Alfalfa Genotypes Research Articles

Identification and characterization of regulatory pathways involved in early flowering in the new leaves of alfalfa (Medicago sativa L.) by transcriptome analysis

BackgroundAlfalfa (Medicago sativa L.) is a perennial legume extensively planted throughout the world as a high nutritive value livestock forage. Flowering time is an important agronomic trait that contributes to the production of alfalfa hay and seeds. However, the underlying molecular mechanisms of flowering time regulation in alfalfa are not well understood.ResultsIn this study, an early-flowering alfalfa genotype 80 and a late-flowering alfalfa genotype 195 were characterized for the flowering phenotype. Our analysis revealed that the lower jasmonate (JA) content in new leaves and the downregulation of JA biosynthetic genes (i.e. lipoxygenase, the 12-oxophytodienoate reductase-like protein, and salicylic acid carboxyl methyltransferase) may play essential roles in the early-flowering phenotype of genotype 80. Further research indicated that genes encode pathogenesis-related proteins [e.g. leucine rich repeat (LRR) family proteins, receptor-like proteins, and toll-interleukin-like receptor (TIR)-nucleotide-binding site (NBS)-LRR class proteins] and members of the signaling receptor kinase family [LRR proteins, kinases domain of unknown function 26 (DUF26) and wheat leucine-rich repeat receptor-like kinase10 (LRK10)-like kinases] are related to early flowering in alfalfa. Additionally, those involved in secondary metabolism (2-oxoglutarate/Fe (II)-dependent dioxygenases and UDP-glycosyltransferase) and the proteasome degradation pathway [really interesting new gene (RING)/U-box superfamily proteins and F-box family proteins] are also related to early flowering in alfalfa.ConclusionsIntegrated phenotypical, physiological, and transcriptomic analyses demonstrate that hormone biosynthesis and signaling pathways, pathogenesis-related genes, signaling receptor kinase family genes, secondary metabolism genes, and proteasome degradation pathway genes are responsible for the early flowering phenotype in alfalfa. This will provide new insights into future studies of flowering time in alfalfa and inform genetic improvement strategies for optimizing this important trait.

Adaptability, forage yield and nutritional quality of alfalfa (Medicago sativa) genotypes

Livestocks fed with high-quality forage deliver better milk and meat, which could benefit the nutritional health of their keepers and consumers. Six alfalfa genotypes were assessed across four loca...

Analysis of Variability, Heritability, and Genetic Advance in Yield and Quality Traits of Alfalfa (Medicago Sativa L.) Genotypes

Analysis of Variability, Heritability, and Genetic Advance in Yield and Quality Traits of Alfalfa (Medicago Sativa L.) Genotypes

Evaluation of alfalfa genotypes by seed productivity for drought resistance

Evaluation of alfalfa genotypes by seed productivity for drought resistance

Питательная ценность люцерны различных сортов в процессе роста и развития

В статье представлены материалы отечественных и зарубежных авторов, характеризующие биологические особенности люцерны в зависимости от фазы развития, сортовой принадлежности и в сравнении с другими культурами. В решении проблемы производства энергонасыщенных высокобелковых кормов ей отводится важная роль. Люцерна (Medicago sativa) является важнейшей кормовой и самой распространённой культурой в мире. Она отличается высокой урожайностью, ценными кормовыми характеристиками по протеиновой, витаминной и минеральной питательности. В России площадь посевов люцерны достигает 2,3–2,5 млн га. Онa широко выращивается на территории Центрального и Приволжского экономических районов. Люцерна превосходит многие бобовые и злаковые культуры по содержанию питательных веществ и занимает одно из главных мест в кормопроизводстве Российской Федерации для использования в зелёном конвейере и приготовления сена, сенажа и силоса. Авторами отмечается высокое содержание сырого протеина (в пределах 18–20%) в сочетании с богатым составом аминокислот и омега-3 жирных кислот и энергией (9,9–10,8 МДж в сухом веществе), а также высокое содержание макро- и микроэлементов. В статье проведён обзор научных исследований по оценке питательности люцерны в зависимости от фазы роста, установлено увеличение содержания НДК и КДК в период от бутонизации до полного цветения, снижение содержания протеина, водорастворимых углеводов и переваримости органического вещества. В настоящем обзоре представлены сведения о содержании питательных веществ в листьях и стеблях и отмечены различия в зависимости от сорта растения. Результаты исследований питательной ценности различных сортов люцерны в России, Турции, Польше, Болгарии и Эфиопии показали высокую вариабельность по содержанию сырого протеина, НДК, КДК, сырой золы, сырого жира и переваримости сухого вещества. This paper reports on the biology of alfalfa genotypes at different growth stages described by domestic and foreign literature. Alfalfa has a good potential as a source of high-protein and high-energy feed. Alfalfa (Medicago sativa) is widely cultivated for forage all over the world. This crop has high productivity and is rich in protein, vitamins and mineral elements. In Russia alfalfa fields occupy 2.3–2.5 million ha. Alfalfa is one of the most important crops in the Central and Volga regions. It exceeds most legumes and gramineous in nutritional value and is extensively used for green forage, hay, haylage and silage production. Alfalfa has high concentration of crude protein (18–20%), energy (9.9–10.8 MJ in dry matter), amino acids and omega-3 fatty acids as well as macro- and microelements. The article reviews alfalfa nutritional value as affected by growth stage. Contents of neutral detergent fiber (NDF) and acid detergent fiber (ADF) increases at budding-flowering period while concentrations of protein and water-soluble carbohydrates drops together with organic matter digestibility. This review provides information on leaf and stem nutrients effected by genotype. According to experiments conducted in Russia, Turkey, Poland, Bulgaria and Ethiopia alfalfa genotypes vary significantly in crude protein, NDF, ADF, crude ash, crude fat and dry matter digestibility.

Physiological traits involved in grazing tolerance of alfalfa genotypes

Alfalfa [1] is one of the most largely distributed forage legume species in the world and it is used on more hectares than any other forage legume. Even so, alfalfa production in Brazil is still limited by the low persistence of this species, especially when used for grazing. Therefore, the objective of this study was to evaluate and select grazing-tolerant germplasm by evaluating genotypes based on their physiological traits. Eight alfalfa genotypes were grown in two different and simultaneous experiments. The experiment ‘A’ evaluated physiological traits: a) chlorophyll content b) sum of lateral roots and shoot and c) length of the first internode The experiment ‘B’ consisted of a jasmonate treatment, which induced remarkable effects on alfalfa roots performance. The CRAltR genotype showed the most promising results for length of the first internode 0.429 cm at the last day of evaluation (day 15). Furthermore, this genotype obtained higher rates in the evaluation of chlorophyll. E1C4AltR in addition to being selected in previous studies for grazing tolerance showed variability for decumbent habit and intermediate values for chlorophyll. The genotypes E1C4 AltR and CRAltR presented more promising results and they will be used for further field evaluations in Brazil.

Gross Margin Analysis of Alfalfa (Medicago sativa L.) Genotypes As Influenced By Sowing Dates

In this study the economic performance of different sowing times of alfalfa cultivars were examined. Plots were established in 2015-2017 period, in the area of Siirt University, Faculty of Agriculture, Department of Field Crops,in Turkey. The randomized split block experimental design with three replications was applied in the study. Main plots were consisted from the genotypes and the subplots were consisted from the sowing times. The experimental material comprised of four alfalfa genotypes, three different planting times. The gross margin analysis were used to analyse the data for the study. Gross margin, indicator per unit area was used to evaluate of production success level and compare economic efficiency of different dates of planting for alfalfa genotypes. Kolmogorov-Smirnov test used for data normality test and analysis of variance used to analyze the differences between group means. As a result, maximum gross margin was obtanied at Magnum V planted on 5th April (D2) in 2017, while Nimet planted on 30th April (D3) in 2015 have the minimum gross margin (-13.61).

ITRAQ-based comparative proteomic analysis of differences in the protein profiles of stems and leaves from two alfalfa genotypes

BackgroundTo explore the molecular regulatory mechanisms of early stem and leaf development, proteomic analysis was performed on leaves and stems of F genotype alfalfa, with thin stems and small leaves, and M genotype alfalfa, with thick stems and large leaves.ResultsBased on fold-change thresholds of > 1.20 or < 0.83 (p < 0.05), a large number of proteins were identified as being differentially enriched between the M and F genotypes: 249 downregulated and 139 upregulated in stems and 164 downregulated and 134 upregulated in leaves. The differentially enriched proteins in stems were mainly involved in amino acid biosynthesis, phenylpropanoid biosynthesis, carbon fixation, and phenylalanine metabolism. The differentially enriched proteins in leaves were mainly involved in porphyrin and chlorophyll metabolism, phenylpropanoid biosynthesis, starch and sucrose metabolism, and carbon fixation in photosynthetic organisms. Six differentially enriched proteins were mapped onto the porphyrin and chlorophyll metabolism pathway in leaves of the M genotype, including five upregulated proteins involved in chlorophyll biosynthesis and one downregulated protein involved in chlorophyll degradation. Eleven differentially enriched proteins were mapped onto the phenylpropanoid pathway in stems of the M genotype, including two upregulated proteins and nine downregulated proteins.ConclusionEnhanced chlorophyll synthesis and decreased lignin synthesis provided a reasonable explanation for the larger leaves and lower levels of stem lignification in M genotype alfalfa. This proteomic study aimed to classify the functions of differentially enriched proteins and to provide information on the molecular regulatory networks involved in stem and leaf development.

EVALUATION AND SELECTION OF SOME ALFALFA GENOTYPES FOR HIGH FORAGE YIELD AND PROTEIN

Twenty five genotypes of alfalfa were evaluated for forage and dry yields and protein content at Nubaria Research Station. Planting was carried out at October, 5th 2011, and data were taken during the three years 2012, 2013 and 2014. Data of green and dry forage yields and protein content were collected for four seasons in each year during the three years. Results indicated highly significant differences among genotypes for all traits. Dry forage yield and protein content of the studied genotypes had a highly significant reliance on years and seasons. The values of genotypic coefficient of variation (GCV%) and phenotypic coefficient of variation (PCV%) were 6.48 and 6.89% for green forage yield, 5.72 and 7.53% for dry forage yield and 1.43 and 1.73 % for protein percentage, respectively. Broad-sense heritability for green forage yield was 88.38% which was higher than that for dry forage yields and protein content (57.58% and 68.81%), respectively. The average of expected genetic advance value for total green forage yield, total dry yield and protein content were 8.52, 6.06 and 1.65%, respectively. The population G.15 showed common superiority over other populations (46.163, 48.163 and 55.939 t/ha, in the first, second and third year, respectively) in the summer season. In the context, G.5 showed common superiority in the autumn (24.233 and 26.233 t/ha in the first and the second years, respectively) While, G.3 was the best for previous trait (35.135 t/ha) in the third year in autumn season. It could be concluded that, the genotypes G.15, G.3, G.9 and G.14 are promising to improve green and dry forage yield and protein content and could be used to produce as available a new variety via further breeding programs

Synchrotron-radiation sourced SR-IMS molecular spectroscopy to explore impact of silencing TT8 and HB12 genes in alfalfa leaves on the molecular structure and chemical mapping.

Advanced synchrotron-based vibrational molecular spectroscopy (SR-IMS) has been developed to image molecular chemistry in biological tissues within cellular and subcellular dimension. However, it is seldomly used in gene-transformation and gene-silencing study. The objectives of this study were to apply synchrotron-based vibrational molecular spectroscopy (SR-IMS) to determine the molecular structural changes and chemical mapping of alfalfa leaves induced by silencing of TT8 and HB12 genes in alfalfa in comparison with wild type of alfalfa. Five alfalfa leaves from each alfalfa genotype were selected for FTIR spectra collection and chemical mapping with synchrotron-based FTIR microspectroscopy (SR-IMS). Peak heights and areas of empirical regions were analyzed, and peak areas of previous regions were mapped for each sample using OMNIC 7.3. Results showed that transformed alfalfa had higher peak height and area of carbonyl CO (CCO), compared with wild type (WT). Chemical groups maps for carbohydrate, amide and lipid-related regions were successfully obtained. HB12-silenced (HB12i) had higher carbohydrate intensity both in the mesophyll and epidermises, whereas TT8-silenced (TT8i) and WT only had higher carbohydrate spectral peak intensity in epidermises. In addition, HB12i had higher CCO intensity and lower lignin intensity compared with TT8i and WT. All alfalfa genotypes had higher intensity of amide and asymmetric and symmetric CH2 and CH3 (ASCC) area in mesophylls. In conclusion, silencing of HB12 and TT8 genes in alfalfa both increased CCO profiles of alfalfa leaves, while silencing of HB12 had more impacts on chemical localization in alfalfa leaves.

Evaluation of indigenous Omani alfalfa landraces for morphology and forage yield under different levels of salt stress.

Alfalfa is the major fodder crop of Sultanate Oman, but salinity is a major problem in its cultivation. Therefore, thirty-four alfalfa (Medicago sativa L.) landraces of Oman were evaluated for morphology and forage yield response to different salinity levels viz. 1 (control), 3, 6, 9, and 12 dS m-1 under greenhouse conditions. The experiment was conducted under a completely randomized design. Different alfalfa landraces responded differently to the five salinity levels for plant height, number of branches, number of leaves, leaflet width, leaflet length, forage fresh weight, and forage dry matter yield. Salt stress caused a reduction in growth and dry matter yield of alfalfa landraces with exception of some, which responded positively to the salinity levels of 3 and 6 dS m-1 compared to control for the number of leaves per plant. Moreover, some landraces had better forage fresh weight and dry matter yield at 6 dS m-1 than 3 dS m-1. Alfalfa landraces OMA 257, OMA, 245, OMA 270, OMA 315, OMA 211, OMA 117, OMA 56, OMA 239, OMA 148, OMA 131, OMA 95, OMA 263, OMA 262, OMA 289 and OMA 220 were designated as salt tolerant based on their overall performance across salinity levels of 6, 9 and 12 dS m-1. However, the landraces OMA 305, OMA 100, OMA 211, OMA 148, OMA 60, OMA 248, OMA 9, OMA 88, and OMA 302 collected were sensitive to 6, 9 and 12 dS m-1 salinity stress. The study showed the variation of alfalfa landraces potential for salinity tolerance, and their potential for cultivation in saline areas and/or use in breeding programs aimed to develop salt tolerant alfalfa genotypes.

Quantitative trait locus mapping of yield and plant height in autotetraploid alfalfa (Medicago sativa L.)

Alfalfa (Medicago sativa L.) is the most widely grown forage legume crop worldwide. Yield and plant height are important agronomic traits influenced by genetic and environmental factors. The objective of this study was to identify quantitative trait loci (QTL) and molecular markers associated with alfalfa yield and plant height. To understand the genetic basis of these traits, a full-sib F1 population composed of 392 individuals was developed by crossing a low-yielding precocious alfalfa genotype (male parent) with a high-yielding late-maturing alfalfa cultivar (female parent). The linkage maps were constructed with 3818 single-nucleotide polymorphism (SNP) markers on 64 linkage groups. QTL for yield and plant height were mapped using phenotypic data for three years. Sixteen QTL associated with yield and plant height were identified on chromosomes 1 to 8. Six QTL explained more than 10% of phenotypic variation, representing major loci controlling yield and plant height. One locus on chromosome 1 controlling yield traits had not been identified in previous studies. Three QTL co-located with other QTL (qyield-1 and qheight-7, qheight-5 and qyield-4, qheight-6, and qyield-6). With further validation, the markers closely linked with these QTL may be used for marker-assisted selection in breeding new alfalfa varieties with high yield.

Сравнительная характеристика образцов люцерны в питомнике конкурсного сортоиспытания

Люцерна имеет большое значение в системе устойчивого сельского хозяйства, обеспечивая получение высокопитательных кормов (сена, силоса, сенажа, зелёного корма). Высокая отавность люцерны позволяет даже в Нечерноземье ежегодно получать по три укоса зелёной массы с содержанием в сухом веществе 1424 сырого протеина. При возделывании этой многолетней культуры не требуется внесения азотных удобрений, поскольку она сама пополняет почву азотом. Люцерна обладает устойчивостью к засухе, благодаря мощной корневой системе и высокой густоте стояния травостоев она хорошо защищает почву от эрозии. В условиях увеличения засушливости климата возникает необходимость расширения её посевов в северных регионах страны. В настоящее время необходимо создание сортов люцерны с хорошей адаптацией к современным экологическим условиям, а также улучшение развития семеноводства этой культуры. Часто растения люцерны в высокой степени подвержены поражению болезнями и вредителями. Поэтому для специалистов ВНИИ кормов по селекции люцерны важным является создание перспективного исходного материала, а на заключительном этапе новых сортов многоукосного, сенокосного и пастбищного типов использования с высокой кормовой и семенной продуктивностью, устойчивостью к основным болезням и неблагоприятным факторам среды в условиях Нечернозёмной зоны. В статье приведены результаты оценки образцов люцерны изменчивой в 20142018 годах в питомнике конкурсного сортоиспытания по показателям зимостойкости, продуктивности кормовой массы, питательной ценности, устойчивости к основным болезням и др. Наиболее перспективными можно считать образцы СГП 12, СГП 387, превышающие стандарт (сорт Луговая 67) по продуктивности зелёной массы соответственно на 8,3 и 12,0, продуктивности сухой массы на 14,2 и 12,4, высоте на 3,511,6, устойчивости к болезням (развитие бурой пятнистости, увядания и корневой гнили в среднем на 10,030,0 менее стандарта). Даны рекомендации для селекционной практики. Being a valuable crop for sustainable agriculture alfalfa is cultivated to produce highly nutritious feeds (hay, silage, haylage, green fodder). Regrowing fast it provides three cuts of green mass with 1424 of crude protein even in the Non-Chernozem region. The crop requires no nitrogen application since it obtains its own nitrogen from soil. Alfalfa shows resistance to drought and prevents erosion due to heavy root system and high plant density. It is necessary to breed novel alfalfa varieties adapted to current weather conditions as well as to increase its seed production. Diseases and pests often affect alfalfa significantly. Therefore, it is important to develop new promising parent lines and high-productive resistant varieties for multiple cutting, hay, and green fodder production in the Non-Chernozem region. This paper reports on winter hardiness, forage mass yield, nutritional value, and resistance of bastard alfalfa genotypes in 20142018. SGP 12 and SGP 387 lines performed the best and exceeded the standard variety (Lugovaya 67) in green mass by 8.3 and 12.0, dry mass by 14.2 and 12.4, height by 3.511.6, respectively. They showed higher tolerance to brown spot, wilt, and root rot by 10.030.0. Additionally, the paper contains breeding recommendations.

Impact of water deficit in the relationship among alfalfa traits

This study aimed to evaluate the relationship among traits related to yield and nutritive value of alfalfa genotypes grown under deficit and full irrigation conditions. Seventy-seven alfalfa genotypes were evaluated in two different cuts, the first one with full irrigation, and the second, with water deficit. A randomized block design with three replications was used. The evaluated traits were vigor, plant height, dry matter biomass, stem-to-leaf ratio, dry matter percentage, leaf and stem protein contents, in vitro dry matter digestibility, neutral detergent fiber, acid detergent fiber, and lignin. Significant interaction between genotypes and environments was reported for vigor, plant height, and lignin. The correlation between traits and path analysis of dry matter biomass was performed for each cut, aiming to identify auxiliary traits for indirect selection. Water availability did not alter the phenotypic and genotypic correlations, only their magnitudes. Regardless of the environment, plant height is one of the most promising traits for the selection of alfalfa genotypes with higher dry matter biomass since it showed a high direct effect in the same sense of its phenotypic correlations. However, the coefficient of determination obtained by the model applied to full irrigation was higher than that of the water-deficit environment, indicating the importance of variables not included in this study in the determination of alfalfa dry matter biomass under dry conditions.

Yield and quality changes in lucerne of different fall dormancy ratings under three defoliation regimes

Abstract This study determined how fall dormancy rating (FD2, FD5 or FD10) of lucerne genotypes affected crop yield and quality. One field experiment was measured for three growing seasons as a seedling crop and then three defoliation frequency regimes (DF) of 28 (DF28), 42 (DF42) or 84 (DF84) days were imposed (October 2014 to April 2017). Annual shoot dry matter (DM) yields ranged from 5.2 t DM/ha in DF28 crops to 17.5 t DM/ha in DF84 crops. Higher shoot DM was associated with greater shoot elongation which was modified by photoperiod (Pp). In an increasing Pp environment, the rate of DM accumulation in shoots was ∼ 91 kg/ha for each 1.0 cm increase in shoot height. In a decreasing Pp environment, the rate of DM accumulation in shoots was constant at ∼50 kg/ha/cm. In the DF84 crops, shoot yield declined due to leaf senescence by ∼31 kg/ha/cm when lucerne was ≥65 cm height. The leaf stem ratio (LSR) declined by 0.56 for each 1.0 cm increase in plant height. The crude protein (CP) and metabolisable energy (ME) accumulation in whole shoots or in leaf, soft stem and hard stem followed an allometric relationship. As DM increased, CP and ME increased in a similar pattern for all treatments. Thus the relationship between the yield and quality of lucerne was independent of genotype and phenological stage and was explained allometrically by the leaf and stem ratio, associated with changes in plant height, as affected by photoperiod. These results suggest universal defoliation management strategies can be developed based on ontogeny and independently of genotype, growth stage and growing conditions.

The reaction of self-fertile alfalfa lines to inoculation with nodule bacteria

Under the conditions of a model pot experiments, the reaction of the self-fertile lines of alfalfa Kishvardy 46, Kishvardy 27, Vertus and Ziguen to inoculation with nodule bacteria Sinorhizobium meliloti AC48 and AC88 was studied. As a result of studies, it was found that the intensity of assimilation of N2 by symbiotic systems created with the participation of various genotypes of alfalfa and active strains of S. meliloti is one of the main factors that affects the vegetative mass yield of this important forage crop. Self-fertile lines of Medicago sativa L. plants, inoculated with different strains of rhizobia were characterized by higher rates of the mass formed on the root nodules, compared to the control plants of the alfalfa variety Yaroslavna. The traditional dynamics of nitrogen-fixation activity of root nodules was maintained in all the symbiotic systems studied by us, with low values in the stems formation stage and intensive growth in the budding and flowering stages. The highest level of nitrogen fixation and vegetative growth of plants (values of plants green and dry mass, roots and root nodules mass) was established by inoculation of alfalfa line Kishvardy 46 with strain S. meliloti AC48. During the growing season the indices of the mass of nodules formed on the roots of these plants were higher by 1.8–2.3 times, the green mass by 1.2–1.6 times and the height of the plants 1.2–1.4 times as compared to the control. In the flowering stages the nitrogen-fixation activity of the symbiotic complex of plants of the Kishvardy line 27 and nodule bacteria S. meliloti AC48 exceeded the values in the symbiotic systems formed with the participation of the same strain and plants of the Ziguen and Vertus lines by 13.0 and 39.4 %. The lowest values of nitrogen fixation activity were observed by inoculation of plants of the Vertus and Ziguen lines with active strains S. meliloti AC48 and AC88 compared to the symbioses formed by the plants of the Kishvardy lines 27 and 46, as well as of the control-variety Yaroslavna with the noted strains. A stimulating effect of inoculation of alfalfa seeds of different genotypes on the growth and development of plants was noted, as evidenced by the positive dynamics of the increase in above-ground mass, the accumulation of dry matter and higher than the control values (indicators) of plant height during the growing season.

Variability of symbiotic characters in alfalfa genotypes

Variability of symbiotic characters in alfalfa genotypes

Effects, tolerance mechanisms and management of salt stress in lucerne (Medicago sativa)

Lucerne (alfalfa, Medicago sativa L.) is a forage legume that is widely cultivated in arid and semi-arid regions of the world. The main aim of this review was to highlight the effects of salt stress on the performance of lucerne and to suggest different tolerance mechanisms and management strategies for improving its yield under salt stress. Salt stress significantly affects seed germination, carbon fixation, light harvesting, biological N2 fixation, mineral uptake and assimilation and dry-matter accumulation in lucerne. Accumulation of osmolytes or compatible solutes such as proline, polyamines, trehalose and soluble sugars confers salt tolerance in lucerne. Maintenance of low Na+:K+ ratios, antioxidant enzyme activation, and hormonal regulation also help lucerne to withstand salt stress. The screening of diverse genotypes on the basis of germination indices, gas exchange, biomass production, lipid peroxidation and antioxidant enzymes might be useful for breeding salt-tolerant lucerne genotypes. Novel biotechnological tools and functional genomics used to identify salt-conferring genes and quantitative trait loci will help to improve salt tolerance. Use of rhizobial and non-rhizobial plant growth-promoting bacteria, arbuscular mycorrhizal fungi, exogenous application of osmoprotectants, and seed priming with brassinolide, gibberellic acid and salicylic acid may help to improve lucerne performance in saline environments.

Genetic diversity of salt tolerance in tetraploid alfalfa (Medicago sativa L.)

Alfalfa (Medicago sativa L. subsp. sativa) is the most cultivated perennial forage crop worldwide. It is an autotetraploid (2n = 4x = 32), out-crossing species and it has potential to be cultivated in marginal lands affected by salinity. In this study, genetic diversity for salt tolerance was explored in 36 alfalfa genotypes from continental (15 genotypes) and coastal regions (21 genotypes), under salt stress of 150 mM NaCl. Also, characters and mechanisms that can be used to increase yield under saline conditions were investigated. All genotypes were clonally propagated into 144 seedlings (four plants/genotype) and designed in a randomized complete block under greenhouse conditions. Twelve tolerance traits were scored; fresh and dry aboveground biomasses, stem length, leaf number, [Na+], [K+], K+/Na+ ratio, catalases and superoxide dismutases, proteases, protein and reducing sugar in leaves. Stress tolerance index was calculated for each genotype. High significant variation was found among genotypes and treatments for fresh and dry matters. All genotypes had [Na+] in shoots significantly higher in stressed plants than in control plants and low K+/Na+ ratios, signifying the use of Na+ “inclusion mechanism” to prevent salt stress. The increase in catalase activity in shoots under salt condition demonstrates that this antioxidant enzyme could be playing an essential role in the tolerance mechanism. In contrast, it seems that alfalfa tolerance system to cope salt stress is not related to protease, superoxide dismutase, and proteins accumulation. Based on salt tolerance index and PCA analysis, three tolerant genotypes from coastal origin were selected that can be prominent sources for breeding program of alfalfa.

Balanced Parameters for Genotype X Environment Interaction in Some Alfalfa Genotypes

Identification of alfalfa genotypes, with high yield potential and good forage quality along with the least seasonal fluctuation over a wide range of environments, is important for crop improvement programs. Trials were conducted to evaluate seven alfalfa (Medicago sativa, L) genotypes over three years at the Nubaria Agricultural Research Station Site. Field experiments were carried out in 2014, 2015 and 2016 seasons to evaluate fresh and dry forage yield, protein and fiber percentages and their stability employing parametric and non-parametric measures for the seven genotypes across environments. Results indicated that the local cultivar Ismailia-1 was superior to the introduced genotypes regarding its fresh and dry forage yield in addition to recording the least fiber percentage; however, MI reya produced higher protein percentage. When stability measures for the four traits was considered, Isamilia-1 was considered the most stable for fiber percentage based on four different measures tested. MI reya was most stable for protein percentage and more stable than Ismailia-1 for fresh and dry forage yield based on estimates from larger number of the tested stability measures, suggesting that MI reya is the most promising genotype among the introduced genotypes under study.