Advances in genetic studies of black point disease in wheat

Black point disease seriously affects wheat production around the world. Because the incidence of black point is influenced by both pathogens and the environments, selecting resistant wheat lines and then breeding resistant cultivars under natural field conditions are not reliable, and assessment of disease resistance through inoculation of pathogens under controlled environments is time-consuming and laborious. One effective method to develop wheat cultivars resistant to black point is through molecular marker-assisted selection (MAS). Wheat resistance against black point is determined by quantitative trait loci (QTL) with broad-sense heritabilities of black point incidence in a range of 0.52–0.78. One hundred and ten loci for black point resistance have been identified on all wheat chromosomes. Among them, homoeologous groups 2 and 5 chromosomes contain the most loci, with 21 and 19, respectively, and homoeologous group 6 chromosomes have the fewest loci (11). The A, B, and D genomes contain 34, 41, and 35 loci, respectively. Although many loci for black point resistance have been reported, the effects of major loci are not clear. Further, because of the lack of molecular markers and resistant germplasms screened by pathogen inoculation under controlled conditions, breeding wheat cultivars resistant to black point is still difficult. In this review, these major problems were examined, and suggestions on identifying pathogens and using accurate assessment technology are proposed. It will be conducive to develop molecular markers closely linked to major loci and create resistant germplasms through MAS, which will promote the progress in resistance breeding and the control of black point in wheat.