Introgession of powdery mildew resistance into cultural pea from wild accession of P. fulvum

Abstract

Wildlife pea specimen P. fulvum i-609881 of the UIP collection (Saint Petersburg, Russia) in a greenhouse box has demonstrated full resistance to powdery mildew. As a result of crossing with cultivated peas, interspecific hybrids of Stabil × i-6098881 were obtained. In populations of interspecific hybrids, the BC2F3 Stabil × i-609881 line of the leafless morphotype (af), resistant to the powdery mildew pathogen, was isolated as a result of backcrossing. As a result of crossing plants of this line with susceptible plants of the leafy (Af) variety Temp, the following series of pea hybrids was obtained. Analysis of F1 hybrids showed that all plants were characterized by resistance to the pathogen powdery mildew. In the population of F2 hybrids, a splitting analysis was performed on the basis of resistance to powdery mildew. The analysis revealed that the hybrid population consisted of 66 resistant and 20 affected plants. The actual splitting corresponded to the expected one for monogenic inheritance with a phenotype ratio of 3: 1 phenotype ratio (η05 2 test, p=0.7087438). Based on the analysis of populations of F1 and F2 hybrids, it is concluded that resistance to powdery mildew is the result of introgression of the genetic resistance factor from the genome of the P. fulvum i-609881 sample and is encoded by the dominant allele of a single gene.

Gene-Based Resistance to Erysiphe Species Causing Powdery Mildew Disease in Peas (Pisum sativum L.)

“…Studies on the inheritance of PM disease revealed three genes, namely er1, er2 and Er3, conferring resistance to Erysiphe species [22], (Figure 2). An investigation into the genetics of powdery mildew resistance (PMR) has been carried out in the past, which has shown different modes of inheritance including single recessive [35,36], single dominant [9,37] and duplicate recessive gene actions [38,39] (Table 2). Hammarlund [19] was the first to investigate PM resistance in peas and reported cumulative factors for susceptibility.…”

“…P. fulvum is a wild Pisum species that has little hybridization success with P. sativum and is likely to suffer from linkage drag [127]. However, other researchers have successfully utilized this species to transfer the PM resistance into the cultivated genotypes [37,49,118].…”

“…Er 3 was then introgressed in the cultivated genotypes through hybridization (via male parent) and is now available for use in the breeding program. Recently, Bobkov and Selikhova [ 37 ] have confirmed the presence of another dominant gene ( identity yet not confirmed) in the P. fulvum line (i-609881), which was originally collected from UIP (Saint Petersburg, Russia). This gene is also being successfully introgressed into various cultivated genotypes through repeated backcrossing.…”

“…To date only three resistant genes have been reported, that too, with very limited testing for various isolates and species of PM fungus. Furthermore, of three PM resistance genes, use of er2 and Er3 is still very limited, with only a few reports of their introgression into some of the elite genotypes [ 9 , 28 , 37 ]. Although, er1 , being recessive in nature, is giving a somewhat durable type of resistance to the pea genotypes against PM [ 27 , 59 ].…”

“…This will then result in the potential increase in the durability of PM resistance in such genotypes [ 15 ]. Using linked molecular markers, these genes could be easily brought into a single cultivar [ 37 ], which is otherwise not possible through morphological selection as the genes are located on distinct positions on the genome and exhibit differential resistance expression. Efforts are being made to combine er1 and er2 genes in one background using MAS; however, the published literature on pyramiding of all the three genes is still scanty.…”