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Miniature hyperspectral and thermal cameras onboard lightweight unmanned aerial vehicles (UAV) bring new opportunities for monitoring land surface variables at unprecedented fine spatial resolution with acceptable accuracy. This research applies hyperspectral and thermal imagery from a drone to quantify upland rice productivity and water use efficiency (WUE) after biochar application in Costa Rica. The field flights were conducted over two experimental groups with bamboo biochar (BC1) and sugarcane biochar (BC2) amendments and one control (C) group without biochar application. Rice canopy biophysical variables were estimated by inverting a canopy radiative transfer model on hyperspectral reflectance. Variations in gross primary productivity (GPP) and WUE across treatments were estimated using light-use efficiency and WUE models respectively from the normalized difference vegetation index (NDVI), canopy chlorophyll content (CCC), and evapotranspiration rate. We found that GPP was increased by 41.9 +/- 3.4% in BC1 and 17.5 +/- 3.4% in BC2 versus C, which may be explained by higher soil moisture after biochar application, and consequently significantly higher WUEs by 40.8 +/- 3.5% in BC1 and 13.4 +/- 3.5% in BC2 compared to C. This study demonstrated the use of hyperspectral and thermal imagery from a drone to quantify biochar effects on dry cropland by integrating ground measurements and physical models.

Miniature hyperspectral and thermal cameras onboard lightweight unmanned aerial vehicles (UAV) bring new opportunities for monitoring land surface variables at unprecedented fine spatial resolution with acceptable accuracy. This research applies hyperspectral and thermal imagery from a drone to quantify upland rice productivity and water use efficiency (WUE) after biochar application in Costa Rica. The field flights were conducted over two experimental groups with bamboo biochar (BC1) and sugarcane biochar (BC2) amendments and one control (C) group without biochar application. Rice canopy biophysical variables were estimated by inverting a canopy radiative transfer model on hyperspectral reflectance. Variations in gross primary productivity (GPP) and WUE across treatments were estimated using light-use efficiency and WUE models respectively from the normalized difference vegetation index (NDVI), canopy chlorophyll content (CCC), and evapotranspiration rate. We found that GPP was increased by 41.9 +/- 3.4% in BC1 and 17.5 +/- 3.4% in BC2 versus C, which may be explained by higher soil moisture after biochar application, and consequently significantly higher WUEs by 40.8 +/- 3.5% in BC1 and 13.4 +/- 3.5% in BC2 compared to C. This study demonstrated the use of hyperspectral and thermal imagery from a drone to quantify biochar effects on dry cropland by integrating ground measurements and physical models.

Miniature hyperspectral and thermal cameras onboard lightweight unmanned aerial vehicles (UAV) bring new opportunities for monitoring land surface variables at unprecedented fine spatial resolution with acceptable accuracy. This research applies hyperspectral and thermal imagery from a drone to quantify upland rice productivity and water use efficiency (WUE) after biochar application in Costa Rica. The field flights were conducted over two experimental groups with bamboo biochar (BC1) and sugarcane biochar (BC2) amendments and one control (C) group without biochar application. Rice canopy biophysical variables were estimated by inverting a canopy radiative transfer model on hyperspectral reflectance. Variations in gross primary productivity (GPP) and WUE across treatments were estimated using light-use efficiency and WUE models respectively from the normalized difference vegetation index (NDVI), canopy chlorophyll content (CCC), and evapotranspiration rate. We found that GPP was increased by 41.9 +/- 3.4% in BC1 and 17.5 +/- 3.4% in BC2 versus C, which may be explained by higher soil moisture after biochar application, and consequently significantly higher WUEs by 40.8 +/- 3.5% in BC1 and 13.4 +/- 3.5% in BC2 compared to C. This study demonstrated the use of hyperspectral and thermal imagery from a drone to quantify biochar effects on dry cropland by integrating ground measurements and physical models.

Miniature hyperspectral and thermal cameras onboard lightweight unmanned aerial vehicles (UAV) bring new opportunities for monitoring land surface variables at unprecedented fine spatial resolution with acceptable accuracy. This research applies hyperspectral and thermal imagery from a drone to quantify upland rice productivity and water use efficiency (WUE) after biochar application in Costa Rica. The field flights were conducted over two experimental groups with bamboo biochar (BC1) and sugarcane biochar (BC2) amendments and one control (C) group without biochar application. Rice canopy biophysical variables were estimated by inverting a canopy radiative transfer model on hyperspectral reflectance. Variations in gross primary productivity (GPP) and WUE across treatments were estimated using light-use efficiency and WUE models respectively from the normalized difference vegetation index (NDVI), canopy chlorophyll content (CCC), and evapotranspiration rate. We found that GPP was increased by 41.9 +/- 3.4% in BC1 and 17.5 +/- 3.4% in BC2 versus C, which may be explained by higher soil moisture after biochar application, and consequently significantly higher WUEs by 40.8 +/- 3.5% in BC1 and 13.4 +/- 3.5% in BC2 compared to C. This study demonstrated the use of hyperspectral and thermal imagery from a drone to quantify biochar effects on dry cropland by integrating ground measurements and physical models.

Miniature hyperspectral and thermal cameras onboard lightweight unmanned aerial vehicles (UAV) bring new opportunities for monitoring land surface variables at unprecedented fine spatial resolution with acceptable accuracy. This research applies hyperspectral and thermal imagery from a drone to quantify upland rice productivity and water use efficiency (WUE) after biochar application in Costa Rica. The field flights were conducted over two experimental groups with bamboo biochar (BC1) and sugarcane biochar (BC2) amendments and one control (C) group without biochar application. Rice canopy biophysical variables were estimated by inverting a canopy radiative transfer model on hyperspectral reflectance. Variations in gross primary productivity (GPP) and WUE across treatments were estimated using light-use efficiency and WUE models respectively from the normalized difference vegetation index (NDVI), canopy chlorophyll content (CCC), and evapotranspiration rate. We found that GPP was increased by 41.9 +/- 3.4% in BC1 and 17.5 +/- 3.4% in BC2 versus C, which may be explained by higher soil moisture after biochar application, and consequently significantly higher WUEs by 40.8 +/- 3.5% in BC1 and 13.4 +/- 3.5% in BC2 compared to C. This study demonstrated the use of hyperspectral and thermal imagery from a drone to quantify biochar effects on dry cropland by integrating ground measurements and physical models.

Miniature hyperspectral and thermal cameras onboard lightweight unmanned aerial vehicles (UAV) bring new opportunities for monitoring land surface variables at unprecedented fine spatial resolution with acceptable accuracy. This research applies hyperspectral and thermal imagery from a drone to quantify upland rice productivity and water use efficiency (WUE) after biochar application in Costa Rica. The field flights were conducted over two experimental groups with bamboo biochar (BC1) and sugarcane biochar (BC2) amendments and one control (C) group without biochar application. Rice canopy biophysical variables were estimated by inverting a canopy radiative transfer model on hyperspectral reflectance. Variations in gross primary productivity (GPP) and WUE across treatments were estimated using light-use efficiency and WUE models respectively from the normalized difference vegetation index (NDVI), canopy chlorophyll content (CCC), and evapotranspiration rate. We found that GPP was increased by 41.9 +/- 3.4% in BC1 and 17.5 +/- 3.4% in BC2 versus C, which may be explained by higher soil moisture after biochar application, and consequently significantly higher WUEs by 40.8 +/- 3.5% in BC1 and 13.4 +/- 3.5% in BC2 compared to C. This study demonstrated the use of hyperspectral and thermal imagery from a drone to quantify biochar effects on dry cropland by integrating ground measurements and physical models.

The experiment was conducted at Coconut Research Station, Balaramapuram with an objective to study the effect of nutrient levels and nutrient schedules on physiological parameters and grain yield of upland rice (MO 21- Prathyasa rice variety) intercropped in coconut. Field experiment was conducted in factorial randomized block design with nutrient levels as first factor and nutrient schedules as second factor in three replications. Nutrient levels had significant effect on the physiological parameters. Among the nutrient levels rested, NPK applied @ 120:30:60 recorded higher total chlorophyll (2.803 mg g-1) and chlorophyll b content (1.508 mg g-1), crop growth rate (CGR) (11.23 g m-2 day-1) and relative growth rate (RGR) (0.056 g g-1 day-1) as compared to lower nutrient level tested, NPK @ 60:30:30 kg ha-1. Nutrient schedules also had significant effect (P=0.05) on the physiological parameters viz., total chlorophyll, chlorophyll a, chlorophyll b, CGR and RGR and the treatment receiving 0.2 per cent zinc sulphate and 0.04 per cent sodium borate spray at 45 DAS recorded higher chlorophyll content, RGR and CGR. Though the higher nutrient level, NPK @ 120:30:45 kg ha-1 recorded higher values for physiological parameters, it recorded the lowest grain yield. Application of NPK @ 90:30:45 kg ha-1 recorded the highest grain yield and it was followed by NPK applied @ 70:30:35 kg ha-1. Among the nutrient schedules, N applied as three equal splits, P as basal and K in two equal splits along with foliar spray of zinc sulphate 0.2 per cent and sodium borate 0.04 per cent at 45 DAS recorded the highest grain yield (3.25 t ha-1). The study clearly revealed that excessive vegetative growth is not a desirable parameter for higher grain yield.

Field experiment was conducted at Coconut Research Balaramapuram, during Kharif 2017 to study the effect of nutrient levels and schedule of application on the quality parameters of upland rice intercropped in coconut. The experiment was conducted in randomized block design (RBD) with four different nutrient levels and four different schedules of nutrient application. Quality parameters like crude protein and starch content were significantly influenced by nutrient levels. The crude protein content was found to increase with increase in N level, however starch content was found to increase up to 70 kg N and 35 kg K ha-1 and after that a decline in trend was observed.  The highest crude protein content (8.38 per cent) was recorded with highest nutrient level, NPK @ 120:30:60 kg ha-1.  However, lower nutrient level, NPK @ 70:30:35 kg ha-1 recorded higher starch content (85.03 per cent).  Among the schedule of nutrient application, N applied in three equal splits (15 days after sowing (DAS), active tillering and panicle initiation stage), P as basal and K in two equal splits (15 DAS and panicle initiation stage) along with foliar application of 0.2 per cent zinc sulphate and 0.04 per cent sodium borate at 45 DAS recorded the highest crude protein (7.50 per cent) and starch content (84.17 per cent). The study clearly indicated that the increased level of N and K increased the protein content due to the active role of N and K in protein synthesis. However, high rate of N application decreased the starch content. In addition to the application of NPK, foliar nutrition of zinc sulphate and sodium borate at 45 DAS considerably improved the quality of grain by increasing the starch and protein content.

This study aims to determine the efficiency of water use between genotype and identify the characters of upland rice varieties tolerant to drought stress. The experiment was conducted in a plastic house in North Aceh, in January 2015 to May 2015. The study design was split plot design with three replications and two treatment factors. The first factor is drought stress (C) which consisted of 4 capacity airy levels namely: C1: 20%, C2: 40%, C3: 60% and C4: 80%. The second factor is the 10 upland rice varieties which consists of three groups, namely (tolerant group varieties) which consists of Ciapus, Inpago 4, and Inpago 8; (moderate group varieties) which consist of Inpago 5, Situ Bangendit, Inpago7, Towuti; and (susceptible group varieties) which consists of Inpari 6 Jete, Inpari 33 and Sintanur. The results of the study showed changes in character of dry root weight and ratio of canopy, number of panicles per clump1000, grains and grain production per clump as a result of drought stress at 20% of field capacity (C1). Tolerant varieties (Inpago 4, Inpago 8, Ciapus) shows avoidance mechanisms to drought stress by increasing weight of dry root, reducing the ration of canopy and decreasing the number of 1000 grains and grain production is smaller and stable.

Abiotic stresses negatively affect stable crop production yield world-wide. The yield of rice production is affected by drought or water deficit. Water shortage and uneven rainfall distribution limit the use of available water for rice production. The irrigation costs increase yearly in water limited area. Therefore, developing rice varieties with high water use efficient is needed currently. Upland rice performs better and drought tolerant under water limited environment although the yield is low. Therefore, the upland rice can serve as genetic resources for genetic manipulation of susceptible crops. The objectives of the study were: (i) to screen for drought-tolerant upland rice varieties, (ii) to isolate and identify the expressed drought-responsive genes in drought-tolerant upland rice under water limitation, and (iii) to examine the differential expression of transcripts under drought stress and normal conditions. Investigation was performed to evaluate 38 upland rice varieties with five drought levels at germination and early seedling growth stage using PEG 6000 as drought inducer. Drought tolerant variety, IR5533-15-1-1 (S24) had better germination indices, root length, the highest enzymatic antioxidant activity and non-enzymatic antioxidant level (proline) compared to sensitive varieties. Pot experiment was conducted on IR5533-15-1-1 (S24) variety that were (i) watered regularly (un-treated and control plants) and (ii) treated with PEG 6000 solution (-8 bar) for five days at reproductive stage. Then, isolated mRNA from leaves (control and treated plants) was used to generate subtracted cDNA library. The expressed sequence tags (ESTs) were analyzed. Reverse transcriptase PCR and real-time PCR were conducted to analyze the expression profiles of drought-responsive genes from upland rice. Two EST sequences identified showed 87% and 97% similarities to that of glutathione Stransferase (GST) and dehydrin (DHN) from rice, respectively. The expression levels of GST

Upland rice is a valuable base population for protecting against genetic erosion and broadening the gene pool of rice germplasm. Blast caused by the fungus Magnaporthe oryzae is the most impactful rice disease, and it can be severe in upland/dry land cultures. This study aimed to identify and characterize upland rice germplasm for blast disease resistance. Initially, 50 upland rice genotypes, including one resistant check, Pongsu Seribu-1, and one susceptible check, MR219, were evaluated to identify new sources of resistance and assess diversity based on reactions to M. oryzae. Resistant reactions were observed in the genotypes Biaw Bood Pae, Blau Noc, Chirikata 2, IPPA, IR 5533-50-1-10, IR 5533-55-1- 11, Ja Hau, Ja No Naq, BR26, BRRI dhan42 and BRRI dhan43. The 50 genotypes were grouped into five clusters based on the greater similarities of their reactions to the blast fungus. The morphological, physiological and yield trait characteristics of 27 globally diverse blast-resistant genotypes were further evaluated. Additionally, the genotypes were analyzed to determine the correlations between and diversity among these characteristics. The BRRI dhan43, C, Choke Tang and Chirikata 2 were identified as early-maturing genotypes that provided the best yields. The largest heritability coupled with a high genetic advancement was recorded for a number of filled grains/panicle and yield/plant, demonstrating that these traits can be successfully transferred to offspring if selection of these characteristics is performed via a hybridization program. The 27 genotypes were grouped into six clusters based on the contributing morphological, physiological and yield characteristics. The blastresistant, early-maturing, high-yield genotype BRRI dhan43 was then finally characterized to determine the molecular mechanism underlying the plant-microbe interaction using next generation sequencing (NGS). The reference-based alignment produced total reads of 66.9 and 66.2 million in the unino

This study aims to determine the efficiency of water use between genotype and identify the characters of upland rice varieties tolerant to drought stress. The experiment was conducted in a plastic house in North Aceh, in January 2015 to May 2015. The study design was split plot design with three replications and two treatment factors. The first factor is drought stress (C) which consisted of 4 capacity airy levels namely: C1: 20%, C2: 40%, C3: 60% and C4: 80%. The second factor is the 10 upland rice varieties which consists of three groups, namely (tolerant group varieties) which consists of Ciapus, Inpago 4, and Inpago 8; (moderate group varieties) which consist of Inpago 5, Situ Bangendit, Inpago7, Towuti; and (susceptible group varieties) which consists of Inpari 6 Jete, Inpari 33 and Sintanur. The results of the study showed changes in character of dry root weight and ratio of canopy, number of panicles per clump1000, grains and grain production per clump as a result of drought stress at 20% of field capacity (C1). Tolerant varieties (Inpago 4, Inpago 8, Ciapus) shows avoidance mechanisms to drought stress by increasing weight of dry root, reducing the ration of canopy and decreasing the number of 1000 grains and grain production is smaller and stable.

This study aims to determine the efficiency of water use between genotype and identify the characters of upland rice varieties tolerant to drought stress. The experiment was conducted in a plastic house in North Aceh, in January 2015 to May 2015. The study design was split plot design with three replications and two treatment factors. The first factor is drought stress (C) which consisted of 4 capacity airy levels namely: C1: 20%, C2: 40%, C3: 60% and C4: 80%. The second factor is the 10 upland rice varieties which consists of three groups, namely (tolerant group varieties) which consists of Ciapus, Inpago 4, and Inpago 8; (moderate group varieties) which consist of Inpago 5, Situ Bangendit, Inpago7, Towuti; and (susceptible group varieties) which consists of Inpari 6 Jete, Inpari 33 and Sintanur. The results of the study showed changes in character of dry root weight and ratio of canopy, number of panicles per clump1000, grains and grain production per clump as a result of drought stress at 20% of field capacity (C1). Tolerant varieties (Inpago 4, Inpago 8, Ciapus) shows avoidance mechanisms to drought stress by increasing weight of dry root, reducing the ration of canopy and decreasing the number of 1000 grains and grain production is smaller and stable.

Abiotic stresses negatively affect stable crop production yield world-wide. The yield of rice production is affected by drought or water deficit. Water shortage and uneven rainfall distribution limit the use of available water for rice production. The irrigation costs increase yearly in water limited area. Therefore, developing rice varieties with high water use efficient is needed currently. Upland rice performs better and drought tolerant under water limited environment although the yield is low. Therefore, the upland rice can serve as genetic resources for genetic manipulation of susceptible crops. The objectives of the study were: (i) to screen for drought-tolerant upland rice varieties, (ii) to isolate and identify the expressed drought-responsive genes in drought-tolerant upland rice under water limitation, and (iii) to examine the differential expression of transcripts under drought stress and normal conditions. Investigation was performed to evaluate 38 upland rice varieties with five drought levels at germination and early seedling growth stage using PEG 6000 as drought inducer. Drought tolerant variety, IR5533-15-1-1 (S24) had better germination indices, root length, the highest enzymatic antioxidant activity and non-enzymatic antioxidant level (proline) compared to sensitive varieties. Pot experiment was conducted on IR5533-15-1-1 (S24) variety that were (i) watered regularly (un-treated and control plants) and (ii) treated with PEG 6000 solution (-8 bar) for five days at reproductive stage. Then, isolated mRNA from leaves (control and treated plants) was used to generate subtracted cDNA library. The expressed sequence tags (ESTs) were analyzed. Reverse transcriptase PCR and real-time PCR were conducted to analyze the expression profiles of drought-responsive genes from upland rice. Two EST sequences identified showed 87% and 97% similarities to that of glutathione Stransferase (GST) and dehydrin (DHN) from rice, respectively. The expression levels of GST

Upland rice is a valuable base population for protecting against genetic erosion and broadening the gene pool of rice germplasm. Blast caused by the fungus Magnaporthe oryzae is the most impactful rice disease, and it can be severe in upland/dry land cultures. This study aimed to identify and characterize upland rice germplasm for blast disease resistance. Initially, 50 upland rice genotypes, including one resistant check, Pongsu Seribu-1, and one susceptible check, MR219, were evaluated to identify new sources of resistance and assess diversity based on reactions to M. oryzae. Resistant reactions were observed in the genotypes Biaw Bood Pae, Blau Noc, Chirikata 2, IPPA, IR 5533-50-1-10, IR 5533-55-1- 11, Ja Hau, Ja No Naq, BR26, BRRI dhan42 and BRRI dhan43. The 50 genotypes were grouped into five clusters based on the greater similarities of their reactions to the blast fungus. The morphological, physiological and yield trait characteristics of 27 globally diverse blast-resistant genotypes were further evaluated. Additionally, the genotypes were analyzed to determine the correlations between and diversity among these characteristics. The BRRI dhan43, C, Choke Tang and Chirikata 2 were identified as early-maturing genotypes that provided the best yields. The largest heritability coupled with a high genetic advancement was recorded for a number of filled grains/panicle and yield/plant, demonstrating that these traits can be successfully transferred to offspring if selection of these characteristics is performed via a hybridization program. The 27 genotypes were grouped into six clusters based on the contributing morphological, physiological and yield characteristics. The blastresistant, early-maturing, high-yield genotype BRRI dhan43 was then finally characterized to determine the molecular mechanism underlying the plant-microbe interaction using next generation sequencing (NGS). The reference-based alignment produced total reads of 66.9 and 66.2 million in the unino

Java Island is one of origins of a large number of indigenous upland rice accessions, which may serve as valuable plant genetic resources for future crop improvement in Indonesia. However, these landraces especially non-glutinous and glutinous rice are rapidly being lost because of land-use, agricultural practices and other factors. A better understanding of genetic diversity of local upland rice is important for crop improvement program, crop management and conservation strategy. This study aimed to evaluate the genetic diversity of upland rice landraces originating from Java Island. A total of 82 upland rice accessions comprising of 55 non-glutinous rice and 27 glutinous type were genotyped using the 16 simple sequence repeat (SSR) markers. The result showed that a total of 74 alleles were found with major allele frequency found on RM431 (0.96). Most of the SSR markers (56.3%) showed high discriminating power as represented by polymorphic informa-tion content (PIC) value higher than 0.5. A moderate genetic diversity index was detected in all landraces, which was 0.55. Genetic diversity index of non-glutinous and glutinous rice were 0.54 and 0.53, respectively. Their genetic distance was about 0.057. The phylogenetic tree generated two main clusters that demonstrated discrimination among landraces according to the individual genetic properties rather than their geographical origins and grain types (non-glutinous and glutinous type). The levels of genetic diversity were varied across rice types and geographical origins. According to the regions, the closest genetic distance was found between upland rice landraces from Central Java and West Java (0.040). The information derived from this study is important, in combination with phenotypic data, to identify desired useful traits came from different origins of the gene pool to be used for breeding purposes.

In Asia, the rice root-knot nematode, Meloidogyne graminicola, is an important pathogen of Asian rice (Oryza sativa) in most rice producing countries including Myanmar. In the first part of our study, the damage potential of M. graminicola on commonly cultivated newly released high-yielding lowland rice varieties and upland rice varieties (traditional, improved and aerobic), which are being grown in different regions in the summer-irrigated lowland and rainfed upland rice ecosystems in Myanmar, was investigated under screenhouse conditions. In the second part of our study, a field experiment was carried out in the Ayeyarwady River Delta, the major lowland rice producing area of Myanmar, to investigate the impact of M. graminicola on plant growth and yield of the same lowland rice varieties included in the screenhouse experiment in a naturally-infested farmer’s field. None of the 15 lowland varieties and none of the nine upland varieties included in the screenhouse experiments was resistant to M. graminicola. Although differences in susceptibility were observed among the lowland and upland varieties, and between the two types (lowland and upland) of rice varieties, with an Mf–eggs (multiplication factor of the second-stage juveniles without counting the eggs) ranging from 13.2 to 52.8 for the lowland varieties vs 39.8 to 108.4 for the upland varieties, all varieties included in our study can be considered as highly susceptible to M. graminicola when the nematode population densities are assessed at harvest. Also in the field experiment, all the 15 lowland varieties were susceptible to M. graminicola infection. This part of our study shows that upland rice varieties are more susceptible to M graminicola infection than lowland rice varieties. The percentage reduction in lowland and upland varieties was very similar in six out of the ten plant growth and yield-contributing traits measured. The highest differences in percentage reduction were observed for fresh root weig

In Asia, the rice root-knot nematode, Meloidogyne graminicola, is an important pathogen of Asian rice (Oryza sativa) in most rice producing countries including Myanmar. In the first part of our study, the damage potential of M. graminicola on commonly cultivated newly released high-yielding lowland rice varieties and upland rice varieties (traditional, improved and aerobic), which are being grown in different regions in the summer-irrigated lowland and rainfed upland rice ecosystems in Myanmar, was investigated under screenhouse conditions. In the second part of our study, a field experiment was carried out in the Ayeyarwady River Delta, the major lowland rice producing area of Myanmar, to investigate the impact of M. graminicola on plant growth and yield of the same lowland rice varieties included in the screenhouse experiment in a naturally-infested farmer’s field. None of the 15 lowland varieties and none of the nine upland varieties included in the screenhouse experiments was resistant to M. graminicola. Although differences in susceptibility were observed among the lowland and upland varieties, and between the two types (lowland and upland) of rice varieties, with an Mf–eggs (multiplication factor of the second-stage juveniles without counting the eggs) ranging from 13.2 to 52.8 for the lowland varieties vs 39.8 to 108.4 for the upland varieties, all varieties included in our study can be considered as highly susceptible to M. graminicola when the nematode population densities are assessed at harvest. Also in the field experiment, all the 15 lowland varieties were susceptible to M. graminicola infection. This part of our study shows that upland rice varieties are more susceptible to M graminicola infection than lowland rice varieties. The percentage reduction in lowland and upland varieties was very similar in six out of the ten plant growth and yield-contributing traits measured. The highest differences in percentage reduction were observed for fresh root weig

Three upland rice cultivars namely Vandana, Brown Gora and Kalinga collected from the Central Rainfed Upland Rice Research Station (CRURRS), Hazaribag, Jharkhand of the Central Rice Research Institute, are mycorrhiza sensitive genotypes. Their affinity towards mycorrhizal colonization varied. The cv. Kalinga had the highest colonization followed by Vandana and Brown Gora. Variation of arbuscular mycorrhizal fungi affinity of the rice genotypes might be due to the variable demands of phosphorus nutrition of the different genotypes. To justify these variable demands of phosphorus among these three cultivars of rice, four different doses of phosphorus (5, 10, 15 and 20 ppm) were imposed to them in a system of hydroponics. Overall, among the three cultivars, the highest uptake efficiency (34% at 30 days, 57% at 45 days, 68% at 60days and 70% at 75 days interval) throughout the growth period was noticed in the cv. Brown Gora, followed by Kalinga and Vandana. The physiological demands of phosphorus of these cultivars were finally estimated as the contribution of uptake phosphorus to the total dry matter production of the plants with respect to available phosphorus. The overall results of these estimations gave the highest value in cv. Kalinga followed by the cv. Vandana and Brown Gora. Therefore, the cultivars Brown Gora and Kalinga could be recommended for the cultivation of the vast upland rain-fed areas of the country for higher yield and increased phosphorus use efficiency which could ultimately contribute significantly to the food grain production of the country.

Crops with high biomass and marketable yield were aimed to be identified to be used in Conservation Agriculture Production Systems (CAPS). This is done in order to provide good soil cover and high profitability at the same time.

Crops with high biomass and marketable yield were aimed to be identified to be used in Conservation Agriculture Production Systems (CAPS). This is done in order to provide good soil cover and high profitability at the same time.

The main objective of this study was to assess the impact of biochar rate (0, 8, 16 and 32 Mg ha-1) on the water retention capacity (WRC) of a sandy loam Dystric Plinthosol. The applied biochar was a by-product of slow pyrolysis (~450 °C) of eucalyptus wood, milled to pass through a 2000 µm sieve that resulted in a material with an intrinsic porosity =10 µm and a specific surface area of ~3.2 m2 g-1. The biochar was incorporated into the top 15 cm of the soil under an aerobic rice system. Our study focused on both the effects on WRC and rice yields 2 and 3 years after its application. Undisturbed soil samples were collected from 16 plots in two soil layers (5–10 and 15–20 cm). Soil water retention curves were modelled using a nonlinear mixed model which appropriately accounts for uncertainties inherent of spatial variability and repeated measurements taken within a specific soil sample. We found an increase in plant-available water in the upper soil layer proportional to the rate of biochar, with about 0.8% for each Mg ha-1 biochar amendment 2 and 3 years after its application. The impact of biochar on soil WRC was most likely related to an effect in overall porosity of the sandy loam soil, which was evident from an increase in saturated soil moisture and macro porosity with 0.5 and 1.6% for each Mg ha-1 of biochar applied, respectively. The increment in soil WRC did not translate into an increase in rice yield, essentially because in both seasons the amount of rainfall during the critical period for rice production exceeded 650 mm. The use of biochar as a soil amendment can be a worthy strategy to guarantee yield stability under short-term water-limited conditions. Our findings raise the importance of assessing the feasibility of very high application rates of biochar and the inclusion of a detailed analysis of its physical and chemical properties as part of future investigations.

We assessed the interplay of artificial and natural selection in rice adaptation in low-input farming systems in West Africa. Using 20 morphological traits and 176 molecular markers, 182 farmer varieties of rice (Oryza spp.) from 6 West African countries were characterized. Principal component analysis showed that the four botanical groups (Oryza sativa ssp. indica, O. sativa ssp. japonica, O. glaberrima, and interspecific farmer hybrids) exhibited different patterns of morphological diversity. Regarding O. glaberrima, morphological and molecular data were in greater conformity than for the other botanical groups. A clear difference in morphological features was observed between O. glaberrima rices from the Togo hills and those from the Upper Guinea Coast, and among O. glaberrima rices from the Upper Guinea Coast. For the other three groups such clear patterns were not observed. We argue that this is because genetic diversity is shaped by different environmental and socio-cultural selection pressures. For O. glaberrima, recent socio-cultural selection pressures seemed to restrict genetic diversity while this was not observed for the other botanical groups. We also show that O. glaberrima still plays an important role in the selection practices of farmers and resulting variety development pathways. This is particularly apparent in the case of interspecific farmer hybrids where a relationship was found between pericarp colour, panicle attitude and genetic diversity. Farmer varieties are the product of long and complex trajectories of selection governed by local human agency. In effect, rice varieties have emerged that are adapted to West African farming conditions through genotype 6environment 6society interactions. The diversity farmers maintain in their rice varieties is understood to be part of a risk-spreading strategy that also facilitates successful and often serendipitous variety innovations. We advocate, therefore, that farmers and farmer varieties should be m

This study offers evidence of the robustness of farmer rice varieties (Oryza glaberrima and O. sativa) in West Africa. Our experiments in five West African countries showed that farmer varieties were tolerant of sub-optimal conditions, but employed a range of strategies to cope with stress. Varieties belonging to the species Oryza glaberrima – solely the product of farmer agency – were the most successful in adapting to a range of adverse conditions. Some of the farmer selections from within the indica and japonica subspecies of O. sativa also performed well in a range of conditions, but other farmer selections from within these two subspecies were mainly limited to more specific niches. The results contradict the rather common belief that farmer varieties are only of local value. Farmer varieties should be considered by breeding programmes and used (alongside improved varieties) in dissemination projects for rural food security.

Shifting cultivation in Southeast Asia is rapidly transforming due to increased land pressure, governmental policies and improved access to infrastructure and markets. The forced use of shortened fallow lengths questions its ecological sustainability, a concern as the livelihoods of resource-poor farmers may be affected. The objective of the study was to assess the ecological sustainability of short fallow shifting cultivation systems in Lao PDR; specifically, how fallow length and topography influence soil quality and upland rice yields. Upland fields of 2-, 3-, 5-, 10- and 11- year fallows of similar topography, parent soil and land use history were selected; the 5-year fields were used to assess topographical influence. Soil organic carbon and permanganate oxidisable carbon were identified as key indicators of soil quality as they were positively correlated to the soil nutrients, N, P and K, and led to higher upland rice yields. Although fields of longer fallows were associated with higher yields, no such correlations were found with soil quality; the positive association between fallow length and upland rice yields may rather reflect weed suppression, less pest or disease infestation or a combination. The results indicate that a length of five years for fallow will give the greatest return to the soil; the increase in upland rice yields when fallowed for longer than five years will depend on the technical skill and management practices of the farmer. Soil quality or upland rice yields were not significantly influenced by slope position, thus erosion is not a major constraint; nitrogen and potassium show an accumulation at the bottom of the slope possibly due to leaching effects and the downward movement of ash. It appears the use of appropriate scales in such studies whereby soil quality and yields are both measured from marked plots will improve accuracy. The impact of fallow length on soil quality and upland rice yields remains ambiguous; more future studies a

Shifting cultivation in Southeast Asia is rapidly transforming due to increased land pressure, governmental policies and improved access to infrastructure and markets. The forced use of shortened fallow lengths questions its ecological sustainability, a concern as the livelihoods of resource-poor farmers may be affected. The objective of the study was to assess the ecological sustainability of short fallow shifting cultivation systems in Lao PDR; specifically, how fallow length and topography influence soil quality and upland rice yields. Upland fields of 2-, 3-, 5-, 10- and 11- year fallows of similar topography, parent soil and land use history were selected; the 5-year fields were used to assess topographical influence. Soil organic carbon and permanganate oxidisable carbon were identified as key indicators of soil quality as they were positively correlated to the soil nutrients, N, P and K, and led to higher upland rice yields. Although fields of longer fallows were associated with higher yields, no such correlations were found with soil quality; the positive association between fallow length and upland rice yields may rather reflect weed suppression, less pest or disease infestation or a combination. The results indicate that a length of five years for fallow will give the greatest return to the soil; the increase in upland rice yields when fallowed for longer than five years will depend on the technical skill and management practices of the farmer. Soil quality or upland rice yields were not significantly influenced by slope position, thus erosion is not a major constraint; nitrogen and potassium show an accumulation at the bottom of the slope possibly due to leaching effects and the downward movement of ash. It appears the use of appropriate scales in such studies whereby soil quality and yields are both measured from marked plots will improve accuracy. The impact of fallow length on soil quality and upland rice yields remains ambiguous; more future studies a

Crops with high biomass and marketable yield were aimed to be identified to be used in Conservation Agriculture Production Systems (CAPS).

The diversity of spiders and impact of pest population on spider density has been studied in the upland rice agroecosystem in Bharathy variety at Hybrid Rice Evaluation Centre, Tamil Nadu Agricultural University, Gudalur, The Nilgiris during Kharif 2010 and 2011. Three aspects, population of spiders and pests in different rice establishment techniques, diversity of spider species in different rice establishment techniques and impact of pest density on the population of spiders were studied. A total of 11 species of spider from 7 different families were observed from all the three different techniques of upland rice crop at different days after transplantation. Among the spider species, Lycosa pseudoannulata was higher in early growth stage and Tetragnatha javana was predominant in later stages of the crop. Population of brown plant hopper, green leaf hopper and stem borer showed significant positive impact on L. pseudoannulata and Oxyopes javanus population. Regression analysis revealed that 97 percent of L. pseudoannulata, 72 percent of O. javanus, 94 percent of T. javana and 80 percent of Clubiona sp. population depends on the incidence of pests in the upland rice ecosystem. Diversity indices revealed that diversity of spider was more in the direct sown method than transplanting and seedling throwing method.

Crops with high biomass and marketable yield were aimed to be identified to be used in Conservation Agriculture Production Systems (CAPS).

Crop models are ideally suited to quantify existing climatic risks. However, they require historic climate data as input. While daily temperature and rainfall data are often available, the lack of observed solar radiation (Rs) data severely limits site-specific crop modelling. The objective of this study was to estimate Rs based on air temperature solar radiation models and to quantify the propagation of errors in simulated radiation on several APSIM/ORYZA crop model seasonal outputs, yield, biomass, leaf area (LAI) and total accumulated solar radiation (SRA) during the crop cycle. The accuracy of the 5 models for estimated daily solar radiation was similar, and it was not substantially different among sites. For water limited environments (no irrigation), crop model outputs yield, biomass and LAI was not sensitive for the uncertainties in radiation models studied here.

[EN] Sprinkler irrigation can reduce the irrigation water needed to grow rice. However, most available information on weed control with herbicides is related to flood irrigated rice because this is the main growing method. Field experiments were conducted at Zaragoza (Spain) during two years to study weed control and tolerance of sprinkler irrigated rice to several herbicides. The main weeds were Atriplex prostrata Bouchér ex DC., Cyperus rotundus L., Echinochloa crus-galli (L.) Beauv. and Sonchus oleraceus L. Rice cv Guadiamar was tolerant to preemergence (PRE) application of clomazone at 0.36 kg ha-1 and oxadiazon at 0.5 kg ha–1. PRE application of pendimethalin at 1.32 kg ha–1 combined with clomazone at 0.36 kg ha-1 decreased rice yield. Postemergence (POST) application of bentazon at 1.6 kg ha–1 + MCPA at 0.25 kg ha–1 did not injure rice but POST application of azimsulfuron at 0.025 kg ha–1 produced visual crop injury. Only treatments that controlled grassy weeds since rice was planted and by more than 80% at harvest time lead to acceptable rice yield (> 5,000 kg ha–1). Clomazone applied PRE at 0.36 kg ha–1 provided good control of grassy weeds (> 80%) and the highest rice yield, so it is recommended as a selective and efficacious PRE treatment for weed control of annual weeds in sprinkler irrigated rice. The perennial purple nutsedge was difficult to control at high plant densities (> 150 plants m–2) and the recommended herbicide is azimsulfuron applied at POST at 0.02 kg ha–1., [ES] El riego por aspersion puede reducir el riego necesario en arroz. Sin embargo, casi toda la información sobre control de malas hierbas con herbicidas se refiere a arroz inundado por ser la forma principal de cultivo. Se realizaron ensayos de campo durante dos años para estudiar el control de malas hierbas y la selectividad de diversos herbicidas en arroz regado por aspersión. Las principales malas hierbas fueron Atriplex prostrata Bouchér ex DC., Cyperus rotundus L., Echinochloa crus-galli (L.) Beauv. y Sonchus oleraceus L. El arroz cv Guadiamar toleró las aplicaciones en preemergencia (PRE) de clomazona a 0,36 kg ha–1 y de oxadiazón a 0,5 kg ha–1. La aplicación en PRE de pendimetalina a 1,32 kg ha–1 combinada con clomazona a 0,36 kg ha–1 disminuyó el rendimiento del arroz. La aplicación en postemergencia (POST) de bentazona a 1,6 kg ha–1 + MCPA a 0,25 kg ha–1 no afectó al arroz, pero la aplicación en POST de azimsulfurón a 0,025 kg ha–1 produjo fototoxicidad visual. Solamente los tratamientos que controlaron más de un 80% las gramíneas desde la siembra del arroz hasta la cosecha obtuvieron rendimientos aceptables de arroz (> 5.000 kg ha–1). La aplicación de clomazona en PRE a 0,36 kg ha–1 controló de forma eficaz las gramíneas (> 80%) y produjo los mayores rendimientos de arroz, recomendándose para el control de malas hierbas anuales en arroz regado por aspersión. La junquilla fue difícil de controlar a densidades altas (> 150 plantas m–2), siendo el herbicida recomendado el azimsulfurón a 0,02 kg ha–1.

The cultivation of upland rice had an important role as a pioneer culture during the opening and occupation of the agricultural sector of the Brazilian cerrados. This system was characterized by low production cost, due to the low adoption of techniques and practices, which resulted in low average productivity of the system. The purpose of this study was to evaluate the response of the culture of upland rice to fertilizer N, P and K in three Oxisols in the city of Ji-Parana, central state of Rondonia. We used a randomized block design with factorial arrangement with eight treatments and three replications. The upland rice under conventional tillage in the area surveyed had a higher productivity when received nitrogen and did not respond significantly to fertilization, to potassium fertilization, as well as possible interactions with fertilizer., A cultura do arroz de sequeiro teve um importante papel como cultura pioneira durante o processo de abertura e ocupação da fronteira agrícola dos cerrados brasileiros. Este sistema caracterizou-se pelo baixo custo de produção, conseqüência da baixa adoção das técnicas e práticas recomendadas, o que resultou na baixa produtividade média do sistema. O objetivo do presente trabalho teve como objetivo avaliar a resposta da cultura do arroz de sequeiro à adubação com N, P e K em três Latossolos do município de Ji-Paraná, região central do Estado de Rondônia. Foi utilizado o delineamento em blocos ao acaso com arranjo fatorial, com oito tratamentos e três repetições. O arroz de sequeiro sob sistema de plantio convencional na região pesquisada apresentou maior produtividade quando recebeu adubação nitrogenada e não respondeu significativamente, à adubação fosfatada, à adubação potássica, bem como às interações possíveis com NPK., El cultivo de arroz de secano tiene un importante papel como pionero de la cultura durante la apertura y la ocupación de los sectores agrícola del Cerrado brasileño. Este sistema se caracteriza por bajo costo de producción, debido a la escasa adopción de tecnologías y prácticas, que se tradujo en una menor productividad media del sistema. El propósito de este estudio fue evaluar la respuesta de arroz de secano a los fertilizantes N, P y K en tres Oxisoles de la ciudad de Ji-Paraná, en la región central del estado de Rondonia. Se utilizó un diseño de bloques completos al azar con arreglo factorial con ocho tratamientos y tres repeticiones. El arroz de secano con la labranza convencional en la región estudiada mostró una mayor productividad de nitrógeno cuando se reciben y no respondió de manera significativa al fósforo, la fertilización de potasio, así como las posibles interacciones con NPK.

The cultivation of upland rice had an important role as a pioneer culture during the opening and occupation of the agricultural sector of the Brazilian cerrados. This system was characterized by low production cost, due to the low adoption of techniques and practices, which resulted in low average productivity of the system. The purpose of this study was to evaluate the response of the culture of upland rice to fertilizer N, P and K in three Oxisols in the city of Ji-Parana, central state of Rondonia. We used a randomized block design with factorial arrangement with eight treatments and three replications. The upland rice under conventional tillage in the area surveyed had a higher productivity when received nitrogen and did not respond significantly to fertilization, to potassium fertilization, as well as possible interactions with fertilizer., A cultura do arroz de sequeiro teve um importante papel como cultura pioneira durante o processo de abertura e ocupação da fronteira agrícola dos cerrados brasileiros. Este sistema caracterizou-se pelo baixo custo de produção, conseqüência da baixa adoção das técnicas e práticas recomendadas, o que resultou na baixa produtividade média do sistema. O objetivo do presente trabalho teve como objetivo avaliar a resposta da cultura do arroz de sequeiro à adubação com N, P e K em três Latossolos do município de Ji-Paraná, região central do Estado de Rondônia. Foi utilizado o delineamento em blocos ao acaso com arranjo fatorial, com oito tratamentos e três repetições. O arroz de sequeiro sob sistema de plantio convencional na região pesquisada apresentou maior produtividade quando recebeu adubação nitrogenada e não respondeu significativamente, à adubação fosfatada, à adubação potássica, bem como às interações possíveis com NPK., El cultivo de arroz de secano tiene un importante papel como pionero de la cultura durante la apertura y la ocupación de los sectores agrícola del Cerrado brasileño. Este sistema se caracteriza por bajo costo de producción, debido a la escasa adopción de tecnologías y prácticas, que se tradujo en una menor productividad media del sistema. El propósito de este estudio fue evaluar la respuesta de arroz de secano a los fertilizantes N, P y K en tres Oxisoles de la ciudad de Ji-Paraná, en la región central del estado de Rondonia. Se utilizó un diseño de bloques completos al azar con arreglo factorial con ocho tratamientos y tres repeticiones. El arroz de secano con la labranza convencional en la región estudiada mostró una mayor productividad de nitrógeno cuando se reciben y no respondió de manera significativa al fósforo, la fertilización de potasio, así como las posibles interacciones con NPK.

In northern Laos, shortened fallows in the slash-and-burn upland rice system are not sustainable either from a production or economic standpoint. This paper evaluates the potential for using the indigenous fast-growing tree, Broussonetia papyrifera L. Vent. (paper mulberry) as an economic fallow crop. The objectives of this study are to assess the inner bark yield of paper mulberry, and to evaluate rice productivity following paper mulberry cultivation. In addition, allometric models for estimating the inner bark yield of paper mulberry are developed. Inner bark yield of paper mulberry stands ranging in age from 9 to 48 months ranged from 10 to 208 g m−2, and increased with age. The models using diameter at breast height and stem height, or diameter at breast height only as independent variables explained well the variation in inner bark yield. When paper mulberry was completely removed during the rice growing season, rice yields in these areas were similar to those following weedy bush fallow. When paper mulberry was allowed to grow, rice yields were negatively correlated to paper mulberry stem density. When paper mulberry lateral branches were pruned back, rice yields could be maintained if the paper mulberry stem density was <0.22 stems m−2, suggesting that if paper mulberry is managed properly, rice yields can be maintained at current levels. The paper mulberry-upland rice rotation system improves the productivity of a traditional slash-and-burn system through harvesting paper mulberry inner bark; however the long-term sustainability of such a system remains unclear and warrants further investigation.

Nitrate uptake characteristics and ammonium effects were compared between upland rice (Brazilian upland rice) and paddy rice (Wuyujing 3 and Yangdao 6) through the glass microelectrode technique and the concentration gradient method of uptake kinetics. Results indicated that nitrate uptake by rice seedlings and ammonium effects were related to transmembrane potential difference, and upland rice and paddy rice presented obviously different responses. Nitrate induced a rapid depolarization and then a slow repolarization of transmembrane potential in root epidermal cells, and even hyperpolarization was observed when nitrate concentration was low. Resting transmembrane potential of epidermal cells in Brazilian upland rice roots was lower and its response to NO3- was bigger than that of two paddy rice species. Depolarization of membrane potential was amplified when ammonium was simultaneously added with nitrate into the measure medium, but repolarization was reduced, even disappeared. Brazilian upland rice seedlings had high Vmax of nitrate uptake and low Km, furthermore, Vmax and Km were little affected by ammonium, but Vmax of Wuyujing 3 was reduced significantly. Therefore, inhibition of ammonium to nitrate uptake possibly due to decrease of membrane potential and influence of nitrate transporters. Moreover, inhibition of NH4+ differed obviously between upland rice and paddy rice.

Nitrate uptake characteristics and ammonium effects were compared between upland rice (Brazilian upland rice) and paddy rice (Wuyujing 3 and Yangdao 6) through the glass microelectrode technique and the concentration gradient method of uptake kinetics. Results indicated that nitrate uptake by rice seedlings and ammonium effects were related to transmembrane potential difference, and upland rice and paddy rice presented obviously different responses. Nitrate induced a rapid depolarization and then a slow repolarization of transmembrane potential in root epidermal cells, and even hyperpolarization was observed when nitrate concentration was low. Resting transmembrane potential of epidermal cells in Brazilian upland rice roots was lower and its response to NO3- was bigger than that of two paddy rice species. Depolarization of membrane potential was amplified when ammonium was simultaneously added with nitrate into the measure medium, but repolarization was reduced, even disappeared. Brazilian upland rice seedlings had high Vmax of nitrate uptake and low Km, furthermore, Vmax and Km were little affected by ammonium, but Vmax of Wuyujing 3 was reduced significantly. Therefore, inhibition of ammonium to nitrate uptake possibly due to decrease of membrane potential and influence of nitrate transporters. Moreover, inhibition of NH4+ differed obviously between upland rice and paddy rice.

The development of new plant type of upland rice in relatively short time can be done by using anther culture technique. The technique has been recognized as a rapid and efficient technology for plant improvement. Plant materials used in this research were 320 s doubled haploid lines derived from anther culture and their 4 parents namely Fatmawati, SGJT-28, SGJT-36 and Way Rarem. Observation was conducted on plant height, number of productive tillers, days of flowering and maturity, length of panicle, number of grains per panicle, number of filled grains per panicle, percentage of unfilled grains, weight of 1000 grains and weight of grains per hill. The result showed that there were broad variations in the agronomic characters of doubled haploid lines. There were 58 upland rice lines can be obtained with new plant type characters (NPT). Several lines showed superior characters. Line P6-105, P3-134, P3-135, P3-175 had productive tiller more than that of parental, P3-160, P3-196, P6-274 had long panicle, number of grain per panicle and low percentage of unfilled grain, P3-135, P6-271, P6-274, and P6-276 had weight of grains per hill. These lines had potential as new plant type of upland rice. Length of panicle, number of grains per panicle, number of filled grains per panicle, and weight of grains per hill had high heritability and wide genetic variability.

Nitrate uptake characteristics and ammonium effects were compared between upland rice (Brazilian upland rice) and paddy rice (Wuyujing 3 and Yangdao 6) through the glass microelectrode technique and the concentration gradient method of uptake kinetics. Results indicated that nitrate uptake by rice seedlings and ammonium effects were related to transmembrane potential difference, and upland rice and paddy rice presented obviously different responses. Nitrate induced a rapid depolarization and then a slow repolarization of transmembrane potential in root epidermal cells, and even hyperpolarization was observed when nitrate concentration was low. Resting transmembrane potential of epidermal cells in Brazilian upland rice roots was lower and its response to NO3- was bigger than that of two paddy rice species. Depolarization of membrane potential was amplified when ammonium was simultaneously added with nitrate into the measure medium, but repolarization was reduced, even disappeared. Brazilian upland rice seedlings had high Vmax of nitrate uptake and low Km, furthermore, Vmax and Km were little affected by ammonium, but Vmax of Wuyujing 3 was reduced significantly. Therefore, inhibition of ammonium to nitrate uptake possibly due to decrease of membrane potential and influence of nitrate transporters. Moreover, inhibition of NH4+ differed obviously between upland rice and paddy rice.

In northern Laos, shortened fallows in the slash-and-burn upland rice system are not sustainable either from a production or economic standpoint. This paper evaluates the potential for using the indigenous fast-growing tree, Broussonetia papyrifera L. Vent. (paper mulberry) as an economic fallow crop. The objectives of this study are to assess the inner bark yield of paper mulberry, and to evaluate rice productivity following paper mulberry cultivation. In addition, allometric models for estimating the inner bark yield of paper mulberry are developed. Inner bark yield of paper mulberry stands ranging in age from 9 to 48 months ranged from 10 to 208 g m−2, and increased with age. The models using diameter at breast height and stem height, or diameter at breast height only as independent variables explained well the variation in inner bark yield. When paper mulberry was completely removed during the rice growing season, rice yields in these areas were similar to those following weedy bush fallow. When paper mulberry was allowed to grow, rice yields were negatively correlated to paper mulberry stem density. When paper mulberry lateral branches were pruned back, rice yields could be maintained if the paper mulberry stem density was <0.22 stems m−2, suggesting that if paper mulberry is managed properly, rice yields can be maintained at current levels. The paper mulberry-upland rice rotation system improves the productivity of a traditional slash-and-burn system through harvesting paper mulberry inner bark; however the long-term sustainability of such a system remains unclear and warrants further investigation.

Fitomejoramiento participativo del arroz de secano en Nicaragua: metodologías, resultados y lecciones aprendidas. En varias regiones de Nicaragua, el cultivo de arroz de secano asume un papel importante para la seguridad alimenticia de las familias campesinas, además es fuente de ingresos para éstas. Apartir del 2002, el CIRAD y el CIAT implementan en colaboración en Nicaragua un proyecto de investigación en fitomejoramiento participativo del arroz de secano dirigido a los pequeños y medianos productores.Este proyecto esta manejado en asociación con la Institución Nacional de Investigación Agropecuaria, varias ONGs e instituciones de extensión y organizaciones campesinas locales. En este trabajo, se describen la metodología general aplicada en el proyecto, los actores involucrados y los marcos de concertación entre los socios, las estrategias y métodos de evaluación y selección participativa aplicados y los principales resultados obtenidos al final de tres años. Esta experiencia deriva lecciones, con respecto al manejo de un proyecto de investigación asociando estrechamente fitomejoradores y productores, la selección de los socios, los métodos de trabajo, las competencias adquiridas por los actores y la diversidad genética explorada y valorizada, las que podrían ser utilizadas en la implementación de otros proyectos en este tema. Para la continuación del proyecto, los cambios de escala (scalingup), la organización de una producción descentralizada de semilla de calidad, el desarrollo de investigaciones en agronomía y la creación de un sistema permanente de evaluación y selección del arroz, reuniendo todos los actores de la cadena productiva, son los mayores retos.

Fitomejoramiento participativo del arroz de secano en Nicaragua: metodologías, resultados y lecciones aprendidas. En varias regiones de Nicaragua, el cultivo de arroz de secano asume un papel importante para la seguridad alimenticia de las familias campesinas, además es fuente de ingresos para éstas. Apartir del 2002, el CIRAD y el CIAT implementan en colaboración en Nicaragua un proyecto de investigación en fitomejoramiento participativo del arroz de secano dirigido a los pequeños y medianos productores.Este proyecto esta manejado en asociación con la Institución Nacional de Investigación Agropecuaria, varias ONGs e instituciones de extensión y organizaciones campesinas locales. En este trabajo, se describen la metodología general aplicada en el proyecto, los actores involucrados y los marcos de concertación entre los socios, las estrategias y métodos de evaluación y selección participativa aplicados y los principales resultados obtenidos al final de tres años. Esta experiencia deriva lecciones, con respecto al manejo de un proyecto de investigación asociando estrechamente fitomejoradores y productores, la selección de los socios, los métodos de trabajo, las competencias adquiridas por los actores y la diversidad genética explorada y valorizada, las que podrían ser utilizadas en la implementación de otros proyectos en este tema. Para la continuación del proyecto, los cambios de escala (scalingup), la organización de una producción descentralizada de semilla de calidad, el desarrollo de investigaciones en agronomía y la creación de un sistema permanente de evaluación y selección del arroz, reuniendo todos los actores de la cadena productiva, son los mayores retos.

The research was conducted to study the correlation between deficit of evapotranspiration and yield decreasing. Factorial experiment was arranged in Randomized Block Design. First factor was irrigation frequency of 1, 2, 4 and 6 days. Second factor were nine upland rice lines. Evapotranspiration was measured with simple lysimeter based on water balance. There was positive correlation between deficit of evapotranspiration and yield decreasing. Defisit of evapotranspiration as much as 240.06 mm caused yield decreasing of 90% and dry matter weight decreasing of 72.5%. The relation between total evapotranspiration (E, mm) and dry matter weight (DM, g/plant) was DM = 0.0245 E + 13.85. Water use efficiency or yield and evapotranspiration ratio correlated with leaf width and sum of seed each panicle positively . Increasing leaf width and sum of seed each panicle could increase water use efficiency.

The objective of the research was to determine anther culture ability of 7 rice accessions in an improved media supplemented with spermine. The seven accessions were Hawara Bunar, Grogol, Sigundil. Krowal. CT-650-24-J-3. Lembayau, dan Mendali. Media N6 was used for callus induction and MS was used for regeneration. Both media was supplemented with spermine at J0 -4M . Result of the experiment showed that Grogol. Sigundil. and Lembayau gave green plantlet. Sigundil and Mendali possessed highest anther culture ability and therefore best suited for parent in rice breeding involving anther culture technique.

Rice is a profligate user of water. It takes 3,000–5,000 liters to produce 1 kilogram of rice, which is about 2 to 3 times more than to produce 1 kilogram of other cereals such as wheat or maize. Until recently, this amount of water has been taken for granted. Now, however, the water crisis threatens the sustainability of the irrigated rice ecosystem. In Asia, 17 million ha of irrigated rice areas may experience ‘physical water scarcity’ and 22 million ha ‘economic water scarcity’ by 2025. To safeguard food security and preserve precious water resources, ways must be explored to grow rice using less water. IRRI, together with Plant Research International of Wageningen University and Research Centre, organized a thematic workshop on Water-Wise Rice Production held 8-11 April 2002 at IRRI, Los Baños, Philippines. The objectives were to present and discuss the state-of-the-art in the development, dissemination, and adoption of water-saving technologies at spatial scales ranging from the field to irrigation system. This book contains the papers presented at the workshop.

At six sites in 1987, and two sites in 1988 in the Tai region of south-west Cote d'Ivoire, long-term field trials were started to study the supply of nutrients from the soil and the response of food crops to fertilizers. The results for P during the first season after removal of the primary or secondary forest vegetation in experiments with rice are described. P rates were 0 or 50 kg/ha in 1987, and 0, 12.5, 25 or 50 kg in 1988. The application of 50 kg P increased grain yield by 0.5-1.0 t/ha at five of the six sites in 1987. In 1988, a similar response could be obtained with lower rates of 12.5 or 25 kg P ha. At all sites, P application increased P uptake significantly, but the recovery of fertilizer P decreased with increasing P application rates. The soil P supply was best described by an equation including P-Dabin (a modified P-Olsen method), total P and pH. The recovery of fertilizer P could best be described by equations including silt plus clay content, P-Dabin, and/or total P. Since some soils had a high gravel content, soil analytical data, referring to the fine earth)

In the Tai region of south-west Cote d'Ivoire P is the yield-limiting nutrient on (moderately) well drained soils. In order to find the optimum P application rate, a factorial experiment (2N x 4P x 2K) in three replicates was conducted at two sites during six seasons. The factors investigated were N (0 or 50 kg/ha), P (0, 12.5, 25 or 50 kg P) and K (0 or 50 kg K). N (urea) and K (muriate of potash) applications were split into two equal parts and broadcast. From the third season onwards the N application was raised to 100 kg N. P (triple superphosphate) was placed near the young plants. Upland rice and maize were used as test crops. The experimental sites were located at the crest (Site VII) and lower slope (Site VIII) of a catena. In the first season after clearing at Site VII highest yields were obtained with 12.5 kg P and at Site VIII with an application of 25 kg P. At the latter site also N application increased yields. In an extended cropping period the rice yield level could not be maintained. The efficiency of utilization of absorbed P (EUP) of rice was high in the first season after clearing but decreased in subsequent seasons. This is in contrast to EUP for maize which remained constant with time. Hence, it is concluded that the rice yield decline is caused by other factors than nutrient deficiencies. In all seasons yields were higher at Site VII than at Site VIII. The residual effect of fertilizer-P could reasonably well be described by a simple formula: RFP1 = (0.9 - RFP1)t-1 x RFP1, where RFP and RFP1 are the apparent recovery fractions of fertilizer P in year t and year 1, respectively. In all seasons, except in the first season after clearing, the potential P supply was higher at the crest (Site VII) than at the lower slope (Site VIII). Extending the cropping period proved possible when fertilizers were applied and maize was grown. For both sites fertilizer guidelines could be formulated. Comparison of soil chemical data (pH, organic C, total N and tot

Methods and sampling strategies for measurement of soil hydraulic functions in puddled and non-puddled rice soils are discussed. A method was developed to measure in situ water percolation rate and soil water pressure head gradients in puddled soils. The number of measurements needed to estimate field-average infiltration rates was determined using a sequential t -test. It was concluded that sampling strategies for soil hydraulic functions and the choice of spatial interpolation techniques are best based on preliminary simulation and sensitivity analyses of the impact of soil heterogeneity and weather variability on yield variability and associated cost/benefit calculations. Several possibilities for water saving in rice-based cropping systems are discussed. Field and laboratory experiments indicated that the use of a pre-tillage operation before reflooding a dry, cracked rice field may allow earlier transplanting and reduce the risk of late drought. Maintaining shallow depths of ponded water and construction of extra bunds after puddling the field, close to bunds that are left undisturbed from year to year, may also reduce water use. Drought stress responses of two lowland rice cultivars to temporary drought at different growth stages were studied. Drought in the vegetative phase delayed flowering and maturity. Drought in the reproductive phase resulted in large yield reductions. The following morphological and physiological responses to soil moisture content were quantified: (1) rate of leaf production, (2) rate of leaf rolling, (3) rate of senescence and (4) relative transpiration rate. A simulation model for rainfed rice growth was developed, validated and used to estimate regional rice yield losses due to drought in a province of the Philippines, as a function of soil and climate variability.The results of this study are discussed in relation to the increasing use of simulation models in rice growing countries for estimation of potential and water limited yield