Effect Of Vernalization Research Articles

The Effects of Vernalization and Photoperiod Genes Composition on Heading Date in Wheat

The vernalization characteristics of wheat are mainly controlled by vernalization and photoperiod genes, which determine the winter-spring habit and heading-flowering of wheat, and affect its environmental adaptability. In order to understand the effects of vernalization and photoperiod genes on heading date, 12 common wheat varieties widely cultivated in the Huang-Huai region were used as experimental materials, and the effects of different low-temperature vernalization treatments on wheat heading date were studied. Using molecular markers from previous studies, the allelic variations and genotypes of vernalization genes (VRN-A1, VRN-B1, VRN-D1 and VRN-B3) and photoperiod genes (Ppd-A1, Ppd-B1, Ppd-D1) were detected. By identifying the heading date in a controlled greenhouse, the relationship between the vernalization and photoperiod genes composition and the heading date phenotype was analyzed. The experimental results showed that different wheat varieties had different phenotypes after different vernalization treatments. Tian min 198 carried a dominant vernalization gene, and its vernalization characteristics were expressed as spring wheat varieties, with low requirements for low-temperature vernalization. Wheat without a dominant vernalization gene had winter wheat characteristics, with high requirements for low-temperature vernalization. Wheat varieties carrying a dominant vernalization gene can be used to improve late-maturing wheat varieties, and serve as valuable germ plasma resources for variety improvement and introduction. Exploring the effects of different wheat vernalization and photoperiod genes composition on heading date is beneficial to provide a scientific basis for the rational use of wheat varieties, and studying the vernalization and photoperiod genes composition has guiding significance for wheat introduction and ecological breeding.

Vernalization affects the germination performance of the wetland endangered species Eleocharis carniolica

AbstractEleocharis carniolica W.D.J. Koch (Cyperaceae) is an endangered wetland spike rush mainly threatened by habitat loss and fragmentation. Understanding the germination ecology of this species is essential to perform successful conservation and restoration actions. In this study, we investigated the effect of vernalization (i.e. cold stratification), gibberellic acid (GA3) and chemical scarification on seed germination of E. carniolica from wild populations in northern Italy. The results showed that vernalization (i.e. 8-weeks at 4 °C) significantly improved germination probability, speed, and uniformity compared to non-stratified seeds. Gibberellic acid treatment alone or in combination with vernalization did not show a significant improvement in germination. Chemical scarification using sodium hypochlorite increased germination probability, with 8 h of scarification showing the highest success rate. However, 24-h scarification had a negative impact on germination. Overall, vernalization was found to be the most effective method to enhance germination in E. carniolica. These findings provide valuable insights into the seed germination ecology of this endangered species, aiding in its exsitu conservation, propagation, and in-situ restoration efforts. Moreover, they have important implications on future germination dynamics of this endangered species, especially with predicted climate change scenarios.

Vegetative response of shallot (Allium cepa Aggregatum group) bulbs on vernalization and gibberellin treatment in different environments

This research is an initial study of the effects of vernalization and Gibberellins in two different environments. The research was conducted in a split-split plot design with three factors and three times repetition. The main plot was the environment (environment 1, environment 2), the split plot was vernalization temperature (3±2 and 9±2°C), and split-split plot was Gibberellin concentration (0, 50, 100, 150 ppm). The result showed that the vernalizations and Gibberellin have significantly affected plant height (p<0.01). The environment significantly affected plant height, number of tillers, and number of leaves. There was an interaction between Gibberellin and environment treatment on plant height and an interaction between vernalization, Gibberellin, and environment on the number of leaves. The environment with temperature: 29±2.18°C, RH: 45±9.14%, light intensity: 9272±7669 μmol m-2 S-1 showed plant height and the number of tillers higher than other environments, contrary to the number of leaves. According to the principal component analysis, this environment is more suitable for all vernalization and Gibberellin treatments than other environments. The results of this study indicate that the environment more influences vegetative growth than the other two treatments.

Effects of Vernalization on Off–Season Flowering and Gene Expression in Sub-Tropical Strawberry cv. Pharachatan 80

Off-season strawberry production may diversify the yield, thereby increasing costs, but the environmental conditions are a limiting factor. This experiment aimed to study the effects of vernalization on off-season flowering and gene expression in sub-tropical strawberry cv. Pharachatan 80. The factorial (2 × 2) + 1 in a completely randomized design was used in this study. Factor A was the vernalization temperatures: 2 °C and 4 °C. Factor B was the vernalization periods: 1 week and 2 weeks, compared with non-vernalization (control). The expression profile of genes was determined after vernalization treatments. The results revealed an interaction between the two factors on the number of days it took the plants to bloom, the percentage of flowering, the number of inflorescences, the number of flowers per inflorescence and the number of flowers per plant, whereas the number of first flower bloom days, inflorescence length and flower size were not affected by the interaction between the two factors. Strawberry plants vernalized for 1 and 2 weeks at 2 °C showed earlier flowering (21.4 and 23.1 days, respectively) than did those vernalized at 4 °C (24.9 and 25.7 days, respectively). On the other hand, non-vernalized strawberry plants took longer to bloom, at 62.2 days. Strawberry plants vernalized at 2 °C for 2 weeks had the highest percentage of flowering, number of inflorescences, number of flowers per inflorescence and number of flowers per plant. The analysis on gene expression showed that VRN5, SOC1 and FT genes were upregulated after vernalization at 2 °C for 2 weeks, whereas gene expression of the control treatment was not detected. This study demonstrates that vernalization treatment could induce off-season flowering in sub-tropical strawberry cv. Pharachatan 80 by activating flowering genes.

Phenocam observed flowering anomaly of Rhododendron arboreum Sm. in Himalaya: a climate change impact perspective.

Flowering exhibits a significant relationship with environmental stimuli and changes. Effect of photoperiodism and vernalization have been well studied in flowering phenology; however, the effect of soil temperature on flowering is less explored which is one of the major factors of vegetation growth in alpine ecosystem. This study thus focuses on the effects of soil and air temperature on flowering response of Rhododendron arboreum Sm., a Himalayan tree species, which is also an indicator of spring initiation in high altitude regions. To monitor the flowering pattern, we employed automated phenocam, which was set up at 3356 masl in Tungnath (Indian Alpine region of Uttarakhand) for time-lapse photography of timberline ecotone. Soil and air temperature were recorded continuously at the timberline ecotone. Three years (2017 to 2020) of datasets were used for the present study. The phenocam observations displayed an interesting event in the year 2019-2020 with complete absence of flowering in R. arboreum population at Tungnath timberline ecotone. From the soil temperature data, an increase in winter (Dec-Jan, during which floral buds form) soil temperature, by > 1°C, and no accumulation of freezing degree-days were found for the year 2019-2020. Air temperature however did not display any relationship with the failure of flowering, ruling out aerial chilling or frost injury of floral buds. From the results, a possible relationship between soil temperature and flowering can be suggested pointing towards necessary root apex vernalization stimulus in shallow rooted Rhododendrons. However, the dependency of flowering in Rhododendrons on winter soil temperature further requires continuous monitoring and more observations to make concrete inferences.

Temperature and duration of vernalization effect on the vegetative growth of garlic (Allium sativum L.) clones in Indonesia

Abstract Garlic is usually propagated asexually from the cloves. Clove as the propagation source for garlic has many weaknesses. Alternatively, bulbils could be used for the propagation. The aim of this study was to know the effect of temperature and time of vernalization from several clones of Indonesian garlic to bulbil production. This research was conducted at a farmer’s field at Banjarnegara, Central Java, Indonesia. The experiment was arranged in a Completely Randomized Block Design with three factors: temperature of vernalization, i.e., 0, 5, and 10°C, duration of vernalization, i.e., 20, 40, and 60 days, and on 12 garlic varieties/clones (V1–V12). Cloves of garlic were vernalized in cold storage according to the treatments and then planted in the field. The results revealed that a temperature of 5°C and duration of 20 days of vernalization independently single factor increased the number of bulbils of V3. Bulbil variables of V4 and V7 were enhanced with vernalization at 0°C for 20 days, although it did not significantly differ from the control. Therefore, these clones do not need particular vernalization treatment in order to produce bulbils.

Transcriptomic and metabolic analyses revealed the modulatory effect of vernalization on glucosinolate metabolism in radish (Raphanus sativus L.)

Vernalization is the process by which long-term cold like winter triggers transition to flowering in plants. Many biennial and perennial plants including Brassicaceae family plants require vernalization for floral transition. Not only floral transition, but dynamic physiological and metabolic changes might also take place during vernalization. However, vernalization-mediated metabolic change is merely investigated so far. One of secondary metabolites found in Brassiceceae family plants is glucosinolates (GSLs). GSLs provides defense against pathogens and herbivores attack in plants and also exhibits inhibitory activity against human cancer cell. Profiles of GSLs are highly modulated by different environmental stresses in Brassciaceae family plants. To grasp the effect of vernalization on GSLs metabolic dynamics in radish (Raphanus sativus L.), we performed transcriptomic and metabolic analysis during vernalization in radish. Through transcriptome analysis, we found many GSLs metabolic genes were significantly down-regulated by vernalization in radish plants. Ultra-High Performance Liquid Chromatography analysis also revealed that GSLs compounds were substantially reduced in vernalized radish samples compared to non-vernalized radish samples. Furthermore, we found that repressive histone modification (i.e. H3K27me3) is involved in the modulation of GSLs metabolism via epigenetic suppression of Glucoraphasatin Synthase 1 (GRS1) during vernalization in radish. This study revealed that GSLs metabolism is modulated by vernalization, suggestive of a newly identified target of vernalization in radish.

Effect of the variation in vernalization temperature and gibberellic acid concentration on coriander productivity

Compared to the other plants of family Apiaceae, production of coriander fruits requires longer periods. Thus, controlling of flowering duration and shorten the period is considered a crucial act to reduce the production period with save irrigation water. Therefore, an experiment was conducted during the two successive seasons (2018/2019 and 2019/2020) to investigate the effect of vernalization by four different temperatures (control without cold, 0° C, 3° C and 6° C) and three concentrations of gibberellic acid, GA3, (0, 50 and 100 ppm) on vegetative growth, number of days to 50% flowering and maturity, fruits production and volatile oil percentage of coriander fruits. The experimental design was a Split-plot design with three replications. Results showed that the vernalized seeds at 3° C caused high significant effect on all studied characteristics where it gave the highest average of plant height, number of branches and umbls /, fruits yield, volatile oil percentages and oil yield (ml / plant), and reduction number of days to 50% flowering and maturity compared with other treatments. The application of GA3 at 100 ppm gave the highest average in above-stated parameters compared to other GA3 treatments. Concerning the effect of interaction treatments, the obtained results cleared that all studied characteristics showed the highest average as a result of the combination between vernalized seed at 3° C and 100 ppm of gibberellic acid (GA3). Treatments under study gave a pronounced effect on essential constituents where linalool is the main constituent. In conclusion, to decrease the number of days from planting to complete maturity and increased dry herb weight/plant vernalized seeds at 3° C treated with GA3 at 100 ppm should be exploited in coriander production systems.

Morphological and Flowering Characteristics of Shallot (Allium cepa Var. Aggregatum) in Response to Gibberellic Acid and Vernalization

Shallot plants have variations in morphological and flowering characters. Flowering ability can be induced by the treatment of gibberellic acid (GA3) and exposing to cold temperature (vernalization). The objectives of the research were to determine the effect of GA3 and vernalization on the morphological and flowering characters of 5 shallot varieties. Field study was organized in a completely randomized block design with three replications to evaluate the responses of 5 varieties of shallots (Bauji, Bima Brebes, Super Philip, Tajuk, and Thailand) to GA3 with the concentrations ranged from zero to 150 mg L-1. Plants were maintained for 65 days until harvesting. The second study was organized in a completely randomized design with 3 replications to evaluate the responses of the five varieties of shallot to vernalization. The vernalization of shallot bulbs were done at 8 o C for 6 weeks. The results indicated that a Super Phillip variety showed the highest response to GA3 observed in the number of leaves and bulbs. At 100 mg L-1 of GA3 increased the plant height up to 45.74 cm. The results from the second study showed that vernalization was effective to increase flowering only on the Ilokos variety. But the other varieties were not sensitive to vernalization. Based on morphological and flowering characters, 5 varieties of shallots were clustered into 3 groups, namely: sensitive flowering included Bentanis, Bma Brebes and Tajuk variety, medium sensitive flowering included Ilokos variety, and non-sensitive flowering included Sumenep variety.

Effect of vernalization (Vrn) genes on root angles of bread wheat lines carrying rye translocation

Effect of vernalization (Vrn) genes on root angles of bread wheat lines carrying rye translocation

Vernalization and benzylamino purine treatments on the generative growth of shallots (allium cepa var. ascalonicum l.) bauji variety in the lowlands

True shallot seeds (Allium cepa var. ascalonicum L.) or True Shallot Seed (TSS) has begun to be used widely as planting material. However, not all types of shallot plants can flower and produce true seeds perfectly because the majority of shallot plants in Indonesia are grown in the lowlands with temperatures of more than 30°C. Although there are some local varieties, which naturally flower, they have not been tested until producing true seeds. This study aims to determine the effect of vernalization and benzyl amino purine (BAP) on the Bauji variety onion plants’ generative growth. The research was conducted from July to November 2020 in Jember Regency at an altitude of 89 asl. The research design using a factorial randomized block design. The first factor is vernalization, while the second factor is BAP concentration at 50, 100, and 150 ppm. The results showed an interaction between vernalization factors and the use of BAP, and single-use of BAP did not significantly affect the generative growth of Bauji variety shallot. The vernalization treatment separately actually gave an increasing effect on the percentage of flowering plants, the number of umbels per planting, the number of flowers per umbel, the number of capsules per umbel, the number of seeds per umbel, the TSS weight per umbel, and the weight per 100 seeds.

Effect of vernalisation on the diurnal changes in fatty acid profile and nutrient composition of chicory in response to defoliation frequency

ABSTRACT The effect of defoliation frequency and severity on FA and nutrient composition of forage chicory (Cichorium intybus L.) before and after vernalisation were compared. Before vernalisation, the FA and nutrient components exhibited little variation with defoliation frequency and severity irrespective of the time of day. After vernalisation, total FA more than halved compared with pre vernalisation levels (52.2 versus 19.2 mg/g DM). Concentrations of total FA and polyunsaturated FA: linoleic and linolenic declined by 63%, 50%, and 74%, respectively. Furthermore, extending the defoliation frequency from 300 to 600 growing degree-days after vernalisation caused a decline of 28% of linoleic, 40% of linolenic and 33% of total FA concentrations. Diurnal fluctuations were detected for linoleic and oleic acids after vernalisation (P < 0.01). In terms of nutrient composition, vernalisation decreased CP, digestibility and ME, while fibre contents increased. Between morning and afternoon, there were general declines in CP and fibre contents as well as increases in soluble sugars the herbage regardless of vernalisation. Overall, the feeding value and the concentration of FA were greater on chicory herbage managed under shorter regrowth intervals than that under longer regrowth intervals, which is likely to favour animal production and the concentration of the desirable FA in ruminant products.

Interactive Effects of Vernalization and Photoperiod Loci on Phenological Traits and Grain Yield and Differentiation of Iranian Wheat Landraces and Cultivars

Phenological stages and allelic variation of vernalization and photoperiod response genes play an important role in wheat environmental adaptation and grain yield. In the present study, phenological stages of 260 Iranian wheat landraces and cultivars were studied during two cropping years. In addition, allelic variation of vernalization and photoperiod markers were also investigated to identify the genetic basis of different phenological stages. Ppd-D1 and then Ppd-B1 were highly variable in cultivars and landraces, while Ppd-A1 showed lower variation. Distribution patterns of allele frequency in Vrn-B1b, Ppd-D1b-D001, and Ppd-D1 markers were remarkably different in cultivars and landraces. About 98% and 96% of landraces showed photoperiod-sensitive allele of Ppd-D1b-D001 and Ppd-D1 markers, respectively, while most of cultivars had photoperiod-insensitive alleles. The frequency of Vrn-B1a was 82.2% in cultivars and 100% in landraces. However, Vrn-A1a-E4 was 43% and 79% in cultivar and landraces, respectively. We have found that Ppd-D1, Ppd-B1, and Vrn-A1 have a decisive effect on phenological stages and the combination of Ppd-B1a, Ppd-D1b, and Vrn-A1b is the most abundant allelic compound. The combination of aaa, bbb, and aab alleles for these three loci led to increased yield, thousand kernel weight (TKW), and grain filling period and shortening of phenological stages. Cluster analysis based on phenological stages and growing degree-days (GDD) of phenological stages clearly separated cultivars from landraces. This clustering pattern was consistent with marker data. The findings of this study provide a comprehensive insight into the basis of genetic control of the phenological stages of Iranian wheat landraces and cultivars. Therefore, this information can be used to select desirable genotypes in future breeding programs.

Combined Effects of Vernalization and Gibberellic Acid on Quality Seed Production of Summer Onion (Allium cepa L.)

The purpose of the present study was to evaluate the effect of vernalization and GA3 on seed yield and reproductive quality of summer onion. There were three vernalization treatments viz., no vernalization (control), vernalization at 5°C for 14 days and vernalization at 10°C for 14 days and four GA3 treatment viz., 0, 50, 100 and 150 ppm. The two-factor experiment was conducted in the Randomized Complete Block Design (RCBD) with three replications. Combination between vernalization and GA3 was significant on the parameters such as plant height, number of leaves plant-1, the highest number of flowering stalk, number of umbels plant-1, number of bud umbel-1, percent flowering at 45 and 60 DAP, number of seeds umbel-1, weight of seeds umbel-1, weight of seeds plant-1, weight of seeds plot-1, 1000 seed weight, seed yield, number of fruits umbel-1, percent of fruit set umbel-1and percent germination. Combined effect of vernalization &amp; GA3 was considered the highest seed yield (280.42 kgha-1) was obtained from vernalization at 5°C for 14 days with 100 ppm GA3. The lowest values of all the parameters were recorded in the control treatment. No limitation is found in the present experiment. Combined use of proper vernalization of mother bulb and suitable concentration of gibberellic acid can be one possible way to expand onion production during the summer.

Agronomic performance of durum wheat landraces and modern cultivars and its association with genotypic variation in vernalization response (Vrn-1) and photoperiod sensitivity (Ppd-1) genes

This study analyzed the relationship between important agronomic traits and major genes regulating flowering time in a panel of 151 Mediterranean durum wheat landraces and 20 modern cultivars. Field experiments were conducted under rainfed conditions during six crop seasons in northeastern Spain. Multivariate analysis of agronomic traits and genotypic data allowed the modern cultivars to be differentiated from the landraces and germplasm pools to be identified within the landraces associated with their geographic origin. The high frequency of the Vrn-A1c allele and the photoperiod insensitive alleles GS105 and GS100 at Ppd-A1 reduced time to anthesis and enlarged the grain filling period of the modern cultivars compared with the landraces. Ancient durums collected close to the domestication area of wheat showed a high frequency of the winter allele vrn-B1 and the photoperiod sensitivity allele Ppd-B1b. None of the allele variants or allelic combinations accounted significantly for variations in any agronomic trait of modern cultivars. Vernalization and photoperiod genes acted additively in explaining the genotypic variance for the agronomic traits of the landraces. Vrn-A1 alleles and Vrn-A1+Vrn-B1 allelic combinations significantly affected the number of grains per spike (NGS), thousand kernel weight (TKW) and grain filling rate (R), accounting for 9%?12% of the genotypic variance for these traits. Ppd-1 accounted for 6%?21% of the genotypic variance for R, grain filling duration (GFD), plant height (PH), biomass at anthesis (CDW) and harvest index (HI). Vrn-1+Ppd-1 allelic combinations accounted for 21%?26% of the genotypic variance for these traits. Except for NGS, the effect of vernalization and photoperiod genes on the agronomic traits was linked to their effect on anthesis time. The three-day delay in anthesis time caused by the allele Vrn-A1d irrespective of the allele Vrn-A1c resulted in increases of 10 % in R and 7% in TKW. The eight-day delay in anthesis time caused by the allele Ppd-A1(DelCD) compared with Ppd-A1(GS105) increased R by 19 % and PH by 28 %, but reduced GFD and HI by 10 %. None of the allele variants or allelic combinations at the Vrn-1 or Ppd-1 genes accounted significantly for variations in yield or number of spikes m?2 (NSm2).

Phytohormone profile and CiFL1 expression in young seedlings of Cichorium intybus L. var sativum exposed to high temperature in relation to vernalization and de-vernalization processes

Cichorium intybus is a biennial plant species forming a taproot and a leaf rosette during the first year and which requires low temperature during vernalization to flower during the second year of its cycle. Heat stress, however, is known to induce premature flowering during the first year. The present work aims to compare the effect of heat treatment (38 °C during 3 days) and vernalization (4 °C during 6 weeks) on the phytohormonal profile and the expression of two chicory genes (CiFL1 and CiFT) homologous to the Arabidopsis flowering genes FLOWERING LOCUS C (FLC) and FLOWERING LOCUS T (FT). In Arabidopsis, FLC and FT code, respectively, for a repressor and an activator of flowering. Although CiFL1 was inhibited by vernalization, its expression was increased by heat treatment in both vernalized and non-vernalized seedlings while high temperature unexpectedly inhibited FT expression in vernalized seedlings. Vernalization induced a modification in the hormonal profile of C. intybus (cv. Melci) in a sense of a decrease in ethylene production, abscisic acid and total jasmonates content, while the level of salicylic and benzoic acids as well as polyamine spermidine increased. A limited effect on the gibberellins’ profile was observed. The subsequent impact of heat stress on phytohormone content was different in non-vernalized and vernalized seedlings, with a higher abscisic acid and jasmonates and a lower 1-aminocyclopropane-1-carboxylic acid concentration in the former than in the latter. These data are discussed in relation to the putative involvement of phytohormones in stress-induced flowering. It appears that heat stress implies different pathways than vernalization to hasten flowering process.

Effect of artificial vernalization on the production of Tunisian globe artichoke derived from nursery’s ovoli: earliness, yield and quality traits

Effect of artificial vernalization on the production of Tunisian globe artichoke derived from nursery’s ovoli: earliness, yield and quality traits

Yield and quality of summer onion seeds as influenced by vernalization and boron application

The experiment was conducted at the Horticultural Farm, Bangladesh Agricultural University, Mymensingh during the period from October, 2018 to April, 2019. The present study was aimed at determining the effect of vernalization and doses of boron on seed yield and quality of summer onion. There were three vernalization treatments viz., no vernalization (control), vernalization at 10°C for 25 days and vernalization at10°C for 40 days and four boron treatment viz., 0 kg ha-1, 1 kg ha-1, 2 kg ha-1 and 3 kg ha-1. The two-factor experiment was laid out in the Randomized Complete Block Design with three replications. The results of the experiment showed that the vernalization had significant and positive influence on all the parameters studied. Boron had also significant effects on all the parameters. Interaction between vernalization and boron was significant on all the yield and yield contributing parameters. The highest seed yield (191.01 kg ha-1) was obtained from vernalization at 10°C for 40 days and lowest (137.88 kg/ha) from control. The highest seed yield (255.38kgha-1) was obtained from 3 kg ha-1 boron and lowest (83.48 kg ha-1) from control. When combined effect was considered the highest seed yield (293.36 kgha-1) was obtained from vernalization at 10°C for 40 days with 3 kg ha-1 boron. The lowest value (69.50 kg/ha) was recorded in the control treatment.&#x0D; Progressive Agriculture 30 (4): 371-378, 2019

VERNALIZATION AND GIBBERELLIC ACID RESPONSE IN SUMMER ONION’S (ALLIUM CEPA L.) REPRODUCTIVE PHASES

The present study was aimed at determining the effect of vernalization and Gibberellic Acid (GA3) on seed yield and quality of summer onion. There were three vernalization treatments viz., no vernalization (control), vernalization at 5°C for 14 days and vernalization at 10°C for 14 days and four GA3 treatment viz., 0, 50, 100 and 150 ppm. The two-factor experiment was laid out in the Randomized Complete Block Design with three replications. The results of the experiment showed that the vernalization and GA3 had significant influence on all the parameters studied. Solitary Effect of vernalization and GA3 was significant on the parameters such as plant height, number of leaves plant-1, the highest number of flowering stalk, number of umbels plant-1, number of bud umbel-1, percent flowering at 45 and 60 DAP, number of seeds umbel-1, weight of seeds umbel- 1, weight of seeds plant-1, weight of seeds plot-1, 1000 seed weight, seed yield, number of fruits umbel-1, percent of fruit set umbel-1and percent germination. The highest seed yield (248.16 kg ha-1) was obtained from vernalization at 5°C for 14 days. The lowest values of all the parameters were recorded at control treatment. The highest seed yield (191.77 kgha-1) was obtained from 100 ppm GA3. The lowest values of all the parameters were recorded in the 0 ppm GA3 treatment. Use of suitable vernalization of mother bulb and proper concentration of gibberellic acid can be a possible way to expand onion production at the time of summer.

Susceptibility of Winter Wheat and Triticale to Yellow Rust Influenced by Complex Interactions between Vernalisation, Temperature, Plant Growth Stage and Pathogen Race

Environmental factors influence the disease susceptibility of crop plants. In this study, we established an experimental system to investigate the effects of vernalisation, temperature and plant growth stage on the susceptibility of winter wheat and winter triticale to Puccinia striiformis, the causal agent of yellow (stripe) rust. Two temperature regimes: standard (18 °C day/12 °C night) and low (12 °C day/6 °C night), vernalised and non-vernalised seedlings, vernalised adult plants and two pathogen races were investigated. At low temperatures, vernalisation reduced the susceptibility of seedlings exposed to the ‘Warrior’ race, while this was only the case for five out of eight varieties exposed to the ‘Kranich’ race. Changing from standard to low temperature resulted in increased susceptibility of non-vernalised seedlings of seven varieties inoculated with the ‘Warrior’ race and five varieties inoculated with the ‘Kranich’ race. Increased susceptibility at low temperature was also detected for several varieties at the adult plant growth stage. Comparisons between vernalised seedlings and adult plants revealed an effect of plant growth stage on disease susceptibility (e.g., Adult Plant Resistance) in five varieties at standard temperature for the ‘Warrior’ race and in five and four varieties at standard and low temperature respectively, for the ‘Kranich’ race. The complex and unpredictable interactions between environment and pathogen influencing yellow rust susceptibility of individual varieties stress the importance of phenotyping for disease resistance under different environmental conditions and pathogen populations. The environmental impact on rust susceptibility should also be taken into account in early-warning systems targeting wheat and triticale breeding programmes and growers.