For the first time, the authors assessed and mapped the chromosome QTLs (Quantitative Trait Loci) for the manifestation of morpho-physiological and agronomic indices of plant water status and related quantitative traits, such as plant height, weight, and dry matter content in spring bread wheat (Triticum aestivum L.). Following the study of ten agronomic traits, 13 QTLs were mapped on linkage groups 1A, 1B, 2B, 2D, 4A, 5A, 5B, 5D, 6A, and 6D. Some of the identified QTLs concurrently determined several traits. The physiological components of water status were shown to correlate with quantitative traits in wheat plants, such as plant height, weight, and dry matter content, and the correlation coefficients were calculated for all traits under study. Water retention capacity after 3 h correlated with water retention capacity after 24 h (r xy = 0.47). The correlations were also established between water retention capacity after 3 h and plant height at booting stage (r xy = 0.29) and between water retention capacity after 3 h and plant dry weight (r xy = 0.33). Statistical calculations supported generally observed negative correlation (up to −1) between leaf water and dry matter contents, as well as between the root indices of variance in the mapping population of wheat lines. The results obtained in the present study will promote future efforts to fine-map the genes residing within the identified QTLs, to eventually clone these genes in order to establish the physiological mechanisms for maintaining water homeostasis in higher plant cells and to accomplish the practical implementation of marker-assisted assessment of water status in wheat plants studied on the basis of morpho-physiological and economical indices.

Впервые проведена оценка и физиолого-генетическое картирование локусов хромосом – QTL (Quantitative Trait Loci), отвечающих за проявление морфо-физиологических и основных параметров водного статуса растений и связанных с ними количественных признаков высоты, массы и содержания сухого вещества у яровой мягкой пшеницы (Triticum aestivum L.). В результате проведенных исследований по 10 изученным признакам было выявлено 13 QTL, расположенных на 1А, 1В, 2В, 2D, 4A, 5A, 5B, 5D, 6A и 6D группах сцепления. Некоторые из идентифицированных QTL определяли проявление нескольких признаков. Выявлены корреляционные связи физиологических составляющих водного статуса с количественными признаками высоты, массы и содержания сухого вещества у растений пшеницы и установлены коэффициенты корреляции для всех изученных признаков. Показана положительная средняя корреляция между признаками “водоудерживающая способность через 3 ч” и “водоудерживающая способность через 24 ч” (rxy = 47). Установлены корреляции между водоудерживающей способностью через 3 ч и высотой растения на стадии трубкования (rxy = 29), а также между водоудерживающей способностью через 3 ч и массой растения (rxy = 33). Статистические расчеты подтвердили наблюдавшиеся отрицательные корреляционные связи, значения которых близки к –1, между оводненностью листьев и содержанием сухого вещества в целом, а также по вариационным показателям корней линий картирующей популяции пшеницы. Полученные в настоящей работе результаты имеют ключевое значение для последующего проведения тонкого картирования генов, расположенных внутри выявленных QTL, их возможного клонирования с целью установления физиологических механизмов поддержания водного гомеостаза в клетках высших растений и практического осуществления маркер-вспомогательной оценки водного статуса растений пшеницы по изученным морфо-физиологическим и практически значимым признакам.

For the first time a set of 110 recombinant inbred lines of a spring wheat mapping population was evaluated in different ecogeographical regions of Russia. Thirty-nine economically important traits that manifest themselves at different stages of growth have been examined in each ecogeographical locality under study for five years. A total of 186 quantitative trait loci (QTL) with LOD scores above 2,5 were identified. We have determined 97 QTLs with LOD scores exceeding 3,0. QTLs for traits studied, mapped on 21 chromosomes, manifested themselves under contrasting environmental conditions with varying degrees of reliability. It has been shown that manifestation of identified QTLs can depend or not depend on the environment, but the evaluated quantitative traits interact and correlate with each other. Relationships of identified homologous and homoeologous QTLs with known major genes or QTLs responsible for the manifestation of the studied traits in wheat or other Triticeae genera are discussed. The identified QTLs may be of interest for further experiments on the genetic control of the corresponding agriculturally valuable traits and for marker assisted selection in wheat breeding.

For the first time, a set of 110 recombinant inbred lines of a spring-wheat mapping population were evaluated in different ecogeographical regions of Russia. Thirty-nine economically important traits that manifest themselves at different stages of growth have been examined in each ecogeographical locality under study for 5 years. A total of 186 quantitative trait loci (QTLs) with LOD scores above 2.5 were identified. We have determined 97 QTLs with LOD scores exceeding 3.0. The QTLs for traits were studied, mapped onto 21 chromosomes, and manifested themselves under contrasting environmental conditions with varying degrees of reliability. It has been shown that the manifestation of identified QTLs can depend or not depend on the environment, but the evaluated quantitative traits interact and correlate with each other. The relation-ships between identified homologous and homeologous QTLs with known major genes or QTLs responsible for the manifestation of the studied traits in wheat or other Triticeae genera are discussed. The identified QTLs may be of interest for further experiments on genetic control of the corresponding agriculturally valuable traits and for marker-assisted selection in wheat breeding.

The maximum grain productivity can be achieved only taking into account plant biological needs. The need in mineral nutrients depends on the plant hereditary nature and environmental conditions. The greatest demand for nitrogen is characteristic in cereals for spring and winter wheat, the lowest one for barley and rye. The use of mineral nutrients in amounts exceeding plant needs does not result in yield increasing and can worsen the production quality. We were studying reaction of spring bread wheat (Triticum aestivum L.) genotypes to changes in nutrition soil conditions. In the experiment, ITMI mapping population consisting of 110 recombinant inbred lines was evaluated for a number of morphological, biological and economically important traits under different levels of the nitrogen supply. To create different soil nutrition level and to prevent leaching of fertilizers during the plant vegetation season we prepared trenches with depth 0.4 m, width 1 m and length 20 m; the bottoms of which were covered with plastic films. The trenches were filled with soil from the lower soil horizons. In first variant of the experiment, nutrient mixture on the basis of the physiological rate for cereals (N – 0.15 g, P - 0.1 g, K - 0.1 g of active substances per 1 kg of dry soil) was applied. In the second variant, nitrogen dose was reduced half with the same phosphorus and potassium doses. Variant without fertilizers applying was used as a control. Thirty nine characters were analyzed during the all growing season. The combination of field and vegetation experiment conditions allowed approximating maximally to real conditions of the experiment and at the same time to control strictly plant vegetation. QTLs identified in our study can be differentiated as dependent and independent on environmental conditions. For example, some QTLs controlling such traits as a wax bloom, phenological phases, etc. are stable under different conditions of soil nutrition. QTLs of traits determining the yield structure were unstable and changed their locations on chromosomes under different conditions of nitrogen supply. The most of identified QTLs changed their locations at different nitrogen doses, and in some cases additional QTLs were found which also influenced to a particular trait expression. The activity of genes blocks determining the physiological and morpho-agronomical and biological quantitative traits was experimentally shown to depend on the mineral nitrogen doses. Identification of chromosomal loci involved in the nitrogen metabolism allows planning more accurately breeding programs directed to increase the plants productivity.