Genetic Diversity of Phenotypic and Biochemical Traits in VIR Radish (Raphanus sativus L.) Germplasm Collection

Small radish and radish are economically important root crops that represent an integral part of a healthy human diet. The world collection of Raphanus L. root crops, maintained in the VIR genebank, includes 2810 accessions from 75 countries around the world, of which 2800 (1600 small radish, 1200 radish) belong to R. sativus species, three to R. raphanistrum, three to R. landra, and four to R. caudatus. It is necessary to systematically investigate the historical and modern gene pool of root-bearing plants of R. sativus and provide new material for breeding. The material for our research was a set of small radish and radish accessions of various ecological groups and different geographical origin, fully covering the diversity of the species. The small radish subset included 149 accessions from 37 countries, belonging to 13 types of seven varieties of European and Chinese subspecies. The radish subset included 129 accessions from 21 countries, belonging to 18 types of 11 varieties of European, Chinese, and Japanese subspecies. As a result of the evaluation of R. sativus accessions according to phenological, morphological, and biochemical analyses, a wide variation of these characteristics was revealed, which is due to the large genetic diversity of small radish and radish of various ecological and geographical origins. The investigation of the degree of variation regarding phenotypic and biochemical traits revealed adaptive stable and highly variable characteristics of R. sativus accessions. Such insights are crucial for the establishment and further use of trait collections. Trait collections facilitate germplasm use and contribute significantly to the preservation of genetic diversity of the gene pool.

The possibility of using of an aqueous extract from stevia (Stevia rebaudiana Bertoni) leaves as a biostimulant of plant growth in photoculture

Relevance. Plant growth biostimulants based on natural raw materials are ecologically safe and harmless to humans. Stevia (Stevia rebaudiana Bertoni) contains in its leaves sweet diterpene steviol glycosides, which are similar in structure and properties to gibberellins, as well as a number of other valuable biologically active compounds. Water extracts from stevia leaves are capable to accelerate growth, to increase the yield and quality of plants. However, further study and development of application technologies of the extracts for specific crops and different growing conditions are required. The purpouse of this work is to investigate the effect of an aqueous extract from stevia leaves on the yield and quality of lettuce and small radish under photoculture conditions. Materials and methods. The objects of the study were lettuce var. Typhoon and small radish var. Riesenbutter. The plants were grown in photoculture at the biopolygon of the FSBSI Agrophysical Research Institute (St. Petersburg) at an illumination of 10–20 klx, a temperature of 22–26°С (day) and 18–20°С (night). Watering was carried out with water, top-dressing was carried out with Knop's nutrient solution three times a week. Peat with mineral additives was used as a substrate. The original extract was prepared by extraction from stevia dry leaves powder with hot water (80°С) in a ratio of 1 g of leaves: 100 ml of water. Foliar treatment of plants was carried out twice at dilution of the original extract from stevia leaves 1:10, 1:50, and 1:100 (extract : water) at the rate of 0.20-0.25 ml / lettuce plant and 0.09-0.1 ml / radish plant; control plants were treated with water. The data were processed according to standard procedures using the Excel 2016 software. Results. Foliar treatment with an extract from stevia leaves did not significantly affect the size and weight of radish root crops, but increased the yield due to a decrease in the number of bolting plants. A significant decrease of bolting was observed in all treatment options (by 34-51%). When using a dilution of 1: 100, the yield of marketable root crops increased by 20% and the yield per sq. m. – by 25%. Foliar treatment with stevia extracts increased the mass of lettuce plants, as well as their biological value. The content of photosynthetic pigments, sugars, and vitamin C significantly increased, and a tendency towards a decrease in the content of nitrates was observed. According to data, we recommend for foliar treatment are dilutions of the original extract 1:50 and 1: 100. The effect of using of an extract from stevia leaves is similar in action to some biostimulants from plants with hormone-like properties, which determines the possibility of using it as a safe plant growth stimulant.

Genetic diversity of VIR Raphanus sativus L. collections on aluminum tolerance

Radish and small radish (Raphanus sativus L.) are popular and widely cultivated root vegetables in the world, which occupy an important place in human nutrition. Edaphic stressors have a significant impact on their productivity and quality. The main factor determining the phytotoxicity of acidic soils is the increased concentration of mobile aluminum ions in the soil solution. The accumulation of aluminum in root tissues disrupts the processes of cell division, initiation and growth of the lateral roots, the supply of plants with minerals and water. The study of intraspecific variation in aluminum resistance of R. sativus is an important stage for the breeding of these crops. The purpose of this work was to study the genetic diversity of R. sativus crops including 109 accessions of small radish and radish of various ecological and geographical origin, belonging to 23 types, 14 varieties of European, Chinese and Japanese subspecies on aluminum tolerance. In the absence of a rapid assessment methodology specialized for the species studied, a method is used to assess the aluminum resistance of cereals using an eriochrome cyanine R dye, which is based on the recovery or absence of restoration of mitotic activity of the seedlings roots subjected to shock exposure to aluminum. The effect of various concentrations on the vital activity of plants was revealed: a 66-mM concentration of AlCl3 · 6Н2О had a weak toxic effect on R. sativus accessions slowing down root growth; 83 mM contributed to a large differentiation of the small radish accessions and to a lesser extent for radish; 99 mM inhibited further root growth in 13.0 % of small radish accessions and in 7.3 % of radish and had a highly damaging effect. AlCl3 · 6Н2О at a concentration of 99 mM allowed us to identify the most tolerant small radish and radish accessions that originate from countries with a wide distribution of acidic soils. In a result, it was possible to determine the intraspecific variability of small radish and radish plants in the early stages of vegetation and to identify genotypes that are contrasting in their resistance to aluminum. We recommend the AlCl3 · 6Н2О concentration of 83 mM for screening the aluminum resistance of small radish and 99 mM for radish. The modified method that we developed is proposed as a rapid diagnosis of aluminum tolerance for the screening of a wide range of R. sativus genotypes and a subsequent study of contrasting forms during a longer cultivation of plants in hydroponic culture (including elemental analysis of roots and shoots, contrasting in resistance of accessions) as well as reactions of plants in soil conditions.

Создание новых форм редиса и редьки (Raphanus sativus L.) с прогнозируемым комплексом хозяйственно ценных признаков при использовании методологии ускоренной селекции

В Агрофизическом научноисследовательском институте (ФГБНУ АФИ) при использовании оригинальной методологии ускоренной селекции получены новые высокопродуктивные формы Raphanus sativus L., предназначенные для выращивания в открытом грунте Ленинградской области (дайкон) и в условиях интенсивной светокультуры (линии редиса и гибриды F1 редиса и дайкона). Цель исследований усовершенствование разработанной авторами методологии ускоренной селекции при создании новых высокопродуктивных форм Raphanus sativus L., адаптированных к конкретным условиям выращивания. При проведении исследований изучено внутривидовое разнообразие корнеплодных культур вида Raphanus sativus L. (более 60 образцов разных экологогеографических групп и происхождения) при выращивании их в интенсивной светокультуре. Растения культивировали под лампами ДНаТ400 и ДНаЗ400 при облучении 70 80 Вт/м2 ФАР. Корнеобитаемой средой служил торф с минеральными добавками, увлажняемый ежедневно раствором 1 н Кнопа при чередовании с водой. Оценена реакция различных сортов лобы и дайкона (35 образцов) на действие длинного дня (18часовой фотопериод) и низких яровизирующих температур, провоцирующих преждевременное цветение. Выделены наиболее резистентные к этим факторам образцы, при гибридизации которых получены трансгрессивные формы дайкона с комплексной устойчивостью к раннему стеблеванию. На их основе создан высокопродуктивный сорт дайкона Петербургский, обладающий устойчивостью к действию длинного дня и пониженных температур, предназначенный для весенних посадок в открытый грунт Ленинградской области. При селекции редиса разработана и реализована стратегия получения высокопродуктивных форм, адаптированных для выращивания в интенсивной светокультуре. Выявлены сорта, способные обеспечивать урожай корнеплодов товарного качества до 3 кг/м2 за 25 суток вегетации, а также сорта редиса источники хозяйственно ценных признаков, реализуемых в этих условиях (максимальная длина/диаметр корнеплода, короткий вегетационный период, устойчивость к стеблеванию, компактная розетка листьев, неопушенный лист и др. Подобраны комбинации скрещивания, в потомстве которых получены гетерозисные и трансгрессивные гибриды, на 160 230 превышающие по массе корнеплодов родительские сорта. На их основе созданы высокопродуктивные скороспелые линии редиса для светокультуры с урожайностью 4,5 5 кг/м2 за 23 25 суток от посева. Показана перспективность работы с гибридным потомством в комбинации скрещивания редис дайкон. Получены гетерозисные гибриды F1 с массой корнеплода 100 150 г (товарная урожайность до 7 кг/м2), формирующиеся за 42 дня от посева.New highly productive forms of Raphanus sativus L. were obtained at the Agrophysical Research Institute (FSBSI ARI) agrophysical Research Institute), using the original methodology of accelerated breeding. They are intended for cultivation in the open ground of the Leningrad Region (daikon) and under conditions of intensive light culture (small radish lines and F1 hybrids of small radish and daikon). The aim of the research is to improve the methodology of accelerated selection developed by the authors for the creation of new highly productive forms of Raphanus sativus L. adapted to specific growing conditions. At first stage, the intraspecific diversity of root crops of the species Raphanus sativus L. (more than 60 cultivars of different groups and origin) was studied in intense light culture. Plants were grown under DNAT400 and DRIKZ400 lamps with irradiation intensity of 70 80 W/m2 of PAR. Root medium was the peat with mineral additives, moisturize daily with a Knop solution by alternating with water. The reactions of different varieties of the East Asian radishes (35 cultivars) on long day conditions (18hour photoperiod) and low spring temperatures were evaluated. The most resistant to these stressors cultivars were identified, and hybridization of them produced transgressive forms of daikon with complex resistance. The revealing of these forms and the subsequent stabilizing selection were performed in the open ground in the Leningrad region at sowing in the first decade of may. As a result of the research, a highly productive variety of daikon Peterburgskyi, adapted to spring sowing in the open ground of the Leningrad region, was obtained. When breeding new forms of radish for light culture, the collection of cultivars of different origin was studied and varieties were identified with a yield of commercial root crops up to 3 kg/m2 for 25 days of vegetation, as well as varieties that are sources of economically valuable traits implemented in conditions of intensive light culture (the maximum length/diameter of the root crop, early maturity, resistance to bolting, compact rosette, glabrous leaf type and etc). Combinations of crosses were selected, in the progeny of which heterotic and transgressive hybrids are obtained, that are 160 230 higher than the parent varieties by weight of root crops. On their basis, highly productive early ripening lines of radish for light culture were created with a yield of 4.5 5 kg/m2 for 23 25 days from sowing. Moreover, the prospectivity of selection work with hybrid offspring in a crossbreeding combination of small radish and daikon in light culture is shown. Heterotic F1 hybrids with a root mass of 100 150 g (yield up to 7 kg/m2) formed 42 days after sowing, were obtained.

SMALL RADISH FOR LIGHT CULTURE: CHALLENGES AND PROSPECTS

Intense light culture, the most impotent part of a regulated agroecosystem, makes it possible to produce high quality plant products all year round in any region of the world in close proximity to the consumer. It is most economically viable to use light culture for growing vegetables in the Far North, where there is an acute shortage of fresh vegetables and vitamins. Our studies of the range of different vegetable crops have shown that when using artificial lighting and low-volume cultivation technologies, many plant species and varieties have low productivity, low adaptability to the relevant conditions, and therefore unprofitable for mass production. To expand the range of vegetable products intended for cultivation in the light culture, it is necessary to do a massive screening of the varieties and hybrids of various crops available in the world assortment with the aim of selecting the best and also purposeful breeding of new forms and varieties maximally adapted to the appropriate cultivation technologies. The purpose of this work was to create new forms of small radish for light culture, having the necessary complex of economically valuable characters. The use of the previously developed methodology of predicting transgressions for economically valuable plant traits allowed us to obtain new promising forms of radish with using purposeful hybridization and subsequent stabilizing selection. Their characteristics are high productivity and early maturity (ripeness to harvesting for 21-25 days from seeding), the ability to produce marketable yield of roots in a small volume of root medium, resistance to bolting at higher temperatures. A number of the obtained forms also has a compact rosette of leaves and an almost glabrous leaf of the salad type. Marketable productivity of new forms of radish in intense light culture conditions reaches 5,5 kg/m2 (for hybrids F1) and 4 kg/m2 for stable lines, which is twice or more than the productivity of the parental cultivars and one and a half times more than the best in productivity cultivars that were tasted in light culture.

Биологические особенности редиса (Raphanus sativus L.) при выращивании в условиях интенсивной светокультуры

Описаны биологические особенности редиса (Raphanus sativus L.) коллекции ВИР в условиях интенсивной светокультуры. Результаты свидетельствуют о высоком разнообразии сортовой реакции редиса на выращивание в ИС. Определена амплитуда изменчивости основных морфологических, фенологических признаков и продуктивности в зависимости от сортотипа. Выделены источники хозяйственно ценных признаков для селекции.The present study describes biological features of small radish (Raphanus sativus L.) grown under the intense light culture conditions. Results, obtained using regulated system, demonstrated high variability of reaction to intense light conditions among the varieties of small radish. Amplitude of variability of the main morphological, phenological traits and productivity depending on variety type, was assessed. Samples of small radish, which can be potential sources of economic-valuable traits for future breeding (such as resistance to bolting under the intense light culture, compact rosette, high productivity and marketability) were identified.

STUDY OF THE RAPHANUS SATIVUS L. (SMALL RADISH) BIODIVERSITY UNDER CONDITIONS OF INTENSIVE LIGHT-CULTURE AND IDENTIFICATION OF DONORS OF ECONOMICALLY LUABLE CHARACTERS FOR BREEDING

Supply of the domestic fresh vegetables commodity to the population of Northern regions of Russia is one of the most priority tasks of the national economy. Lack of the local, high-quality and adopted breeding material is highly problematic for breeding programs. Generation of the new, highly productive vegetable cultivars for the glass-covered ground, including light culture, will promote to expand significantly the volume of local production of vegetables in protected ground, especially in regions with a cold climate. One of the most prospective crops for protected ground is small radish, an early ripening crop with a valuable biochemical composition. А strategy for creation of the new, highly productive forms of small radish, beard predictable complex of economically valuable characters for growing in conditions of intensive light culture, has been developed in the Agrophysical Research Institute (SaintPetersburg). At the first stage, represent interspecific set of 26 small radish cultivars from different regions, was investigated in controlled conditions (artificial light, climate cell) to reveal a complex of economically valuable properties (early maturity, productivity, morphological traits). The plants were grown in original plant grooving light equipment (lamps DNaZ-400, photoperiod 12 hours, irradiation 15-20 klk), in a small volume of substrate (peat with mineral additives). It was observed that the small radish varieties have significant diversity in precocity, productivity, resistance to bolting, also they vary in a number of morphological features of roots and leaves. Bov, Estella, Rocco (Netherlands), Nobo Chind Criollo (Peru) were the most productive cultivars. They can produce yield of commercial roots during 30 days of vegetation up to 3.5 kg/m2. In addition, cultivars – genetic resources of economically valuable properties (compact rosette, glabrous leaf, resistance to bolting) were revealed for a breeding. Parent pairs for crossing were selected. It is planned to obtain offspring small radish forms with a complex of economically valuable properties, more productive than the parents. In all matched hybrid combinations, F1 hybrids were obtained. They have a degree of hybrid superiority in roots weight from 110 to 230% over the best of the parent form. They will become the ancestors of the original forms of small radish, intended for cultivation in conditions of intense light culture.