Resistance to Pepper huasteco yellow vein virus and its heritability in wild genotypes of Capsicum annuum

Abstract

<p><strong>Background: </strong><em>Pepper huastecto yellow vein virus</em> (PHYVV) is one of the main viruses affecting pepper (<em>Capsicum</em> spp.) plants in Mexico.</p><p><strong>Question: </strong>Why there are no pepper resistant cultivars to PHYVV currently? Could it be due for the lack of new pepper resistant sources and knowledge about the heritability of the resistant trait?</p><p><strong>Study species: </strong><em>Capsicum annuum, Pepper huasteco yellow vein virus </em>and<em> Bemisia tabaci</em>.</p><p><strong>Study site: </strong>Culiacan<strong> </strong>Sinaloa, Mexico; January 2013 to August 2014.</p><p><strong>Methods: </strong>Two assays were performed in 2013 and 2014 with three resistant wild lines of <em>Capsicum annuum</em> in the S2 and S3 generation under greenhouse conditions to analyze the resistance to the <em>Pepper huasteco yellow vein virus</em> (PHYVV) and its heritability. Plants were inoculated with PHYVV through <em>Bemisia tabaci</em> G. and by grafting.</p><p><strong>Results: </strong>Line UAS12 showed a significantly higher proportion of resistant plants, longer incubation time, and less amount of viral DNA, followed by lines UAS13, UAS10 and the Maverick cultivar under both inoculation methods in both assays. Distribution of symptoms revealed a bimodal tendency in both assays. The novel gene "<em>CchGLP</em>" which confer resistance to PHYVV in pepper plants, was identified in the three lines evaluated on this study. Heritability of line UAS12 was of 0.35 and 0.26 in the insects and grafting inoculations, and of 0.58 and 0.10 in the first and second assays, respectively. Lines UAS13 and UAS10 showed close to zero heritability in the first and second assays with both inoculation methods.</p><strong>Conclusions: </strong>Line UAS12 is the most promising genetic resource for its high resistance and for showing heritability for the resistance trait. The intermediate resistance of lines UAS13 and UAS10 could be also useful for breeding programs. At least two genes are involved in the resistance trait to PHYVV. Part of the resistance shown in these lines may be due to the presence of the "<em>CchGLP</em>" gene. Line UAS12 count with variability for the resistant trait and can, therefore, be used to improve resistance and the other two lines possibly are stable as they did not show heritability.