Periods Of Plant Development Research Articles

ЕКСПРЕС-ДІАГНОСТИКА ХЛОРОФІЛУ НА ПОСІВАХ ПШЕНИЦІ ОЗИМОЇ

The purpose of this research is a comparative analysis of the chlorophyll content in two varieties of winter wheat in different periods of plant development using an autonomous field device (N-tester) for operational measurement of nitrogen content and calculation of the optimal dose of nutrient application on winter wheat crops during different phases of vegetation. Methods and materials. The research was conducted in the Oleksandrivskyi and Bobrynetskyi districts of Kirovohrad region on the fields of two farms on winter wheat crops (varieties «Memory» and «Avenue») with selected control plots with an area of 3 m2 each. At the key moments of plant development, before applying fertilizers, chlorophyll was measured using the N-tester «CSM-200 Plus GPS» and the sugar content was measured with a refractometer «HT116ATC», after which the required dose of application of drugs was calculated. In both farms, fertilizing was carried out at the optimal time of fertilizer application, but the rates of fertilizer were radically different. Results. Wheat of the «Memory» variety in the control plot (the total amount of applied nitrogen was 198 kg/ha), starting from the earing phase, looked greener, taller, the ear had a larger size, the indicators of the N-tester and the content of sugars in the control plot had higher indicators, but also the ripening period in the control plot lasted longer than in the rest of the field (the total amount of applied nitrogen per year was 101 kg/ha). Winter wheat of the «Avenue» variety in terms of the main indicators in the control plot (the total amount of applied nitrogen 145 kg/ha) and in the field (the total amount of applied nitrogen 183 kg/ha) almost did not differ: the length of the ear, the height of the plant, and the color are the same, the indicators of the N-tester and the content of sugars are also almost the same. Therefore, it can be concluded that the introduction of an additional amount of 38 kg/ha per year was ineffective and did not increase productivity. Conclusions. Operational measurement of the nitrogen content in field conditions using the N-tester made it possible to effectively calculate the doses of nutrients applied to winter wheat crops during different phases of vegetation and contributed to increasing the yield level of the investigated crop varieties. Keywords: fertilizers, plant nutrition, winter wheat, refractometer, harvest, phases of plant development, chlorophyll, N-tester.

ОЦЕНКА УСТОЙЧИВОСТИ СОРТОВ ЯРОВОЙ МЯГКОЙ ПШЕНИЦЫ К СЕПТОРИОЗУ ЛИСТЬЕВ И ЭФФЕКТИВНОСТЬ ЗАЩИТЫ РАСТЕНИЙ ОТ ПАТОГЕНОВ В УСЛОВИЯХ ПРЕДКАМСКОЙ ЗОНЫ РЕСПУБЛИКИ ТАТАРСТАН

The article analyzes data on the study of the susceptibility of new varieties of spring soft wheat, having different ecological and geographical origins, to septoria, which has become widespread in recent decades in the Middle Volga region. Studies by many authors have shown the harmfulness of this disease, which causes significant damage to the yield and seed quality of grain, which makes it urgent to select more immune varieties for cultivation in industrial crops and for use in plant breeding. Varieties with a consistently low level of development of septoria leaf blight, both by year and by periods of plant development, were identified. The least widespread pathogen Septoria tritici in crops during the formation of the reproductive zone of plants (earing and milky ripeness) were varieties Arhat of the Penza Research Institute of Agriculture, Chernozemnouralskaya selection of the Research Institute of Agriculture of the Central Emergency Plant named after. V.V. Dokuchaev, Ekada 113 – Samara Research Institute of Agriculture named after. N.M. Tulaikova and Yoldyz - selections of the Tatar Research Institute of Agriculture. Based on the results of studying the responsiveness of genotypes to the timing of fungicidal protection, varieties Arhat, Yoldyz, Ekada 70, Simbirtsit with a slow spread of the pathogen, bred in breeding institutions of the Volga region, were identified. These varieties generated the maximum yield in the variant without fungicidal treatment and are valuable for breeding as sources of the trait of resistance to septoria. On the varieties Kazanskaya Yubileynaya, Zlata, Tulaikovskaya Nadezhda, Idelle, Uralosibirskaya, the effectiveness of fungicidal protection was manifested during treatment in the heading phase, and on the varieties Margarita, Ekada 113, Ester, Ekada 66, Tulaikovskaya 108, Ekada 109, Khayat, Chernozemnouralskaya 2, Ekaterina v - phase of milk ripeness.

Characteristics of safety and harmlessness conditions labor of operators at the sorting facilities of table root crops and potatoes

The article notes the influence of production factors on operators when sorting table root crops. The most harmful production factors acting on a person have been identified, as this is the most important barometer of the state of working capacity and prevention of production-related and occupational diseases. It is established that the content of soil dust depends on many factors (weather conditions during harvesting, soil type, the amount of incoming pile of root crops for sorting). Information is given on the granulometric composition of the soil coming together with root crops from harvesting machines to the refinement line. It is noted that from the point of view of labor protection the dustiness of the air in the zone of refinement of root crops, exceeding the regulatory requirements by 2 or more times, is of particular concern. Attention is drawn to the fact that the emissions of the ventilation system into the environment from the vegetable store, where fruit and vegetable products are unloaded from the harvested field areas, pollute the external (as well as internal) air space not only with dust, but also with harmful substances damaged during harvesting of perishable products and imported with it residues of vegetation and a large amount of land stuck to the products in connection with the harvesting of potatoes and table root crops during a period of high humidity; this is typical for the Northwestern zone during the harvesting period (September-October). The soil stuck in the gaps of the treads of the wheels of tractors, cars and trailers gets into the vegetable storage room during the unloading of field products. In connection with the treatment of crops with agrochemicals during the period of plant development, the remains of agrochemicals, which adversely affect the working conditions of operators at the objects of sorting table root crops and potatoes, also enter the premises with the soil. product sorting. The patent solution has been introduced into production at the workplace of operators, providing a reduction in dust content by 1.5-2.0 times below the maximum allowable concentrations.

ПРОДУКТИВНОСТЬ КАРТОФЕЛЯ В ЗАВИСИМОСТИ ОТ ФАКТОРОВ ВОЗДЕЛЫВАНИЯ НА ТЕМНО-КАШТАНОВЫХ ПОЧВАХ САРАТОВСКОГО ЗАВОЛЖЬЯ ПРИ ОРОШЕНИИ

The aspects of increasing potato productivity under the influence of the developed agrotechnical techniques and factors of cultivation in the irrigated agrocenosis are considered. The research was carried out on experimental plots of fields of the experimental production farm of the Volga Research Institute of Hydraulic Engineering and Land Reclamation on dark chestnut medium loamy soils with an area of 200 hectares. It was found that the studied factors had different effects on the productivity of potato varieties. The most important determining factor affecting potato productivity is the choice of potato varieties with high adaptive characteristics for use in regional crop cultivation technology. Analysis of the formation of the photosynthetic potential of potato plantings was best performed by the Colombo variety, the net productivity of photosynthesis of plantings was 5.5 g/m2 per day, and the accumulation of dry biomass was 48.6 t/ha. Based on the dynamics of the growth of tubers over the periods of plant development, the most effective was the planting density of 40-50 thousand pieces / 1 ha. The productivity of this crop is significantly influenced by the irrigation regime. It was found that the most favorable pre-watering soil moisture is 80% HB, where the yield of Flamingo, Memphis and Colombo varieties was 45.0, 42.0 and 52.0 t/ha, respectively

Sunflower cultivation technology with strip tillage in the Ciscaucasian zone

The article presents research materials devoted to evaluating the technology of sunflower cultivation with strip basic soil cultivation using elements of Strip-till technology in comparison with the recommended one. The originality of the approach to the cultivation system, in comparison with the classic Strip-till technology, consists in preliminary surface stubble cultivation in two tracks, which retains productive moisture, provokes more intensive germination of weeds, and, accordingly, a more effective effect of subsequent spraying of the stubble with glyphosate. It was found that during the growing season of sunflower with abnormally harsh climatic conditions in 2020 (GTC = 0.07) the soil density in the flowering phase of sunflower was 1.30-1.32 g/cm3, with low moisture reserves in layer 0-100 cm both in spring (57 and 65 mm, respectively) and in bloom (5 and 16 mm, respectively). Applying the fractal dimension method with the calculation of the development index of the root system D, it was found that the harder the agrophysical parameters were during the period of plant development, the less intensively the roots developed: at GTC = 0.22, the D index with the recommended technology and Strip-till technology was 1.63 and 1.76 units respectively, and at GTK = 0.07 — 1.46 and 1.51 units. The low yield of sunflower is associated with a deficit of productive moisture in the summer-autumn period of 2019 and 2020, with a lower reserve of 23 and 102 mm from the long-term norm; nevertheless, a significant increase in the yield of sunflower over the years of research was established by 0.96 and 0.14 tons/ha when cultivating a crop with strip tillage based on the introduction of elements of Strip-till technology in comparison with the recommended one, with a decrease in costs by 11% and an increase in profitability up to 136%.

ECDYSTEROIDS AND FLAVONOIDS OF SILENE GRAEFFERI

In this paper Silene graefferi Guss. is recommended for the first time as a promising source of flavonoids and is a well-known producer of ecdysteroids. This perennial species is adapted to the conditions of Western Siberia and has been successfully cultivated in the Siberian Botanical garden of TSU since 2015. It was interesting to study the composition and features of accumulation of biologically active substances during the growth and development of S. graefferi. It was shown that 20-hydroxyecdysone and polypodine B are present in the aerial and underground parts of introduced in culture S. graefferi plants during the entire vegetative development. An unidentified ecdysteroid was detected in the aerial part at the beginning of the vegetation and in the roots during the flowering phase. During vegetative development, common flavonoids and characteristic ones at different periods of plant development were found. The phase of maximum accumulation of ecdysteroids and flavonoids of S. graefferi is the beginning of vegetation, and the minimum is flowering. In the age dynamics the highest levels of biologically active substances in plants were noted at 2 and 3 years of life, then there is a general tendency to decrease with the age of the plant. From the aerial part of S. graefferi, 20-hydroxyecdysone, polypodine B and vitexin were isolated and identified by HPLC.

Response of wheat (Triticum aestivum) growth and yield to the different water shorthage periods

Wheat plants can grow and produce well on the island of Lombok, ranging from highlands to lowlands around 400 m above sea level, and have opportunities for further development. This adaptation effort needs to be followed by development of cultivation technology, including proper irrigation. Irrigation is a fundamental factor in achieving maximum yields in a crop land. Wheat crop does not require a large amount of irrigation as rice plants, but it is not yet known which growth periods are critical to the water requirements for wheat plants grown on Lombok Island. This study aims to determine the effect of water stress at different growth phases of wheat on the growth and yield of wheat plants. This research was conducted using the Experimental Method in a greenhouse, with 9 water stress treatments at different phases. The treatment of water stress at different period of plant development does not show a different effect on plant growth and development. However, it significantly reduces yield and yield components. The critical period of water requirements for wheat plants occurs when the plants reach the generative phase; plants experience pressure in grain production, especially when water stress occurs in the phases of heading and flowering (anthesis). Stress in the booting and milk-development phases also experiences reduction on grain production, even at the lower levels.

Perspectives Culture of the <i>Lophanthus anisatus Benth.</i> and Peculiarities of Its Ontogenesis in the Conditions of the Lowland Zone of Transcarpathian

The lowland zone of Transcarpathia has a number of advantages and potential opportunities (natural and climatic conditions, economic and organizational prospects) for growing Lophanthus anisatus Benth. However, this culture is not widespread in Ukraine. The following issues remain unresolved during its cultivation - enrichment of species and varietal composition, study of morphological and biological features of plant development and adaptive potential of the species and obtaining high yields of good quality, regardless of the extreme climatic conditions observed recently. The article highlights the results of scientific research on the ontogenesis of Lophanthus anisatus Benth., reveals its economic significance and the possibility of expanding the scope and creation of a market for plant raw materials (spicy greens, medicinal raw materials) in this region. Based on the scientific literature and the results of their own research, the authors proposed a more detailed classification of the species of the genus Agastache L., which includes the species Lophanthus anisatus Benth. A deep study of the collected samples of home selection of the species helped to identify the features of the life cycle in the lowlands of the Transcarpathian region. The article presents the results of the study of the influence of the hydrothermal regime on the formation of anise hyssop and ecological plasticity of the samples of the source material. We have identified the main stages and periods of plant development and conditions that affect the formation of vegetative and generative organs of plants, which helped to identify the most adaptive samples for further selection of this valuable aromatic plant. We have created a competitive variety Pochatok with high: adaptive properties, quality of raw materials and a significant amount of essential oil for specific agro-climatic conditions. The issues covered in the article are important, valuable and relevant not only for this region in particular, but also for Ukraine as a whole. The results of the scientific research with anise hyssop show that the agro-climatic conditions of the lowland zone of Transcarpathia are favorable, and the cultivation of this non-traditional aromatic plant is economically profitable. In these conditions it passes through all the stages of its development and forms a huge green mass, the yield of which makes up 14,5 t/hа (output of the dry matter– 4,4 t/hа, еssential oil – 1.27% of the a. d. m. (absolutely dry mass). The level of profitability from growing and use of Lophanthus аnisatus Benth. makes up – 61,7%, the economic effect (additional profit) is 15732 UAH.

Decoding Wheat Endosphere-Rhizosphere Microbiomes in Rhizoctonia solani-Infested Soils Challenged by Streptomyces Biocontrol Agents.

The endosphere and the rhizosphere are pertinent milieus with microbial communities that perturb the agronomic traits of crop plants through beneficial or detrimental interactions. In this study, we challenged these communities by adding Streptomyces biocontrol strains to wheat seeds in soils with severe Rhizoctonia solani infestation. Wheat plants were grown in a glasshouse standardized system, and the bacterial and fungal microbiomes of 233 samples of wheat roots (endosphere) and rhizosphere soils were monitored for 20 weeks, from seed to mature plant stage. The results showed highly dynamic and diverse microbial communities that changed over time, with Sphingomonas bacteria and Aspergillus, Dipodascus, and Trichoderma fungi increasing over time. Application of biocontrol Streptomyces strains promoted plant growth and maturation of wheat heads and modulated the root microbiome, decreasing Paenibacillus and increasing other bacterial and fungal OTUs. The soils with the highest levels of R. solani had increased reads of Thanatephorus (Rhizoctonia anamorph) and increased root disease levels and increased Balneimonas, Massilia, Pseudomonas, and unclassified Micrococcaceae. As we enter the era of biologically sustainable agriculture, it may be possible to reduce and limit the effects of serious fungal infestations by promoting a beneficial microbiome through the application of biocontrol agents during different periods of plant development.

ФОРМИРОВАНИЕ ПРОДУКТИВНОСТИ СОРТОВ ГОРОХА ПОСЕВНОГО С ДЕФОРМАЦИЕЙ ЛИГНИНА В СТВОРКАХ БОБА В ЗАВИСИМОСТИ ОТ ПЛОТНОСТИ ПОСЕВА

The optimal sowing density for realizing the potential of varieties is regulated by the seeding rate, which is subject to a strong dependence on genotypic features, the influence of agroecological, meteorological factors. The aim of the research is to study the effect of various seeding rates on the realization of the productivity potential of new pea varieties Kaban and Fregat with parchment-free beans in contrasting conditions of moisture and heat supply in plant development phases. The conditions of 2014 were characterized by a deficit of moisture and an elevated temperature during the critical periods of plant growth. The size of the potential of varieties in 2015 was limited to a strict regime in the period of plant development and the formation of reproductive organs. The optimal sowing structure of Kaban variety was formed with a planting density of 1.0–1.2 million viable seeds. The best values of survival and conservation of plants in dry conditions were obtained when sowing with the minimum rate. With an improved moisture supply regime, they reached 95.0 and 98.3%. The planting structure of the leafless small seed Fregat variety under conditions of moisture deficiency was characterized by an increase in field germination, plant survival and survival, respectively, up to 100.0, 97.8 and 97.9% when sown with a density of 1.4 million germinating seeds. The optimal structure was formed at a seeding rate of 1.2 million viable seeds with field germination values of 97.5, a survival rate of 93.3 and a plant life of 95.7%. The increase in planting density led to an aggravation of the competitive relationship of plants, manifested in a decrease in the value of the seed mass with plants, regardless of the varietal characteristics. A high proportion of the effect on the variability of this indicator was proved, depending on the seeding rate, reaching 70.8-90.3% for varieties. The significant effect of the conditions of the year was estimated by a low proportion of influence (8.3–9.7%), the interaction of these factors did not have a significant effect. The maximum productivity of sowing per unit area, determined by the density of plants and their seed mass, when deducting seeds spent on sowing, Kaban variety was formed at a seeding rate of 1.2 million viable seeds, regardless of the conditions of the year. The optimum planting density of Fregat variety is 1.0 in arid and 1.2 million viable seeds with an increase in moisture supply.

Use of antibiotics to control endophytic bacterial growth migration onto culture medium in Eucalyptus cloeziana F.Muell.: a micropropagation approach

The natural endophytic bacterial growth migration onto a culture medium is commonly associated with unnecessary microplant discards. In micropropagation procedures, some bacteria can exude from the internal tissues of plants to colonize the culture medium and compete with the plants for nutrients, which may lead to a reduction in plant development. To find an efficient antibiotic protocol to control this bacterial growth migration onto the culture medium without affecting plant development, Eucalyptus cloeziana F.Muell. microstumps were subjected to four antibiotic treatments for 30 d. They were treated with gentamicin, ciprofloxacin, rifampicin, or Timentin®, in addition to the control treatment (antibiotic free). The effects of the antibiotics were monitored weekly, and the endophytic bacterial community structures were evaluated in two periods of plant development (15 d and 30 d).The denaturing gradient gel electrophoresis (DGGE) technique was used to compare the control and post-antibiotic treatment plant microbiological composition, to determine if the antibiotic treatment played a specific role on the endophytic bacterial community structure. The gentamicin treatment was composed of a distinct community from the control treatment. Nonetheless, the plants treated with ciprofloxacin and rifampicin manifested similar endophytic community structures compared to the control. In contrast, plants treated with Timentin® showed a specific bacterial community composition and a higher plant dry mass, number of shoots, and nutritional content. These results suggested that Timentin® treatment could be applied for 30 days to control endophytic bacterial growth migration onto the culture medium, without affecting the homeostatic balance between the bacteria and plants.

TERMS OF WINTER WHEAT TREATMENT BY FUNGICIDES TO CONTROL DEVELOPMENT OF BROWN RUST PATHOGEN

The terms of winter wheat treatment against brown rust pathogens (PucciniareconditeRob. exDesmf. sp. tritici) can greatly differ depending on climatic conditions and applied materials. The question is not studied enough for the Tambov region. In the production brown rust control fungicides are often used at the early periods of plant development (tillering, stem-extension stage). It makes the second treatment necessary as the preparation effect finishes at the maximum manifestation of disease (plant development phase-milky ripeness of kernels). In the Tambov region, the first pustules of brown rust appear on winter wheat plants in the beginning of the earing phase. This period occurs at the end of May/beginning of June. It is logical to assume that the maximum suppression of the disease on wheat will be achieved by spraying precisely at these times. To test this assumption, the field trials were conducted using the preparations ‘Reks duo’ and ‘Abakus’. They were used in the stem-extension stage and earing phase of winter wheat. Biological efficiency of fungicide spraying in earing phase of wheat was significantly larger (98.2–98.8%). Application of fungicides spraying in stem-extension stage was 85.6-86.5%. The amount of the saved yield was 0.60–0.81 t/ha (14.2–19.1%). Maximum values of winter wheat productivity (5.05 t/ha) was obtained when the preparation ‘Abakus’ was applied in earing phase. Wheat treatment by the preparations ‘Reks duo’ and ‘Abakus’ in earing phase was found more economically profitable, and the level of profitability was 130.9 and 55.0%, in stem-extension stage it was 109.2 and 35.4% respectively. The results of the trials showed that fungicides spraying in earing phase is the most optimal.

THE INTENSITY OF TRANSPIRATION OF THE LEAVES OF GLYCINE MAX (L.) MERR. DEPENDING ON THE GROWTH PHASE AND THE TIERED ARRANGEMENT ON THE PLANT

The thematic core facilities plan, CCU of Orel state agrarian university Genetic resources of plants and their use for a joint program with Shatilovskay of Institute of leguminous and cereal crops, of field and vegetation experiments on the study of specific features of manifestation of the activity of transpiration leaves of soybean are achieved. The object of the study were 10 varieties of soybeans that were grown on plots of 15 m 2 in four replications. Seeding was carried out breeding seeder calculated 600 thousand of viable seeds per hectare. the way the plots were allocated systematically with offset. The care of crops was carried out in accordance with the recommended regional events. It was demonstrated that leaf transpiration activity of the culture increases sharply in the transition of plants to the generative period of development, reaching a maximum in the phase of mass fruit formation, when the most active growth and, consequently, the demand for assimilate. The intensity of transpiration of leaves during this period of plant development was by 8.22 mmol H 2 O/m 2 c. The highest transpiration activity was typical for the upper leaves located in the generative sphere of plants, the lowest - activity was fount for the lowerst leaves. On the 5th node from the bottom, its value was 2.2 times lower compared to the assimilating leaves at the top of the plants (3-4 knots top). Thus, the most intensive evaporation of the water by leaves are held from 9:00 to 13:00 hours Moscow time. The intensity of transpiration in this period amounted to an average of 5.42 mmol H 2 O/m 2 c, which was 19.9% higher than in the morning (from 7:00 to 8:00) and 42.3% in the afternoon (from 15:00 to 17:00).

Влияние предпосевной обработки семян КВЧ на пораженность растений болезнями и урожайность озимой пшеницы

Under the sharp increase of energy costs, man-made pollution of agro-ecosystems we need find environmentally safe and cost-effective material and energy resources. As an alternative, new nanotechnology SHF (superhigh frequency) and EHF (extremely-hifh frequencies) of preplant seed treatment are introduced, as an alternative to chemical methods. Among the promising agricultural practices, that have a stimulating effect on plant growth and development, should include the use of electric and magnetic fields, which are used as for pre-sowing preparation of seeds and during the growing season by increasing the resistance of plants to stress factors and an increase in the utilization rate of nutrient substances from soil. The research has shown, that under the influence of the electromagnetic field there is a mobilization of power and release of the energy reserves of an organism, the physiological and biochemical processes in the early stages of seeds germination are activated, there is an increase of intro-changably processes and a steady increase of germinative energy, capacity, initial growth froce, spring and summer survival rate, which favorably affect the entire subsequent period of plant development. The aim of our research is the introduction of short-wave technology in agriculture in wheat cultivation. The results of our studies showed, that in the Kama region of the Republic of Tatarstan the presowing seed treatment with “EHF - 15 meters + Vialt - 2 kilogram per ton + Tsirkon10 millilitre per ton”, reduced the infestation of seeds compared with seed treatment option without Bipolaris sorokiniana 11.9 times, Fusarium spp. 12.8 times, Alternaria spp. - 7.5 times and the musty seeds in 5.2 times. In this option, we noted the minimal plant damage by phytopathogens, compared to the control one, the spread of root rots in the phase of wax ripeness decreased to 13%, leafy mycoses - to 9%. The use of electromagnetic influence (EHF) for 15 minutes + protectant + growth stimulator increases the winter wheat productivity to 0.46 and 0.48 tons per hectare. Application of calculated doses of NPK of 4.0 tons per hectare increases crop yield to 1.31-1.37 tons per hectare.

Screening for Salinity Tolerance in Lowland Rice

Screening for breeding materials for salinity tolerance is most accurately done by measuring grain yields. However, mass screening during the vegetative period of plant development using pots in a greenhouse is more effective for rapid evaluation of large amounts of germplasm.In this study, Pokkall and IR 22 cultivars were grown in pots which contained five kilograms of soil. The soil had been fertilized with four liters of Hoagland's solution which was salinized with a given concentration of 0, 1000 ppm, 2000 ppm, 3000 ppm, 4000 ppm, 5000 ppm, and 6000 ppm NaCl. Four of two weeks old seedlings were transplanted into each pot. The experiment unit were arranged in a Randomized Complete Block Design (RCBD) with two replications.A salinity level of 4000 ppm NaCl (8.5 mmhos/cm EC) showed the best differentiation of phenotypic performance for the salinity tolerance evaluation four weeks after transplanting.This technique was also used for screening of 23 traditional cultivars from South Kalimantan at salinity level of 8.5 mmhos/cm EC. Pokkal was used as tolerant check, and IR 22 was use as a susceptible check.Bayar Putih, Pandak, Pucuk, Lemo, and Duyung cultivars were identified as the most tolerant cultivars. It was also found that the percentage of sodium was greater in susceptible plants than in tolerant ones. However, the differences in N, P, and K were relatively small.

Efeito de épocas de semeadura sobre cultivares de girassol, no Sul do Estado do Tocantins

This study had as its objective, evaluating the agronomic performance of sunflower (Helianthus annuus L.) cultivars when sown at different times, under the environmental conditions in the south of the State of Tocantins. The experiment was carried out during the 2008/2009 agricultural year, in randomized blocks in a 4 x 5 factorial design (four sowing dates and five sunflower cultivars) with three replications. Each plot consisted of four rows 5.0m in length, spaced 0.80 m apart with 0.20 m between plants. For all sowing dates, the characteristics evaluated were: flowering, plant height, stem diameter, head diameter, normal achenes, grain weight per thousand and grain yield. There was significant correlation of sowing dates with the evaluated cultivars for the traits of flowering, plant height and grain yield. In relation to periods of sowing, there was generally a negative influence on all evaluated traits for the later dates, due to an Indian summer causing moisture stress during the critical period of plant development and the occurrence of disease, especially alternaria leaf-spot. The first sowing period (November) showed higher productivity with an average of more than 3,000 kg ha-1. Irrespective of sowing dates, the more productive cultivars were the hybrids Helio 360 and Helio 884, with an average of 1,709 and 1,697 kg ha-1 respectively.

Review. Deficit irrigation in fruit trees and vines in Spain

Water has become the most precious of natural resources in many areas of Spain and, since agriculture is the major consumer of water, improvements in water use efficiency are increasingly sought. Regulated deficit irrigation (RDI) is an irrigation strategy based on applying only a fraction of the plant water requirements during certain periods of plant development. The paper reviews the available information on RDI strategies, in woody tree crops and vines based on studies by Spanish research groups. Both the promising results obtained and the drawbacks are covered.

Triangle tests indicate that irrigation timing affects fresh cabbage sensory quality

A replicated triangle test was employed to determine if judges could distinguish, by tasting, between shredded samples of fresh cabbage drip-irrigated during different periods of plant development. Irrigation was provided either: (1) throughout plant development (no stress, NS), (2) during frame development only (head stress, HS), or (3) during head development only (frame stress, FS). Control plants received no irrigation for the duration of plant development (frame and head stress, FHS). In a total of three sessions, 14 judges evaluated two replications each of the six possible treatment comparisons in triangle tests. Results were analyzed using the beta-binomial model. Judges detected differences ( α=0.05) between cabbage from NS plots and cabbage from the two plots that received no irrigation during head development (HS, FHS), as well as between heads from FS and FHS plots. Physical traits of cabbage heads (e.g. weight, mean diameter, shape) at harvest were also affected by irrigation treatment. This is the first report to suggest that the timing of irrigation relative to crop development may influence the sensory characteristics of fresh cabbage. The data also suggest that cabbage head physical traits may respond more frequently to irrigation than cabbage sensory attributes.

214 Yield and Quality Response of Carrot (Daucus carota L.) to Simulated Storm Damage

Parts of Colorado receive more hail than almost any other area in the nation. Severe storms can injure crop tissue and, thus, lower yield and predispose the crop to disease infection. Our study was conducted to determine the yield and quality response of carrot (Daucus carota L.) to simulated storm damage during different periods of plant development. We removed 33% and 67% of the carrot foliage at four dates, spaced 10 days apart, during the middle of the growing season. In 1997 and 1998, 67% defoliation significantly reduced total and marketable yields more than did 33% defoliation. Total yield components, length and diameter, were similarly affected. Defoliation, in general, decreased yield the greatest when it when it occurred at the later stages of development. Carrot foliage continued to develop and grow after all defoliation events. Nonetheless, moderate (33%) and severe (67%) foliage loss reduced marketable yield and yield components of carrots.

Yield and Quality Response of Muskmelon to Simulated Storm Damage

Severe storms with high winds, hail, and rain can severely injure muskmelon (Cucumis melo L. var. reticulatus Naud.) leaf and fruit tissues. Our study was conducted to determine the yield and quality response of muskmelon to simulated storm damage during different periods of plant development. We removed 33% and 67% of the muskmelon foliage at 10, 20, 30, and 40 days before the first anticipated harvest. In 1994, 67% defoliation significantly reduced marketable yields and fruit number more than did 33% defoliation. The same trend existed in 1993. At both levels, defoliation had a greater impact on marketable yield when it occurred just before the canopy had covered all bare ground in the plots (about 30 or 40 days before the first harvest). Defoliation, in general, decreased fruit soluble solids concentration (SSC). In 1993, SSC decreased as the severity of damage increased. The reduction in SSC was most prominent when defoliation occurred in the later stages of fruit development (10 or 20 days before harvest). Both moderate (33%) and severe (67%) foliage loss reduced marketable yield and fruit quality of muskmelons.