Cereal Research Communications

The objectives of this study were (a) to compare the effectiveness of the two methods of pedigree selection in barley: the ear-to-row classical pedigree method and the honeycomb method and (b) the evaluation of the selection criteria of the honeycomb methodology. Five F12 lines developed by classical pedigree method were used as checks in order to compare seven lines developed by honeycomb methodology. Five honeycomb pedigree lines were selected by PYI basic selection criterion of honeycomb methodology and two more (rejected by PYI) were selected by YC, a new criterion proposed for improving selection of high yielding plants in honeycomb design. Also, the original local population from which all these lines were derived and two commercial barley cultivars were used as the basic checks. All genotypes selected by classical and honeycomb pedigree method out yielded the original local population. Many of them reached or out yielded the commercial cultivars used as checks and thus both classical and honeycomb pedigree methods were able to promote some homozygous genotypes in order to be used as new cultivars. Yield performance of progeny lines selected by classical pedigree method was better than honeycomb’s. Only when YC was used as selection criterion honeycomb pedigree lines showed high yielding performance. Comparing PYI and YC selection criteria, it seems that the second is better for promoting high yielding and stable lines for next generations to be used as future new cultivars. Grain yield and bulk density are safer traits than 1000-kernel weight, for efficient selection that ensures high and stable yields.

Contribution to yield of cereals has traditionally been studied using yield and various yield components, thus neglecting the role of other organs such as ear awns and flag leaf. Here, we studied the effects of genotypes on the photosynthetic activity of the flag leaf blade and the ear awns of spring wheat. The parameters related to the photosynthetic activity were analyzed in relation to the grain yield and various yield components at maturity. In the present study, ten wheat varieties/lines were tested to find out the effects of flag leaf and ear awns detachment on grain yield. There was much genetic variability among different varieties/lines for different traits. Awns detachment exhibited less effect on yield and yield related characters as compared to flag leaf detachment, while detachment of both had more significant effects than individual treatment. Flag leaf area and some other components showed positive and significant correlation with grain yield. Which suggested that flag leaf + awns might be used a morphological marker, while selecting wheat varieties/lines for good photosynthetic activity and high yield.

The aim of this study was to find genetic variability within established cultivars of barley, bread and durum wheat, after applying salinity stress for five years. Bread wheat varieties Irnerio, Generoso and Yecora, together with durum wheat varieties Mexicali81, Simeto and Bob, and barley varieties Athinais and Cannon were used. For this purpose, certified seed of the above-mentioned varieties was sown in pots containing a mixture of soils salinized by different quantities of salt. Following a certain experimental scheme that produced progressively new treatments at the same or higher salinity level and after five cycles of evaluation, there were formed new seed partitions for final evaluation under honeycomb designs. The results showed that wheat and barley genomes are quite flexible, allowing selection within variety for certain agronomic performance. Salt stress proved to be a serious stress for the health of evaluated plants (for all species) and thus, we were not able to discover genotypes exhibiting salt tolerance. Seed germination and plant yield declined rapidly at higher concentrations of salt. In spite of this, comparing two-year honeycomb experimental data, these stress conditions resulted indirectly to drought tolerance (due to the flexibility of genomes for species used), confirmed from additional data after evaluation of barley varieties in pots. The genetic mechanism for such phenotypic behavior remains to be studied.

The High Molecular Weight Glutenin Subunits (HMW GS) in bread wheat landraces were studied using the SDS-PAGE technique. Out of the 32 landraces, 23 were homogeneous while nine showed heterogeneity with respect to the HMW glutenin subunits. Novel variants were observed in HMW GS in four of the landraces. One novel subunit coded by the Glu-B1x locus and two novel subunit pairs at the Glu-D1 locus were identified. A modified system of nomenclature over that of Payne and Lawrence (1983) is suggested for numbering the new subunits. Accordingly, the novel subunits are numbered as 71 (Glu-B1x) and 2+122; 51+122; 52+123 and 53+123(Glu-D1x + y) and the allelic designations are given as Glu-B1 bh for 71+9; Glu-D1bp for 2+122. Glu-D1bq for 51+12; Glu-D1br for 51+122; GluD1br for 52+123 and GluD1bt for 53+123.

The objectives of the study were to test diversity among winter barley breeding lines exhibiting various sensitivity to FHB and to find RAPD markers and AFLP markers that will distinguish between susceptible and moderately resistant genotypes. A test of a set of winter barley genotypes artificially infected in field trials by fusaria was carried out. Based on the results from field and laboratory evaluation and deoxynivalenol (DON) content assessment, barley genotypes with different responses to FHB were selected. The genotypes were hybridized and doubled haploid (DH) lines were derived in F1 generation using the in vitro androgenesis method. Initial parental components and derived DH lines were tested for FHB infection and DON content. A set of parental genotypes of winter barley was tested with 80 RAPD markers. Based on analyses of 80 RAPD primers in a set of parental genotypes of winter barley, the primer H15 was selected that provides specific product of 650-bp size for moderately resistant winter barley genotypes. In consecutive detection, this specific product was found in 4 DH lines. During the study, some DH lines were selected that exhibited improved resistance to Fusarium infection. A low infection level and low DON content were found in the winter barley line DH 610 from the combination of Br2611m × Duet. The AFLP technique was used to analyze parental genotypes of winter barley as well as 7 selected DH lines of winter barley. The detected markers can be further evaluated and employed to select breeding materials.

Microsatellite, được biết đến như một trong những dấu hiệu mạnh mẽ nhất để xác định các giống lúa mạch, đã được sử dụng để đánh giá sự đa dạng di truyền và cấu trúc quần thể nhằm thúc đẩy việc sử dụng hiệu quả các nguồn gen. Trong nghiên cứu này, tập hợp 284 giống lúa mạch đã được phân tích gen sử dụng 30 dấu hiệu microsatellite. Các dấu hiệu SSR được chọn nằm ở hầu hết tất cả các nhóm liên kết và bao trùm cả ba bộ gen. Các kiểu gen được sử dụng có nguồn gốc từ 24 trung tâm chọn lọc khác nhau trên toàn thế giới và được đưa vào một bộ sưu tập cốt lõi rộng lớn của Viện Nông nghiệp và Cây trồng Rau ở Novi Sad, Serbia. Tổng số allele được phát hiện là 349 tại tất cả các locus đã phân tích. Số lượng biến thể allelic trung bình được phát hiện mỗi locus là 11,5. Giá trị trung bình của nội dung thông tin đa hình là 0,68. Theo xác suất dữ liệu thu được từ chương trình Structure, kết quả đã chỉ ra sự hiện diện của 6 tiểu quần thể trong tập hợp kiểu gen đã nghiên cứu. Cấu trúc quần thể cho thấy có một mối tương quan tích cực ở một mức độ nào đó với nguồn gốc địa lý. Dữ liệu gia phả có sẵn đã được đưa vào để giải thích thêm về cấu trúc quần thể. Kết quả của nghiên cứu này được kỳ vọng sẽ cung cấp thông tin quý giá cho các nghiên cứu liên kết trong tương lai sử dụng tài liệu giống lúa mạch đa dạng.

Application of salt stress (100 mM) through root growing medium caused a considerable decrease in plant fresh and dry biomass, maximum quantum yield (Fv/Fm), chlorophyll contents, leaf water potential, and leaf Ca, K, P and N concentrations of two maize cultivars (Apex 836 and DK 5783). However, salt-induced increase was observed in leaf osmolality (LO), proline, hydrogen peroxide (H2O2), malondialdehyde (MDA), Na+ concentration and activities of enzymatic antioxidants, such as catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD). Of five humic acid (HA) levels used under non-stress and stress conditions in an initial experiment, 100 mg L−1 was chosen for subsequent studies. Exogenous application of humic acid (HA) at the rate of 100 mM as a foliar or pre-sowing seed treatment significantly increased the plant biomass, Fv/Fm, chlorophyll pigments and proline contents, while it considerably reduced the leaf water potential, H2O2 and MDA contents as well as the activities of all the afore-mentioned enzymatic antioxidants. Of both modes of exogenous treatment, foliar spray was better in improving plant biomass, chlorophyll contents, LO, leaf Na+ as well as the accumulation of all nutrients measured, however, in contrast, seed pre-treatment was more effective in altering leaf proline, H2O2 and MDA contents. Of both maize cultivars, cv. DK 5783 excelled in plant biomass, chlorophyll contents and leaf N, Ca and K concentrations as well as in the activities of all three antioxidant enzymes, whereas cv. Apex 836 was superior in leaf Na+ and P concentrations, H2O2 and MDA contents. Cv. DK 5783 was comparatively better in salt tolerance as compared to cv. Apex 836. Overall, exogenous application of HA was effective in improving salinity tolerance of maize plants which can be attributed to HA-induced increase in plant biomass, chlorophyll contents, mineral nutrients and activities of key antioxidant enzymes.

Nuôi cấy thân đỉnh cung cấp một phương pháp thay thế để điều chỉnh dịch chất tế bào trong sự chuyển hóa carbon và nitơ của hạt lúa mì trong điều kiện gần giống như in vivo. Sử dụng kỹ thuật này, vai trò của sucrose và glutamine trong dòng vận chuyển liên quan đến chuyển hóa sucrose, đồng hóa amoniac và hoạt động aminotransferase đã được đánh giá nhằm hướng tới việc tích lũy tinh bột và protein ở hai kiểu gen lúa mì PBW 343 (năng suất thấp) và PBW 621 (năng suất cao). Tại giai đoạn nửa chín, các nhánh đã tách ra được nuôi cấy trong môi trường lỏng hoàn chỉnh chứa nồng độ glutamine và sucrose khác nhau trong bảy ngày trong các năm 2012–13 và 2013–14. Việc tăng nồng độ glutamine từ 17 đến 25 mM trong môi trường nuôi cấy có 117 mM sucrose đã làm tăng hoạt động của nitrate reductase, glutamate synthase, glutamate oxaloacetate transaminase (GOT) và glutamate pyruvate transaminase (GPT) sau 4 ngày nuôi cấy (DAC) tương ứng với một sự gia tăng trong hàm lượng protein hòa tan. Tuy nhiên, tại 7 DAC, hàm lượng protein hòa tan giảm trong khi tích lũy tinh bột tăng, cho thấy, do đó, một tác động bù trừ lên chuyển hóa carbon và nitơ. Rõ ràng, hoạt động của sucrose synthase, invertase acid và trung tính hòa tan giảm đáng kể. Tăng nồng độ sucrose từ 117 đến 125mM dẫn đến một sự gia tăng trong việc chuyển đổi đường thành tinh bột trong hạt nhưng hàm lượng protein giảm. PBW621 cho thấy hàm lượng protein cao hơn do có hoạt động cao hơn của GOT, GPT tại 4 DAC, điều này sau đó làm tăng khung carbon của protein để tổng hợp tinh bột tại 7 DAC. Quá trình lấp đầy hạt liên quan đến lượng đường hòa tan/tinh bột có mối tương quan mạnh mẽ với hoạt động của invertase, trong khi protein liên quan đến aminotransferase.

Soil salinity is a major global environmental factor limiting plant growth and productivity. Wheat seeds need to be able to germinate and establish seedlings in saline soils for sustained productivity. In this study, we investigated seed germination-related traits under salt stress conditions in 239 diverse Iranian wheat landraces for evaluation of salt stress tolerance. Seed of the landraces along with relevant checks was germinated in salt and control solutions until 14 days. Initially, 10 randomly selected accessions were subjected to six different (25 mM, 50 mM, 75 mM, 100 mM, 125 mM, 150 mM) salinity levels for standardization. The salinity level 125 mM NaCl was found more effective concentration for the discrimination of genotypes for various physiological indices, viz. germination percentage, coleoptile length, root and shoot length, fresh root and shoot weight, dry root and shoot weight, and vigor index. After 14 days, germination percentage and all seedling traits were found to be affected due to salinity. Salt tolerance index maintained a significant positive correlation with seedling traits which indicates that these parameters could be used as selection criteria for screening wheat genotypes against salt stress. Significant differences were observed for coleoptile length, root–shoot length, fresh root–a shoot weight, dry shoot weight, and vigor index among the wheat landraces. From the overall observation of germination percentage and early seedling growth, it was concluded that the wheat landraces accessions including IWA 8600278, IWA 8600291, IWA 8611786, IWA 8600179, IWA 8600303, and IWA 8610487 showed better salt tolerance than Kharchia 65, the universal salt-tolerant variety used so far in wheat-breeding programs.