SPECIFIC FEATURES OF THE TRACE ELEMENT COMPOSITION OF THE CULTIVATED FLAX AND SOME OF ITS WILD RELATIVES

Controlling the content of trace elements in human food is a major problem. Lack of them, as well as their excess, can seriously affect a person’s health. Commonly, people do not receive enough minerals they need. Though these minerals are found in products of both animal and plant origin, many ethnic groups have a significant preference for plant food, which is very often obtained from cereal plants. Not infrequently, though, these plants are poor in mineral elements, or a specific processing technology depletes a product of minerals. This article shows the content of such trace elements important for people as zinc, copper, cobalt, and nickel in the seeds and leaves of cultivated flax (L. usitatissimum) and its three wild perennial relatives (L. austriacum, L. hirsutum, and L. thracicum). We focus on flax, because, besides containing valuable trace elements, it is also a source of unsaturated fatty acids which are no less important for the human body. To date, there is but little information on the content of certain trace elements in the seeds of cultivated flax, and practically nothing is known about their content in its wild relatives, which are used mainly as decorative verdure. It has been established that the seeds contain 37.1-64.2 mg/kg of zinc, 5.3-9.3mg/kg of copper, 2.9-7.3mg/kg of nickel, and 1.4-3.3mg/kg of cobalt. In the leaves, these trace elements are present in far smaller amounts (1.1-4.3mg/kg). The highest in these trace elements is the wild species L. thracicum, and the lowest is L. austriacum. It has been found that in the plant material of cultivated flax, the ratio of the microelements under study was similar to that in the wild species. Zinc predominates in the flax seeds, but in the leaves, it exceeds other elements only insignificantly. Generally, both cultivated flax and its three wild relatives can be viewed as valuable and worthwhile sources of zinc, cobalt, copper, and nickel.

Inheritance of Plant Habitus Traits in F1 Inter- and Intra-species Hybrids of Oil Flax

The effectiveness of the selection of oil flax is largely dependent on the expansion of genetic diversity due to the attraction of hybrid sources of wild species with n = 15, which easily interbreed with cultivated flax, in particular L. angustifolium, L. hispanicum, bienne, L. crepitans. The aim of the work was to establish the inheritance characteristics of interspecific and intraspecific hybrids of the first generation of quantitative traits of plant habit, which are important economic traits for creating valuable source material and using it in breeding programs with oilseed. The material of the study was the interspecific and intraspecific hybrids of the first generation, obtained by crossing two wild annual homostilous species L. angustifolium, L. hispanicum and three samples of cultivated flax M 32/2 (IOC NAAS), L 5 (Czech Republic) according to the full diallel pattern L 6 (India), contrasting in terms of habitus (height, number of stems and lateral shoots). Studies were carried out at the Institute of Oilseed Crops NAAS in 2017-2018. Hybrids were studied in an F1 hybrid nursery in blocks according to the scheme: maternal form – direct and reverse hybrids F1 – paternal form. Structural analysis was carried out on 10 plants of the parent components and on all F1 plants. The nature of inheritance of habit characters in the first generation of hybrids was determined by the degree of dominance (Beil, Atkins 1965). As a result of studies, it was found that in the inheritance of plant height in interspecific hybrids positive overdomination prevailed (in 41,3%); in intraspecific hybrids – intermediate inheritance (in 50,0%). In the inheritance of the number of stems per plant in interspecific hybrids, intermediate inheritance was predominant (in 47,4%); in intraspecific hybrids, 50% had intermediate inheritance and 50% had negative dominance. According to the trait “number of lateral shoots per plant” in interspecific hybrids, intermediate inheritance was predominant (in 41,2%); in intraspecific hybrids, 50% had positive overdomination and 50% had intermediate inheritance. The degree of dominance of the signs of plant habit depended on the conditions of the year, the genetic characteristics of the experimental material, the trait under study, and the type of crossing (interspecific or intraspecific). For high selection efficiency, the nature of inheritance in each case should be taken into account. Hybrid combinations of M 32/2 / L. angustifolium and M 32/2 / L. hispanicum, which showed heterosis during the years of research on the basis of the number of lateral shoots per plant, are valuable for creating varieties of oil flax with large branching.

Flax latitudinal adaptation at LuTFL1 altered architecture and promoted fiber production

After domestication in the Near East around 10,000 years ago several founder crops, flax included, spread to European latitudes. On reaching northerly latitudes the architecture of domesticated flax became more suitable to fiber production over oil, with longer stems, smaller seeds and fewer axillary branches. Latitudinal adaptations in crops typically result in changes in flowering time, often involving the PEBP family of genes that also have the potential to influence plant architecture. Two PEBP family genes in the flax genome, LuTFL1 and LuTFL2, vary in wild and cultivated flax over latitudinal range with cultivated flax receiving LuTFL1 alleles from northerly wild flax populations. Compared to a background of population structure of flaxes over latitude, the LuTFL1 alleles display a level of differentiation that is consistent with selection for an allele III in the north. We demonstrate through heterologous expression in Arabidopsis thaliana that LuTFL1 is a functional homolog of TFL1 in A. thaliana capable of changing both flowering time and plant architecture. We conclude that specialized fiber flax types could have formed as a consequence of a natural adaptation of cultivated flax to higher latitudes.

Genetic structure of cultivated flax (Linum usitatissimum L.) based on retrotransposon-based markers

Flax (Linum usitatissimum L.) is one of the most important fiber and oil crop plants cultivated since ancient time. The flax seeds contain high amount of omega- 3-fatty acids and biologically active lignans. In spite of economic importance of cultivated flax, no information is available on its genetic variability and population structure in Iran. Therefore, we used six inter-retrotransposon amplified polymorphism (IRAP) markers and 15 combined IRAP markers to reveal within and among population genetic diversity in this crop plant. We used 30 randomly selected plants in three geographical populations for present investigation. AMOVA test produced significant genetic difference (PhiPT = 0.40, P = 0.010) among the studied populations and also revealed that, 40% of total genetic variability was due to within population diversity while, 60% was due to among population genetic differentiation. Gst (0.78, P = 0.001), Hedrick, standardised fixation index (G'st = 0.83, P = 0.001), revealed that the studied populations are genetically differentiated. STRUCTURE plot based on admixture model revealed that the studied populations differed extensively in their genetic content, but some degree of shared alleles occurred between them. Some adaptive IRAP loci were identified by LFMM analysis. These loci were private alleles restricted to geographical populations. Data obtained may be used in breeding and hybridization program of flax in the country.