Search

The research was conducted in areas of the Technological Scientific Base Unit "Los Palacios" (UCTB Los Palacios), Pinar del Rio, part of the National Institute of Agricultural Sciences of Cuba. Two short cycle cultivars (INCA LP -5 and Reform), and two half cycle cultivars (INCA LP-2 and J-104). Were used which were planted in four planting dates of the cold season, on a Gley Nodular Hydromorphic Ferruginous Petroferric soil. The objective was to determine the influence of the phenological phases duration in yield of rice cultivars (Oryza sativa L.) under the conditions of spring season. A randomized block experimental design was used with four replications. Based on the results of this study, it can be concluded that the duration of the reproductive phase in rice cultivars closely positive and direct relationship with of yield in the conditions of the spring season. [ABSTRACT FROM AUTHOR]

The agribusiness company of grains ̏ Fernando Echenique Urquiza ̋ from Granma dedicate to the production of rice consumption and seed, through different processes including agro-technical and plant health, where a large volume of information related to planting and crop care is controlled. The accounting process is performed manually or through Microsoft Excel electronic tab to which different documents are required, causing delays and the possibility of mistakes. In response to these needs, this research aims to develop a web application. To implement the methodology of software development Extreme Programming was used, also the programming languages Hypertext Preprocessor, HyperText Markup Language, Cascading Style Sheets and JavaScript, the Web application server Apache, the CodeIgniter and Extend JavaScript frameworks, the integrated development environment NetBeans and database manager My Structure Query Language database. With its use the information management and data processing related to agro-technical and plant health data so that it can be quickly provided, enabling greater consistency, security and raising the level of efficiency from the organizational control and the analysis information. [ABSTRACT FROM AUTHOR]

The work was developed in Bahía Honda, Manicaragua and Gibara municipalities, located in the western, central and eastern Cuba respectively. Smallholder farms linked to the Local Agricultural Innovation Programme (PIAL, according its acronyms in Spanish) were visited. For the collection of information a face survey, structured with open and closed questions was used. Basic varietal diversity of species studied for Cuban food such as: rice, beans, corn, tomato, cassava and banana, whose productions depend of an appropriate supply of seeds. The results showed that in Bahía Honda a greater diversity of varieties and generally recorded in the three municipalities, an average of three varieties of each of the basic food species are used. The varietal diversity potentially decreased with the increase in cultivated surface. The coexistence of local and improved varieties was demonstrated in the west and east farms of the country, while in the farms located in the central region food production is based mainly in planting local varieties. Analysis of the spatial distribution of each species, in order to know their potential for seed production in local agrifood strategic projection showed that coincidently maize is grown in small areas in most of the farms in the three municipalities which is an opportunity for diversification, meanwhile, it should be paid more attention to the cultivation of tomato in order to encourage their production as many farms. [ABSTRACT FROM AUTHOR]

Low yields, climate change effects and heterogeneous culture conditions are some reasons for the development of new rice cultivars. This trial was developed with the objective of studying the behavior of sixteen advanced lines of rice under flooded conditions and to select the best for moving on to a higher stage. A Completely Randomized Design with three replications was used, the genotypes constituted the treatments and four commercial control were used. The available information was processed statistically by the combination of univariate and multivariate analysis. Results showed correlation of the yield with all their components, the cluster analysis detected that the maximum genetic diversity between types V and VI and the minimum was detected between types I and II and the regression indicated that the model had a good adjustment (93.5 %). The combination of statistical analyses used allowed to select five more promissory lines and to propose its validation. [ABSTRACT FROM AUTHOR]

Rice cultivation transplant traditionally spends most of its life cycle with flooding and exhibits high adaptability to these conditions, consequently its production consumes a lot of water, although less than in the cultivation by direct seeding. This research was conducted to evaluate the effect of irrigation water management in the agricultural and industrial yield of rice transplanting technology. Plants remained in flooded conditions throughout the cycle and plants undergoing suspension of the water surface for a period of 15 at three different times tillering stage were evaluated. The suspension of the water level increased agricultural yields between 16 and 32 % over the flooded control and industrial yield was 67 % on average. The highest percentage of whole grains were obtained in the treatments under suspension of the sheet, achieving the best results with the suspension at 30 DDT. This operation allows water savings of approximately 1 931,4 m3 ha-1, for the flooded treatment. The water saved would increase the area under irrigation by 11,19 % for rice cultivation. [ABSTRACT FROM AUTHOR]

This research was conducted in areas from "Los Palacios" Scientific-Technological Base Unit (UCTB) in Pinar del Rio province, pertaining to the National Institute of Agricultural Sciences. Two short-season cultivars (INCA LP-5 and Reform) and two half-season cultivars (INCA LP-2 and J-104) were used and seeded in four sowing dates (January-2004, December-2004, February-2005 and January-2006) over the winter season, on a Petroferric Ferruginous Nodular Gley Hydromorphic soil. The objective was to determine the influence of environmental temperature and seeding date on the phenological phase variation of four rice cultivars. A randomized block design with four replications was used. Based on the results, it can be concluded that the longest vegetative and reproductive phase was recorded at the dates of December-2004 and January-2006, corresponding to the lowest temperature values reported in this work. The accumulated temperature necessary to complete the biological cycle of INCA LP-5, Reform and INCA LP-2 cultivars is within a range from 1900 to 2150 °C, whereas for J-104 is between 2200 and 2260 °C. Highest yields correspond to the longest reproductive phase forevery cultivar studied. [ABSTRACT FROM AUTHOR]

The present work is part of the researches that are carried out in the Regional Project of the International Organization of Atomic Energy (IAEA) "Mutation Breeding of Alimentary Cultivations in Latin America" where Cuba participates. The aim of this project is to obtain new rice varieties tolerant to drought using nuclear techniques, for that which is necessary to determine indicators for early selection of tolerant genotypes and to identify somaclones and/or mutants of good behavior under low water supply. For this study were used, 13 mutants obtained in the National Institute of Agricultural Sciences (INCA) as well as the rice varieties Amistad-82 and J-104. The response to the hydric stress under field conditions was determined, using irrigation during the first 45 days, interrupting later for the plant cycle, were determined: I) the height of the plant, II) weigh of 1000 grains, III) length of panicle, IV) number of full grains, V) vain grains, VI) number of panicle for lineal meter and VII) yield for square meter. Likewise in vitro the answers to the drought with a concentration of 5 g L-1 of PEG-6000 to simulate the hydric stress and the Relative Tolerance Index of root and of height were evaluated. Some indicators for early selection of tolerant genotypes starting from the existent correlation among the characters evaluated in the field in vivo and in vitro were also determined. The INCA genotypes LP-10 and 8552 showed a better behavior under conditions of low supplies of water and INCA LP 16 genotypes and mutant 8553 were the most susceptible because they could not panicular under the same conditions. [ABSTRACT FROM AUTHOR]

The study was carried in the rainy season in areas of "Los Palacios" Technological Scientist Unit of Base, belonging to the National Institute of Agricultural Sciences with the objective of selecting promissory lines resultants of Rice Breed Program. The materials were distributed according to a Modified Augmented Design (MAD), which was structured by a Latin Square (3x3), with three controls lines (INCA LP-5, IACUBA-25 and Reforma) and 66 test lines. The data were processed by statistical multivariate techniques of Cluster Analysis and Multiple Lineal Regression. Panicle length, panicle for m2, full grains for panicle, barren grains for panicle, weight of 1000 grains, agricultural yield, cycle to 50% flowering and final height of the plants were evaluated. The results showed strong correlations between yield and full grains for panicle and weight of 1000 grains; the multiple lineal regression analysis proposes a model for the yield dependent variable and the combination of MAD and Cluster Analysis allowed the selection of 27 promissory lines to include in advanced studies in this crop, completing their characterization and evaluating their resistance to pests. [ABSTRACT FROM AUTHOR]

The research was conducted to evaluate the behavior of new rice lines (Oryza sativa L.) obtained by hybridization with the aim of increase yields and crop genetic diversity. fifthteen lines were studied from different hybrid combinations and two cultivars used as test and also as progenitors which were involved in some of the originated lines crossing. twenty two characters were considered, qualitative and quantitative one, which were measured in the stages of flowering, ripening and post-harvest of the crop, using a Completely Randomized design with five replications. The data obtained were subjected to univariate and multivariate statistical analyzes. The lines evaluated were similar in some qualitative characters and different in all quantitative characters; also it was possible to determine the most important variables for the characterization. The lines G/S-L1, G/S-L10, G/S-L13 that make up the group I were the best behavior, combining good plant erection, well emerged panicles, late or intermediate senescence and higher yield, beating the test used. [ABSTRACT FROM AUTHOR]

It is estimated that the world population will continue to increase; however the water resources available to meet crop right now is not enough, it is working to find alternatives that save water and maintain or increase agricultural crop yields. The use of arbuscular mycorrhizal fungi (AMF) is certainly a way that contributes to such purposes. The research was conducted at the Experimental Station of Zaidín, Granada, Spain, in plastic pots with plants of mycorrhizal and non-mycorrhizal rice in semi-controlled conditions, with three water supplies, no stress (25 mL), moderate stress (10 mL) and severe stress (5 mL) for 15 days, with the aim of evaluating the effect of the inoculation of Rhizoglomus intraradices in rice plants under water stress and then retrieved on some biochemical parameters. The results showed that the symbiosis HMA reduces the accumulation of hydrogen peroxide and oxidative damage to lipids from an increased accumulation of the antioxidant glutathione. The combined effects of plant metabolism improved after a period of water stress and can be suggested as indicators under conditions of water deficit in plants [ABSTRACT FROM AUTHOR]

The chitosan is widely used in agriculture for having a strong fungistatic effect, also it has other properties such as extending the post harvest life of fruits and vegetables and stimulating the plant growth, among others. However, the use of this biopolymer for inducing salinity tolerance has been few studied, so the objective of this work was to check if chitosan-treated seeds are able to reverse the effects caused by salinity in the rice seedling growth and some biochemical indicators associated to this response. To do this, rice (Oryza sativa L.) seeds variety INCA LP-5 were treated for 24 hours with different concentrations of chitosan (0, 100 and 500 mg L-1). The germinated seeds were transferred to pots containing diluted Hoagland nutritive solution supplemented or not with NaCl 100 mmol L-1 and they were placed in a growth chamber with controlled conditions. The growth and biochemical indicators were evaluated eleven days after stress treatment. Seeds treated with chitosan 100 mg L-1 stimulated shoot length and dry matter in saline medium grown seedlings and lowered malondialdehyde and increased proline levels. Both chitosan concentrations enhanced the activities of catalase and peroxidase enzymes, although a higher effect was obtained with chitosan 500 mg L-1. [ABSTRACT FROM AUTHOR]

They were carried out studies in the period understood among the years 2008 at the 2010, initially under experimental conditions of the UBPC "Los Palacios" to determine the promissory cultivars for the ratoon cultivation, being evaluated in 26 cultivars the number of fertile shafts, yields of the initial cultivation and ratoon. In the obtained results it is demonstrated that all the proven cultivars produce shafts after the crop of the main cultivation, and a group of them they take place but of 250 fertile children for square meter, the agricultural yields of humid rice of the sprout between 2,5 and 4,27 t ha-1 with alone in 69 at 80 days of cultivation. The total production of the cultivars IAC-36, INCA LP-2, INCA LP-4, INCA LP-5, INCA LP-7 and J-104 in both crops overcome 10 t ha-1 totals, being able to recommend for their use in production condition. [ABSTRACT FROM AUTHOR]

The current development of researchers in the field of genetic improvement in Cuba and the necessity of economizing experimental area and resources outlines the necessity to value experimental designs that facilitate an appropriate efficiency with a maximum of economy. This work intends to combine the kindness of DAM, with the adjustment method for line-column to control the soil heterogeneity, and the statistical multivariate techniques, offering the investigator a mathematical tool in the selection of test lines in rice breeding programs. DAM was structured by means of a Latin Square (4x4), with four controls lines (INCA LP-5, INCA LP-2, J-104 and Reforma) and 120 test lines distributed at random in the corresponding subplot. The use of DAM that allows to compare a considerable number of test lines, overcoming the limitations of a not replied experiment, what presupposes an economic benefit for the area reduction, the economy of experimental material and control of the environmental heterogeneity, in combination with statistical multivariate techniques provides a methodology more efficient in the selection of promissory lines in rice breeding program. [ABSTRACT FROM AUTHOR]

The work carry out in the Scientific Technological Base Unit (UCTB) Los Palacios, Pinar del Río, on a soil Hidromórfico Gley Nodular Ferruginoso, during the campaigns little rainy 2004-2005 and 2006 - 2007, with the objective of knowing up to where the border effect can arrive and all could falsify the data of the sample so much in the field of the investigation like in the production if one doesn't keep in mind this aspect. This way you could economize area and resources when to mount an experiment or to make a works planning production used. To carry out the evaluations the INCA variety LP-5 it was used in four parcels of 2 x 2 m where it was measured height and yield following the methodology described by JICA in the 2008. The results showed that contrary to those reported under other conditions the border effect it can reach until 30 cm of the event that provokes it, and the data vary significantly with regard to the affected area. Considering the high cost of the field experiments this result has particular importance since it allows to economize resources being able to use experimental parcels of smaller size, also has application in the rice production where most of the cultural activities that are carried out to the cultivation depend on mensurations and observations, allowing to make an appropriate planning of the crop, herbicide applications, fungicides, insecticides and fertilizers, among other works. [ABSTRACT FROM AUTHOR]

The present study aimed to perform biochemical studies to search possible indicators for differentiation in the early development stages of rice varieties, in relation to their degree of tolerance to saline stress. Leaf samples of two varieties with different degrees of tolerance to salinity (Pokkali and Amistad-82) and grew up in greenhouses growing in nutrient solutions simulating the salt stress (8 and 12 dS.m-1), were analyzed. At 35 days after planting, it was assessed the activity of the enzyme peroxidase, total protein content, proline and lipid peroxidation. The results showed a differential behavior of the varieties in their degree of tolerance when using the EC 12 dS.m-1 which allows using the activity of the enzyme peroxidase, proline concentration and lipid peroxidation in the discrimination of rice genotypes tolerant to salinity. [ABSTRACT FROM AUTHOR]

Brassinosteroids are steroidal compounds which are required to plant growth and development and they are, also, implied in plant response to abiotic stress. The central objective of this paper was to evaluate if rice seed treatment with different concentrations of a natural brassinosteroid and an spirostane analog reduces the impact of salt stress in the seedling growth. Two experiments were performed, at the first one, a salt sensitive variety, J-104 was used and at the second one, a tolerant genotype, Ginés, was employed. In both experiments, the seeds were treated, for 24 hours, with different concentrations (0; 0,01; 0,1 y 1,0 µmol.L-1) of a natural brassinosteroid, 24-epibrassinolide, and an spirostanic analog of brassinosteroids, 25(R)-3α,5α, dihydroxy-5α-spirostan-6-one, which formulation is known as BIOBRAS-16. After germination, the seedlings were placed in pots containing Hoagland diluted nutritive solution with the addition or not of 100 mmol.L-1 sodium chloride. In the first experiment, the seedlings remaining during eleven days in a growth room with 12 h photoperiod and 25±2°C temperature; while in the second one, the seedlings were grown for thirteen days at a 28±2°C temperature. At the end of the experiments, root and shoot length and dry mass were evaluated. Results showed that 24-epibrassinolide and BIOBRAS-16 were able to reverse partially the seedling growth inhibition of both rice genotypes induced by the presence of sodium chloride; being the more effective treatments in the tolerant variety. [ABSTRACT FROM AUTHOR]

In the Base Technological Scientist Unit «Los Palacios» seeds first generation of harvested rice isogenic lines, coming from F2 in vitro anthers culture from crossings Amistad'82/2077, 2077/Amistad'82, Amistad'82/IR759-54-2-2 and Moroberekan/Amistad'82, were sowed in field, with the objective to evaluate their behaviour in natural Blast field infection. The absence of dominant genes in heterocigosis involved in the inheritance to Blast was confirmed and, apparently, the behaviour could be governed by major genes in homocigosis and small genes with additive effect. Four isogenic lines wit good agronomic behaviour and Blast resistant were selected. The same will be very useful to obtain new varieties. [ABSTRACT FROM AUTHOR]

The study was carried out at the Research Experimental Plot (RE1) from Tsukuba International Center (TBIC) located in Ibaraki Prefecture, Japan, with the objective of analyzing the productive structure and yield of four rice (Oryza sativa L.) varieties of different origin. Treatments correspond to J-104, Bluebonnet-50, Suweon-294 and Nipponbare varieties. Dry matter content and light intensity were determined, also yield and its components were evaluated and the relationship existing between yield and light intensity was analyzed. A Single Classification Variance Analysis and Duncan's Multiple Range Test were used. Results showed differences between treatments and the indica-japonica variety Suweon-294 presented the best behaviour in the productive structure analysis, while the indica variety J-104 reached the highest yields. The regression between studied variables indicates a direct relationship. [ABSTRACT FROM AUTHOR]

Rice (Oryza sativa L.) is the most important crop for human consumption is grown conventionally in flooded conditions throughout their cycle. However, approximately half the surface of rice in the world does not have sufficient water to maintain optimal growth conditions. One possible way to increase rice production to meet demand is to improve the efficient use of water by arbuscular mycorrhizal fungi (AMF). The research was conducted at the Experimental Station of Zaidín, Granada Spain, with mycorrhizal and non-mycorrhizal rice plant under controlled conditions and with three water management, without stress (25 mL), moderate stress (10 mL) and severe stress (5 mL) for 15 days, in order to evaluate the effect of AMF inoculation of rice plants subjected to hydric stress and after the plants recovered. The results show that rice can benefit from the symbiosis MA and improve long-term development after a period of water stress. In fact, at each level of irrigation, the mycorrhizal plants showed a 50 % increase in aerial fresh mass and 40 % photosynthetic efficiency compared to non-mycorrhizal plants. Besides, the proline content increased with hydric stress in mycorrizal and non-mycorrizal plants. [ABSTRACT FROM AUTHOR]

Experimental work was carried out in CCSf-- «Menelao Mora» with a Petroferric Nodular Gley Hidromorfic soil, during the period 2006-2009 with de purpose to know the agricultural yield of rice ratoon crop for the medium cycle rice variety (Prosequisia). Results showed lower ratoon height cutting gave higher yields compared with the main crop (first crop). Similar results was achieved for the foliar area index (IAF) and the number of fertile stems. The sprout cycle was reduced between 60 and 65 days in relation with the main crop. It was no necessary herbicides applications and a less irrigation water was used. [ABSTRACT FROM AUTHOR]

In the months of March until July (rainy season) of the year 2003, in areas of the «Blas Roca» farm belonging to «Los Palacios» Rice agroindustrial enterprise, on a «Gley Nodular Concretionary soil, the behavior of six lines (3981, 8748, 8738, 4482, 8554, 8741) and three varieties (INCA LP-7, IACUBA-25 and the commercial variety J-104 as comparison control of rice, seven of them obtained in the breeding program for tolerance to salinity, was studied. The quantitative characters (final plant height, full grains per panicle, panicle per square meter, 1000 grain weight, empty grains per panicle, cycle in days and the agricultural and industrial yields), as well as the qualitative characters (resistance to lodging, shattering, blast and discoloured grain diseases and to the mite Steneotarsonemus spinki Smiley) were evaluated. Some differences among studied genotypes were observed. The highest agricultural and industrial yield and the best behavior to the main plagues and illnesses were obtained for the lines 3981, 8748 and 8554, and the variety INCA LP-7. [ABSTRACT FROM AUTHOR]

The work was made in the Plant Phytopathology Laboratory belonging to the Scientific and Technological Base Unit Base Los Palacios. The aims of this research was to evaluate the antifungal activity of four chitosan formulates Q (100, 500, 1000 mg.L-1) y chitosan and copper (QCu-100 mg.L-1) on the mycelial growth and in vitro sporulation rate of Pyricularia grisea Sacc fungus. Results showed that 1000 mg.L-1 chitosan and QCu-100 mg.L-1 had the greatest inhibitory effect on four day with 27 y 30 %, respectively. However fungal sporulation was inhibited in 100 % by el QCu, while Q 100 y Q 500 had inhibitory percentages between 80 y 96 % on center and peripheral zones respectively. In addition, Q-1000 mg.L-1 chitosan had not a noticeable effect on fungal sporulation. [ABSTRACT FROM AUTHOR]

Rice genotype behaviour, obtained by somatic cultivation, as well as, of a group of mutants and crosses under low water supply conditions was studied at «Los Palacios» Rice Research Station from National Institute of Agricultural Sciences during poorly rainy, 2006, and rainy, 2007 stations. The genotypes 8476, 8479, 8480 (obtained by somatic culture), 8551, 8552, 8553, 5454 and 8555 (mutations), Amistad-82, Reforma varieties (crossing) and the commercial J-104 as a control variety. To cause the conditions of low water supplies, the following handling was used: the water lamina was established at 15 days after seed germination, the water entrance was suspended at 35 days after germination and it was again recovered from the primordium change until 50 % flowering stage. At harvest time, the final plant height, cycle, agricultural yield (t.ha-1) and its components were evaluated, also, the industrial yield (% of whole grains), as well as resistance to lodging, shattering, Pyricularia grisea, Sarocladium oryzae, Steneotarxonemus spinki, Borer smiley and grain discoloration. Results showed that 8554 genotype and Reforma variety reached excellent agricultural and industrial yields as well as a good behavior to principal diseases that affect economically this crop as the grain discoloration. [ABSTRACT FROM AUTHOR]

Aluminium toxicity is a very important factor limiting growing and crop productivity in acid soils. The aim of this research was to study the aluminium effects on cell division and elongation process and their relationship with root growing on two rice commercial cultivars. Different AlCl3 levels were employed to impose stress condition. Root apical segments were processed by traditional procedure to optic microscopy. The stained sections were viewed with on optic microscopy (Zeiss) and photographed with a digital camera coupled to microscopy. Morphometric Program ImajeJ was employed to determine cell dimensions. Root elongation was reduced in rice seedlings as a consequence to aluminium toxic effect. A mitotic index inhibition and reducing length and radial expansion was observed on meristematic root cells with the increase of aluminium level. The obtained results evidence some changes caused by aluminium toxic levels in both cellular process which are responsible of cell growing inhibition. [ABSTRACT FROM AUTHOR]

The study was developed at Sierra Maestra, Cubanacán, Agricola Vueltabajo and Caribe farms, all belonging to «Los Palacios» Rice Agroindustrial Complex in Pinar del Río province, where three rice commercial varieties were evaluated (INCA LP-5, J-104 y Reforma) with the objective to analyze the behavior of these under different fertility conditions, during the cold season of 2005-2006. The obtained data were processed by means of simple classification analysis with bifactorial arrangement. The results showed that the INCA LP-5 variety had a good behavior, independently of the place where it was sowed; J-104 variety had the worse results, mainly for yields in Agrícola Vueltabajo and Caribe farms, being these and those of Reform variety, less to the national means in all the studied areas. In Sierra Maestra and Cubanacán areas, the best results in the whole Rice Agroindustrial Complex of Pinar del Río were reached. [ABSTRACT FROM AUTHOR]

Salinization of soils is one of the most alarming facts worldwide, it remarks the necessity of find natural products which omdice the saline stress tolerance on plants. On this paper, the effect of 24 epibrassinolide (EBL), a natural brassinosteroid, on growth, proline level and lipid peroxidation on rice seedlings var. J-104 (susceptible) under stress caused NaCl during seven days, was evaluated. Rice seeds were sowing on distilled water during 24 hours, then were germinated on Petri dishes and 48 hours later, were planted on flasks containing a Gley nodular ferritic hydromorphic soil, whichs were placed on a plastic basket containing Hoagland nutritive solution, to allow the normal growth of plants. At the moment of the appearance of the 3th true live (five to six weeks after planting), the treatment of salinity was imposed with NaCI (100 mmol.L-1) on Hoagland solution during seven days and in this moment leaves were sprinkled with 24 epibrassinolide (0,5; 1 and 2 µmol.L-1). Plants were maintained on Hoagland solution during 14 days to their recovering. At the moment of the salinity treatment application, at the end of the stress period, seven days after beginning of recovering period and at the end of this period, the length and biomass of radical and aereal parts of plants were measured. Proline and malondialdehyde levels were also evaluated, as well as lipid peroxidation at the end of the recovering period. The results showed that the effects of NaCI and EBL on the growth and malondialdehyde level on leaves of seedlings, depends on the temperature during the growing period. The increase of proline levels, caused by the stress due to NaCl after 14 days of recovering, diminished significatively with the application of 1 to 2 µmol.L-1 de EBL on both repetitions. [ABSTRACT FROM AUTHOR]

The knowledge of rice morphology is important in the investigation because in this it is based varieties differentiation and physiology and improvement studies. The work was developed with the objective to make morphoagronomic characterization varieties and to know the variables that contribute to differentiate them and the characteristics that could be important to select the parents of the Plant Breeding Program with the purpose to get crop bigger efficiency. Were evaluated 10 rice genotypes with different origin and varietal group. The seeding was carried out in trays and then it was transplanted in rows of 2.40 m of longitude.Were carried out evaluations in two cultivation stages that included quantitative and qualitative variables, also Standard Evaluation System and Description Varietal Form was methodologies used. Data obtained were processed by Main Components and Cluster with MINITAB statistical program and Pearson Correlations were determined. The results revealed the existence of morphoagronomic differences in rice varieties and correlations among the quantitative variables evaluated; also were confirmed marked contrasts between Indicas and japonicas types for most of the studied characters. Two obtained components explained 69.3% of total variation. The genotypes were contained in six groups or classes, almost all the individuals with common varietal group concentrated to exception of Nipponbare, Nerica-1 and Bluebonnet-50 that were located in independent classes. Only there was similarity forall the varieties in two of 12 qualitative characters evaluated. [ABSTRACT FROM AUTHOR]

The discovery of aquaporins in plants hascaused a major change in the way of studying the waterrelations of plants, so that in recent years considerable effortshave been made to investigate the functions and regulationsof these, since in nature the plants are continuously exposedto stress conditions that retard its growth and development,being drought, salinity and low temperatures common stressesto which they face. The aim of this work is to compile updatedinformation about the discovery and types of aquaporins, theirfunction in water transport of plants, their interaction witharbuscular mycorrhizal fungi, and some research in ricecultivation. [ABSTRACT FROM AUTHOR]

This work was carried out in the areas from Los Palacios Rice Research Station of INCA, Pinar del Río, using INCA LP-5 and Reforma as short-cycle varieties, besides INCA LP-2 and J-104 as mid-cycle ones, during the dry season of January 2004 and February 2005, on an Ironstone Nodular Gley Hydromorphic soil, with the objective of evaluating the behavior of rice varietal growth and productivity. A direct seeding technology was employed with a pattern of 120 kg.ha-1. Agrotechnical activities followed rice crop technical instructions. A randomized block design with four replications and 25-m² experimental plots was used. Dry matter of the aerial part of plants (g.m-2) was determined in a 25-m² frame and samplings were fortnightly performed 25 days after germination until harvest. The absolute growth rate and leaf area index were calculated, besides determining agricultural yields and its main components; all data were processed by means of a single Anova through Duncan's multiple range test (p<0.05). Considering the results, it should be highlighted that agricultural yield was higher in short-cycle varieties than in the mid-cycle ones, with higher leaf area index values in those varieties. Radiation availability during the reproductive phase at the sowing date of February 2005 was a limiting factor for the varieties to reach top dry matter production and so to achieve higher yields. The best results of INCA LP-5 and Reforma could be related to varietal genetic characteristics, which are recommended for the breeding programs to search for new more productive cultivars. [ABSTRACT FROM AUTHOR]

The work was developed at Los Palacios Rice Research Station for three years and later at small-scale producers' areas belonging to a non-specialized system (popular rice) as an agricultural extension. The study consisted of determining the effect of seedling age, plant spacing and seedling number per site on agricultural yield. Results showed a seed amount reduction in the nursery, to the value of 5 kg.ha-1.year-1, which represent between 35 and 40 % of that used in the traditional transplanting system. In addition, agricultural yields increased up to 2.0 t.ha-1; there was a greater tillering and root system development per plant compared to the check control. On the other hand, when crop irrigation was discontinued for 21 days, 3 300 m³.ha-1.year-1 of water were saved. [ABSTRACT FROM AUTHOR]

The study was carried out from 2000 to 2006, in the areas of 'Los Palacios' Rice Agroindustrial Complex (CAI), Pinar del Río, with the objective of studying the monthly behavior of leaf blast (Pyricularia grisea Sacc.) occurrence, which is the most important rice disease worldwide and its relationship with temperatures: maximum (Tmax), minimum (Tmin) and mid (Tmid), relative humidity (Hr) and rainy days (Dcll). Thus, data were subjected to variance analysis, tendency and correlation; besides, a study of temporary series was made by using the additive seasonal decomposition method. Results showed that monthly disease occurrence was not correlated with Hr but with Tmax, Tmin and Tmid, as well as Dcll. Meanwhile Hr kept a slightly growing tendency of its mid monthly values, Tmax, Tmin, Tmid and Dcll as well as P. grisea occurrence had an increasing-decreasing tendency, which constitutes a year-on-year variability example of these variables. The resulting seasonal decomposition indexes enabled a better understanding of the studied variable behaviour patterns that make this variability evident, besides keeping with the tendencies and variations observed in the current climate of Cuba. [ABSTRACT FROM AUTHOR]

The investigation was conducted from 1999 to 2003, with the objective of determining the effect of three different cropping systems on soil particle, bulk density, total soil porosity and rice yield. The factors evaluated were years of study and cropping systems: 1. "rice-rice" monoculture, two sowings were performed every year in the same soil area; 2. "rice-fallow-cattle-rice" annual rotation, sowing was done in the rainy season every year of the study, then a short fallow after harvest, later on cattle grazing followed by a new sowing; 3. "rice-soybean" annual rotation, rice was sown in the rainy season, then soybean and later on rice crop. Rice monoculture and cattle grazing deteriorated soil physical properties, whereas the annual rice-soybean rotation modified them just a little after three years. Also, agricultural yield was strongly affected where soil physical properties were degraded in a short time. The best measurements of soil bulk density and total porosity for rice production are between 1.12-1.20 Mg.m-3 and 54-57 %respectively. [ABSTRACT FROM AUTHOR]

At Tsukuba International Center (TBIC), belonging to Japan International Cooperation Agency (JICA), located at Ibaraki Prefecture, some growth and development parameters were studied, from March to September 2006, in four rice varieties: J-104, Bluebonnet-50, Suweon-294 and Nipponbare. During crop development since May 5, the following growth development parameters: stalk number, leaf number, plant height, fertilized tillers, agricultural yield (t.ha-1) and its components, as well as green color intensity were weekly evaluated and some differences were observed. J-104 variety showed the best behavior for green color intensity of leaves, panicle grain number, 100-grain weight and agricultural yield, whereas the best results were obtained by the Japanese variety, Nipponbare, for the other growth and development parameters. [ABSTRACT FROM AUTHOR]

This work was carried out at Los Palacios Rice Research Station, Pinar del Río, using INCA LP-5 and Reforma varieties, within the dry season of 2004, on a Ferruginous Nodular Gley Hydromorphic soil, with the objective of determining growth dynamics, yield and its main components. The direct seeding technology was applied with a norm of 20 kg.ha-1. Cropping activities followed rice technical instructions. A randomized block design with four replications was used and experimental plots had a 25 m2 area. Dry matter from the aerial part of plants (g.m2) was calculated in a 25-m2 frame and samplings started 25 days after germination, at variable intervals, up to grain maturity. Absolute growth rate (AGR) of the aerial part, agricultural yield and its main components were also calculated, whereas means were compared through T Student test (p<0.05). Results proved that INCA LP-5 kept a quicker growth rate and biomass accumulation than Reforma variety during the whole cycle, besides surpassing the latter one regarding agricultural yield, showing highly significant differences. [ABSTRACT FROM AUTHOR]

Participatory plant breeding (PPB) is a relatively new approach for germplasm development, which includes crop improvement and participatory varietal selection (PVS). In Cuba, PPB started on rice crop in 2001, based upon centralized PVS at the beginning; however, it was further participatory and decentralized. This work study was aimed at presenting the experiences gathered on rice crop, not only in some regions of Cuba but also over the world. In our country, diversity fairs constituted the best form for providing a quick and efficient varietal entry through non-specialized rice growers'participation. [ABSTRACT FROM AUTHOR]

In 2005, the monthly behavior of the mid-cycle rice variety INCA LP-4 was studied on a Hydromorphic Nodular Gley Petropheric soil with a randomized block design at "Los Palacios" Rice Research Station. Thus, agricultural yield and other characters were evaluated, in order to know varietal response seeded at different times; the information recorded was processed by means of a Two-way Classification Variance analysis whereas differences between means were docimated according to Duncan's Multiple Range test for p≤0.05. The best behavior was observed in January and February sowings, when plants reached the characteristic height of a mid-cycle variety; agricultural yield and its components were the best as well as industrial quality, which is recommended to be seeded during these months. [ABSTRACT FROM AUTHOR]

Rice monoculture affects soil fertility, helps pest development, causes salinization and declines yields after three consecutive harvests. Thus, holding back such effects is strategic; the special agronomic rice management inexorably damages its agronomic qualities. Outlining a possible solution to the problem, the present paper summarizes the main results of a sustainable management in the rice-growing areas from "Los Palacios" Rice Experimental Station, where 31 alternatives were tested in seven crop rotation systems, besides a survey performed in Caribe farm from "Los Palacios" agro-industrial rice complex. It was proved that rice monoculture impoverishes soil physical and chemical fertility whereas crop rotation allows recovering lost fertility and achieving stable and sustainable productions. Also, the work shows it is possible to establish a sustainable rice-growing area. [ABSTRACT FROM AUTHOR]

Removing bacteria from seed surface is one of the main issues when identifying endophytic bacteria as well as with microorganism-inoculating trials. Disinfection by chemical methods has been a commonly used strategy with this goal. However, it is very hard to fully disinfect rice seeds, due to its particular characteristics (rough and velvety surface), so that most disinfection methods described by literature are often useless. Therefore, this investigation was aimed at searching an efficient rice seed disinfection methodology. Then, seeds from cv. J-104 were used and four disinfection protocols were assessed by employing different disinfecting solutions (chloramine T, calcium hypochlorite and alcohol, among others), exposure times and solution combination. Results showed that by disinfection protocol 4, using calcium hypochlorite in two plant growth stages, the best germination and disinfection rates were achieved, obtaining an efficient disinfection method, which could be applied to plant- microorganism interaction studies, from the practical point of view. [ABSTRACT FROM AUTHOR]

Some aspects on the physiologic and biochemical mechanisms of salinity tolerance in rice plants, such as osmotic adjustment, ion extrusion, protein induction and oxidative stress are collected in this work. Brassinosteroid protective effects on salt stress as well as some results from our institute about Cuban brassinosteroid analogue effects on saline-stressed rice plants are also discussed. [ABSTRACT FROM AUTHOR]

Shoot meristem culture is a potential alternative to the more commonly used methods for in vitro cereal regeneration, as they are less genotype-dependent, and more efficiently established seedbeds can be used as donor material. In the present work, de novo morphogenesis processes were induced by indirect organogenesis in apical meristems from in vitro rice plantlets of Reforma cultivar germinated on a MS basal medium. Shoot meristems were obtained when cutting three 2.0-cm segments from the bottom portion of seedling stem. At callus phase, different concentrations of 2,4-D were trialed in the culture medium, also testing the effect of stem segment position on callus formation. In general, two types of calli were observed: morphogenic and nonmorphogenic ones, which differed in their structure and growth. The highest proportion of morphogenic calli was obtained at the bottommost stem segment, using 2.0 mg/L 2,4-D. These calluses were subcultured for 10 days under light or dark conditions, to study their effect on shoot regeneration. At the regeneration media, macro and microelements from MS and N6 media were evaluated separately. From subcultured calluses in dark regenerated more shoots at the regeneration medium with MS macro and microelements rather than with N6, whereas in subcultured calluses in the light, shoot regeneration efficiency diminished radically in both media tested. [ABSTRACT FROM AUTHOR]

The effect of two formulations based on spirostane brassinosteroid analogs known as BIOBRAS-6 (BB6) and BIOBRAS-16 (B16) on seedling growth of two rice varieties under saline conditions was studied in the present paper. Seeds of J-104 and INCA LP-7 varieties were dipped in water, 100 mM NaCl or 100 mM NaCl supplemented with different concentrations (1, 0.5, 0.05 and 0.005 mg.L-1) of B16 or BB6 for 24 hours. Later, seeds were placed in Petri dishes with filter paper dampened with distilled water for germination and maintained in a growth chamber at darkness during 48 hours. Germinated seeds were transferred to pots containing the different assayed solutions and placed in a growth chamber with 16 hour- photoperiod and 25±2°C temperature for seven days. At the end of the experiment, shoot and root lengths as well as fresh and dry weights were evaluated. Results showed that, in general, 0.005 mg.L-1 of B16 was the most effective treatment to revert adverse effects induced by salinity in both varieties, whereas the response to BB6 depended on the variety. [ABSTRACT FROM AUTHOR]

In 2004/2005 cold season and 2005 spring, the behavior of short and mid-cycle rice lines and varieties in presence of Blast (Pyricularia grisea Sacc.) was studied in the experimental area of "Caribe" Farm, Pinar del Río. A trial was carried out in Blast Infection Beds (CIP), besides a Regional Study of Varieties (ERV), and leaf disease severity was evaluated during the vegetative stage as well as its occurrence in panicle necks during the reproductive stage. Results from CIP within the cold season proved a strong disease severity, only mid-cycle lines being resistant at the regional phase when firstly evaluated 29 days after germination; disease was not detected in panicle neck. In spring season, severity was very low, so that all the lines were qualified as resistant; however, they had a susceptible panicle neck. In the ERV, for cold season, all varieties were susceptible to leaf infection, the short cycle ones showing a better behavior: INCA LP-6, INCA LP-11 and INCA LP-14; later, they became resistant to panicle neck disease. In spring, leaf disease was not recorded, but all of them were susceptible to panicle neck infection, INCA LP-16 standing out, as it was significantly different from the rest. The experiment proved that varietal performance before the disease varies from one season to another, depending on crop cycle and its developing stage. [ABSTRACT FROM AUTHOR]

Rice is one of the most important food and work supplies worldwide, besides that it is highly consumed. As a sustainable agriculture strategy, crop yield increments have been encouraged through combining chemical fertilizers and biofertilizers adequately. In this sense, the application of microbial inoculants has been proved as an ecological alternative to preserve the environment and ecosystem. The Plant Growth Promoting Bacteria (PGPB) are among the main groups of microorganisms used with this purpose, due to their abilities of interacting with plants through different mechanisms of action, such as phytohormone production, biological nitrogen fixation and pathogen biocontrol. The aim of this work was to review the importance of employing PGPB, dealing with some relevant subjects, such as their isolation and identification methods, as well as their main mechanisms of action, showing their potential to be used in an essential crop like rice. [ABSTRACT FROM AUTHOR]

The morphological disorders of rice (Oryza sativa) seedling rootlets affected by salinity were studied in INCA-LP-10 cv., which has a certain salt-tolerance degree. Seeds were germinated in two saline concentrations, besides a separate control treatment just with water. After five days, rootlets were sampled, fixed to formaldehyde at 4 % and later processed until they were included in Epon resin. The semithin cuts were stained with blue toluidine. Longitudinal rootlet sections showed that salinity provoked morphological changes, according to NaCl concentrations employed, which mainly consisted of rootlet morphological changes and disorganized tissues, then opening large cavities among cell lines. [ABSTRACT FROM AUTHOR]

This research study was conducted at "Los Palacios" Rice Research Station, Pinar del Rio, where the variety INCA LP-5 was planted on a Ferruginous Nodular Gley Hydromorphic soil in May, 2003, with the aim of analyzing its growth and yield, following the basic principles of the Intensive Rice Cultivation System (SICA) under two different soil fertility conditions. A randomized block design with two treatments and four replicates was used, at a plant spacing of 0.30 x 0.30 m, by placing a single plant per site 13 days after rice germination. Growth variables were evaluated 50 days after transplanting and seven samplings were performed at different intervals of 50 to 113. Results indicate that the variables studied affected crop yield under these conditions, the most associated one being leaf area length (DAF) and the Maximum Growth Rate Point of Dry Weight (PMVC); therefore, a deeper study is recommended to attain more information to improve this variety management with such a new production approach in those areas devoted to obtain seed and popularization. [ABSTRACT FROM AUTHOR]

This work was carried out with the objective of determining the answer to plant growth and water relations of two rice varieties (Oryza sativa L.) when being exposed to different NaCl levels. Plants were developed in a growth chamber under hydroponic conditions. Evaluations were carried out at the beginning of the experiment, at seven and 14 days of having applied treatments and after seven days of recovery. Evaluations consisted of the biomass expressed as fresh and dry matter from roots and the air part, stomatal conductance, transpiration as well as leaf, osmotic, pressure and osmotic potentials at full turgor. The analysis of plant behavior indicated that they modified growth as much as water relations when exposed to saline conditions. It was also appreciated that under these conditions, plants developed the osmotic adjustment mechanism. [ABSTRACT FROM AUTHOR]

The effect of Cuban biostimulants Biostan and Liplant on the in vitro callogenesis and regeneration of rice (Oryza sativa L.) cvs. INCA LP-5, IACuba-28 and LC88-66 was studied, aimed to improve the amount and quality of the material disposed for the genetic transformation in this species. To study callogenesis, seeds were grown on a Murashige and Skoog medium, supplemented or not with biostimulants, and the percentage of callus formation, color, consistency and fresh weight were evaluated at 28 days. In vitro plant regeneration was studied six weeks after transferring calluses to KIBAN medium, supplemented or not with biostimulants. The variables evaluated were: callus regeneration ability, number of roots and shoots. Biostan and Liplant were found to potentiate the induction effect of 2,4-D on in vitro rice callogenesis. The lowest concentrations of Biostan and Liplant favoured INCA LP-5 regeneration, while biostimulants did not increase regeneration in the remaining varieties with respect to the control. Results suggest the use of these biostimulants supplementing 2,4-D to obtain rice calluses for the genetic transformation of this species. [ABSTRACT FROM AUTHOR]

This work was developed in the laboratory of Biotechnology from "Los Palacios" Rice Research Station, belonging to the National Institute of Agricultural Sciences (INCA), from March to July, 2000 and 2001. Anthers of the genotypes J-104, Perla de Cuba, Amistad 82, INCA LP-10, IR-36, IR-42, Amistad-82/C4 153, Amistad-82/IR-36, Amistad-82/IR-20, INCA LP-10/C4 153, 8073/C4 153 and INCA LP-10/Amistad-82 were disinfected and sown in vitro in a N6-1 culture medium. The formed calluses were transferred to a regeneration culture medium containing Murashige and Skoog mineral salts, as well as 1 mg.L-1 of NAA, 4 mg.L-1 Kinetine and 2 mg.L-1 of IAA. The percentage of calluses formed with buds, as well as the percentage of green plants and regenerated albino plants were determined, obtaining differences as for the in vitro answer of anthers, standing out the hybrid combinations INCA LP-10/C4 153, Amistad-82/C4 153 and INCA LP-10 as well as Amistad-82 varieties during green plant regeneration. [ABSTRACT FROM AUTHOR]

The work was carried out in "Los Palacios" Rice Research Station, where the behavior of rice genotypes selected for cold tolerance under field conditions in early cold seeding was studied. A group of morphologic and agronomic traits previous to crop harvest was evaluated. Data were statistically processed by multivariate techniques of Principal Components and Cluster. Genotypes were grouped in 15 classes and there was a differentiated answer of genotypes to cold conditions. [ABSTRACT FROM AUTHOR]

The work was carried out at "Los Palacios" Rice Research Station under controlled conditions in 2002 to ±18°C and relative humidity of 85 %; the behavior of rice lines and varieties selected for cold tolerance was studied. Seed germination, plant height and root length were evaluated at 5, 10 and 15 days. Data were statistically processed by means of multivariate cluster analysis. Genotypes were collected in five classes and the best ones are in the classes I, IV and III. [ABSTRACT FROM AUTHOR]