Monday, July 17, 2006
B.S. Kurlovich, V.N. Dyubin and J. Heinänen
The response of lupins to different environmental factors
Response to light. It was shown by the researches conducted by the scientists of VIR, that the majority of grain legumes including lupin belong to the group of long-day plants, though there are some forms with neutral photoperiodic reaction (Дорошенко, Разумов, 1929). Our research (Kurlovich and Ivanova, 2000) has revealed positive but not identical reaction of the majority of the investigated accessions of narrow-leafed lupin to the lengthening of the photoperiod.
For example, the line of narrow-leafed lupin Mut-1 (k-2803) from Poland developed flowers and formed pods only in long daylight, i.e. it manifested a long-day photoperiodic reaction. The rest of accessions were early maturing in both photoperiodic modes. However, under short-day conditions the plants of these accessions were less in height.
Variation of characteristic features is observed in the accessions of lupin with different ecogeographic origin. The forms of lupins from northern latitudes and mountain areas responded to a short 10- and 12-hour day much stronger, than southern forms. The greatest changes in short-day environments were marked in wild forms, especially the ones from Portugal, Spain and Algeria. The samples from Greece, Turkey and Palestine were more neutral (Курлович, 1991б). Photoperiodic response of lupins was usually combined with the effect of other factors, especially with the response to vernalization (Kurlovich and Ivanova, 2000). Table 7 presents the influence of photoperiod duration and the complex effect of both factors (vernalization and photoperiod duration) on the growth and development of Mut-1 accession.
Mut-1 accession, which had shown long-day photoperiodic response, under the influence of short-day conditions and after vernalization showed determinate branching not on the main stem, but on its lateral branches. Ladny accession appeared to be the most thermo- and photo-neutral.
Photoperiodic response is also closely connected with spectral structure and intensity of the light. Long-day plants pass their reproductive phase faster with 24-hour illumination when in addition they are exposed to red light. Prevalence of long-wave rays in the light spectrum also provided for acceleration of plant development (Синская, 1946; Кашманов, 1970).
Besides, lupin plants respond to the intensity of illumination. Byszewski (1959) studied the effect of different light intensity of 7200, 10800 and 14400 lx on plants. With increased intensity of light, the plants grew faster, developed a more advanced root system, and produced higher yield at the increased intensity of light. Alkaloid content in seed was thus reduced. High light intensity produced an even greater effect on plants than lengthening of the daylight. Practically all lupin species are characterized by strongly expressed heliotropism, and turn their leaflets to the sun. Leaf dormancy is observed in many forms in the night when leaves lose turgor and droop. Lupin most effectively uses active photosynthetic radiation in comparison with other crops. Coefficient of its utilization in lupin is 4.79%, whereas in rye it is 2.42%, in wheat 2.68%, in oats 2.74%, and in vetch 1.98% (Шарапов, 1935). It is connected with high photosynthetic activity of plants and high calorific capacity of protein and oil contained in plants.
Response to heat. Multifoliate or Washington lupin (L.polyphyllus Lindl.) is the most resistant to cold among cultivated species. In Russia, the northern border of its cultivation for seed production passes along the line from Petrozavodsk to Syktyvkar. Narrow-leafed lupin is the least demanding of temperature among annual species. Its early forms ripen even in the northwest of Russia. The most heat loving is white lupin. Yellow lupin occupies an intermediate position. The data of Dyubin (Дюбин, 1981) describing heat requirements of different lupin species are presented in Tab. 8. In Russia, the sum of average daily temperatures ensuring maturity of narrow-leafed lupin is 1650-1690°C; for yellow lupin this figure is 1810-1950°C; and for white lupin it is about 2140°C. The sum of average daily temperatures for multifoliate lupin (L. polyphyllus Lindl.) for the period from the beginning of spring growth to the ripeness of seed makes 1325°C. The northern borders of growing areas for the considered lupin species for different maturity ensuring levels are also shown in Tab. 8. The vegetation period of cultivated lupins is constantly reduced, and accordingly aggregate heat requirement is decreased in the process of breeding more and more early-ripening cultivars and enhancement of their cultivation techniques. Already available are early thermo- and photo-neutral cultivars with determinate branching, which would make it possible to expand the area of lupin cultivation ever farther northwards.
For a majority of lupin species, minimum temperature for seed germination is low (+1… +2°C). Optimum temperature is +4 … +6°C. According to Sawichev (Саввичев, 1961), low air temperature at the time of shooting brings about reduction of the period from young plantlets to flowering. In the phase of stem growth and branching, lupin prefers moderately warm temperature. Flowering goes most intensively and effectively at moderate air temperatures (+15 … +25°C). Pollen sterility increases at higher temperatures and with absence of moisture. Seed ripening time is considerably reduced at higher temperatures, but is essentially longer with low temperatures and high humidity, especially in white lupin. In the north, tolerance of annual lupins to low temperature plays a significant role in their progress. According to Sharapov (Шарапов, 1935), annual species can tolerate the following temperature: L. albus down to –4°C, L. luteus down to –6°C, and L. angustifolius to –7°C. Barbacki (1960) states that lupin species can endure even more severe frosts: down to –6°C for white lupin, down to –8°C for yellow lupin, and down to –9°C for narrow-leafed lupin. These data testify that the researcher dealt with newer cultivars that had not only shorter vegetation period, but also, as a rule, increased tolerance to low temperatures. Resistance to low temperatures also depends on ecogeographic features of accessions and on the phases of plant development.
Our investigations (Курлович and Гаджиев, 1989) showed that in fall planting a winter form of white lupin of the Georgian ecotype endured the temperatures of –10°C down to –15°C during the whole winter period in Sheki-Zakatalsk zone of Azerbaijan. Lupin plants are more resistant to frost on the initial stages of development both in spring and fall plantings. Early frosts in autumn exert stronger influence on yellow lupin at the moment of seed ripening in spring planting. As to narrow-leafed and white lupins, they are able to go on growing even after long frosts. Perennial lupin species, in general, tolerate frosts quite well owing to their biological features, though some variance between species and variety also exists.
In most of the lupin species there are spring, intermediate and winter forms. Majority of wild forms belong to the winter type. In natural environments, seed of wild forms use to fall down on the ground from dehiscent pods. In autumn, with the beginning of a rainy season, these seed germinate, and young shoots remain for the whole winter in the state of rosette. During the Mediterranean winter with average temperatures between –5°C and +5°C, the plants stop growing and pass a stage of vernalization. They renew the process of growth in spring when air temperature becomes higher. Such cycle of development had been evolving for a long time in wild forms, and helped them to exist without any intervention from outside. When the plants are sown in spring without preliminary vernalization, majority of them would remain in the phase of rosette during the whole summer, and only with coming of colder weather in the fall some of them may start growing. Their cultivation as a spring crop is possible only after artificial vernalization within 30-40 days at a temperature of 0 … +1°C (Курлович, 1991б). It is necessary, however, to take into account that among wild forms there are plants with different demand for duration and intensity of vernalization. There are also typically summer forms with thermo-neutral habit used by breeders in Russia, Poland and other northern countries in spring plantings. Domesticated forms also manifest different responses to vernalization, which is testified by our experience in the study of genetic and environmental effects on branching in narrow-leafed lupin (L. angustifolius L.). The greatest effect of vernalization (Tab.9) was observed in accession Lanedeks-1.
Accession Mut-1 was transformed into the form with usual non-determinate branching under the influence of vernalization. Besides, it displayed determinate branching not on the main stem, but on lateral branches in these conditions.
But in the majority of the countries with warmer climate (Australia, southern Portugal, southern France, USA, and Chile) lupin is sown in the fall. For these purposes, winter and intermediate forms are used (Cowling, 1994; Erik von Baer, 1994; Huyghe et al., 1994; Nelson, 1994). Their cultivation with autumn sowing, wherever it is possible, provides for more efficient utilization of agroclimatic resources, higher productivity of lupin, and lesser degree of disease and pest incidence.
Response to moisture. The amount of free and bound water required for normal life of lupin reaches 80-85%. Lupin is xeromesophyte by nature, with sufficiently high resistance to drought and moisture. Its different species grow in different ecological conditions. However, if domesticated species are concerned, they are moisture-loving plants, suitable for cultivation in the areas supplied with moisture. Their transpiration rate is 600-700. Rather high moisture requirement of lupin is explained, first of all, by the fact that these plants accumulate much green matter. Secondly, plenty of moisture (120% of seed weight) is needed for the swelling of seed at germination. It is twice more than in cereal crops. On the other hand, lupin often endures drought quite well due to the well-developed tap root system, which supplies a plant with moisture and nutrients from deep underground. The first critical period in relation to the absence of moisture happens in lupin at the time of seed germination when the root system of plants does not work yet. The second period comes at the time of budding before flowering and fructification. The lack of moisture in this period results in considerable underdevelopment of pods and reduction of productivity. In the seed-ripening phase, higher humidity noticeably lengthens the vegetation period. The native land of domesticated annual lupin species is the Mediterranean region where they grow in mountainous areas. Rather damp and cool weather prevails there during the period of plant growth, and drought comes in the seed-ripening period. In the process of evolution lupin has adapted to such conditions. In Russia, on the contrary, in the time of seed maturing it often rains, so the period of ripening grows considerably longer, and in northern areas in some years seed do not ripen at all. Therefore, the plants are treated by defoliants and desiccants before grain harvest.
Laboratory evaluation of lupin accessions with various geographic origin for drought resistance based on the principle of seed germination in sucrose solutions has revealed (Курлович and Чернышева, 1986) the existence of interspecific and intraspecific variability in this parameter. Among the lupin species cultivated in Russia, higher relative resistance was found in the accessions of yellow lupin. The accessions of white and narrow-leafed lupins were characterized, on the whole, by lower resistance to drought, though among them there were some forms with high resistance. Yellow lupin shows rather low requirements to humidity in the soil and even in the air, as its native Mediterranean region it grows in dry mountainous areas. On the other hand, domesticated yellow lupin is grown basically on sandy soils than warm up quickly and are incapable to preserve moisture for a long time. In view of this, frequent spring droughts in the areas of its cultivation produce harmful effect on its seed and plantlets. This fact has created the problem of drought resistance for lupin, especially at early stages of its development, as seed of this crop require significant amount of moisture for the swelling. By now, too little effort has been made to solve this problem. Optimum soil humidity at a level of 60-80 % from full moisture capacity plays an essential role in formation of nitrogen-fixing nodules, promotes accumulation of higher protein content, and decreases the content of alkaloids (Byczwski, 1959; Barbacki, 1960). Especially high requirements to soil and air humidity are found in the cultivars with fast initial growth rate. The forms of lupins from the eastern Mediterranean region are, as a rule, more resistant to drought than the forms from the western Mediterranean. Eastern Mediterranean forms have leaflets with more xeromorphic structure (less stomas, presence of pubescence, etc.).
Excessive humidity of soil results in oppression of the root system and nodule bacteria that also lead to a decrease in the productivity of plants.
Responses to soil types and fertilizers. Lupin has aroused special interest because it is able to grow on poor light-textured sandy soils where the conditions are economically unfavorable for cultivation of other crops. Owing to its well-developed root system and high nitrogen-fixing ability, it is also widely used for reclamation of poor sandy soils. It is specifically so with yellow lupin, which shows in Russian conditions the least demand for soils. Most of all light loamy soils and sandstone may meet its requirements. Narrow-leafed lupin is a little more demanding of soil types. It prefers grounds with more coherent texture. However, narrow-leafed lupin like yellow one badly endures heavy clay soils, and suffers from superfluous humidity and high level of ground waters. White lupin is different in having the greatest requirement to soils among the domesticated species. Most favorable for it appear coherent loamy soils or sandstone, clay and even black prairie. Major criterion in the assessment of soil suitability for lupin cultivation is the reaction of soil environment. Lupins, even wild ones, grow only on acid and neutral soils where parent breeds or lava are on the ground surface. Almost all domesticated species of lupin also prefer subacid soils. Yellow lupin is considered as the most attached to subacid soils. There are very few species (L. casentinii, L. atlanticus and L. digitatus) adapted to fine-textured and alkaline soils (Buirchell, 1994). As to other domesticated species, they show high stability to soil acidity, prefer subacid or neutral reaction of soil environment, and poorly endure alkaline reaction. It is considered that рН 5.0-6.0 is the optimum of soil acidity for lupin (Майсурян and Атабекова, 1974). Thus, the response of lupin to soil reaction varies with the age of plants. In the early periods of development, optimum soil reaction is рН 4.6-5.0, while after flowering it is neutral, рН 6.0-7.0. The problem of lupin’s optimal reaction to soil environment is linked with sensitivity of lupin to the content of calcium in soil. It was generally accepted that lupin negatively responded to increased calcium content. However, it has also been established that its deficiency produces negative effect on the productivity of plants. Nonetheless, the limit of favorable effect produced by calcium on this crop is lower than in other plants. Negative effect of large amounts of lime results in significant accumulation of ammoniac nitrogen in plants, greater combustion of carbohydrates, and intoxication of plants with ammoniac (Майсурян and Атабекова, 1974).
Especially negative is lupin’s reaction to lime when the soil lacks for magnesium and other trace elements. However, profound and all-round study of the role of calcium conducted in the past years disproved the common opinion concerning incompatibility between lupin cultivation and calcification. It was observed that the negative effect of calcium is removed by applying magnesium into the ground, and iron on the same soils (Шутов, 1982). Therefore, in the fields where lupin is included in crop rotation, it has been recommended to calcify soil with flour containing magnesium that would neutralize the negative effect of lime (Курлович, 1985). Besides, it is undesirable to plant lupin on the sites that have recently been calcified. During a number of years after calcification, it is better to grow other crops prior to lupin. Different sensibility of lupin to the content of calcium in soil is also connected with the activity of nodule bacteria whose development goes well only with neutral and weak alkaline reaction of soil environment. They develop poorly with acid reaction of environment, and the process of nitrogen fixation proceeds inadequately. It is necessary to take into account the specified inconsistent factors of lime effect when working out an optimum technology of lupin cultivation as well as in breeding practice. The study of the genetic diversity of lupins preserved in the collection of VIR has revealed interspecific and intraspecific variation in the response of different forms to the content of calcium in soil. It opens prospects for breeding cultivars with good reaction to an excessive content of this element in soil. One of the valuable features of lupin as a leguminous crop is its ability to make symbiosis with nodule bacteria responsible for fixing free nitrogen from the atmosphere. Therefore, retention of nutrient elements is closely connected with the ability to provide biological nitrogen fixation by Bradyrhizobium sp. (Lupinus). These bacteria are especially sensitive to a surplus of mineral nitrogen. But its large amounts lead to abrupt reduction of nitrogen-fixing ability. Biological nitrogen fixation processes reach their greatest efficiency at the phase of plant flowering. To enhance this process, special preparations containing the most effective race of bacteria are applied. On the other hand, lupin is also capable to grow and develop at the expense of mineral nitrogen, especially if lupin is planted for the first time on a given site, and bacteria are absent in the soil. In this case, application of nitric fertilizers provides an essential increase in the yield. More efficient, however, is treatment of seed by an effective strain of nodule bacteria, or its application into the soil (Kurlovich et al., 1995, 1996). The process of biological nitrogen fixation begins only after the emergence of leaves. In view of this, initial dozes of mineral nitrogen are also effective at the first stages of plant development. The intensity of biological nitrogen fixation depends on the specific and varietal features of lupin, conformity of the applied strain of bacteria to a definite lupin cultivar, and also the conditions of supplying plants with other nutrient elements. Phosphoric and potassium fertilizers also render strong influence on the development of lupin plants, content of nitrogen, and formation of nodules. The lack of these fertilizers would greatly reduce general plant productivity. Phosphoric fertilizers stimulate growth of the root system; in particular its absorbing root hairs through which bacteria penetrate from soil, and enhance nitrogen-fixing ability by reducing the unfavorable effect of increased amounts of mineral nitrogen (Макашева, 1979). Nodule bacteria capable of transforming nearly insoluble forms of phosphorus into more absorbable forms provide for enrichment of plants with not only nitrogen, but also phosphorus. Great effect is produced by potassium, which also helps to increase assimilation of phosphorus. Phosphorus, in its turn, does not exert essential influence on the exchange of potassium. Plants absorb almost all potassium from soil in the flowering phase. The lack of potassium also causes a decrease in nitrogen fixation and impedes the growing processes. Low content of this element severely hampers the movement of nitrogen substances and carbohydrates from leaves to seed. Application of phosphoric and potassium fertilizes provides for an increase in the chlorophyll content in leaves and intensified photosynthesis and transpiration. As a result, general plant productivity becomes higher.
Not only simple presence of nutrients is important, but also their ratio which varies depending on various conditions. Significant prevalence of phosphorus against potassium in soil disrupts the exchange of substances and the transition of plants into the stage of reproductive development (Гукова, 1962). Best conditions for high-grade development of lupin are created by an increased supply of potassium and rather low level of phosphoric nutrients. In this respect, application of phosphoric and potassium fertilizers in the required proportions is very important for obtaining a high yield of lupin. It is necessary to take into account that lupin consumes twice more potassium, than phosphorus (Курлович, 1985). Besides, it responds well to magnesium (20 kg/ha), and also to the treatment of seed by micro fertilizers containing iron, molybdenum, boron, cobalt, zinc and manganese. Magnesium contains in the structure of chlorophyll. Its deficiency may lead to premature falling of leaves, breach in nitrogen supplies, and reduction of the efficiency of phosphoric and potassium fertilizers and lime (Магницкий, 1967) Iron also plays an important role during photosynthesis and nitrogen fixation. However, when it is present in excessive amounts, decomposition of chloroplasts is observed (Рубин and Германова-Гавриленко, 1956; Трепачев, 1967).
Molybdenum raises efficiency of symbiosis with nodule bacteria. It is accumulated in roots and nodules. This element is especially effective in neutralizing the negative effect of excessive calcium content in a plant.
Boron also enhances growth of the root system in all legumes. Cobalt makes part of the structure of vitamin B12, stimulating the formation of chlorophyll in plants. Microelements have an essential effect, specifically on the development of generative organs in lupin. Responsiveness of plants to their application depends on the type of soil, dozes and ways of application of fertilizers, and also on specific and varietal features of plants.
Biology of development
Prof. Kuperman (Куперман, 1961, 1977) identified 12 stages of organogenesis in individual development of all angiospermous plants. These 12 stages of organogenesis have also been accepted for lupin (Наймарк, 1976). Description of these stages was given in the following works: Жуков, 1961; Наймарк, 1976; Наймарк and Таранухо, 1982; Пронин et al., 1961; Шалыганова, 1961. At stage I, when the plants are in the phase of cotyledons, there is no differentiation in the apical point of plants. Stage II is characterized by formation of leaves and the rudimentary stalk at the basis of the apical point. At stage III, sheathing leaves are formed, the apical point is extended and its size increases. At stages IV and V, floral tubercles and bracts are developed, and also differentiation in the floral tubercle is observed on the bodies of flowers. At stages VI-IX, the processes of formation of sexual cells and fertilization take place. At stages Х-ХII, the process of sees formation and ripening takes place; then the plants grow older and die. Analysis of visible morphological changes in separate organs and plant habit in lupin development has shown that the process of plant development has a number of phenological phases.
As a result of the study of ontogenesis, the following phenological phases have been described for lupin (Наймарк, 1976): 1) sowing / sprouting; 2) rosette (8-10 leaves in lupin); 3) stem formation / branching; 4) budding; 5) flowering and fruit formation (on the central truss); 6) grain formation / grain plumpness (on the central truss); 7) green ripeness of grain; 8) whitish or waxen ripeness of grain; and 9) yellow, complete, firm or fully ripened stage of grain. Duration of the phases of growth and development depends on genetic features of species and cultivars, soil type, climate conditions, and the level of agriculture.
Sowing / sprouting. The duration of this phase varies in yellow lupin, on the average, from 10 to 16 days (Наймарк, 1976). Such variation depends on the level of daily average temperatures in soil, presence of moisture, and depth of sowed of seeds. Differences between varieties have had no effect on the duration of this phase under identical conditions of cultivation. In this phase, the growing point is on stages I-II of organogenesis.
The phase of rosette (stage II of organogenesis) comes after the complete emergence of young shoots, and lasts depending on the temperature regime, e.g. from 22 to 26 days with cv. Academichesky 1 (L. luteus L.), and from 22 to 31 days with cv. Bystrorastushchy 4 (also L. luteus L.). By the end of this phase, 8-10 leaves are formed, roots penetrate down to 30-35 cm deep, and nodules are developed.
The phase of stem formation / branching begins when plants are coming out of the rosette. This period lasts in different years from 9 to 14 days with cv. Academichesky 1 and 13-23 days with cv. Bystrorastushchy 4 (stages III-V of organogenesis).
The phase of budding is characterized by appearance of flower buds on the central truss and lasts until the beginning of flowering. With cv. Academichesky 1, its duration is 8-9 days, while with cv. Bystrorastushchy 4 it is 10-15 days (stages VI-VII-VIII of organogenesis).
The phase of flowering and fruit formation starts with the opening of the first flower and comes to an end with the development of pods on the central truss. With cv. Academichesky 1 it lasts 9-12 days, and with cv. Bystrorastushchy 4 it is 10-13 days (stage IX). This whole period is delayed in lupin when flowering takes place on lateral branches.
The phase of grain formation / grain plumpness on the central truss (stages X-XI) lasts in yellow lupin for 17-23 days with cv. Academichesky 1, and 16-22 days with cv. Bystrorastushchy 4. After complete plumpness of grain, three phases of ripeness take place, i.e. green, whitish (waxen), and yellow or firm (stage XII of organogenesis).
Green ripeness of grain. This phase lasts 14-18 days with cv. Academichesky 1 and 13-19 days with cv. Bystrorastushchy 4. By the end of this phase, grain cotyledons become firm, and the radicle of the embryo turns white. This is an evidence of physiological maturity of seed. If necessary, it is possible to apply plant defoliants during this phase. In this period, it is also possible to harvest seed with normal germination.
Whitish (waxen) ripeness of grain. This phase lasts 7-12 days. In this period the valves of pods turn dirty-brown, leaves of the main stem and lateral branches of the first order die off, the embryonic radicle in seed becomes yellow, and the seed is completely shaped. The inflow of nutritive substances in seed has not yet stopped, but is considerably slowed down. Such plants are quite suitable for separate harvesting.
The phase of yellow or firm ripeness of grain lasts 5-9 days. In this period, the plants are completely dried up, the pods become brown, and the cotyledons turn yellow (Наймарк, 1976). Essential influence on the duration of certain phases of development and the period of vegetation on the whole is rendered by agro-meteorological conditions, mainly by daily average air temperatures in combination with soil humidity level. Besides, the duration of the vegetation period is determined by a plant genotype.
In Russia and adjacent countries lupin is cultivated basically as a spring crop. Early maturity is an extremely valuable trait that makes it possible to expand the area of cultivation of this crop. As shown by the results of the long-term study of VIR’s lupin collection, the duration of the growth period for summer forms of narrow-leafed lupin sown in spring varies depending on the cultivar, year of planting and place of cultivation with an amplitude from 72 to 170 days. With yellow lupin, this character varies from 90 to 175 days, and with white lupin, from 106 to 180 days. Besides, duration of separate intervals is also signifying. For instance, in yellow lupin the period from young growth to flowering is the longest; in white lupin, on the contrary, it is short, but the period from flowering to maturity is the most drawn out. Great variability of the vegetation period is also observed in different years of cultivation. Narrow-leafed lupin begins to blossom simultaneously with white lupin, and a little earlier than the yellow one. It ripens much earlier then white and yellow forms. In Kiev Province, in damp years yellow lupin has blossomed on the 63rd day after the emergence of young shoots, white lupin on the 45th day, and narrow-leafed lupin on the 62nd day, whereas the duration of the flowering/maturity period in these three forms is respectively 54, 97 and 52 days. Processing of mathematical data of these observations has shown that there is a close positive correlation between the period from young growth to flowering and the whole period of vegetation. Coefficient of correlation (r) is +0.50.
In the environments of Russia, white lupin is the most thermophilous among all cultivated annual species. Its period of vegetation is longer than those of two other species. The study of white lupin collection was conducted in Kiev Province (Ukraine) where accessions were sown in spring sowing and at the former Sukhumi Station of VIR (Abkhazia) where they were planted in autumn. In the conditions of Kiev Province, variability of the vegetation period of early forms was studied, because late accessions do not ripen there. The period of their vegetation varied from 106 to 180 days. Majority of the accessions available in the collection are late-ripening, so they were studied near Sukhumi in autumn plantings. Their vegetation period there showed variation within the range of 230-260 days. Sown in autumn in damp subtropics near Sukhumi, white lupin produced high yield of seeds and green matter. In these environments, the vegetation period also displayed strong variability under different weather conditions (Tab.11).
In the damp subtropics of Abkhazia, the most valuable winter and intermediate forms of white lupin showed an increase in the yield of seed and green matter for green manure. Among them, the most promising are the accessions from France (k-1547), Argentina (k-1582 and 1583), Australia (k-1779 and 1791), and the forms of Georgian ecotype (k.k-1423, 2910, 3292).