The effect of seed size, seed treatment, seeding date and depth on Rhizoctonia seedling blight of canola

Abstract

2014. The effect of seed size, seed treatment, seeding date and depth on Rhizoctonia seedling blight of canola. Can. J. Plant Sci. 94: 311Á321. Rhizoctonia solani can have a substantial impact on seedling establishment and productivity of canola (Brassica napus). The effects of seeding date, seeding depth, seed size, and seed treatment on seedling blight of canola were evaluated under greenhouse and field conditions. Early seeding resulted in higher seedling emergence in one trial year and higher seed yield in all trial years relative to a late-seeded treatment. Mid-sized seed (range 0.7Á2.0 mm diam.) had greater seedling emergence in R. solani-inoculated growth medium in a greenhouse trial and higher seed yield in one of two field trials compared with smaller seed (B0.7 mm). In the greenhouse study, sowing of large seed resulted in greater plant height and shoot weight compared with sowing of smaller seed. The effect of seeding depth was significant only on shoot dry weight, which increased at a seeding depth of 2.6 cm. Seed treatment with Helix Xtra (thiamethoxam'difenconazole'metalaxyl'fludioxonil), and Prosper FX (clothianidin'carboxin' trifloxystrobin'metalaxyl) resulted in a significant increase in seedling emergence and yield compared with the inoculated control. These results indicate that fungicidal seed treatment can minimize the impact of R. solani on canola. . 2014. Incidence du calibre des graines, du traitement des semences ainsi que de la date et de la profondeur des semis sur la fonte des semis du canola par Rhizoctonia. Can. J. Plant Sci. 94: 311Á321. Rhizoctonia solani peut avoir un impact majeur sur l'implantation et le rendement du canola (Brassica napus). Les auteurs ont e´value´les effets de la date et de la profondeur des semis, du calibre des graines et du traitement des semences sur la fonte des semis du canola, en serre et au champ. L'ensemencement haˆtif a donne´lieu a`une leve´e plus importante une anne´e, lors des essais, et a de´bouche´sur un meilleur rendement grainier que celui obtenu avec un ensemencement tardif, toutes les anne´es de l'expe´rience. Les graines de calibre moyen (de 0,7 a`2,0 mm de diame`tre) ont mieux leve´dans le milieu du culture ensemence´avec R. solani lors d'un essai en serre et ont donne´un rendement grainier plus e´leve´que les graines plus petites ( B0,7 mm) a`l'occasion de deux essais au champ. Dans l'expe´rience re´alise´e en serre, les graines de gros calibre ont donne´des plants plus grands et des pousses plus lourdes que les graines plus petites. La profondeur des semis n'a eu un effet significatif que sur le poids sec des pousses, qui est plus e´leve´quand les graines sont plante´es a`2,6 cm de profondeur. Le traitement des semences avec du Helix Xtra (thiame´thoxam'difenconazole' me´talaxyl'fludioxonil) et du Prosper FX (clothianidine'carboxine'trifloxystrobine'me´talaxyl) a entraıˆne´une hausse significative du taux de leve´e et du rendement, comparativement au te´moin inocule´. Ces re´sultats indiquent que traiter les semences avec un fongicide pe...

Effects of damping-off caused by Rhizoctonia solani anastomosis group 2-1 on roots of wheat and oil seed rape quantified using X-ray Computed Tomography and real-time PCR

“…R. solani AG2-1 is most aggressive to young seedlings and host resistance to infection increases with age ( Verma, 1996 ). Therefore faster developing OSR cultivars are more likely to escape the disease and traits related to early germination and establishment, such as seed size will be important for breeding new varieties that are more likely to tolerate R. solani infection ( Hwang et al, 2014 ).…”

Seed size and seeding rate effects on canola emergence, development, yield and seed weight

“…Canola seed size effects on crop emergence and yield have been inconsistent. Under greenhouse conditions, Hwang et al (2014) showed that midsize seed (0.7 to 2.0 mm) had a higher emergence rate than smaller or larger seed, but that larger seed led to greater shoot weight and plant height. Under field conditions, the same authors found no seed size effect on canola emergence, but at one of two very low-yielding sites inoculated with Rhizoctonia solani, midsize seed (0.7 to 2.0 mm) yielded greater than smaller or larger seed.…”

Rhizoctonia solaniinjuries in oilseed crops in Finland and impacts of different crop management practices on disease incidence and severity

“…R. solani has been shown to cause severe damping off in Brassica crops in Finland (Linnasalmi, ; Tahvonen et al , ) but formation of stem symptoms in older OSR plants has not been studied before. R. solani , predominantly AG 2–1, has been shown to be the major cause of post‐ and pre‐emergence damping off of OSR crops worldwide (Berkenkamp & Vaartnou, , Gugel et al , ; Kataria & Verma, ; Verma, ; Khangura et al , ; Hwang et al , ).…”

“…A late sowing date in our study increased considerably the risk of high stem lesion incidence, while an effect of sowing date on root rot risk was less evident. The effect of sowing date on Rhizoctonia attack is dependent on soil temperature, soil moisture and the predominant R. solani anastamosis group present in the field and therefore results on the effect of sowing date are variable in different studies and sometimes conflicting (Hwang et al , ). In Canadian studies, the high incidence of Rhizoctonia seedling blight is often connected to early sowing when the soil is relatively cool and wet and AG 2–1 is predominant (Yitbarek et al , ; Kataria & Verma, ; Verma, ), whereas attack by AG 4 isolates later in the season is favoured by warm temperatures (Teo et al , ; Verma, ).…”