Date Published: February 16, 2016
Publisher: Springer Berlin Heidelberg
Author(s): Sushma Kumari Pawar, Davinder Sharma, Joginder Singh Duhan, Mahender Singh Saharan, Ratan Tiwari, Indu Sharma.
Stripe rust caused by Puccinia striiformis f. sp. tritici is most important and devastating disease of wheat worldwide, which affects the grain yields, quality and nutrition. To elucidate, the genetic basis of resistance, a mapping population of recombinant inbred lines was developed from a cross between resistant Cappelle–Desprez and susceptible cultivar PBW343 using single-seed descent. Variety PBW343 had been one of the most popular cultivars of North Western Plains Zone, for more than a decade, before succumbing to the stripe rust. Cappelle–Desprez, a source of durable adult plant resistance, has maintained its resistance against stripe rust for a long time in Europe. Map construction and QTL analysis were completed with 1012 polymorphic (DArT and SSR) markers. Screenings for stripe rust disease were carried out in field condition for two consecutive crop seasons (2012–2013 and 2013–2014). Susceptible parent (PBW343) achieved a significant level of disease i.e., 100 % in both the years. In present investigations, resistance in Cappelle–Desprez was found stable and response to the rust ranged from 0 to 1.5 % over the years. The estimated broad-sense heritability (h2) of stripe rust rAUDPC in the mapping population was 0.82. The relative area under the disease progress curve data showed continuous distributions, indicating that trait was controlled multigenically. Genomic region identified on chromosome 2D, was located within the short arm, with flanking markers (Xgwm484–Xcfd73), explained phenotypic variation (PVE) ranged from 13.9 to 31.8 %. The genomic region identified on chromosome 5B was found with the effect of maximum contribution with flanking DArT markers (1376633|F|0–1207571|F|0), PVE ranged from 24 to 27.0 %. This can, therefore, be utilized for marker assisted selection in developing much needed stripe rust resistant lines for the northern wheat belt of India.
Stripe rust caused by Puccinia striiformis is one of the major biotic constraints of wheat production in areas where the cool temperature prevails and affects the grain yield, quality and nutrition. Stripe rust is one of the most important diseases that can cause tremendous losses in wheat production worldwide (Stubbs 1988). Stripe rust can cause yield losses up to 10–70 % and in some cases as high as 100 % yield loss, if the infection occurs at a very early stage and continues to the later stage of the plants (Syed et al. 2007). Major wheat producing area in India fall under North Western Plains Zone (NWPZ) along with the strategic area of wheat cultivation under Northern Hills Zone (NHZ). The disease can be controlled by the use of chemicals, although this method is neither cost effective nor environmentally safe (Rosewarne et al. 2013). Other important effective strategy to control disease is the use of resistant cultivars and the deployment of resistance gene in high yielding varieties. Resistance could be either race specific or non-race specific. Race-specific, also called vertical/seedling/non-durable type of resistances often when deployed is effective only for short-time period (4–5 years). Generally, it is overcome by the new races of pathogen because of constant evolution/selection of races in the nature. On the other hand, non-race-specific resistance (horizontal/partial/slow-rusting/durable or adult plant resistances) shows pleiotropic effect is hard to match by the pathogen and can combat the disease for wide range of pathotypes. A number of such type of slow-rusting genes (showing additive effect) need to be pyramided together to achieve effective genetic control against disease progress in the field. Some of the durable/slow-rusting genes namely Lr34/Yr18, Lr46/Yr29, Lr67/Yr46 and Sr2/Yr30 have been reported and found effective in providing rust resistance at field level (Rosewarne et al. 2012). Therefore, it is necessary to search for new source(s) of resistance to identify durable adult plant effective stripe rust resistance against the evolving pathotypes in bread wheat.
Stripe rust severity for the susceptible parent (PBW343) achieved a significant level of disease i.e., 100 % in both the years. In India, PBW343 had been one of the most popular and ruling varieties of North Western Plains Zone (NWPZ). Lines PBW343 and Inqualab 91 along with their derivatives not only carried high levels of resistance to leaf and stripe rusts or both, but also showed about 5–15 % higher yield potential than the original cultivars (Singh et al. 2004). Stripe rust resistance in PBW343 (in India), Inquilab-91 and Bakhtwar (in Pakistan), Chamran and Shiroudi (in Iran), Kubsa (in Ethiopia) and Cham 8 (in Syria) was based on Yr27. Breakdown of Yr27 resistance in PBW343, Inquilab 91 and Chamran, in India, Pakistan and Iran, respectively, was reported between 2002 and 2004. Although occasional stripe rust outbreaks appeared in some other wheat growing areas of the world as well but due to unfavorable environmental conditions increase in the severity of Yr27 virulent pathotypes got restricted.