Anatomical and hormonal factors determining the development of haploid and zygotic embryos of oat (Avena sativa L.)

A critical step in the production of doubled haploids is a conversion of the haploid embryos into plants. Our study aimed to recognize the reasons for the low germination rate of Avena sativa haploid embryos obtained by distant crossing with maize. Oat cultivars of ‘Krezus’ and ‘Akt’ were investigated regarding embryo anatomy, the endogenous phytohormone profiles, and antioxidant capacity. The zygotic embryos of oat were used as a reference. It was found that twenty-one days old haploid embryos were smaller and had a less advanced structure than zygotic ones. Morphology and anatomy modifications of haploid embryos were accompanied by extremely low levels of endogenous auxins. Higher levels of cytokinins, as well as tenfold higher cytokinin to auxin ratio in haploid than in zygotic embryos, may suggest an earlier stage of development of these former. Individual gibberellins reached higher values in ‘Akt’ haploid embryos than in the respective zygotic ones, while the differences in both types of ‘Krezus’ embryos were not noticed. Additionally to the hormonal regulation of haploid embryogenesis, the poor germination of oat haploid embryos can be a result of the overproduction of reactive oxygen species, and therefore higher levels of low molecular weight antioxidants and stress hormones.

Hybridization and Factors Influencing Seed Set in Oat

Background: Oat is mostly neglected crop for hybrid development due to its floral structure which results in high damage rate during hybridisation. Due to the cumbersome in acquiring a sufficient number of hybrids and subsequent backcrosses are difficult that lead to lack of much inheritance studies in Oats. Methods: The procedure for crossing used was almost identical to that used by oat breeders which was conducted for 2 years viz., 2019-20 and 2020-21 at Forage Station, Punjab Agriculrural University, Ludhiana. Result: The experiment was conducted to know the seed set percent in oat cultivars. Since the oat flower is fragile compared other cereals and it is easily harmed during the emasculation and pollination process. The seed set percent observed was only 12 and 10 percent in the year 2019-20 and 2020-21, respectively.

Screening of oat cultivars developed in omsk for conditions of the southern foreststeppe in Western Siberia

Spring oats are one of the most important crops among grain crops, and they are well adapted to the conditions of Western Siberia. To realize qualitative and quantitative characteristics of yield and increase productivity, new varieties should be characterized by responsiveness to changing environmental factors (adaptability) with sufficient potential productivity and ability to realize it even in the stressful conditions of this region. The aim of the research was to determine adaptive properties of spring oat cultivars developed in Omsk Agrarian Scientific Center. The experiments were carried out on the experimental fields of the Omsk Agrarian Scientific Center, located in the southern forest-steppe zone of Western Siberia, in 2011-2019. The st following adaptability parameters were calculated: stress tolerance Kst (according to A.V. Bykov), homeostaticity Hom (V.V. Khangildin), breeding value of cultivar Sc (according to N.A. Orlyansky), genotypic effect Ɛi (B.P. Guriev), coefficient of variation V and coefficient of uniformity B (B.A. Dospekhov), resilience of stability index У (R.A. Udachin and P.A. Golovchenko), rate of reaction of varieties to the environmental conditions Re (V.V. Novokhatin), equivalent plasticity Wi (C. Wricke). Using a significant number of indicators to obtain a final assessment of adaptability, a ranking of cultivars was carried out. Among hulled oat cultivars, Orion (control), Irtysh 13 and Irtysh 21 had increased adaptability (the sum of the ranks was 23, 35 and 36, respectively). In naked oat cultivars, Progress was more stable (the sum of the ranks was 79). These cultivars are recommended for cultivation in conditions of the southern forest-steppe of Western Siberia.

Effects of cultivar, seed rate, N rate and plant growth regulator on key processing quality parameters of winter and spring-sown oats

The effects of three seeding rates (250, 350 and 450 seeds/m2), six applied N rates (40, 70, 100, 130, 160 and 190 kg N/ha) and the application of plant growth regulator on the grain quality of two spring oat cultivars (Husky and Keely) were evaluated at four spring-sown sites over a 3-year period (2016–2018). The same cultivars, seeding rates and five applied N rates (80, 110, 140, 170 and 200 kg N/ha) were evaluated at three winter-sown sites, in 2017–2019. Keely had a significantly higher kernel content (KC) in spring (0.7%) and winter-sown (0.6%) oats. Specific weight (SW) decreased as N rate increased in spring-sown crops (1 kg/hl) with no effect observed in winter-sown oats. Hullability (HB) increased (0.92%) in spring-sown crops as N rate increased with a reduction (0.9%) observed when winter-sown. Increases in grain protein percentage (GPP) were observed in spring (1.8%) and winter (1.2%) sowings in response to N rate. The application of plant growth regulator reduced SW (0.4 kg/hl), GPP (0.3%), KC (0.6%) with no effect on HB. Kernel size was highly responsive too applied N rate, with reductions in grains >2.5 mm and increases in grains of smaller size observed as N rate increased. HB had a marked relationship to kernel size with GP inconsistently linked to SW. The results of this study suggest that cultivar, N rate and PGR application are of importance to milling quality and that changes in grain size in response to agronomic practices contribute to changes in specific weight and hullability.

Discovery and Chromosomal Location a Highly Effective Oat Crown Rust Resistance Gene Pc50-5

Crown rust, caused by Puccinia coronata f. sp. avenae, is one of the most destructive fungal diseases of oat worldwide. Growing disease-resistant oat cultivars is the preferred method of preventing the spread of rust and potential epidemics. The object of the study was Pc50-5, a race-specific seedling crown rust resistant gene, highly effective at all growth stages, selected from the differential line Pc50 (Avena sterilis L. CW 486-1 × Pendek). A comparison of crown rust reaction as well as an allelism test showed the distinctiveness of Pc50-5, whereas the proportions of phenotypes in segregating populations derived from a cross with two crown rust-susceptible Polish oat cultivars, Kasztan × Pc50-5 and Bingo × Pc50-5, confirmed monogenic inheritance of the gene, indicating its usefulness in oat breeding programs. Effective gene introgression depends on reliable gene identification in the early stages of plant development; thus, the aim of the study was to develop molecular markers that are tightly linked to Pc50-5. Segregating populations of Kasztan × Pc50-5 were genotyped using DArTseq technology based on next-generation Illumina short-read sequencing. Markers associated with Pc50-5 were located on chromosome 6A of the current version of the oat reference genome (Avena sativa OT3098 v2, PepsiCo) in the region between 434,234,214 and 440,149,046 bp and subsequently converted to PCR-based SCAR (sequence-characterized amplified region) markers. Furthermore, 5426978_SCAR and 24031809_SCAR co-segregated with the Pc50-5 resistance allele and were mapped to the partial linkage group at 0.6 and 4.0 cM, respectively. The co-dominant 58163643_SCAR marker was the best diagnostic and it was located closest to Pc50-5 at 0.1 cM. The newly discovered, very strong monogenic crown rust resistance may be useful for oat improvement. DArTseq sequences converted into specific PCR markers will be a valuable tool for marker-assisted selection in breeding programs.

Effect of Nitrogen Levels on Forage Yield and Quality of Multi Cuts Oat Cultivars

A field experiment was conducted at Main Forage Research Station, Anand Agricultural University, Anand during rabi-2019-20 to study the effect of nitrogen levels on yield and quality of multi cut oat cultivars with aim to find out nitrogen levels on green fodder yield and quality of oat. There were total four varieties (V1: OL 1874, V2: JO-05-304, V3: UPO 212 and V4: RO 19) and four levels of nitrogen (N1: 35 kg N/ha, N2: 70 kg N/ha, N3: 105 kg N/ha and N4: 140 kg N/ha) was tested. Experiment was laid out in split plot design with three replications. Experiments results revealed that significantly the highest green fodder yield was reported in RO 19 (V4) treatment, while average plant height and average number of tiller per meter row length were reported in V1: OL 1874 and V2: JO 05-304 treatment, respectively. Average plant height, Green fodder yield, average dry matter, average crude protein, total crude protein yield and dry matter yield were found highest by application of 140 kg N/ha. Average tiller per meter row length was higher in N4 (140 kg N/ha) and average dry matter was higher in N1 (35 kg N/ha). Response of nitrogen non-significant in case of average ADF and NDF content.

Virulence Characterization of Puccinia graminis f. sp. avenae and Resistance of Oat Cultivars in China

Oat stem rust, caused by Puccinia graminis f. sp. avenae (Pga), is one of the most devastating diseases of oat. The most cost-effective and eco-friendly strategy to control this disease is the use of resistant cultivars. However, P. graminis f. sp. avenae can overcome the resistance of cultivars by rapidly changing its virulence. Thus, information on the virulence of P. graminis f. sp. avenae populations and resistance of cultivars is critical to control the disease. The current study was conducted to monitor the virulence composition and dynamics in the P. graminis f. sp. avenae population in China and to evaluate resistance of oat cultivars. Oat leaves naturally infected by P. graminis f. sp. avenae were collected during 2018 and 2019 and 159 isolates were derived from single uredinia. The isolates were tested on 12 international differential lines, and eight races, TJJ, TBD, TJB, TJD, TJL, TJN, TGD, and TKN, were identified for the first time in China. The predominant race was TJD, virulent against Pg1, Pg2, Pg3, Pg4, Pg8, Pg9, and Pg15, accounting for 35.8% and 37.8% in 2018 and 2019, respectively. The sub-predominant races were TJN (30.2% in 2018, 28.3% in 2019) and TKN (20.8% in 2018, 12.3% in 2019). All isolates were virulent to Pg1, Pg2, Pg3, and Pg4, and avirulent to Pg6 and Pg16. The three predominant races (TJD, TJN, and TKN) were used to evaluate resistance in 30 Chinese oat cultivars at the seedling and adult-plant stages. Five cultivars, Bayan 1, Baiyan 2, Baiyan 3, Baiyan 5, and Baiyan 9, were highly resistant to the three races at both seedling and adult-plant stages. The results of the virulences and frequencies of P. graminis f. sp. avenae races and the resistant cultivars will be useful in understanding the pathogen migration and evolution and for breeding oat cultivars with stem rust resistance.

CO2 Responses of Winter Wheat, Barley and Oat Cultivars under Optimum and Limited Irrigation

Field crop production must adapt to the challenges generated by the negative consequences of climate change. Yield loss caused by abiotic stresses could be counterbalanced by increasing atmospheric CO2 concentration, but C3 plant species and varieties have significantly different reactions to CO2. To examine the responses of wheat, barley and oat varieties to CO2 enrichment in combination with simulated drought, a model experiment was conducted under controlled environmental conditions. The plants were grown in climate-controlled greenhouse chambers under ambient and enriched (700 ppm and 1000 ppm) CO2 concentrations. Water shortage was induced by discontinuing the irrigation at BBCH stages 21 and 55. Positive CO2 responses were determined in barley, but the CO2-sink ability was low in oats. Reactions of winter wheat to enriched CO2 concentration varied greatly in terms of the yield parameters (spike number and grain yield). The water uptake of all wheat cultivars decreased significantly; however at the same time, water-use efficiency improved under 1000 ppm CO2. Mv Ikva was not susceptible to CO2 fertilization, while no consequent CO2 reactions were observed for Mv Nádor and Mv Nemere. Positive CO2 responses were determined in Mv Kolompos.