Total Number Of Tillers Research Articles

Efisiensi Pupuk P dan Hasil Padi (Oryza Sativa L.) pada Sawah Pasir Pantai Kulonprogo yang Diberi Zeolit

Title : Efficiency of P Fertilizer and Yield of Rice ( Oryza sativa L.) at Sandy Soil Paddy Field Kulonprogo that Added Zeolite. The aim of this research were to study the effect of Zeolite to the efficiency of P fertilizer at Sandy Soil Paddy Field Kulonprogo and to know the rate of P fertilizer that gives the highest yield of rice ( Oryza sativa L.) . This research was conducted at Krembangan, Panjatan, Kulonprogo from October 2006 to January 2007. This field experiment was arranged in Split Plot Design. Zeolite as a main plot consists of no Zeolite and 750 kgha-1 Zeolite. P fertilizer as sub plot consist of five levels of P fertilizer, i.e. 0, 20, 40, 60, 80 kg SP 36 ha-1. Each treatment was replicated three times so there are 30 plot treatments. Data were analyzed with F test, Kruskal-Wallis Test, DMRT and Correlation test. There is no interaction effect of P fertilizer and Zeolite to P uptake and Physiological Efficiency. Added 750 kg ha-1 Zeolite can increase P uptake 3.04 g/plant and increase efficiency of P fertilizer up to 62.99% in comparison with control. P Fertilizer has significant effect on total tiller number, weight of rice, weight of 1,000 seeds and percentage of rice empty. Until dosage that used in the experiment, response to P fertilizer is linier. P fertilizer 80 kg ha-1 gives the highest rice yield (6.12 kg/7 m2). Keywords: Efficiency, Zeolite, rice plant

Competition ability of selected amenity varieties of Festuca rubra in mixture with Deschampsia caespitosa

The aim of the research was to evaluate the competition capacity and find suitable proportion of different types of Festuca rubra and Deschampsia caespitosa in grass mixtures for decorative lawns. A field experiment with Deschampsia caespitosa cv. Kometa in monoculture or in mixtures with Festuca rubra L. varieties Viktorka (ssp. trichophylla), Barborka (ssp. commutata) and Petruna (ssp. rubra) was established in Větrov in 2007. The sowing rate was 40 000 viable seeds per m<sup>2</sup> (0, 25, 50 or 75% of F. rubra). The sward was mown at 3 cm. The number and weight of tillers of the turf components were evaluated during three years. The highest number of tillers (on average 63.3 thousand/m<sup>2</sup>) and weight of the dry aboveground phytomass (on average 196 g/m<sup>2</sup>) were found with F. rubra ssp. trichophylla. Its particular tillers had the lowest dry weight (0.32 g/100 tillers). The lowest number of tillers (32.9 thousand/m<sup>2</sup>) and low weight of dry aboveground phytomass (134 g/m<sup>2</sup>) showed mixtures with F. rubra ssp. rubra, whose tiller weight was relatively high (0.42 g/100 tillers). The size of F. rubra tillers was not influenced either by the mixture composition or by vegetation years. The number of F. rubra tillers was not significantly different in the third and first vegetation year. The number of D. caespitosa tillers in monoculture decreased during the years from 45 to 30 thousand/m<sup>2</sup>, but the weight of dry aboveground phytomass increased significantly from 233 g/m<sup>2</sup> to 318 g/m<sup>2</sup>. Poor competition of D. caespitosa was found in the mixture with F. rubra ssp. commutata (on average 4% of total number of tillers and 7% of the total weight of the dry aboveground phytomass). F. rubra ssp. trichophylla was less competitive and the least competition with D. caespitosa was found in F. rubra ssp. rubra, After three years the proportion of D. caespitosa in mixtures with F. rubra ssp. rubra significantly increased to 36% of the total number of tillers and to 55% of the total weight of phytomass. Mixtures of D. caespitosa and F. rubra ssp. rubra were found to be promising for low input lawns.

Effect of spacing and number of seedlings per hill on the performance of aus rice cv. NERICA 1 under dry direct seeded rice (DDSR) system of cultivation

An experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh during the period from April to August 2011 to find out the effect of spacing and number of seedlings hill-1 on the performance of Aus rice cv. NERICA 1. Four spacing viz. 25 cm × l5 cm, 20 cm × l5 cm. 20 cm × 10 cm and 15 cm × 10 cm and four number of seedlings hill-1 viz. 2, 3, 4 and 5 were included in the experiment. The experiment was laid out in a randomized complete block design with three replications. The highest number of total tillers m-2, number of effective tillers m-2, number of grains panicle-1, grain yield, straw yield, biological yield and harvest index were obtained from 20 cm × 10 cm spacing. Plant height and 1000- grain weight were not significantly affected by spacing. Number of seedlings hill-1 exerts a significant effect on plant height. The highest value of total tillers m-2, number of effective tillers m-2, total grains panicle-1, grain yield, straw yield, biological yield and harvest index were obtained from five seedlings hill-1. The interaction between spacing and number of seedlings hill-1 significantly influenced yield and plant characters. The highest number of effective tillers m-2, grains panicle-1, grain yield, straw yield and biological yield were recorded from the interaction between 20 cm × 10 cm and five seedlings hill-1. DOI: http://dx.doi.org/10.3329/jbau.v10i2.14681 J. Bangladesh Agril. Univ. 10(2): 191-195, 2012

Seletividade de herbicidas influenciada pelo estado nutricional da cana-de-açúcar

Para validar a hipótese de que a cana-de-açúcar adequadamente adubada é menos prejudicada pelos herbicidas, foram avaliadas características fitotécnicas e o perfil isoenzimático da α-esterase e peroxidase nas cultivares de cana-de-açúcar IACSP96-2042 e IACSP95-5094, submetidas a diferentes adubações de plantio e tratadas ou não com herbicidas. No campo foram realizados dois experimentos, um para cada cultivar, em vasos (43 L), utilizando-se do delineamento inteiramente casualizado com os tratamentos dispostos em fatorial 3 x 3 + 1, com quatro repetições. O primeiro fator constituiu-se por herbicidas: clomazone (1000 g ha-1), diuron (1440 g ha-1) + hexazinone (396 g ha-1) e sulfentrazone (800 g ha-1); e o segundo fator pela adubação: doses de NPK (ausência, 20-120-100 e 40-240-200 kg ha-1) e a testemunha pela ausência dos fertilizantes e herbicidas. Na aplicação dos herbicidas as plantas apresentavam altura de 20 cm e 3 a 4 folhas. No campo, foram avaliados os sintomas visuais de intoxicação, teor de clorofila total, altura, comprimento de folhas, número de perfilhos e massa fresca e seca das plantas. Em laboratório caracterizou-se o perfil isoenzimático da α-esterase e peroxidase antes da aplicação dos herbicidas e aos 58 dias após, por eletroforese em gel de acrilamida. IACSP96-2042 apresentou menor sensibilidade aos herbicidas, sem prejuízo à massa fresca e seca, teor de clorofila total, altura, comprimento de folha e número de perfilhos. As isoformas da peroxidase diferiram em número e intensidade, e da α-esterase foram alteradas na intensidade das bandas. A IACSP95-5094 foi sensível aos efeitos da intoxicação dos herbicidas por prejudicar na altura, acúmulo de massa fresca e seca, particularmente no tratamento com diuron+hexazinone.

The Effects of Controlled Release Fertilizer and Conventional Complex Fertilizer on the Dry Matter Accumulation and the Yield in Winter Wheat

In order to research the use ratio of controlled release fertilizer in winter wheat. So, the experiment about the effects of Controlled Release Fertilizer (CRF) and Conventional Complex Fertilizer (CCF) on the dry matter accumulation and the grain yield in winter wheat has studied with pots in the open field. The results indicated that the CRF improved the proportion of the number of effective tillers to the total number of tillers. And the mixture of the CRF and equivalent CCF have more improved the proportion of the dry root weight to the total dry matters of the after of wheat flowering stage than that of the CRF used alone (T1, T2, T3). The treatment T6 was more improved the accumulation of the dry matters of aerial part than others. And the weight gain of T6 after a thesis was higher than other treatments and the control treatment (CK). In the facts of grain number per spike, thousand grain weight and yield, the treatments of the mixture of the CRF and equivalent CCF (T4,T5,T6) were higher than that of the treatments of CRF used only (T1,T2,T3) and CK, in which the T6 was highest. So, we think that this treatment namely T6 was used fertilizers least and gained the highest yield of grain.

Effects of Plant Density and the Application of Silica on Seed Yield and Yield Components of Rice (Oryza sativa L.)

In order to investigate the effects of plant density and the role silicon plays in determining the agronomic features of rice transplanted as single plants and planted in hills, an experiment in the split factorial design in the format of randomized complete block design with three replications was conducted in Sari in 2007. The main factor consisted of two levels of silica (applying and not applying it), and the subordinate factor included two modes of planting rice (in hills and as individual plants) and three plant densities (40, 80, and 120 plants/m2). Results obtained showed that applying silica improved some agronomic features. For example, the total number of tillers per plant increased by 11.6%, the number of effective tillers per plant by 14.2%, and the seed yield by 18.2%; and, therefore, the harvest index, compared to the control (in which silica was not applied), increased by 4.4%; but the percentage of filled spikelets decreased by 13.9% (which was a significant reduction). Increasing plant density from 40 to 120 plants per m2 caused deterioration in some agronomic features. For example, plant height, the total number of tillers, the number of effective tillers per plant, and the total number of spikelets per panicle decreased by 5.04, 51.94, 55.1, and 20.44%, respectively. The mode of planting had a significant effect only on the total number of effective tillers per plant, and on the total number of spikelets per panicle, at the one percent probability level; and it also significantly influenced the percentage of filled spikelets at the five percent probability level. Under the interactive effects of the three variables, the maximum seed yield was obtained in the treatment of applying silica and planting density of 80 plants per m2 in transplanting rice as single plants and in hill planting (424.1 and 414.6 g/m-2, respectively).

Tiller organization within the tussock grass Schizachyrium scoparium: a field assessment of competition–cooperation tradeoffs

Tussock grasses are characterized by a compact spatial arrangement of tillers that contributes to intense intratussock competition. This investigation was designed to directly assess the magnitude of competition among autonomous subunits of tillers within individual tussocks (i.e., integrated physiological units) to further define the mechanisms of tiller organization within this successful growth form. Experimentally constructed tussocks of Schizachyrium scoparium (Michx. Nash) were grown in the field in central Texas, USA, for 2 years with 1, 4, 8, or 12 autonomous subunits to span the range observed in naturally occurring local populations. Increasing numbers of subunits per tussock did not affect tiller density or the mean mass of individual vegetative or reproductive tillers, but it did intensify intratussock competition as evidenced by a large reduction in total tiller mass and number per subunit. This pattern of tiller organization is indicative of a division of labor within the tussock that is manifested as a tradeoff between competition among autonomous subunits and cooperation among tillers within these physiologically integrated subunits. We conclude that an increasing number of autonomous subunits associated with tussock basal expansion contributes to coarse-scale resource preemption and competitive ability, while resource sharing among tillers within subunits supports new tiller establishment and growth within this highly competitive microenvironment.

Salinity Induced Effects on Growth Parameters, Chemical and Biochemical Characteristics of Two Forage Sorghum (Sorghum bicolor L.) Cultivars

Plant production stability under saline condition compared to normal has had limited success due to lack of knowledge on salt tolerance mechanisms. To evaluate the changes in chemical and biochemical characteristics (content of free proline and total protein, Na+ and K+) and growth parameters (leaf area, plants height, total tiller number, leaf number, shoot and root weight, percent of emergence, growth rate and growth power) of sorghum under salinity stress, a pot experiment was carried out at Shiraz University, Shiraz, Iran in 2010. Four salinity levels containing 3, 6, 9, 12 ds m-1 using NaCL and without using NaCL (as control) and also two sorghum cultivars consist of Pegah (Iranian cultivar) and Speedfeed were evaluated in a factorial experiment design with three replications. Results showed that salinity decreased accumulation of K+, emergence percentage and all growth parameters but increased amount of Na+, proline and total protein content in shoot and leaves of treated plants. Multiple regression, stepwise selection, selected root weight and their ratio (shoot/root), leaf area and leaf number per plant, tiller number per plant, photosynthesis rate and also content of K+ as most significant factors for contributing in shoot weight. Stepwise selection and correlation coefficient cleared that root weight is the most important factor in plant shoot production under salinity condition and breeding program must be carried out to screen cultivars with higher root density in order to increase resistance to salinity. Based on the results, Speedfeed is proper cultivar to be used in breeding programs to achieve higher salinity resistance by screening or crossing programs.

Studies on Genetic Variability and Correlation among the Different Traits in Solanum lycopersicum L.

In present study the genetic diversity in some tomato genotypes were investigated in two years at North-west of Iran where due to its geographical situation is one of the most favourable regions for tomato cultivation. Twenty five tomato genotypes were evaluated for yield and important morphological traits during 2006-2007. Experiment was conducted in a 5 lattice square design with 3 replications in each one of years. Data on morphological traits were collected from central row on individual plants basis on mean values of five plants of each genotype selected at random. Analysis of variance on the studied traits revealed significant differences among genotypes for all the characters except for fruit yield, total soluble solids, titratable acidity and number of tillers. Genotype year interaction was only significant for some of the characters including number of fruit per plant, titratable acidity and for fruit yield. Mean data revealed high range for most of studied traits. Maximum and minimum variability were observed for number of fruit per plant and pH respectively. Hierarchical cluster analysis allowed the assessment of similarity and clarified some of the relationships among tomato genotypes. UPGMA produced a dendrogram with four clusters. The first cluster included 64% of studied tomato genotypes. Results from the PCA indicated that more than 91% of the variability observed can be explained by the first seven components. Based on PCA, PC1 can be considered as representatives of fruit size, while properties that show high correlation with PC2 are the ones related to plant characteristics.

Sélection de variétés performantes de riz pluvial (Oryza sp.) dans la région subéquatoriale du Congo Brazzaville

Selection of rice ( Oryza sp.) elites upland varieties in the subequatorial region of Congo BrazzavilleTo assess the problem of dependency on other countries for rice production, fields’ studies were conducted in the north part of the republic of Congo Brazzaville to identify high yield upland varieties. The 18 varieties evaluated in this experiment were obtained from West Africa Rice Development Association (WARDA) collection, Côte d’Ivoire. Each variety was grown in replicated trials at SADC production centre in 2003 and 2004 in the District of OYO. The agronomic characters such as the number of total tillers, the number of total fertile tillers, the plants height at maturity, the period of 50 % flowering, lodging, disease resistance and yield were measured. Each one of the tested varieties was adapted to the region at different levels. However, three varieties may be selected among the others. These varieties are WAB 450-24-1-BP33-HB, WAB 377-B-5-H1 and WAB 32-55 which presented high yield compared to the others. The yields were respectively, 7.03, 4.30 and 5.10 t / ha. The results also showed that these varieties were less affected by diseases and did not lodge.

The effect of simulated rat damage on irrigated rice yield and compensation

A field experiment was conducted to investigate the impact of simulated rat damage on grain yield in irrigated lowland rice in An Giang province, in the Mekong Delta of Vietnam. Rat damage was simulated by making a 45° cut at the base of the rice tillers about 3–5 cm above the soil surface. 0% (control), 5%, 10%, 25% and 50% of the tillers were removed at the tillering (25 days after sowing, DAS), panicle initiation (43 DAS), flowering (72 DAS) and ripening (87 DAS) stages. The total number of mature tillers, immature tillers and percent filled grains, the weight of 1000 grains and grain yields were recorded. The rice crop completely compensated by increased tillering and yield for tillers damaged up to 50% at the tillering stage. However, the damage and yield loss were highly variable. The ability of the rice crop to compensate at later stages progressively reduced. The implications for managing rat damage to rice crops are (1) rodent control activities should be applied before 10% of tillers are damaged at the tillering stage, and (2) a well balanced nitrogen supply during the tillering stage could potentially assist the rice plants to better compensate for rat damage.

Biomasses in Different Organs of Rice Cultivars Developed During Recent Forty-Seven Years in Jilin Province, China

To understand the changes in yield, harvest index (HI) and biomass of aboveground parts of rice, 33 japonica rice cultivars released from 1958 to 2005 were planted. During the 47 years, the grain yield increased from 9 118.36 to 15 060.1 kg/hm 2 and HI from 0.46 to 0.55. In the genetic improvement, the total number of tillers per plant decreased, and the biomass per unit area slightly increased at the harvest stage. The increases of yield and HI resulted from the increased biomasses of effective tillers and single stem, and the increase of biomass per stem was related to the increased biomasses of different organs along with the genetic improvement. The stem and sheath biomass at heading and the leaf biomass at 30 days after heading showed the highest increase, up by 75.17% and 49.94%, respectively. The biomasses of leaf and stem-sheath at 10 days after heading, and biomass per stem at 30 days after heading were obviously correlated with the yield. The results indicate that the genetic improvement has resulted in the increase of yield and HI. This increase is correlated with the decrease of total tiller number per plant, and increase of biomasses of effective tillers and single stem. The leaf biomass after heading and the stem and sheath biomass at 10 days after heading can be used as selection criteria for breeding high yielding rice cultivars.

Características agronômicas e nutricionais do capim-Marandu em função da aplicação de resíduo líquido de frigorífico

This experiment was carried out to evaluate the effect of liquid slaughterhouse effluent (LSE) on values of total dry mass, leaf area index, culture growth rate, total tiller number and weight, plant height and the levels of N, P and K+ in plant tissue of the pasture Marandu grass in Entisol. Three levels of LSE (37.5, 75 and 112.5 m³ ha-1) were applied, as well as a control. The experimental design was completely randomized blocks. The total dry mass production of leaf area index, culture growth rate, tiller number and weight and plant height increased linearly (p < 0.05) with increasing levels of LSE. The levels of N, P and K+ responded according to a linear regression model (p < 0.05) with application of LSE. The concentration of N was in the range suitable for Marandu grass. The levels of P and K+, in spite of the positive response to LSE doses, were lower than the adequate rate of variation in the plant tissue of Marandu grass.

The Effect of Salinity on Morphological Characteristics of Seven Rice (Oryza sativa) Genotypes Differing in Salt Tolerance

The effect of salinity on morphological characters of salt tolerant genotypes PVSB9, PVSB19, PNR381, PNR519, Iratom24 and salt sensitive genotype NS15 along with one standard check salt tolerant rice cultivar Pokkali were assessed in two factors Completely Randomized Design with four replications. Seven rice genotypes in combination with six levels of salinity (0, 3, 6, 9, 12 and 15 dS m(-1)) were randomly assigned in 168 experimental plastic pots. The different morphological characters studied include plant height, total number of tillers, Root Dry Weight (RDW), Shoot Dry Weight (SDW) and Total Dry Matter (TDM) content of the selected rice genotypes in view to evaluate their response at different salinity levels. The results on the effect of morphological characters indicated that plant height, total tillers, root, shoot and total dry matter were significantly decreased by the application of salinity. The genotypes Pokkali, PVSB9, PVSB19 showed significantly higher values and the lowest value of all these characters were recorded in NS15. A sharp decrease in percent relative-plant height, RDW, SDW, TDM, total tillers were found in susceptible genotype NS 15 after 3 dS m(-1) level of salinity, but these characters were found to decrease slowly in tolerant genotypes.

Effect of soil applied zinc sulphate on wheat (Triticum aestivumL.) grown on a calcareous soil in Pakistan

A field experiment was conducted to investigate the effect of soil application of zinc fertilizer on yield and yield components of wheat ( Triticum aestivum L. cv. Inqlab 91) grown on calcareous soil in Pakistan. The levels of zinc sulphate were 0 (control), 5, 10, 15, 20, 25 and 30 kg ha −2 and the zinc sulphate was combine-drilled at the time of sowing. Zinc sulphate increased the Leaf Area Index, the total number of fertile tillers m −2 , number of spikelets spike −2 , spike length, grain spike −2 , thousand grain weight, grain yield, straw yield and biological yield and decreased harvest index. Most of the response trends were curvilinear although the decrease in harvest index was linear. All applications of zinc sulphate gave economic increases in margins over costs but the application of 5 kg ha −2 gave the highest marginal rate of return. It is recommended that under such calcareous soil conditions growers can expect good returns from the application of 5 kg zinc sulphate ha −2 at the time of sowing but if the grain price were to increase or the price of zinc sulphate were reduced economic responses could be expected from higher levels of zinc sulphate.

Tolerance of 42 Bread Wheat Genotypes to Drought Stress after Anthesis

The present research characterized yield and yield components of 42 wheat genotypes after terminal drought stress. The experiment was in twice replicated simple rectangular lattice design, conducted at irrigated and terminal stress conditions during 2006-2007. These study genotypes had significant differences for grain yield at level of 1%. Genotypes 4057, Viking/5/Gds/4.., Sabalan and 5041 respectively with 6.313, 6.159, 5.793 and 5.774 t ha(-1) had the highest yield and Gascogen has the lowest yield with 2.561 t ha(-1). Mean of total grain yield for under study genotypes was 5.628 t ha(-1) in non-stress and 3.305 t ha(-1) in drought stress conditions. Drought stress decreased amount of grain yield 2.323 t ha(-1) that was noticeable. Interaction of Genotype x environmental conditions was significant at probability level of 1% for grain yield. Yield of all genotypes in drought condition was lower than non-stress condition. Genotypes Viking/5/Gds/4/Anza/3/Pi.., Sabalan, 4061,4057 and 4041 had more yield in non-stress condition and MV17/Zrn, Sabalan, Saysonz and 4032 in stress condition. Stress intensity pay attention to total grain yield was 42%. Genotypes Viking/5/Gds/4/.. and Sabalan had high grain yield and was better than other genotypes and controls (Toos and Crosse Shahi), according to GMP, STI and MSTI. And had the most amount of stress tolerance index as compared with other genotypes confirms this subject. Correlation of yield with other traits was not significant in non-stress condition. In drought condition, correlation of grain yield with 1000 grain weight and total number of tillers per plant was positively significant. ANOVA showed significant differences between osmotic pressures for coleoptile length, between genotypes for mean and maximum coleoptile length and between interactions of genotypes x osmotic pressures for mean and maximum coleoptile length. Mean comparisons showed the highest total, mean and maximum coleoptile length in -7 bar PEG+I ml L(-1) potassium humate treatments. Genotypes Sardari and Sabalan had the highest amounts of total, mean and maximum coleoptile length. With due attention to interaction genotype x osmotic pressures, genotypes Sardari, Sabalan and 4057 in -7 bar PEG+1 ml L(-1) potassium humate had the most amounts of noted characters than others. In conditions of this experiment, potassium humate caused increase in tolerance rate of genotypes against drought stress.

Effect of Seedling Age and Planting Space on Yield and Yield Components of Rice (Neda Variety)

Rice is the most important crop at the global level, as it used as a staple food in the most countries of the world. Achieving a sustainable increase in rice production can improve global food security and contribute to poverty alleviation. Selection of suitable planting density and seedling age are the most important factors for maximizing rice production. In order to study the effects of seedling age and planting spaces on yield and yield components of rice (Neda variety) a fi eld experiment was carried out in fi eld of Ghaemshahr Azad University. Experimental design was arranged in split plot in basis of Randomized Completely Block Design with four replication. Some agronomical traits such as total tiller number, fertile tiller number, panicle number per m2, total spikelet per panicle, total strile spikelet per panicle, 1000 grains weight and grain yield were measured. Results showed that the effect of seedling age on total tiller number and panicle number per m2 was signifi cant at 0.01 probability level. Also seedling age had a signifi cant effect on fertile tiller number at 0.05 probability levels. Planting spaces had a signifi cant effect on total tiller, fertile tiller, panicle per m2, total spikelet per panicle and grain yield. When the age of seedling is less than optimum, the tender seedlings may die in greater number due to high temperature and ultimately the plant population is reduced. For this variety transplanting in seedling age at 25 day and 15 cm×15 cm planting space for the best performance of yield attributes were recommended.

Gamma ray induced variation for lodging resistance and its associated characters in littlemillet (Panicum sumatrense Roth Ex-roem and schult)

An investigation was carried out to study the nature and amount of gamma ray induced genetic variability in littlemillet during kharif, 2006 and rabi, 2006-2007. Two released varieties CO3 and CO(Samai) 4 were treated with gamma rays. The maximum variability was observed for plant height and total number of tillers in M2 generation of both CO3 and CO(Samai)4. A high heritability associated with a high genetic advance as percentage of mean was observed for total number of tillers and grain yield in M2 generation. With reference to lodging character CO (Samai)4 mutants showed high heritability with genetic advance in the progenies of 500 and 600 Gray of M2 generation. Mutants in 500 and 600 Gray also exhibited maximum variability, heritability and genetic advance for plant height, total number of tillers, number of nodes, inter-nodal length, culm thickness and grain yield. Therefore, selection in these progenies would be rewarding to have lodging resistance with reduced plant height and inter-nodal length and increased number of nodes, culm thickness and grain yield. These desirable mutants would be forwarded to further generation until they obtain homozygosity.

Variability among barley landraces in response to waterlogging stress in the greenhouse

Barley production, in some parts of the Ethiopian central highlands, is constrained by seasonal waterlogging. The aim of this study was to investigate differences in growth, nutrient uptake and concentration under waterlogging stress between landraces varying in tolerance. A three week waterlogging treatment was done in the greenhouse and was compared with a free drainage treatment. Waterlogging reduced the total number of tillers per pot of the tolerant landraces Mage and Feleme by 43% and 48%, respectively compared to the control plants while a 23% reduction was seen for the susceptible landrace Feres Gama. Total shoot dry matter accumulation under waterlogged conditions was comparable for all three landraces. Tillers produced by Feres Gama had significantly less dry matter than Mage and Feleme, however. Differences between the susceptible and tolerant landraces in response to waterlogging were largely due to less dry matter accumulation of the tillers and slower growth in the susceptible landrace. Moreover, apparent differences were noticed in N concentration and uptake between the tolerant and susceptible landraces, the effect being less for the tolerant than the susceptible landraces. Difference in N concentration of shoots between the tolerant and susceptible landraces was also observed, though not comparable to that observed in P.

The effect of planting date on the African rice gall midge Orseolia oryzivora (Diptera: Cecidomyiidae) damage under irrigated conditions in Boulbi, central Burkina Faso

Experiments were conducted during the rainy seasons in 2003 and 2004 in central Burkina Faso to assess the importance of the African rice gall midge Orseolia oryzivora Harris & Gagne in relation to the planting date under irrigated conditions. The young midge larva feeds at the growing point of the rice tiller, which stimulates the plant to produce an oval hollow gall that prevents the plant from heading. Experiments consisted of three treatments arranged randomly within each of the four replications. Treatments were planting dates separated by 7 days. The rice cultivar planted in the experiment was FKR 14, which matures in 120 days. Nine entomological evaluations (assessment of the number of galls per hill) were performed for each planting date, starting at 25 days after transplanting (DAT) and ending at 81 DAT. Evaluations were conducted on 20 randomly selected hills and consisted of counting the total number of tillers and galls per hill. These hills were identified on one of the two diagonals of each treatment. At the rice maturation stage, 20 randomly selected hills were harvested and the grains from each hill were weighed and recorded. Yield loss was estimated for each treatment from these data. Results showed that the later the planting date, the higher the damage caused by O. oryzivora. The damage was low (>10%) during the vegetative phase but increased dramatically (<20%) during the reproductive phase of the rice plant, regardless of the planting date. Yield losses were correlated to the observed damage: In 2003, for the first planting date, 1% of galling was associated with 1% yield loss, while the same level of damage was associated with 1.3% yield loss for the second planting date.