Hybrid Carrot Research Articles

Genetic analysis of root traits in tropical carrots (Daucus carota L.)

Carrot root being used as vegetable and salad due to the nutritional value, hence consumers demanding carrot production. Thus, the production can be achieved by an understanding of the genetics of root traits namely root length, root weight, root diameter, core diameter, flesh thickness and root to top (shoot) ratio. Thus, the results assist in the development of carrot hybrids or varieties. Genetic analysis of economic traits of carrot was estimated through three cross combinations, and the results revealed the existence of additive [d], dominance [h], additive × additive [i], additive × dominance [j] and dominance × dominance [l] gene actions. The nature and magnitude of gene interaction and effects showed the importance of the inheritance modes, and the complimentary type of non-epistatic gene action of traits could be used for the exploitation of heterosis through favourable positive [h] and [l] gene interaction and effects. This information on root genetics aided to the adoption of suitable breeding method, handling and selection of segregates with desirable economic traits.

Morpho-Biometrical, Nutritional and Phytochemical Characterization of Carrot Landraces from Puglia Region (Southern Italy)

The explorations as a part of the regional BiodiverSO Programme of vegetable genetic resource rescue revealed that in the arenili (sandy shores) of “Salterns of Margherita di Savoia” (SMS), a coastal landscape area of Puglia region (southern Italy), along the commercial genotypes of small rooting species, landraces are still cultivated. The morpho-biometrical, nutritional and phytochemical properties of two carrot landraces (“Carota a punta lunga” and “Carota a punta tonda”) and a commercial carrot hybrid (“Presto”) collected from the SMS area are examined. The study highlighted that the pedological conditions of the arenili of the SMS area are the main driving force in controlling the nutritional and nutraceutical characteristics of carrot, conferring to genotypes grown in this area a high profile in comparison with literature data. In the site of cultivation of arenili, a large variability in the morpho-qualitative traits emerged among carrot genotypes. “Carota a punta tonda” stands for a promising genotype being very rich in phenols (209.8 mg kg−1 fw) (mainly di-caffeic acid derivative and chlorogenic acid), ß-carotene (21,512 µg 100 g−1 fw), and high antioxidative proprieties. “Carota a punta tonda” could be considered as a healthy product for consumers and also amenable to selection for breeding purpose. Increasing the knowledge about nutritional and nutraceutical properties of local landraces may push the preference of consumers beyond the local community and, at the same time, farmers can be stimulated to continue their cultivation. Thus, the promotion of their on-farm/in situ conservation (cultivation) could represent an efficient strategy for agro-biodiversity preservation.

Seasonal nutrient partitioning and uptake in hybrid carrot seed production

AbstractCentral Oregon is an important production region for hybrid carrot (Daucus carota L.) seed. Hybrid carrots are favored by the fresh vegetable market, but often produce lower and less consistent seed yields than traditional open‐pollinated varieties. Understanding how hybrid carrots use nutrients to support seed production for hybrid varieties can help growers manage soil fertility for optimal seed yield. The objective of this research was to evaluate seasonal nutrient partitioning and uptake in a modern Nantes‐type hybrid carrot grown for seed. Plants from four randomized replicated plots in two commercial fields were destructively sampled throughout the growing season, separated into roots, tops, and umbels; seed samples were collected at harvest. Plant samples were weighed and dried for biomass content and analyzed for N, P, K, S, Ca, Mg, Na, Zn, Fe, Mn, Cu, and B concentration. Mean whole plant nutrient uptake at crop maturity for N, P2O5, K2O, S, Ca, Mg, and Na was 137, 35, 229, 16, 105, 38, and 25 kg ha−1, respectively; Zn, Fe, Mn, Cu, and B uptake was 156, 1,984, 414, 35, and 305 g ha−1, respectively. Our findings highlighted the critical need for Cu in initial crop establishment, for N, K, Zn, and Fe in crown development, and for P and Zn in seed development, based on nutrient uptake proportion relative to the other nutrients taken up during that period. This information is available as a resource to agronomists, crop advisors, and growers who are interested in optimizing nutrient management practices for hybrid carrot seed production.

Resistance of carrots to diseases as a factor of increasing production profitability

The main reason for the decline in production of commercial products is the loss of crop during its long storage. From March to July, the difference between demand and production is made up by imported products from near and far abroad. As a result, this leads to an increase in prices relative to the autumn months from April by 44% and from July by 50%, until going of a new crop of domestic products on the shelves. As a result of the conducted research, it is shown that domestic varieties and hybrids due to a higher level of resistance to local populations of pathogens are economically profitable in terms of production costs and crop losses during storage. Growing high-yielding varieties and hybrids of carrots with complex stability, such as Margosha and Shantane 2461, Rif F1 and Nadezhda F1 breeding of FSBSU “Federal Scientific Center of Vegetable Growing” (FSBSU FSCVG) allows for the sale after long-term storage to make a profit of about 240-600 thousand rubles/ha, to achieve profitability of 59-150%. This contributes to solving one of the key tasks - reducing the dependence of the vegetable market on imports and ensuring food security of the Russian Federation.

Assessing the processability of Russian varieties and hybrids of root crops

Biochemical and organoleptic properties of varieties and hybrids of carrots and beets after their processing were studied. Minchanka and Marlinka carrot varieties, as well as Gazpadynya and Nesravnennaya beet varieties were the best for making of vegetable purees. In terms of preservation of vitamin C, the best indicators were characteristic of the F1 Nadezhda hybrid and the Minchanka variety. Preservation of carotenoids is the greatest in the F1 Nadezda hybrid and Marlinka varieties.

ПРОДУКТИВНІСТЬ МОРКВИ СТОЛОВОЇ ЗАЛЕЖНО ВІД ГІБРИД

In order to obtain a significant level of yield of table carrots in the Right-Bank Forest-Steppe of Ukraine, it is necessary to select varieties and hybrids in accordance with the soil and climatic conditions of cultivation. The comparative estimation of productivity of hybrids of carrots of table foreign selection in the specified conditions is carried out. The results of phenological observations of plant development, their biometric indicators depending on the genetic features are presented. The indicator of the total yield of table carrots according to the experiment was in the range of 65.6–80.7 t/ha. Saturno F1 had higher and this exceeds the control of Abaco F1 by 15.1 t/ha. In the structure of the yield of this hybrid marketable products are 96.0 % or 77.1 t/ha, which is more than the control of 5 % or 17.1 t/ha. In Saturno F1 non-marketable products 3.6 t/ha, which is 2.0 t/ha less than the control, and the yield of standard products 75.3 t/ha, which is a larger indicator of the experiment and exceeds the control by 17.3 t/ha. Non-standard products amounted to 1.8 t/ha. The productivity of table carrots is significantly influenced by the weight of the root, which, in turn, is affected by its length and diameter. On average, according to the years of research, their weight was at the level of 190–240 g. The roots in Abaco F1, which was the control, were smaller in weight. Larger roots formed in Saturno F1. Hybrids Baltimore F1, Bolivar F1 and Gerada F1 formed roots of 208 g, 218 g and 233 g, respectively. The diameter of the roots of the studied carrot hybrids was 4.6–5.2 cm. They were smaller in Saturno F1 and larger in Baltimore F1. The average values of root diameter for the years of study in Abaco F1 (control) are 5.1 cm; Bolivar F1 4.7 cm, and Gerada F1 5.0 cm, which is less control by 0.4 and 0.1 cm, respectively. An important varietal feature of table carrots is the length of the root. In Abaco F1 it was 18.5 cm. This is the lowest value in the experiment. In Baltimore F1 and Bolivar F1 the roots were formed of almost the same length 19.0 and 19.3 cm, respectively, which is more control by 0.5 and 0.8 cm. In Gerada F1, the roots were 23.2 cm, which is more control by 4,7 cm. Roots of Saturno F1 were longer compared to other variants of the experiment 24.5 cm, which is more control by 6 cm. The suitability of the studied hybrids of table carrots for foreign selection for growing in the conditions of the Right-Bank Forest-Steppe of Ukraine has been established.

Сохраняемость современных сортов и гибридов моркови столовой и ее зависимость от биохимического состава

Цель исследований – дать оценку сохраняемости и болезнеустойчивости современных сортов и гибридов моркови столовой и определить корреляционные зависимости влияния биохимических показателей качества на сохраняемость и степень поражения моркови столовой различными видами болезней в процессе хранения. Исследования проводились в 2011–2016 годах во ВНИИО – филиале ФГБНУ ФНЦО по общепринятым методикам. В биохимической лаборатории отдела земледелия и агрохимии содержание сухого вещества определяли высушиванием до абсолютно сухого веса, общего сахара – по Бертрану, аскорбиновой кислоты – по Мурри, нитраты – ионоселективным методом. При характеристике моркови столовой важнейший показатель, определяющий его качество – количество сухого вещества и сахаров. В процессе хранения были выявлены следующие болезни моркови: серая гниль (Botrytis cinerea Pers. ex Fr.), белая гниль (Sclerotinia sclerotiorum (Lib.)), белая парша (Rhizoctonia carotae Rad.), альтернариоз (Alternaria radicina M., Dr. et E.). В большей степени сортообразцы моркови столовой поражались серой гнилью. Лучшими по сохраняемости сортообразцами были Корсар (94,6%), F1Берлин (94,5%), Берликум Роял (94,1%) и F1 Звезда (94%). Сохраняемость у зарубежных сортов и гибридов моркови столовой была немного выше, чем у отечественных (на 0,4%) как за счет меньшей величины убыли массы (6,3% против 6,4%), так и потерь от болезней (1,6% против 1,9%). Сохраняемость корнеплодов моркови находится в прямой корреляционной зависимости от содержания сухого вещества (r=+0,41), каротиноидов (r=+0,39), моносахаров (r­=+0,30) и суммы сахаров (r=+0,27). Проявление серой гнили находится в обратной корреляционной связи с содержанием сухого вещества и каротиноидов (r=-0,37 и r=-0,35 соответственно), белой парши – в прямой корреляции с содержанием сухого вещества , моносахаров и дисахаров (r= +0,21; r= +0,39; r= -0,41 соответственно), белой гнили в обратной корреляционной связи с содержанием сухого вещества, моносахаров и дисахаров. The purpose of the research is to assess the persistence and disease resistance of modern varieties and hybrids of carrots and to determine the correlation between the influence of biochemical quality indicators on the persistence and degree of damage to carrots by various types of diseases during storage. The research was conducted in 2011–2016 at ARRIVG – branch of FSBSI FSVC, according to generally accepted methods. In the biochemical laboratory of the Department of Agriculture and Agrochemistry, the dry matter content was determined by drying to absolutely dry weight, total sugar – by Bertran, ascorbic acid – by Murri, nitrates – by the ion-selective method. When describing carrots, the most important indicator that determines its quality is the amount of dry matter and sugars. During storage, the following diseases of carrots were detected: gray rot (Botrytis cinerea Pers. ex Fr.), white rot (Sclerotinia sclerotiorum (Lib.), white scab (Rhizoctonia carotae Rad.), alternariasis (Alternaria radicina M., Dr. et E.). To a greater extent, varieties of table carrots were affected by gray rot. The best preserved varieties were Corsar (94.6%), F1 Berlin (94.5%), Berlicum Royal (94.1%) and F1 Zvezda (94%). The persistence of foreign varieties and hybrids of table carrots was slightly higher than that of domestic ones by 0.4%. both due to a smaller amount of weight loss (6.3% vs. 6.4%) and losses from diseases (1.6% vs. 1.9%). The persistence of carrot root crops is directly correlated with the content of dry matter (r=+0.41), carotenoids (r=+0.39), monosaccharides (r=+0.30) and the amount of sugars (r=+0.27). The manifestation of gray rot is in inverse correlation with the content of dry matter and carotenoids (r=-0.37 and r=-0.35, respectively), white scab is in direct correlation with the content of dry matter (r= +0.21; r= +0.39; r= –0.41, respectively), white rot is in inverse correlation with the content of dry matter, monosaccharides and disaccharides.

Особенности пораженности болезнями сортов и гибридов моркови и столовой свеклы, созданных на Приморской ООС, в условиях муссонного климата Дальнего Востока

В течение четырех лет (2016–2019 годы) на опытном поле Приморской овощной опытной станции – филиал ФГБНУ «Федеральный научный центр овощеводства» на естественном инфекционном фоне проводились исследования по изучению устойчивости перспективных сортообразцов моркови и столовой свеклы местной селекции к грибным и бактериальным заболеваниям в период вегетации в условиях муссонного климата Дальнего Востока для дальнейшего использования в селекционном процессе. Были испытаны сорта моркови Тайфун, Лидер, Гарант, Приморская 22 и гибрид F1 Форвард, а также сорта столовой свеклы Приморская 4, Приморская цилиндрическая и пять номерных образцов. Оценку пораженности листьев моркови проводили для всего комплекса болезней: Alternaria dauci(Kuhn.) Groves & Skolko, Cercospora carota (Pass.) Solh., Xanthomonas carotae Dows, листьев столовой свеклы – для Сercospora beticolaSass. Первые признаки болезней (A. dauci) обнаруживались на листовой поверхности моркови со второй декады июля – начала первой декады августа и во второй декаде августа – начале сентября их распространенность составляла 100% с максимальным средневзвешенным баллом поражения 2,6. Первые признаки пораженности образцов столовой свеклы церкоспорозом были отмечены в первой – второй декадах июля и ко второй декаде августа распространенность болезни почти на всех образцах составила 100%. При этом прослеживалась прямая зависимость распространенности и степени поражения растений болезнями от количества выпавших осадков и температуры воздуха. Наибольшую устойчивость к заболеваниям на листовой поверхности моркови показал гибрид моркови F1 Форвард и к церкоспорозу – образец столовой свеклы ПООС 22. Сорт моркови Лидер и образец столовой свеклы ПООС 22 могут быть использованы в селекционной работе для создания сортов и гибридов с повышенной устойчивостью к инфекционным болезням. For four years (2016–2019), research on the resistance of promising varieties of carrots and beets of local selection to fungal and bacterial diseases during the growing season in the monsoon climate of the Far East was conducted on the experimental field of the Primorsky vegetable experimental station - a branch of the FSBSI Federal Scientific Vegetable Center against a natural infectious background. Carrot varieties Typhoon, Leader, Garant, Primorskaya 22 and hybrid F1 Forward were tested, as well as beet varieties Primorskaya 4, Primorskaya cylindrical and 5 numbered samples. Carrot leaf infestation was evaluated for the entire complex of diseases: Alternaria dauci (Kuhn.) Groves & Skolko, Cercospora carota (Pass.) Solh., Xanthomonas carotae Dows, and beet leaves – for Cercospora beticola Sass. The first signs of diseases (A. dauci) were detected on the leaf surface of carrots from the second decade of July – the beginning of the first decade of August and in the second decade of August – early September, their prevalence was 100% with a maximum weighted average score of 2.6. The first signs of infection of table beet samples with cercosporosis were noted in the first and second decades of July and by the second decade of August, the prevalence of the disease in almost all samples was 100%. At the same time, there was a direct dependence of the prevalence and degree of plant diseases on the amount of precipitation and air temperature. The greatest resistance to diseases on the leaf surface of carrots showed a hybrid of carrots F1 Forward and cercosporosis – a sample of beet POOS 22. The Leader carrot variety and the POOS 22 beet sample can be used in breeding work to create varieties and hybrids with increased resistance to infectious diseases.

It Is Not All About Being Sweet: Differences in Floral Traits and Insect Visitation among Hybrid Carrot Cultivars.

Cytoplasmically male-sterile (CMS) carrot cultivars suffer from low pollination rates. In this study, insect visitation varied more than eightfold between 17 CMS carrot cultivars in a field-based cultivar evaluation trial. The visitation rates of honey bees, nectar scarabs, muscoid flies, and wasps each significantly differed among these cultivars. No significant difference in visitation rates was observed among cultivars of different CMS type (brown-anther or petaloid) or flower colour, but cultivars of Berlicumer root type had significantly higher insect visitation rates than Nantes. Six cultivars were further compared in regard to selected umbel traits: as umbel diameter increased, so did the visitation of soldier beetles, while that of honey bees decreased. Finally, nectar of these six cultivars was analysed for sugar content, which revealed monosaccharides to be the most common sugars in all. There was high variation in the levels of sugars from individual umbellets but no significant difference in nectar sugar composition among cultivars, suggesting that nectar sugar composition is of minor importance regarding pollinator attraction to hybrid CMS carrot umbels.

Combining ability of carrot genitors for root yield traits and leaf blight tolerance

The market demand for uniformity and productivity of commercial carrot roots has prioritized hybrid materials over open-pollinated varieties. In this sense, the objective of this work was to estimate the combining ability of carrot genitors for root productivity and resistance to leaf scorch. The experiments were conducted in Gama, DF, in the agricultural years 2012/13 and 2013/14. We evaluated 33 carrot hybrids, originated from crosses between three male-sterile populations, with 11 male-fertile S2 lines, all the genitors being of tropical origin. At 90 days after sowing, the severity of the leaf blight disease was estimated in the plots. At 100 days after sowing, harvesting was performed and root yield characters were evaluated. Analysis of variance and partial diallel analysis were performed for each year and jointly for both years. It was found that additive and non-additive genes are important in the manifestation of root yield and leaf blight resistance traits in carrot hybrids. The male-sterile parents with higher overall combining ability for root productivity are strains LM-649 and LM-650 and, among the male-fertile, strain LM-555-2-2. The best hybrids for root yield and leaf blight resistance are LM-649 × LM-555-11-1, LM-650 × LM-555-7-1 and LM-650 × LM-554-8-1.

Inoculation with arbuscular mycorrhizal fungi has a more significant positive impact on the growth of open-pollinated heirloom varieties of carrots than on hybrid cultivars under organic management conditions

To meet the high demand for organic produce, farmers must select crop cultivars that perform well under the low-input conditions of organic production systems. Most cultivars grown on organic farms are genotypes selected through conventional breeding programs, which may impact responsiveness to microbial symbionts. The use of biological inputs such as mycorrhizal inoculants offers the promise of improving yield, quality, and stress-responsiveness of crops, but evidence of efficacy in the field remains elusive. Moreover, interspecific and intraspecific variability may impact the ability of mycorrhizal inoculants to provide benefits. This work evaluated four cultivars (two heirlooms and two hybrids) of carrots and their propensities to benefit from inoculation with isolates of arbuscular mycorrhizal fungi in organic field conditions with and without late-season water restriction. Inoculants included geographically-distinct isolates from four species (Funneliformis mosseae, Rhizophagus clarus, Rhizophagus intraradices, and Septoglomus deserticola). Heirloom cultivars demonstrated a higher propensity to benefit compared to hybrid cultivars from inoculation with arbuscular mycorrhizal fungi. We observed benefits and costs with respect to yield associated with inoculation within four experiments over twoditions. Breeding histories of plant genotypes likely contribute to their mycorrhizal responsiveness.

Изучение генофонда моркови коллекции ВИР для селекционного использования

В Госреестр селекционных достижений, допущенных к использованию на территории РФ, включено более 320 сортов и гибридов моркови. На урожай и его качество значительное влияние оказывают условия выращивания, поэтому возрастает роль сорта/гибрида, созданного применительно к определенным почвенно-климатическим условиям. Приведены результаты оценки коллекционных образцов моркови на устойчивость к вредителям и болезням. Материалом для исследований послужили образцы моркови, поступившие в коллекцию ВИР из 11 стран мира. Выявлены различия по уровню повреждаемости образцов морковной листоблошкой, а также значительное варьирование поражаемости болезнями в зависимости от происхождения образца. В годы исследований (2014 – 2016, Ленинградскя область) степень поражения альтернариозом и фузариозом составила 25 – 40 %, серой гнилью — 0 – 10 %, фомозом и бактериозом — 5 – 15 %. Образцы моркови De Chantenay a cored rouge (Франция), Tip Top (Нидерланды), Rotherz (Венгрия), Арамильская и Принцесса (Россия), Местная (Чили), Royal Chantenay (США), Местная (Литва) отличались повышенной устойчивостью к комплексу болезней. Показана роль сорта в обеспечении стабильности урожаев в разных условиях выращивания. Проанализирован сортовой состав моркови по содержанию основных химических веществ. Образцы моркови Tip Top (Нидерланды), Naga (Япония), Scarlet Nantes (Канада), Грибовская и Принцесса (Россия) выделились по комплексу ценных биохимических компонентов. Выделенные источники послужат ценным исходным материалом для селекции, что позволит решать первоочередные задачи производства этой важной культуры.

Features of the cultivation technology of carrot hybrids in dry steppes of the Lower Volga region on drip irrigation

The paper studies the technology of the hybrid carrot cultivation with drip irrigation in a zone of the Lower Volga Region dry steppes. Carrots prefer medium-sized soil having the medium soil horizon and the pH of 6.0-7.5. However, it is cultivated in the majority of soil types. The crop yield depends on the quality the soil is cultivated with. Carrot taproots prefer the soil density of 1.0-1/3 g/cm3, so it is necessary to provide optimal water and air conditions of the soil. Sowing is done with pneumatic, electronic and mechanical seed drills. Pneumatic seed drills equipped with the metal pressure wheel, the tyne coulter, the small wheel for post-sowing pressing, the rubber wheel for soil smoothing and the distribution disk rotating in a direction opposite to seed drill wheels show the best seeding precision. The carrot cultivation performed under the conditions of the Lower Volga Region is possible only by means of irrigation. Carrot can be watered by corrugation, spray and drip irrigation methods.

Assessment of Pollen Diversity Available to Honey Bees (Hymenoptera: Apidae) in Major Cropping Systems During Pollination in the Western United States.

Global western honey bee, Apis mellifera (L.) (Hymenoptera: Apidae), colony declines pose a significant threat to food production worldwide. Poor nutrition resulting from habitat loss, extensive monocultures, and agricultural intensification is among the several suggested drivers for colony declines. Pollen is the primary source of protein for honey bees; therefore, both pollen abundance and diversity are critical for colony growth and survival. Many cropping systems that employ honey bee colonies for pollination may lack sufficient pollen diversity and abundance to provide optimal bee nutrition. In this observational study, we documented the diversity and relative abundance of pollen collected by honey bees in five major pollinator-dependent crops in the western United States. We sampled pollen from pollen traps installed on honey bee colonies in the following cropping systems—almond, cherry, highbush blueberry, hybrid carrot, and meadowfoam. The pollen diversity was estimated by documenting the number of different pollen pellet colors and plant taxa found in each pollen sample. The lowest pollen diversity was found in almond crop. Relatively higher quantities of pollen collection were collected in almond, cherry, and meadowfoam cropping systems. The information gleaned from this study regarding pollen diversity and abundance may help growers, land managers, and beekeepers improve pollen forage available to bees in these cropping systems.

Morphological and molecular changes on cytoplasmic male sterility (CMS) introgression in Asiatic carrot (Daucus carota L.).

MAIN CONCLUSION: 'Petaloid' cytoplasmic male sterility is commonly used as a stable genetic mechanism in carrot hybrid breeding. Its introgression in tropical carrot showed morphometric changes and molecular markers were identified for detection at early stage. Cytoplasmic male sterility (CMS) is the only genetic mechanism in carrot for commercial exploitation of heterosis and production of low cost affordable hybrid seeds. The 'petaloid' CMS system is stable and commonly used in hybrid breeding in temperate carrot but there is no information available on existence of natural CMS system in tropical Asiatic carrot. Therefore, the present study was aimed to investigate morphometric traits and organizational features of cytoplasmic atp9 gene sequences in newly converted CMS lines (BC4-7) of tropical carrot. The CMS lines had root traits at par with fertile counterparts while floral traits had variation. Petal colour and length, petaloids colour and shape and style length showed differences among the CMS lines and with their maintainers. Molecular markers are effective to establish male sterility at genetic level, for this, six fixed and stable CMS lines were screened with seven novel primer combinations. Out of which five pairs produced clearly distinguishable bands in CMS lines and their fertile counterparts. The study confirmed that the region between 3' end of atp9-1/atp9-3 gene and 5' end of region of homology to Arabidopsis thaliana mtDNA is ideal for developing the trait specific markers. These new CMS lines have potential to use in hybrid development and molecular markers will be useful to confirm male sterility to rogue out fertile plants.

EVALUATION OF THE GARDEN CARROT ACCESSIONS FOR THE POPULATION OF <i>CAVARIELLA AEGOPODII</i> (SCOP.) AND ECONOMICALLY VALUABLE FEATURES OF CULTURE IN THE CONDITIONS OF THE BRYANSK REGION

The article presents the results of research on the biology of willow-carrot aphid and evaluation of varieties and hybrids of garden carrot in the Bryansk region. The aim of scientific research was to study the biological characteristics of willow-carrot aphid - Cavariella aegopodii (Scop.) (Homoptera: Aphididae), the influence of weather and climatic conditions on the pest prevalence, the degree of plant population, as well as the evaluation of varieties and hybrids of garden carrot on the complex of economically valuable traits. It was established that the average daily temperature of 18°C and above contributed to the intensive pest infestation of carrot plants in the first decade of July. The peak of the number of willow-carrot aphids was noted in I-II decades of July. With the increase of temperature increased the fecundity of females of the aphid up to 60-70 larvae. In 2017-2018 detected relatively resistant varieties and hybrids of garden carrot – Minor, Marlinka, Nantskaya 4, Nadezhda F1with an average damage score of 1.0-1.17. The variety Shantena royal is marked with plants with an average score of 2.43, which characterizes the average resistance of the variety to damage. In the Bryansk region on the basis of "mass of roots" on average, over two years of research significantly exceeded the standard (variety Nante 4) Shantena 2461, Shantena Royal, Minor, Nante, Cupar F1, Nadezhda F1, Mars F1by 6.2 - 37.1 per cent. On the basis of "marketable yield" varieties and hybrids of Mars F1, Cupar F1, Nadezhda F1, Shantena royal, Nante, Minor were distinguished. According to the results of biochemical analysis, a variety of Nante with a high content of carotene (185.1 mg/kg), dry matter (13.3%) and low nitrate accumulation (110.2 mg/kg) was isolated. During two years of research in the conditions of the Bryansk region, it was established that Minor, Nadezhda F1combined relative resistance to willow-carrot aphids damage and were distinguished on the basis of “commercial yield”.

Stability of carrots collection for diseases in storage depending on infectious and post-temporary phytosanitary status of plants

Stability of garden carrot to diseases during storage should be considered as an important economic-valuable attribute. They are the main reason for the occurrence of losses, the magnitude of which can reach 30... 60%. Analysis of the persistence and resistance to diseases of varieties and hybrids of table carrot in relation to specific agroclimatic conditions is of scientific and practical interest. On the basis of the studies, a group of varieties characterized by a high degree of resistance to disease during storage was identified, the nature of the lesion being estimated at 0 points, which can be recommended for introduction into industrial vegetable growing and use in selection work. It was found that the damage to the aboveground part of the plant leads to a partial infection of the root growth point, and the root itself remains healthy. Mechanically damaged root crops are more susceptible to disease, since the infection penetrates into the root crop already during harvesting with parts of the earth and continues the development of the disease in the vault, and focal points of infection are formed.

Limited Cross Plant Movement and Non-Crop Preferences Reduce the Efficiency of Honey Bees as Pollinators of Hybrid Carrot Seed Crops.

Pollination rates in hybrid carrot crops remain limited after introduction of honey bee hives. In this study, honey bee foraging behaviour was observed in commercial hybrid carrot seed crops. Significantly more visits were made to male-fertile (MF) rather than cytoplasmically male-sterile (CMS) flowers. Pollen was collected from bees returning to a hive, to determine daily variation in pollen loads collected and to what level the bees were foraging for carrot pollen. Honey bees visited a wide range of alternative pollen sources and made relatively few visits to carrot plants throughout the period of flowering. Visitation rates to other individual floral sources fluctuated but visitation to carrot was consistently low. The underlying rate of carrot pollen visits among collecting trips was modelled and estimated to be as low as 1.4%, a likely cause of the limited success implementing honey bee hives in carrot crops.

Frequent Insect Visitors Are Not Always Pollen Carriers in Hybrid Carrot Pollination.

Insect crop visitations do not necessarily translate to carriage or transfer of pollen. To evaluate the potential of the various insects visiting hybrid carrot flowers to facilitate pollen transfer, this study examines insect visitation rates to hybrid carrot seed crops in relation to weather, time of day and season, pollen carrying capacity, inter-row movement, and visitation frequency to male-fertile and male-sterile umbels. The highest pollen loads were carried by nectar scarabs, honey bees, and the hover fly Eristalis tenax (Linnaeus). Honey bees and muscoid flies were observed to forage mostly within the male fertile carrot row while nectar scarabs and E. tenax foraged across rows, carrying equal pollen loads regardless of their distance from the pollen source. All observed insect taxa were more frequently seen visiting male-fertile than male-sterile umbels. In contrast to other visiting insects, honey bees were abundant and frequent visitors and were observed carrying high pollen loads. Consequently, we suggest both optimizing honey bee management and improving the attraction of carrot lines to honey bees to improve pollination rates for hybrid carrot seed crops.

Comparison of analyses types in carrot experiment: square lattice versus randomized blocks design

ABSTRACT The square lattice 4x4 design was compared to a randomized block design, for carrot F1 hybrids. Sixteen experimental carrot hybrids were evaluated in Brasília, in 2014/15 and 2015/16 agricultural years. A square lattice 4x4 design with three replications was used. The experimental plot consisted of 1.5 m2 useful area. The experimental area was installed on the second half of November 2014 and 2015. Cultural practices were the usually given to the carrot crop in Brazilian savannah region. The incidence of leaf blight was evaluated 90 days after sowing date and, after 100 days, roots were harvested and yield components evaluated. We evaluated the three possible analyses in lattice: 1) as randomized block design; 2) intrablock analysis with adjusted treatments and blocks within unadjusted repetitions; 3) analysis with recovery of interblock information with adjusted treatments. The analysis in lattice permitted to reduce the mean squares of error and coefficients of variation; moreover, these were more efficient than the randomized block design experiments for most evaluated characters. Thus, use of the analysis in lattice is preferred in experiments with carrot when evaluating large number of treatments.