quality before and after cooking in Basmati rice ‘Pusa Basmati 1’. The application of EDTA-chelated Zn (12% Zn) was the best in terms of grain and straw yield and Zn concentrations in grain and straw and kernel quality before and after cooking Basmati rice. Application of ZnSO4∙7H2O (21% Zn) was the second-best treatment followed by ZnSO4∙H2O (33% Zn) and ZnSO4∙7H2O + ZnO (50% + 50%). Application of ZnO (82% Zn) had least effect in increasing the studied parameters. The lowest values were observed with control (no Zn application). Among the summer green manuring crops, incorporation of Sesbania aculeata (Dhaincha) was found to be the best over Crotalaria juncea (Sunhemp), Vigna unguiculata (Cowpea) and summer fallow in terms of grain and straw yield, Zn concentrations in grain and straw and kernel quality before and after cooking in Basmati rice. Zn fertilization with EDTA-chelated Zn (12% Zn) lead to 25.91 and 21.26% higher grain yield; 60.66 and 82.14% Zn-denser grains; with 13.33 and 10.92% increase in head rice recovery in Basmati rice over control (no Zn application) during 2009 and 2010, respectively.

Herbicide-tolerant endophytic bacteria of rice plants as the biopriming agents for fertility recovery and disease suppression of unhealthy rice seeds

BackgroundDirty panicle disease (DPD) caused by several fungal phytopathogens results in damage and depreciation of rice seeds. Unhealthy rice seeds with DPD are potent reservoirs of pathogens and unable to be used as seed stock as they can spread the disease in the paddy fields leading to the severe loss of rice yield and quality. In this study, we aim to search for beneficial endophytes of commercially cultivated rice plants and utilize them as biostimulants in seed biopriming for fertility recovery and disease suppression of unhealthy rice seeds.ResultsForty-three bacterial endophytes were isolated from rice plants grown in the herbicide-treated paddy fields. Five isolates of these endophytes belonging to the genus Bacillus show excellent antifungal activity against fungal pathogens of DPD. Based on germination tests, biopriming unhealthy rice seeds by soaking in bacterial suspensions for 9 or 12 h was optimal as evidenced by the lowest disease incidence and longer shoot and root lengths of seedlings germinated, compared with controls made of non-treated or hydroprimed healthy and unhealthy seeds. Pot experiments were carried out to evaluate the impact of seed biopriming, in which the percentage of healthy rice yield produced by rice plants emerging from bioprimed seeds was not significantly different, compared to the controls originating respectively from non-treated healthy seeds and chemical fungicide-treated unhealthy seeds.ConclusionBiopriming of unhealthy rice seeds with herbicide-tolerant endophytic bacteria could recover seed fertility and protect the full life cycle of emerging rice plants from fungal pests. With our findings, seed biopriming is a straightforward approach that farmers can apply to recover unhealthy rice seed stock, which enables them to reduce the cost and use of agrochemicals in the commercial production of rice and to promote green technology in sustainable agriculture.

Differential activity of the antioxidant defence system and alterations in the accumulation of osmolyte and reactive oxygen species under drought stress and recovery in rice (Oryza sativa L.) tillering

The objective of this study was to investigate the effects of drought stress on the activity of antioxidant enzymes and osmotic adjustment substance content in the tillering period of drought-sensitive and drought-tolerant rice cultivars. The results showed that the superoxide dismutase (SOD), peroxidase (POD), catalase activity (CAT), hydrogen peroxide content, soluble protein content and soluble sugar content increased with the accumulation of time and intensity of drought stress. Compared with the drought-sensitive cultivar, drought-resistant cultivar had a smaller photosynthetic affected area, longer CAT enzyme activity duration, and lower H2O2 accumulation. Unlike POD and CAT enzymes, which maintain the ability to scavenge hydrogen peroxide under long drought conditions, ascorbate peroxidase (APX) enzymes seem to be a rapid response mechanism to scavenge hydrogen peroxide under drought stress. Under a −10 kPa water potential, using soluble sugars on the osmotic adjustment ability of the drought-resistant cultivars was more efficient; under −40 kPa water potential, drought-resistant cultivars can maintain relative high levels of ascorbate (ASA) content in the short term. After the restoration of irrigation, the indices gradually returned to control levels. The ASA content showed faster accumulation ability in drought-resistant cultivars and faster recovery. The soluble protein content recovered more slowly in drought-sensitive cultivars under the −40 kPa treatment. Drought-resistant cultivars showed stronger resistance to drought in the −10 kPa treatment and obtained similar yield to the control, while the drought-sensitive cultivars were more obviously affected by the drought stress.

Measuring Head Rice Recovery in Rice.

Head rice recovery (HRR) is a milling quality attribute that is highly influential toward the market price of rice. It is defined as the proportion of paddy rice that retains 75% of its length after milling. For a new rice variety to be accepted and adopted by farmers, the new variety's HRR should satisfy consumer requirements of at least 55% or above. Hence, HRR is a crucial attribute by which new varieties are selected for release. Although the amount of head rice recovered depends on the genetic background of a rice variety, HRR is also highly affected by postharvest processing conditions that the variety goes through. To determine the maximum HRR, therefore, one must ensure that the processing conditions are as optimal as possible. This book chapter outlines how paddy rice is processed into head rice and how HRR is measured. It also proposes an improved laboratory-scale means for postharvest drying to minimize head rice losses.

Customization of DNDC Model: Simulation of Yield and Nitrogen Balance in Rice (Oryza sativa L.) in Relation to Climate Change, Soil and Management Interventions

A field study was conducted at two different locations at research farms of Department of Soil Science, Punjab Agricultural University, Ludhiana, Punjab, on sandy loam soils during kharif 2015 and 2016 to evaluate the DNDC (Denitrification-Decomposition) model. Simulation were made to assess the impact of climate change scenario, soil and management interventions on past (1986–2016) and future (2020–2050) yield, nitrogen (N) balance and use efficiency of rice, and to made projections for future yield, N balance and use efficiency of rice for different texture soils and different locations of central Punjab. Results indicate that simulated rice grain yield, N uptake, volatilization and leaching increases but agronomic and recovery efficiency decreases at higher N levels. Simulated rice grain yield, N uptake, volatilization, agronomic and recovery efficiency would decrease in future time slices but leaching would increase. Per cent reduction in yield would be more in end part of mid century, lower at higher N levels (150–180 kg N ha−1) and in fine textured soils (silt loam). During time slice-4 (TS-4) (2040–2050) highest reduction in yield is expected at Patiala (54.7%) followed by Ludhiana (50.7%) then Amritsar (43.5%) but under higher N treatments (150 and 180 kg ha−1) yield reduction trend would be in the order of Ludhiana> Patiala> Amritsar. Trend for per cent increase in leaching during TS-4 would be Patiala> Amritsar> Ludhiana but volatilization would be Ludhiana> Patiala> Amritsar. The study suggests that higher N levels could be good option to compensate yield reduction in future however higher N levels would lead to higher N leaching and volatilization.

First evidence of rice (Oryza cf. sativa L.) and black pepper (Piper nigrum) in Roman Mursa, Croatia

This paper presents archaeobotanical evidence of rice (Oryza cf. sativa L.) and black pepper (Piper nigrum) recovered from an early 2nd century AD septic pit excavated near the centre of colonia Aelia Mursa (Osijek, Croatia). Within Roman Panonnia the archaeobotanical record shows evidence of trade consisting mostly of local Mediterranean goods such as olives, grapes and figs, however, the recovery of rice and black pepper from Mursa provides the first evidence of exotics arriving to Pannonia from Asia. Preliminary thoughts on the role of these foods within the colony and who may have been consuming them are briefly discussed. The Roman period represents a time of major change in the diet of newly assimilated regions and the results here highlight the contribution that archaeobotanical remains can make to the growing discourse on the development of societies on the Roman frontier.

Water-saving technologies affect the grain characteristics and recovery of fine-grain rice cultivars in semi-arid environment.

Growing rice with less water is direly needed due to declining water sources worldwide, but using methods that require less water inputs can have an impact on grain characteristics and recovery. A 2-year field study was conducted to evaluate the impact of conventionally sown flooded rice and low-water-input rice systems on the grain characteristics and recovery of fine rice. Three fine grain rice cultivars-Super Basmati, Basmati 2000, and Shaheen Basmati-were grown under conventional flooded transplanted rice (CFTR), alternate wetting and drying (AWD), and aerobic rice systems. Grain characteristics and rice recovery were significantly influenced by different water regimes (production systems). Poor milling, including the lowest percentage of brown (head) rice (65.3%) and polished (white) rice (64.2-66.9%) and the highest percentage of broken brown rice (10.2%), husk (24.5%-26.3%), polished broken rice (24.7%), and bran (11.0-12.5%), were recorded in the aerobic rice system sown with Shaheen Basmati. With a few exceptions, cultivars sown in CFTR were found to possess a higher percentage of brown (head) and polished (white) rice and they had incurred the least losses in the form of brown broken rice, husk, polished broken rice, and bran. In conclusion, better grain quality and recovery of rice can be attained by growing Super Basmati under the CFTR system. Growing Shaheen Basmati under low-water-input systems, the aerobic rice system in particular, resulted in poor grain characteristics tied with less rice recovery.

The dynamics of nitrogen derived from a chemical nitrogen fertilizer with treated swine slurry in paddy soil-plant systems

A well-managed chemical nitrogen (N) fertilization practice combined with treated swine slurry (TSS) is necessary to improve sustainability and N use efficiency in rice farming. However, little is known about the fate of N derived from chemical N fertilizer with and without TSS in paddy soil-plant systems. The objectives of this study were (1) to estimate the contribution of applied N fertilizer to N turnover in rice paddy soil with different N fertilization practices that were manipulated by the quantity of treated swine slurry and chemical N fertilizer (i.e., HTSS+LAS, a high amount of TSS with a low amount of ammonium sulfate; LTSS+HAS, a low amount of TSS with a high amount of ammonium sulfate; AS, ammonium sulfate with phosphorus and potassium; C, the control) and (2) to compare the rice response to applied N derived from each N fertilization practice. Rice biomass yield, 15N recovery in both rice grain and stems, soil total N (TN), soil inorganic N, and soil 15N recovery were analyzed. Similar amounts of 15N uptake by rice in the TSS+AS plots were obtained, indicating that the effects of the different quantities of TSS on chemical fertilizer N recovery in rice during the experimental period were not significant. The soil 15N recoveries of HTSS+LAS, LTSS+HAS, and AS in each soil layer were not significantly different. For the HTSS+LAS, LTSS+HAS and AS applications, total 15N recoveries were 42%, 43% and 54%, respectively. Because the effects of reducing the use of chemical N fertilizer were attributed to enhancing soil quality and cost-effectiveness, HTSS+LAS could be an appropriate N fertilization practice for improving the long-term sustainability of paddy soil-plant systems. However, N losses, especially through the coupled nitrification-denitrification process, can diminish the benefits that HTSS+LAS offers.

The Time of Flooding Occurrence is Critical for Yield Production in Rice and Vary in a Genotype-Dependent Manner

Flash floods occur in rainfed lowland and flood-prone areas and have a profound incidence on crop yield, which is tightly linked to worldwide food insecurity. The most flooding-threatened crop is rice. Under this condition, rice undergoes anoxic and post-anoxic shock that affects its growth, development capacity and ultimately causes an important grain yield loss. Therefore, the introduction of submergence-tolerant varieties in a flood-prone area was proposed as a preventive solution to limit these effects. Such a solution presents room for improvement and would benefit from a post-submergence management to ensure a better rice yield, yet remains to be defined. In this study, we assessed the effect of flooding on growth and yield of different rice varieties submerged at a different time of their developmental stage. We compared three rice varieties, namely Prachinburi 2 (PCR2), Kao Samer 1 (KSM1) and Neang Guang 5 (NG5), for their tolerance to 14 days of 50 cm depth submergence at 30, 60 and 90 Days After Germination (DAG). At 30 DAG, the recovery ability of KSM1 was restricted, showing decreased shoot dry mass and grain yield, whereas photo assimilate transport of PCR2 and NG5 was altered, resulting in high leaf nitrogen (N) concentration but low grain yield. Our data revealed that rice varieties were more tolerant to submergence at 60 and 90 DAG. In opposition to KSM1 and NG5 grain yield, PCR2 showed rapid recovery with a marked increase of shoot dry mass and grain yield. Taken together, our result indicates that de-submergence at late developmental stage promotes rice recovery and yield of tolerant variety. Gene discovery work is required to identify molecular players and pathways that are involved in submergence stress recovery in rice.

Agronomic Bio-fortification of Zinc in Indigenous, High Yielding and Hybrid Rice (Oryza sativaL.) Cultivars

Field experiment was conducted to assess the Zn content of rice grain and straw with and without Zn fertilizer application in a red and lateritic soil of Ranchi (Jharkhand). While, the grain yield of hybrid rice was considerably higher as compared to high yielding and indigenous rice cultivars, the response to added Zn in rice was not significant. Highest content of Zn (37.1 mg kg-1) was recorded in rice grain of indigenous rice cultivars, when Zn was applied @ 100 kg ha-1 of ZnSO4.7H2O (soil application) + 3 foliar application of 0.5% ZnSO4.7H2O. Results suggested that indigenous and high yielding rice cultivars were more suited than hybrids in red and lateritic soil for agronomic bio-fortification. Content of Zn in rice grain of indigenous cultivars was higher (32.1 mg kg-1) followed by HYV (26.7 mg kg-1) and hybrid (24.1 mg kg-1) cultivars of rice. Total Zn removal by rice crop was 0.44, 0.65 and 0.63 kg ha-1, respectively when indigenous; HYV and hybrid rice cultivars were grown without any addition of Zn. Soil as well as soil + foliar application of Zn increased the Zn uptake by rice more than two times, compared to its non-application. Apparent Zn recovery in rice was low i.e. 1.99, 1.49 and 1.08 per cent only with soil application of 100 kg ha-1 of ZnSO4.7H2O, respectively by hybrid, HYV and indigenous rice cultivars. This was considerably higher i.e. 4.32% in hybrid, 3.19% in HYV and 2.53% in indigenous rice cultivars, when Zn was added through soil (100 kg ha-1 of ZnSO4.7H2O) + foliar application of 0.5% ZnSO4.7H2O.

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Response and recovery of rice (Oryza sativa) seedlings to irrigation with microcystin-contaminated water

Irrigation with microcystin-contaminated water threatens plant growth and human health. We studied the accumulation of microcystins, growth, and photosynthesis in rice exposed to different concentrations microcystins (0, 1, 100, 1,000, and 3,000 μg L−1) for 7 days and then without microcystins for 7 days. After a 7-day exposure, the accumulation of microcystins in roots was the highest. High concentration microcystins (≥100 μg L−1) inhibited growth, and decreased photosynthetic rate and chlorophyll content. The decrease was positively correlated with microcystins concentrations. After a 7-day restoration, the accumulation of microcystins in organs was lower than that during the exposure period. The dry weight of roots and leaves in rice seedlings treated with 100 μg L−1 was not significantly different from those of the control, although photosynthetic rate and chlorophyll content in rice seedlings treated with 100 μg L−1 were still lower than those of the control. However, growth and photosynthesis in rice seedlings treated with 1,000 or 3,000 μg L−1 microcystins were still lower than those of the control, even worse than those during the exposure period, indicating an irreversible inhibition of microcystins to plants at high concentrations of microcystins. Our results imply that irrigation with microcystin-contaminated water must be monitored and controlled to avoid harmful accumulation of microcystins and damage to plant growth.

Increasing nitrogen rates in rice and its effect on plant nutrient composition and nitrogen apparent recovery

Rice ( Oryza sativa L.) is one of the essential foods of the human diet; advances in agronomic crop management can improve productivity and profitability as well as reduce adverse environmental impacts. Nitrogen rates in Chile are generally based on crop yield without considering other agronomic factors. The objective of this experiment was to determine the effect of increasing N rates on plant nutrient composition and N apparent recovery in rice cultivated in five different locations in Chile. The five sites located in central Chile belong to one of the following soil orders: Inceptisol, Alfisol, and Vertisol; they were cropped in field conditions with ‘Zafiro-INIA’ rice fertilized with 0, 80, and 160 kg N ha-1. Whole-plant total DM, macronutrient composition, and N apparent recovery efficiency (NARE) were determined at grain harvest. Results indicate that all evaluated parameters, with the exception of K concentration, were affected by the soil used. Nitrogen rates only affected total DM production and P, K, and Mg concentrations in plants. Phosphorus and K response decreased when N was added to some soils, which is associated with its chemical properties. Magnesium concentration exhibited an erratic effect, but it wasSnot affected by the N rate in most soils. Nitrogen apparent recovery efficiency was not affected by the N rate and accounted for approximately 49% and 41% for 80 and 160 kg N ha-1, respectively. Macronutrient composition was 5.1-7.7 g N, 1.3-1.8 g P, 5.4-10.8 g K, 1.68-2.57 g Ca, and 0.81-1.45 g Mg kg-1 of total DM.

Man-environment interaction and its impact since ca. 3600 years BP in West Bengal, India: A multiproxy approach

Climatic variability during the Holocene and corresponding anthropogenic response have gained considerable attention in different parts of India, but surprisingly very little is known on climate-human interrelationship from eastern India especially from the Gangetic plains of West Bengal. As climate has played significant role behind the collapse of many of the ancient human civilizations hence, to explore the reason behind the abandonment of any archaeological site, understanding of the climate of the contemporaneous past is a prerequisite. Agricultural development, subsistence strategies and dynamic behavior of climate in the Lower Gangetic plains of West Bengal since ca. 3600 cal a BP (Chalcolithic period) and post-Chalcolithic period (ca. 2350-2120 cal a BP to recent) were explored using multiproxy approach including plant-animal macro remains, wood charcoals and pollen and non-pollen palynomorphs from an archaeological site at Pakhanna, district Bankura in West Bengal, India. Evidences from palynological and phytolith data suggest that a warm-moist tropical climate during ca. 3600 cal a BP supported the spread of a village farming community in this part of lower Gangetic plains of West Bengal who practiced double-cropping as evidenced by the recovery of cereals (rice) and pulses (black gram) from the cultural deposits of Chalcolithic and Early Historic periods. In addition, a plenty of animal remains (opercula of carp fishes, fragments of plastron of Indian Soft Shelled Turtle, Indian Flap Shelled Turtle, ramus of mandible with teeth of Indian Boar) from similar cultural deposits indicate their probable inclusion in dietary list. The climate started changing during the onset of Early Historic period ca. 2350 cal a BP as revealed by pollen and phytolith proxies and became warmer and drier than that in earlier phase which is continuing till recent. The observations of palynological and phytolith data were also corroborated by the results of correspondence analysis (CA) and canonical correspondence analysis (CCA) respectively. Recovery of rice and mustard from Early Historic deposits suggests their continued cultivation at a later phase. Rich assemblages of animal macro remains from the post-Chalcolithic deposits (ca. 2350-2120 cal a BP) indicate their use as food resources in later phase too. Considering the database obtained from all the proxies it can be concluded that a moist-tropical climatic condition was prevailing during Chalcolithic period (ca. 3600 cal a BP) and later gradually shifted to a slight drier condition in lower Gangetic West Bengal.

Rice Uptake and Recovery of Nitrogen with Different Methods of Applying 15N-Labeled Chicken Manure and Ammonium Sulfate

The effects of different methods of fertilization on rice uptake and recovery of nitrogen were studied using 15N-lablled chicken manure (CM) and ammonium sulfate (AS). The results showed that the application method of totally basal dressing of organic and inorganic fertilizers can increase the N uptake by rice from the fertilizers. The N uptake from CM was obviously higher than that from AS. The N partitioning to rice grain was also higher than other application methods. The effect on increasing yield was obviously higher than the method of application of chemical fertilizers only. This method had such benefits as increasing N use efficiency, increasing N residue in soil and reducing N loss. High rice yield can be obtained while the soil fertility can be maintained with this method. So it is an effective and practical method of fertilization technique thus can be recommended to rice growers.

Herbivory by Resident Geese: The Loss and Recovery of Wild Rice Along the Tidal Patuxent River

Abstract: Well known for a fall spectacle of maturing wild rice (Zizania aquatica) and migrant waterbirds, the tidal freshwater marshes of the Patuxent River, Maryland, USA, experienced a major decline in wild rice during the 1990s. We conducted experiments in 1999 and 2000 with fenced exclosures and discovered herbivory by resident Canada geese (Branta canadensis). Grazing by geese eliminated rice outside exclosures, whereas protected plants achieved greater size, density, and produced more panicles than rice occurring in natural stands. The observed loss of rice on the Patuxent River reflects both the sensitivity of this annual plant to herbivory and the destructive nature of an overabundance of resident geese on natural marsh vegetation. Recovery of rice followed 2 management actions: hunting removal of approximately 1,700 geese during a 4‐year period and reestablishment of rice through a large‐scale fencing and planting program.

Effects of plastic film mulching cultivation under non‐flooded condition on rice quality

AbstractPlastic film mulching cultivation under non‐flooded condition (PFMC), a new high‐efficiency and water‐saving cultivation technique, has been adopted and developed in many regions of china since the 1980s. Field experiments were conducted to evaluate the effects of PFMC on rice quality in three agro‐ecosystems (plain, basin and mountainous area) in 2001. The experiment consisted of three treatments, which were conventional flooded cultivation (CFC), PFMC and non‐mulching cultivation (NMC) under non‐flooded condition in a randomized complete block design with three replications. Compared with CFC, PFMC increased head‐milled rice recovery (with the exception of plain area), rice transparency and alkali spreading value, but slightly decreased gel consistency and obviously decreased chalky grain rate. Compared with NMC, those quality traits under PFMC were changeable at different sites. There were no significant differences for brown rice rate (except hilly area), milling rice quality and amylose content across treatments. In addition, nutritional quality under PFMC was notably improved in comparison with CFC and NMC. With few exceptions, the protein content, total amino acid content, individual amino acid content and Lys content of rice decreased in the order of PFMC > NMC > CFC. In general, rice quality is affected by each agro‐ecosystem and cultivation system to different degrees. PFMC had more influence on rice quality in hilly region than plain and basin regions. Copyright © 2006 Society of Chemical Industry

Satellite Mapping and Monitoring of Wild Rice

Wild rice is the number one natural commodity in the state of Minnesota, and a major food source for Native Americans. Wild rice was estimated and mapped with Landsat data from 1998-2004 on the Leech Lake Indian Reservation in Minnesota. Due to increased precipitation in late 1998-early 1999 the reservation had a 65.7% loss in wild-rice crop area in 1999. In 2000, the wild rice crop returned to 52% of the original area. By 2004, the crop area had increased to 66% of the original crop area before the crop loss. The rate of recovery of wild rice following crop loss should be reflected in Leech Lake's insurance policy for wild rice.

Development of a non-lethal selection system by using the aadA marker gene for efficient recovery of transgenic rice (Oryza sativa L.).

The application of aminoglycoside-3"-adenyltransferase ( aadA) gene-mediated streptomycin resistance for non-lethal selection of transgenic rice resulted in plant regeneration frequencies under selection pressure as high as those in non-transformed controls without selection. Since streptomycin does not kill non-transgenic cells, and allows plant regeneration from them, a selection procedure was developed that made the visual identification of transgenic calli and regenerants possible. For callus-level selection, a vital pH indicator-Chlorophenol Red-was applied together with streptomycin, making use of the phenomenon that fast-growing cell lines lower the pH in the culture medium. Transgenic plants were selected according to their main distinctive features; their green colour (photomixotrophic assimilation), and more intense growth. At the same time, non-transgenic regenerants were bleached (heterotrophic assimilation), and growth was retarded in the presence of streptomycin and sucrose. The final efficiency of genetic transformation based on streptomycin resistance was found to be double that of transformations where the selective agent was l-phosphinothricin, and nearly three times more compared to transformations resulting in hygromycin-resistant regenerants. To the best of our knowledge, this is the first report on producing nuclear transformed rice plants by using a non-lethal selection strategy based on the chimaeric aadA gene.