scholarly journals Recovering Ability of Upland and Rainfed Lowland Rice Varieties against Rice Tungro Disease

2018 ◽  
Vol 21 (1) ◽  
pp. 91-100 ◽  
Author(s):  
MT Khatun ◽  
MA Latif ◽  
MM Rahman ◽  
M Hossain ◽  
TH Ansari ◽  
...  
Keyword(s):  
Upland Rice ◽  
Lowland Rice ◽  
Resistant Variety ◽  
Yield Reduction ◽  
Insect Vector ◽  
Rice Varieties ◽  
Rice Tungro Disease ◽  
Rainfed Lowland ◽  
Endemic Areas ◽  
Almost All

Rice tungro is the most destructive and widespread among virus diseases found in almost all rice growing areas. In susceptible varieties, it causes 100% yield loss under favourable environmental conditions. Control of tungro disease by chemical applications is not effective and eco-friendly. Development of resistant variety against tungro is also difficult, because it is necessary to develop resistance either to the insect vector or to the virus or to the both. Identification of varieties with recovering ability will facilitate farmers to cultivate rice in tungro endemic areas. Bangladesh Rice Research Institute released six upland and eight rainfed lowland rice varieties, which were tested to evaluate their recovering ability against tungro disease. The test varieties including susceptible and resistant checks were artificially inoculated by viruliferous vector (Green leafhopper, Nephotettix virescens) of ten days after seeding in net house condition. Among the tested varieties BR26, BRRI dhan33 and BRRI dhan40 were the most susceptible and showed high infection rate against tungro disease. BRRI dhan37 and BR8 showed the highest recovering ability in rainfed lowland and upland rice, respectively, with the lowest yield reduction compared to the resistant check Kumragoir, which could be used in tungro endemic areas. From these investigations, all the tested varieties expressed distinct tungro disease symptoms after three weeks of inoculation. With the advancement of plant growth, varieties BR8 and BRRI dhan37 recovered from tungro syndrome due to their genetic makeup consisting tolerance potentiality showed better yield, while other varieties like BRRI dhan33 and BRRI dhan40 did not produce any grain yieldBangladesh Rice j. 2017, 21(1): 91-100

scholarly journals Brown spot disease severity, yield and yield loss relationships in pigmented upland rice cultivars from East Nusa Tenggara, Indonesia

2020 ◽  
Vol 21 (4) ◽  
Author(s):  
Yosep S. Mau ◽  
Antonius Ndiwa ◽  
Shirly Oematan
Keyword(s):  
Disease Severity ◽  
Yield Loss ◽  
Upland Rice ◽  
Brown Spot ◽  
Yield Reduction ◽  
Rice Cultivars ◽  
Rice Varieties ◽  
Resistance Level ◽  
Spot Disease ◽  
Brown Spot Disease

Abstract. Mau YS, Ndiwa ASS, Oematan SS. 2020. Brown spot disease severity, yield and yield loss relationships in pigmented upland rice cultivars from East Nusa Tenggara, Indonesia. Biodiversitas 21: 1625-1634. Brown spot is one of the most devastating diseases of rice, which could lead to total yield loss. The disease has a worldwide distribution, more specifically in areas where water supply is scarce, most specifically in the dry upland areas. Almost all stages of rice are affected by the disease, where leaves and grains are mostly affected. Considerable differences exist in susceptibility to brown spot among rice varieties, which may cause a large variation in yield loss caused by the disease. Therefore, the resistance level of rice varieties and their yield reduction has to be regularly evaluated and updated. There are only a few reports on the relationship between brown spot severity with yield and yield loss of upland rice, and is even lacking in pigmented upland rice. The objectives of the present study were to assess the brown spot severity and resistance level in pigmented upland rice cultivars from East Nusa Tenggara Province, Indonesia, and to elucidate their relationships with yield and yield reduction. Twenty four pigmented upland rice genotypes were evaluated in the field during May to October 2019, and their disease responses and yields were recorded. Disease severity was observed weekly and used to calculate Area Under the Disease Progress Curve (AUDPC) for comparison among the genotypes. The relationships between disease severity and AUDPC with yield and yield loss were also examined. The results showed significant variation in brown spot severity and AUDPC, ranging from, respectively, 11.11% to 40.70% and 398.42%-days to 1081.30%-days. Yields and yield losses of test genotypes also varied substantially. Yields under diseased-free and diseased plots ranged from, respectively, 2.34 t ha-1 to 6.13 t ha-1 and 1.68 t ha-1 to 3.74 t ha-1 while yield loss was between 10.46% and 56.15%. Six genotypes were moderately resistant, four genotypes were moderately susceptible and 14 genotypes were susceptible to brown spot. Neither disease severity nor AUDPC had a linear relationship with yield but both exhibited positive and linear relationships with yield loss.

Soil clay content, rainfall, and toposequence positions determining spatial variation in field water availability as estimated by a water balance model for rainfed lowland rice

2012 ◽  
Vol 63 (6) ◽  
pp. 529 ◽  
Author(s):  
T. Inthavong ◽  
M. Tsubo ◽  
S. Fukai
Keyword(s):  
Water Balance ◽  
Water Availability ◽  
Clay Content ◽  
Lowland Rice ◽  
Balance Model ◽  
Yield Reduction ◽  
Growing Period ◽  
Rainfed Lowland ◽  
Soil Clay ◽  
Soil Clay Content

Drought is a major limiting factor for the production of rainfed rice in the Mekong Region. Thus, estimation of the length of growing period (LGP) based on estimation of the development of water deficit is essential for sound planning of agricultural development. A recently developed soil-water balance model was used to quantify the availability of water for rice crops and yield reduction due to water deficit. Field water availability is known to be largely affected by soil type and rainfall pattern, and their separate effects were investigated in this study of a spatial analysis of LGP, using inputs for rainfed lowland rice in Savannakhet province in central Laos. The analysis showed that the start of growing period (SGP) and end of growing period (EGP) were affected largely by geographical variations in rainfall and soil clay content, respectively. Also, the areas having relatively short LGP were generally associated with large yield reduction because of low water availability associated with coarse-textured soils. At local scale, field water availability varied from upper to lower positions of a sloping land (toposequence) in the rainfed lowland ecosystem of the Mekong region, causing variation in yield within the toposequence. Using the level of field water determined around flowering time at different toposequence positions in 45 farms, estimated yield reduction was compared in seven main rice-growing districts of the province. Variability of yield loss, associated with variation in water availability, was larger across the toposequence positions than across districts, showing the importance of local variability in determining yield in rainfed lowland rice. The present approach of a combination of simulation model and GIS is adopted for characterisation of the water environment for rainfed lowland rice in other parts of Laos, as well as in neighbouring Thailand and Cambodia.

scholarly journals VARIASI VIRULENSI VIRUS TUNGRO BERSUMBER DARI INOKULUM DI DAERAH ENDEMIS TUNGRO DI INDONESIA

2015 ◽  
Vol 15 (1) ◽  
pp. 1
Author(s):  
Nyoman Widiarta ◽  
Syahrir Pakki
Keyword(s):  
Free Choice ◽  
Resistant Variety ◽  
Group Variety ◽  
Inoculum Sources ◽  
Green Leafhopper ◽  
Resistant Varieties ◽  
Rice Tungro Disease ◽  
Box Method ◽  
Endemic Areas ◽  
Test Result

Variations in virulence of tungro viruses from various inoculum sources in tungro endemic areas in Indonesia. Rice tungro disease is caused by virus which is effectively transferred by the green leafhopper. Reactions of resistant varieties to virus sources of inocula from 15 tungro endemic areas were employed as indicator of variations of virus virulence. The green leafhopper of Sukamandi’s population was used as the vector and allowed to transfer viruses  acquired from tungro’s infected plants from 15 tungro endemic areas to five groups of virus resistant varieties based on parent source of resistance using free choice screening box method. The results showed that the most resistant variety was group V1-Tukad Petanu, followed by V4-Tukad Unda, V2-Tukad Balian and V3-Bondoyudo. Based on resistance test result group variety of V1-Tukad Petanu is recommended for 15 provinces source of incula except for Sulawesi Utara. Group variety of V4-Tukad Unda is not recommended to plant in Yogyakarta and Banten provinces. Group V2-Tukad Balian is not recommended to plant in Bali, Sulawesi Utara, Banten and Kalimantan Selatan provinces. Group V3-Bondoyudo is not recommended to plant in Jawa Tengah, Yogyakarta, and Banten provinces. There were variations in virus virulence among sources of inocula. Six virulence variants were identified, i.e. 001 (Jawa Barat, Nusa Tenggara Barat, Sulawesi Selatan, Jawa Timur, Lampung, Sulawesi Barat, Sulawesi Tengah, Sulawesi Tenggara, Papua), 011 (Jawa Tengah), 021 (Bali, Kalimantan Selatan), 051 (Yogyakarta), 071 (Banten) and 121 (Sulawesi Utara).

Variation of seed zinc in a local upland rice germplasm from Thailand

2014 ◽  
Vol 13 (2) ◽  
pp. 168-175 ◽  
Author(s):  
Pennapa Jaksomsak ◽  
Narit Yimyam ◽  
Bernard Dell ◽  
Chanakan Prom-u-thai ◽  
Benjavan Rerkasem
Keyword(s):  
Chemical Analysis ◽  
Upland Rice ◽  
Weighted Average ◽  
Zinc Content ◽  
Single Seed Descent ◽  
Rice Varieties ◽  
Slash And Burn ◽  
Rice Germplasm ◽  
Single Seed ◽  
Almost All

This study examined variation in seed zinc (Zn) in a local upland rice germplasm that may affect adaptation in a system of slash-and-burn. Individual seed Zn in farmers' seed lots of local upland rice varieties from a slash-and-burn system was evaluated by staining with dithizone (DTZ). Concentration of Zn in the farmers' seed lots and their single-seed descent genotypes grown at Chiang Mai University was determined by chemical analysis. The DTZ staining of individual seeds in most of the farmers' seed lots covered the intensity of standards that ranged from 19 mg Zn/kg (RD21) to 31 (Nam Roo) mg Zn/kg. Zinc content by chemical analysis was closely correlated with the weighted-average staining for each seed lot. Almost all of the single-seed descent genotypes had higher seed Zn than RD21; two-thirds were higher than Nam Roo. The variation within seed lots detected by DTZ staining was confirmed by seed Zn in the single-seed descent genotypes. Evolutionary adaptation to soil with limited Zn, exacerbated by alkalinity of the ash from slash-and-burn, is made possible by variation in seed Zn among individuals growing together in the same field, and benefits the eaters with Zn-enriched seed.

EFFECTS OF FERROUS TOXICITY ON SEEDLING TRAITS AND ION DISTRIBUTION PATTERN IN UPLAND AND LOW LAND RICE UNDER HYDROPONIC CONDITIONS

2015 ◽  
Vol 78 (1-2) ◽  
Author(s):  
Nusrat Jahan ◽  
Norshila Fauzi ◽  
Muhammad Arshad Javed ◽  
Samiullah Khan ◽  
Siti Zulaiha Hanapi
Keyword(s):  
Upland Rice ◽  
Growth Parameters ◽  
Irrigation System ◽  
Lowland Rice ◽  
Ion Distribution ◽  
Rice Varieties ◽  
Seedling Traits ◽  
Plant Parts ◽  
Experimental Treatments ◽  
Hydroponic Conditions

Environmentally, nutritional disorders are the major constraints due to the change in soil pH for rice crop cultivated under different irrigation system. Iron toxicity is one of the famous nutritional disorders caused by the excessive uptake of ferrous ion in low pH under aerobic conditions. This research study was focused to measure the effect of different levels of ferrous stress on seedling traits, distribution of ferrous, potassium ions in two upland rice and three lowland rice varieties. The mean comparison of growth parameters were formulated using least significant differences, as well as the experimental treatments were compared by analysis of variance. Varieties showed significant differences for growth parameters; however, lowland rice varieties like Pokkali and Firat exhibited the minimum deterioration in growth parameters. The root length was significantly reduced under ferrous stress in all varieties. Ferrous accumulation was high in roots compared to aerial plant parts and flag leaves exhibited the minimum accumulations. Reduction of potassium reflected in all plant parts when an increased in stress was imposed. Upland rice varieties were found sensitive compared to lowland rice varieties. It is therefore; concluded that the growth parameters would be a reflecting index for ferrous toxicity in rice. Furthermore, the availability and uptake of potassium is improved, it may minimize the effects of ferrous toxicity. 

THE RAINFED LOWLAND RICE RESEARCH CONSORTIUM: A MULTI-INSTITUTIONAL APPROACH FOR SUSTAINABLE PRODUCTIVITY INCREASES IN ASIAN RICE-BASED SYSTEMS

1999 ◽  
Vol 35 (2) ◽  
pp. 115-125 ◽  
Author(s):  
R. S. ZEIGLER
Keyword(s):  
Nutrient Management ◽  
Agricultural Research ◽  
Lowland Rice ◽  
Yield Potential ◽  
Multidisciplinary Teams ◽  
Nutrient Deficiencies ◽  
Rice Varieties ◽  
Asian Rice ◽  
Rainfed Lowland ◽  
Research Consortium

Input-responsive, high yielding rice varieties and associated technologies responsible for the doubling of yields on irrigated lands in Asia have not suited the area of more than 40 million hectares of Asian rainfed lowland rice. These environments are home to some of the poorest rural populations in South and Southeast Asia, and the rice crops are subject to drought, prolonged submergence from uncontrolled flooding and nutrient deficiencies. Farmers grow unimproved varieties and these, combined with abiotic stresses and low inputs, result in grain yields often less than 2 t ha−1. The International Rice Research Institute (IRRI) and National Agricultural Research Systems (NARS) have recently joined to form the Rainfed Lowland Rice Research Consortium in order to identify, prioritize and execute strategic research that addresses critical yield and productivity constraints. Principal intervention points for achieving sustainable yield increases are in developing drought- and submergence-tolerant germplasm with good yield potential, improved nutrient management under stress conditions, water use-efficient crop establishment practices, and understanding farmers' approaches to risk management. Multidisciplinary teams of IRRI and NARS scientists execute research at sites selected across the region to represent the key sets of constraints.

Potential of cinosulfuron and CGA152005 seed treatment for control of Striga hermonthica in upland rice

2002 ◽  
Vol 50 (1) ◽  
pp. 7-18 ◽  
Author(s):  
M. A. Adagba ◽  
T. O. Lagoke ◽  
B. N. Singh ◽  
Keyword(s):  
Seed Treatment ◽  
Upland Rice ◽  
Rice Variety ◽  
Striga Hermonthica ◽  
Resistant Variety ◽  
Rice Grain ◽  
Seed Treatments ◽  
Rice Varieties ◽  
Grain Yields ◽  
Four Levels

Field trials were conducted in the dry and wet seasons of 1998 at Samaru (11°11' N, 07° 38' E, 686 m above sea level) in the northern Guinea savanna of Nigeria, to investigate the potential of cinosulfuron and CGA152005 seed treatments on the reaction of upland rice varieties to Striga hermonthica (Del.) Benth. Seven varieties of upland rice formed the main plots treatments while four levels each of cinosulfuron at 0.1, 0.2, 0.4 and 0.6 g/l and CGA152005 at 0.008, 0.016, 0.032 and 0.064 g/l, as well as two no herbicide treatments of dry sowing and distilled water-soaked planting were assigned to the subplots. The experiment was laid out in a split plot design and replicated three times. The resistant varieties FARO 40 and WAB 56-50 did not support Striga emergence and also produced grain yields which were the maximum, or comparable to the maximum. FARO 11, a susceptible variety, produced high grain yields in spite of support for early, high Striga emergence. In spite of delayed emergence of Striga on FARO 38 and FARO 48, these varieties, as well as FARO 46 and FARO 45, supported high Striga emergence, exhibited high crop reaction scores to Striga and produced low grain yields. The seed treatment of upland rice varieties with cinosulfuron at 0.2 to 0.6 g/l and CGA152005 at 0.032 and 0.064 g/l significantly delayed Striga emergence compared with the lower rates. After seed treatment with cinosulfuron at 0.6 g/l, the susceptible rice variety FARO 38 and the resistant variety WAB 56-50 produced rice grain yields comparable to the maximum obtained with FARO 40 given seed treatment with CGA 152005 at 0.064 g/l. The significant interactions of varieties of upland rice and herbicide seed treatments on the number of days to first Striga emergence, Striga shoot count and crop reaction to Striga confirm the differential influence of various concentrations of the herbicide seed treatments on the virulence of Striga hermonthica on varieties of upland rice.

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