Papers by DEVENDRA P SINGH
Phytopathology, 2005
We investigated the interaction of several differentially resistant wheatwith the hemibiotrophic ... more We investigated the interaction of several differentially resistant wheatwith the hemibiotrophic phytopathogenic fungus Bipolaris sorokiniana (teleomorph Cochliobolus sativus). Wheat genotypes Yangmai, M 3 (W7976), Shanghai 4, and Chirya 7 showed higher levels of resistancewith cv. Sonalika, used as a susceptible control. In amicroscopic inspection, we found that fungal penetration intoepidermal layer failed mostly through a cell wall-associated defense. In cases where the fungus successfully overcame epidermal, its spread within the mesophyll tissue (necrotrophic phase) wasin the more resistant genotypes. Epidermal cell wall-associated, spreading as well as the extent of electrolyte leakage of infected, correlated well with field resistance. We propose that cellular hostsuch as formation of cell wall appositions as well as the degreeearly mesophyll spreading of fungal hyphae are indicative of thepotential of the respective host genotype and, therefore, could befor the characterizat...
Spot blotch in wheat (Bread wheat Triticum aestivum L.emend Fiori & Paol., durum wheat T. durum D... more Spot blotch in wheat (Bread wheat Triticum aestivum L.emend Fiori & Paol., durum wheat T. durum Derf, Khapli wheat T. dicoccum Schubl.) is mainly caused by Bipolaris sorokiniana Boerma (Sacc.) in India and neighbouring south Asian countries and capable of causing losses in yield up to 50 % in susceptible varieties as well as results poor grain
quality. A total of 560 blighted leaf samples of wheat were collected from all over the India and cultures were broadly grouped in to 13 from BS 1-BS 13. The single spore cultures were later inoculated on seedlings of a differential set of genotypes, Sonalika, GW 322, HD 2733, PBW 34 and HPW 184 and incubated at 24+10C at 85-95% humidity inside
polyhouse for two weeks. The host pathogen interaction was measured by taking record on incubation period, infection response (IR), number of lesions on flag-2 leaf, necrotic area developed and terminal disease severity. The differences were observed at pathogenic level also amongst isolates. Most virulent isolate was BS 4 from Faizabad in North - eastern plains zone, which produced susceptible type of infection response even on resistant genotype. It is thus concluded that 13 different types of isolates exists in case of B. sorokiniana in India.
The review is prepared to bring the latest update of knowledge and strategies to contain the whea... more The review is prepared to bring the latest update of knowledge and strategies to contain the wheat blast disease in South Asian region with special emphasis to India which shares the larger borders with Bangladesh.The present review will update the earlier published
information on wheat blast (Singh, 2017).
Spot blotch caused by Bipolaris sorokiniana is major disease problem in warm and humid areas of S... more Spot blotch caused by Bipolaris sorokiniana is major disease problem in warm and humid areas of South Asian and other countries. Host resistance is an effective method to manage it and varieties with resistance to spot blotch and rusts are preferred. The stem rust resistant gene Sr2 along with other Sr genes is widely used in wheat and Triticale breeding programme to provide resistance against stem rust pathotypes including new Ug99 (TTKS). The presence of Sr2+ is also associated with morphological marker, pseudo black chaff (PBC) character, a dark pigmentation on the glumes, peduncle and below stem internodes of wheat. A total of 136 numbers of diverse genotypes of wheat and triticale having Sr2+ gene in sole and in combination with other Sr genes (Sr5+, Sr5+, Sr7b+, Sr8b+, Sr9b+, Sr9e+, Sr11+, Sr13+, Sr24+, Sr30+, Sr31+) were evaluated against spot blotch under artificially inoculated and epiphytotics at ten hot spot locations in northern plains agro ecological zones in India during 2000-01 to 2011-12 crop seasons. Based on scoring of spot blotch severity on top two leaves at mild milk stage, the genotypes were categorization of in to R, MR, MS and S category. A total of 69.9% of genotypes possessing Sr2+ genes were susceptible to spot blotch. Twenty genotypes possessing gene combinations of Sr2+5+, Sr2+5+24+, Sr2+5+3+, Sr2+8b+11+, Sr2+9e+11+, and Sr2+24+ were all susceptible to spot blotch. The resistant and susceptible genotypes with Sr2+ gene were 30.1 and 69.9%, respectively. The results suggests that Sr2+ and other stem rust resistant genes may be used cautiously in varieties meant for warm and humid regions where main spot blotch and leaf rust are major diseases.
Ninety four numbers of released varieties and genotypes of wheat and Triticale were evaluated aga... more Ninety four numbers of released varieties and genotypes of wheat and Triticale were evaluated against spot blotch caused by Bipolaris sorokiniana to assess the their levels of resistance under artificially inoculated conditions as well as to see the impact of resistance on grain colour. The seeds were analyzed for the presence of discolouration and black point after harvest. Based on spot blotch score, the genotypes were categorized in to resistant (R), moderately resistant (MR), moderately susceptible (MS) and susceptible (S) categories. The per cent black point and discoloured seeds were counted in one hundred seed sample per genotype. A total numbers of 43, 16, 18 and 17 genotypes were in the category of R, MR, MS and S, respectively against spot blotch. The most promising released varieties and genotypes showing high per cent of healthy looking seeds (99.5% or more) were, HS 375, K 65, Milan/Sha-7, NI 5439, VL 616, VL 804, VL 907, and genotype UP 2691 in T. aestivum (bread wheat), HI 8627 in durum wheat variety, and Triticale variety, TL 2942 and were in first significant group. Amongst different varieties and genotypes having significantly high total diseased seeds, were 7.0, 18.8, 27.8 and 58.8%, in case of R, MR, MS and S categories, respectively (Fig. 1). In statistical terms, the range of entries showing significantly high per cent discoloured, black point and total infected seeds were, 0.0-14.4, 2.3-18.8 and 7.0-18.8% respectively in R-MR types of varieties and genotypes, which was much lower than MS-S types showing 16.7.1-52.9, 16.7-47.1 and 27.8-58.8%, respectively.
Resistance to loose smut (Ustilago segetum var tritiel) in wheats (Triticum aestivum,T. durum and... more Resistance to loose smut (Ustilago segetum var tritiel) in wheats (Triticum aestivum,T. durum and T. dieoeeum) and triticale
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Papers by DEVENDRA P SINGH
quality. A total of 560 blighted leaf samples of wheat were collected from all over the India and cultures were broadly grouped in to 13 from BS 1-BS 13. The single spore cultures were later inoculated on seedlings of a differential set of genotypes, Sonalika, GW 322, HD 2733, PBW 34 and HPW 184 and incubated at 24+10C at 85-95% humidity inside
polyhouse for two weeks. The host pathogen interaction was measured by taking record on incubation period, infection response (IR), number of lesions on flag-2 leaf, necrotic area developed and terminal disease severity. The differences were observed at pathogenic level also amongst isolates. Most virulent isolate was BS 4 from Faizabad in North - eastern plains zone, which produced susceptible type of infection response even on resistant genotype. It is thus concluded that 13 different types of isolates exists in case of B. sorokiniana in India.
information on wheat blast (Singh, 2017).
quality. A total of 560 blighted leaf samples of wheat were collected from all over the India and cultures were broadly grouped in to 13 from BS 1-BS 13. The single spore cultures were later inoculated on seedlings of a differential set of genotypes, Sonalika, GW 322, HD 2733, PBW 34 and HPW 184 and incubated at 24+10C at 85-95% humidity inside
polyhouse for two weeks. The host pathogen interaction was measured by taking record on incubation period, infection response (IR), number of lesions on flag-2 leaf, necrotic area developed and terminal disease severity. The differences were observed at pathogenic level also amongst isolates. Most virulent isolate was BS 4 from Faizabad in North - eastern plains zone, which produced susceptible type of infection response even on resistant genotype. It is thus concluded that 13 different types of isolates exists in case of B. sorokiniana in India.
information on wheat blast (Singh, 2017).