Development and characterization of the 4th CSISA-spot blotch nursery of bread wheat

Abstract

Spot blotch (SB) caused by Cochliobolus sativus is a serious biotic stress to wheat in warm and humid areas, particularly South Asia (SA). In order to support South Asian farmers to combat SB, International Maize and Wheat Improvement Center (CIMMYT) established an efficient SB screening system at Agua Fria, Mexico and developed a nursery under the project -Cereal Systems Initiative for South Asia (CSISA). The materials used to form CSISA-SB nursery were selected from advanced breeding lines from different wheat breeding programs at CIMMYT. Seed of CSISA-SB nursery was produced at diseasefree plots at El Batan and Mexicali, and distributed to SA after rigorous seed health checks. The 4th CSISA-SB, made available in 2012, comprised 50 entries including two resistant and two susceptible checks. The nursery was evaluated in seven locations in Mexico, India, and Bangladesh in the 2012-13 cropping season. The results indicated that although few lines exhibited stable resistance across locations due to strong G × E interaction, promising lines with SB resistance and good agronomy can still be identified in each location. The two most promising lines showing consistent spot blotch resistance across the regions were CHUKUI#1 (CIMMYT germplasm bank identification number, GID 6178575) and VAYI#1 (GID 6279248). These lines Eur J Plant Pathol (2015) 143:595-605 could be promoted as sources of SB resistance or directly released as cultivars in SA.

Spot blotch disease of wheat: the current status of research on genetics and breeding

“…Major known sources of resistance for wheat crop against spot blotch within the wheat gene pool represent the primary gene pool and are listed in Table . These sources are available mainly from Brazil, China, India, Mexico (CIMMYT = International Maize and Wheat Improvement Centre), Nepal and Pakistan, although some of these entries from different countries may have the same origin/pedigree (Mehta, ; Alam et al ., ; Bhatta et al ., ; van Ginkel & Rajaram, ; Joshi et al ., ; Singh et al ., ).…”

“…Breeding for disease resistance is environmentally a sound and cost‐effective means of managing spot blotch. The level of resistance in wheat cultivars grown on the Indian subcontinent is not sufficient to avoid yield loss under high disease pressure (Joshi et al ., ; Singh et al ., ). Early efforts devoted to breeding for spot blotch resistance involved use of donors from southern Africa, Brazil and China (Dubin & van Ginkel, ; van Ginkel & Rajaram, ).…”

Disease Impact on Wheat Yield Potential and Prospects of Genetic Control

“…With major emphasis on breeding SB resistance, CIMMYT has successfully developed moderately resistant germplasm with the desired phenology, i.e., early and semidwarf along with high yield potential (91). Several studies on the association of SB resistance with agronomic and morphological traits, e.g., plant height, leaf angle, maturity, and stay green, have been conducted in association with leaf tip necrosis studied in detail.…”

“…Several studies on the association of SB resistance with agronomic and morphological traits, e.g., plant height, leaf angle, maturity, and stay green, have been conducted in association with leaf tip necrosis studied in detail. The pleiotropic rusts and mildew resistance gene Lr34/Yr18/Sr57/Pm38/Ltn1 was shown to confer partial resistance to SB and designated as Sb1 (91). Recently, Kumar et al (51) and Lu et al (58) mapped the Sb2 and Sb3 genes on chromosomes 5B and 3B, respectively.…”

Hydrogen Peroxide Prompted Lignification Affects Pathogenicity of Hemi-biotrophic Pathogen Bipolaris sorokiniana to Wheat

“…Shoem. ), a hemibiotrophic fungus, and constitutes a significant constraint of the crop in warm, humid, tropical areas of Bangladesh, Bolivia, Brazil, India, Nepal, and Paraguay ( Gupta et al, 2018 ; Gurung et al, 2013 ; Singh et al, 2015 ). Spot blotch of wheat has been documented as causing yield losses ranging between 16 to 20% annually ( Dubin and van Ginkel, 1991 ) and as high as 100% in severe epidemics ( Mehta, 1998 ).…”