in order to study the effects of four concentrations (check, 5, 10 and 15%) of hull extracts on growth of 10 iranian rice cultivars, two experiments were conducted in completely randomized block design with factorial arrangement and three replications at two sites, laboratory and greenhouse. laboratory study showed that same rice hull extracts had stimulat effects and the others had inhibitory ...

Upland rice is typically grown under slash-and-burn systems in the mountainous regions of northern Laos by resource-poor farmers for subsistence. Upland rice cultivars are all traditional and no fertilizer inputs are used. In these systems, grain yields average only 1.7 t/ha. A multi-site experiment was conducted in Luang Prabang province to examine cultivar and fertilizer effects on grain yiel...

Clay H. Sneller Department of Agronomy, University of Arkansas, Fayetteville, AR 72701. Present address: Ohio Ag Resources and Development Center, Department of Horticulture and Crop Science, 1680 Madison Ave., Wooster, OH 44691 Red rice is a major weed in rice production in the southern United States. Red rice and rice intercross because they are the same species. Our objectives were to determ...

In 1966, IRRI released IR8, the first high-yielding modern rice cultivar for the irrigated tropical lowlands. Since the release of IR8 in 1966, 42 additional indica rice (Oryza Since then, the primary emphasis of rice improvement sativa L.) cultivars developed by the International Rice Research Institute (IRRI) for the irrigated and favorable rainfed lowlands have has been directed towards inco...

Sucrose synthase activity in rice is potentially yield limiting. Earlier research indicated that endosperm sucrose synthase activity during grain filling was higher in ‘Guichao’ rice than in U.S. rice cultivars. We set about to purify sucrose synthase from Guichao endosperm as part of an overall research effort to understand the physiological reasons for the high yields of Guichao compared to U...

Ethanol–water (70:30, v/v) extracts from the bran of rice seeds from twenty one pigmented and one nonpigmented rice cultivars were evaluated for antioxidative activities using the following tests: inhibition of peroxidation of linoleic acid; inhibition of peroxidation of rabbit lipid erythrocyte membranes; reduction of potassium ferricyanide, and scavenging of superoxide anions and hydroxyl rad...

Plant breeding programs aim to develop cultivars with high adaptability to the specific conditions in a local region. As a result, unique genes and gene combinations have been accumulated in local elite breeding populations during the long history of plant breeding. Genetic analyses on such genes and combinations may be useful for developing new cultivars with more-desirable agronomic traits. H...

DNA polymorphism of randomly selected genes in rice cultivars was analyzed by the polymerase chain reaction-restriction fragment-single strand conformation polymorphism (PCR-RF-SSCP) technique. Single DNA fragments were amplified from genomic DNA of the Nipponbare cultivar by 671 primer pairs among the 1000 primer pairs tested. PCR-RF-SSCP analysis using the 671 primer pairs detected polymorphi...

DNA methylation is an epigenetic mechanism that play an important role in gene regulation in response to environmental conditions. The understanding of DNA methylation at the whole genome level can provide insights into the regulatory mechanisms underlying abiotic stress response/adaptation. We report DNA methylation patterns and their influence on transcription in three rice (Oryza sativa) cul...

Drought and salinity are the major environmental factors that affect rice productivity. Comparative transcriptome analysis between tolerant and sensitive rice cultivars can provide insights into the regulatory mechanisms involved in these stress responses. In this study, the comparison of transcriptomes of a drought-tolerant [Nagina 22 (N22)] and a salinity-tolerant (Pokkali) rice cultivar with...