Study of inheritance and allelic relation of resistance to spot blotch (Bipolaris sorokiniana) of wheat Kumar Sundeep1,*, Kumar Uttam2, Singh Amit K.1, Singh Rakesh1, Prasad L.C.3, Joshi A.K.2 1Division of Genomic Resources, NBPGR, New Delhi-110012 (India) 2CIMMYT (International Maize and Wheat Improvement Center), El Batan, Texcoco, Edo. de (Mexico) 3Department of Genetics and Plant Breeding, BHU, Varanasi-221005 (India) *Corresponding Author Email: sundeepksharma77@rediffmail.com
Online published on 24 November, 2014. Abstract Six varieties viz., Chirya-1, Chirya-3, Chirya-7, Yangmai-6, Ning-8201 and Ning-8319 known for their resistance to spot blotch were crossed with the most susceptible parent i.e., Sonalika for studying inheritance pattern and establishing allelic relationship among different resistance sources. Disease severity of F1 ’s were intermediate to slightly tilted towards resistant parents and thus indicated either no dominance or partial dominance. Progeny rows of these crosses were evaluated in the F3 and F4 generations. Disease severity for each progeny rows was measured at three different growth stages viz., late anthesis (69), late milk (77) and early dough (83) stages. Based on disease severity, the F3, F4 and F5 progenies were grouped into three classes: homozygous dominant, segregating and homozygous susceptible. Based on this ratio, number of effective genes was estimated following χ2 analysis and quantitative approaches. Chirya-1, Chirya-3, Chirya-7, Yangmai-6 and Ning-8201 showed involvement of two genes in resistance while, Ning-8319 showed the presence of three resistance genes to spot blotch. Resistant × resistant crosses were made to establish the allelic relationship of resistance genes. The F3 progeny of all the crosses did not show susceptible plants. This proved that at least one gene was common among parents for resistance. However, the appearance of transgressive segregants was an indication of the non-allelic relationship. The present study also indicated the possibility of achieving enhanced resistance through gene pyramiding. Top Keywords Bipolaris sorokiniana, inheritance, allelic relation. Top |