Root Rot Of Spring Wheat Research Articles

Root rot of spring wheat in field crop rotations in the forest-steppe of the Irkutsk region

The paper presents the results of the studies to assess the prevalence of root rots and yields of spring wheat in the forest-steppe zone of the Irkutsk region in field crop rotations on different back-grounds of fertilization and tillage practices. The experiment scheme: forecrops – fallow in crop rotation (fallow – wheat – oats), pea-oat mixture and corn in crop rotation (pea-oat mixture – wheat – corn – wheat); tillage methods – plowing with PLN-5-35 plow to a depth of 20-22 cm, BDT-3 disking to a depth of 12-14 cm; fertilization - no fertilizer, complete mineral fertilizer N45P45K45. The prevalence of root rot decreased on average for 3 years in the crop rotation with 33 % saturation of wheat and its sowing on a fallow forecrop in comparison with 50 % saturation in pea-oats by 6.1 %, in corn by 0.9 %; disc tillage compared to plowing in fallow forecrop by 11.8 %, in pea oats by 4.7 %, in corn by 9.2 %; on fertilized background in three-field crop rotation in fallow by 4 %, in pea oats by 1.9 %, in corn by 4.8 %. Statistically reliable highest yield of spring wheat was observed in three-field crop rotation with 33 % saturation of wheat on fallow at soil plowing, which is higher than similar soil treatment in crop rotation with 50 % saturation of wheat at sowing on pea and oat mixture by 31.3 %, on corn by 23.8 %. Application of mineral fertilizers N45P45K45 increased the yield, while tillage with discing and the forecrops such as pea and oat mixture and corn decreased the yield. Over the rotation, root rot incidence decreased from baseline with a concomitant increase in yield – with 33 % wheat saturated in the rotations by 9.0 % and 35.0 %, and with 50 % wheat saturated in the rotations by 6.6 % and 45.7 %.

ЭЛЕМЕНТЫ, СЛАГАЮЩИЕ УРОЖАЙ ЯРОВОЙ ПШЕНИЦЫ СОРТА ЙОЛДЫЗ В ЗАВИСИМОСТИ ОТ ПОРАЖЕНИЯ КОРНЕВОЙ ГНИЛЬЮ В УСЛОВИЯХ ПРЕДКАМЬЯ РТ

The research was carried out to study the effect of the infestation of spring wheat plants of the Yoldyz variety by root rot on individual elements of the crop structure. During 2018-2019, experiments were conducted at the experimental field of the Kazan State Agrarian University on the basis of the Agrobiotechnopark, laboratory analyses were conducted at the Center for agroecological Research of the Institute of Agrobiotechnologies and Land Use. Experiments have shown that the survival rate of spring wheat plants in growing conditions was the lower, the higher the degree of their root rot disease. In the germination phase, 13.2-15.6% of plants were affected, and by wax ripeness, the lesion increased by 9.3-19.1%. Against the background of mineral nutrition N123P73K108, the lesion was 11.2% lower than against the background without fertilizers. With an increase in the degree of the disease, the ear of the ear decreases. In healthy plants, the number of grains in the ear was 21.4-25.3 pieces, and in severely affected plants – 8.0-13.4 pieces. Grain yield losses from root rot amounted to 0.54-0.69 t/ha. On the fertilized background of nutrition, losses were less by 0.15 tons per 1 ha, which is undoubtedly due to an increase in the resistance of spring wheat plants to root rot. The potential of spring wheat of the Yoldyz variety was realized through three main elements of the crop structure: a productive stem per unit area, the ear of the ear and the mass of 1000 grains. The effect of root rot on the elements of the structure of the spring wheat crop depends on the degree of root rot damage. The disease reduces the productive stem, the ear of the ear and the mass of 1000 grains more significantly with a 3-point lesion. Reducing the degree of damage to the root rot of spring wheat under conditions of application of calculated doses of fertilizers contributes to improving the elements of the crop structure and obtaining a high yield of grain of this crop.

Development of Soil-Borne Infections in Spring Wheat and Barley as Influenced by Hydrothermal Stress in the Forest-Steppe Conditions of Western Siberia and the Urals

This is a first-time assessment of the direct and indirect effects of hydrothermal conditions on pathogenesis of root infections in cultivated varieties of spring wheat and barley. Long-term field research (2000–2015) was carried out in the area of risk farming combined with laboratory experiments. The effects of the phytosanitary condition of soil, seeds, and underground plant organs were taken into account. It was found that soil pathogenic population and the development of soil-borne infections largely depend on hydrothermal factors. The development of root rot of spring wheat was stimulated by arid conditions during tillering and heading: the disease rate was increased by 33.5% compared to the optimal moisture supply against a background of a high plant pathogen population of the soil. In drought conditions, the number of saprotrophic microorganisms decreased 3.3 times and suppressive soil activity fell 3.0 times provoking root infections. Microorganisms consuming inorganic forms of nitrogen and cellulolytic agents were found to be highly sensitive to hydrothermal factors. Arid conditions increased the plants’ susceptibility to the inoculum of soil origin, since the increase in the number of conidia in the inoculum from 5–15 to 150–180 per 1 g of soil increased the frequency of infections by root rots by 7.8 times, especially on the epicotyl and the base of the stem. Damage of root rot was increased by pest flies Oscinella frit L., O. pusilla Mg., Phorbia genitalis Schnb., and Mayetiola destructor Say. Their activity increased in warm, arid conditions. Drought-resistant gramineous weeds Panicum miliaceum ssp. ruderales L. (Kitag.) Tzvei., Setaria glauca (L.) Beauv., Avena fatua L., Setaria viridis (L.) Beauv. competed with the crop and consequently increased the development of root rot by 20% or more in dry years. Seeds of gramineous weeds, multiplied after dry years, contributed to reproduction and survival of many soil-borne phytopathogens. Grain ripening in moistened conditions led to transmission of the root rot agents Bipolaris sorokiniana Sacc. Shoem. (syn. Helminthosporium sativum Pam., King et Bakke) and Fusarium fungi via seeds. This led to proliferation of root rot in the germination phase and significantly (53%) affected the cereals’ germ.

Biological control of common root rot of spring wheat by coating seeds with bacillus or trichodea spp

Biological control of common root rot of spring wheat by coating seeds with bacillus or trichodea spp

The impact of crop rotation and N fertilizer on common root rot of spring wheat in the Brown soil zone of western Canada

From 2000 to 2003, spring wheat (Triticum aestivum L.) grown in southwest Saskatchewan 1 or 2 yr after summerfallow, and after lentil (Lens culinaris Medik), flax (Linum usitatissimum L.), or continuously with and without fertilizer N was examined for root rot by measuring discoloration of subcrown internodes. Discolored tissue was also plated on nutrient agar for fungal identification. In general, common root rot was present at consistently highest levels in wheat grown after lentil, and at lowest levels in wheat grown continuously with low N fertility. The most common fungal species isolated from affected subcrown internodes were Cochliobolus sativus (Ito and Kurib.) Drechs. ex Dast. and Fusarium spp. Among the latter, F. avenaceum (Fr.) Sacc., F. equiseti (Corda) Sacc. and F. pseudograminearum O’Donnell & T. Aoki were most frequent. Fusarium avenaceum is one of the most common fusarium head blight pathogens in Saskatchewan. Wheat after lentil had one of the highest levels of this fungus. Continuous wheat grown with recommended N rates and wheat grown after summerfallow had in most cases similar root rot levels, but the frequency of fungi differed. Among the crop rotations examined, it appears that the most favourable for development of root rot in wheat was a wheat-lentil rotation. This cereal-pulse system may also contribute to a build-up of F. avenaceum inoculum for the development of fusarium head blight, an important emerging disease of cereals in Saskatchewan. Key words: Crop rotation, common root rot, wheat, Cochliobolus sativus, Fusarium, nitrogen

Role of root colonization ability of plant growth promoting fungi in the suppression of take-all and common root rot of wheat

Plant growth promoting fungal (PGPF) isolates — GS6-1, GS7-4 ( Phoma sp.) and GU23-3 (non-sporulating fungus), from zoysiagrass rhizosphere, suppressed take-all and common root rot of spring wheat caused by Gaeumannomyces graminis var. tritici (Ggt) and Cochliobolus sativus (Cs), respectively, in the greenhouse. Barley kernels colonized with pathogens (0.1%, 0.5% or 1.0% w w ) and PGPF isolates (1.0%, 1.5% or 2.0% w w ) were added to soil individually and in different combinations of pathogen and PGPF. With an increase in the rate of PGPF amendment, all three PGPF isolates suppressed take-all and common root rot ( P = 0.05), irrespective of the pathogen inoculum level. Among the PGPF isolates, GS6-1 and GS7-4 were more effective than GU23-3. When added to soil individually, PGPF isolates were recovered from 75 to 95% of root segments, and Ggt and Cs from 88–95% of root segments. Both Ggt and Cs were isolated less frequently from roots when the PGPF concentration was high (2.0%); however, the PGPF isolates were isolated from roots in high frequencies even when the pathogen inoculum level was high. Isolate GS6-1 promoted plant growth even when the pathogen inoculum rate was high, as did GS7-4, but to a lesser amount. These fungal isolates suppressed take-all and common root rot, and two of them also increased plant growth. The suppression of take-all and common root rot appeared to be due to the competitive root colonization by PGPF isolates, thus blocking sites available for infection by pathogens.

The effect of soil salinity on common root rot of spring wheat and barley

Samples were taken from several sites across a salinity gradient from areas where plants were visibly unaffected to the edge of saline areas where no plants grew, from commercial fields located near Saskatoon in 1984, 1987, 1990 and 1991. There was a significant (P = 0.05) positive correlation for wheat and barley between salinity and common root rot in all years, except 1991 (1984: r = 0.445, n = 26; 1987: r = 0.390, n = 54; 1990: r = 0.244, n = 75; 1991: r = 0.247, n = 40). The correlation between inoculum level and disease was not significant, except for one barley field in 1990. However, when inoculum level was used as a covariate, the significance of the relationship between salinity and common root rot increased. Growth of Cochliobolus sativus was unaffected on solid and liquid media until conductivity levels were higher than 30–50 mmhos cm−1. Since wheat and barley do not grow at levels higher than 10–15 mmhos cm−1, salinity would have a greater affect on plants than on the pathogen. The relationship between salinity and disease is consistent with the theory that stress increases common root rot in plants. However, the variation in salinity only explains about 20% of the variation in common root rot. Key words: Cochliobolus sativus, common root rot, salinity, cereals

Effects of tillage systems and crop rotations on root and foliar diseases of wheat, flax, and peas in Saskatchewan

The dynamics of root and foliar diseases were studied in spring and winter wheat, peas, and flax and under zero, minimum, and conventional tillage at Indian Head, Saskatchewan, from 1987 to 1990. No disease was observed on flax during the 4 yr. Year-to-year variation was more important than tillage systems in explaining the incidence of bacterial leaf spot and foot rot of peas. Tan spot and septoria leaf blotch were the most important foliar diseases of wheat. Disease ratings (0–9) of the leaf spots were greater on winter wheat (average 2.2) than on spring wheat (average 1.9) and also greater on spring wheat following a cereal (average 2.0) than following peas or summer fallow (average 1.7). Hot and dry weather did not enhance development of foliar diseases, and no consistent effects of tillage on leaf disease ratings were observed. However, take-all and common root rot were affected by crop management. Incidence of take-all was greater on winter wheat (8%) than on spring wheat (1%) and also greater on winter wheat under conventional (11%) than minimum (8%) or zero tillage (6%). Severity of common root rot of spring wheat was greater following either spring (24%) or winter wheat (25%) than peas (22%) and summer fallow (15%). The severity of common root rot varied from year to year. In 3 of the 4 years, minimum-till and zero-till reduced the severity of the disease.Key words: Zero till, minimum till, conventional till, crop rotation, disease, spring wheat, winter wheat

Infrared thermometry leaf temperature measurements and common root rot of spring wheat and spring barley

In field trials done from 1983 to 1985, two cultivars of wheat and two cultivars of barley were rated periodically for common root rot, and leaf temperatures were recorded with a hand-held infrared thermometer. Significant differences for common root rot occurred between cultivars of both wheat and barley but leaf temperatures did not differ among cultivars. Disease rating and leaf temperature were not correlated in wheat and only 2 of 47 comparisons were positively correlated in barley.

Effects of flooding at early growth stages and mechanical damage of foliage on common root rot of spring wheat and spring barley

Effects of flooding at early growth stages and mechanical damage of foliage on common root rot of spring wheat and spring barley

Disease progression in common root rot of spring wheat and barley

Disease progression in common root rot of spring wheat and barley