Hot pepper (Capsicum chinense, Jacq.) inheritance of reaction to powdery mildew

Abstract

The pepper species C. chinense has been considered one of the most important resistance sources to powdery mildew Capsicum spp. However, the inheritance in this species was unknown. The purpose of this work was to study its reaction inheritance. Two powdery mildew resistant parents, 'Pimenta Cheiro' 1 and PI 152225 and two moderately susceptible ones, 'Pimenta Doce' IH-1761 and 'Pimenta Índio', were used to obtain three F 1 and their respective F 2 generations: 'Pimenta Doce' IH-1761 × 'Pimenta Cheiro' 1, 'Pimenta Índio' × PI 152225 and 'Pimenta Doce' IH-1761 × PI 152225. The powdery mildew epidemy was natural using inoculum from a highly-sporulating susceptible pepper host. Powdery mildew host reaction evaluations were carried out during the fruiting stage using a rating system based on disease severity scales varying from 1 (resistant) to 5 (highly susceptible). The experimental design was completely randomized. The following genetic parameters were estimated: gene action, heritability coefficient and expected selection gain in the F 3 generation. The transgressive segregation in F 2 indicated oligogenic inheritance. Results show the presence of additive, dominant, and epistatic gene action. The dominant and epistatic effects detected in crosses presented negative values, tending towards susceptibility. The heritability and selection gain estimates were moderate, with values of 35.5% and 1.7% for 'Pimenta Doce' IH 1761 × 'Pimenta Cheiro' 1, from 50.4% to 3.5% for 'Pimenta Índio' × PI 152225, and 49% and 2.7% for the 'Pimenta Doce' IH 1761 × PI 152225 crosses, respectively. These gene action results are favorable for breeding programs and exploration of hybrids.

Novel sources of resistance to powdery mildew (Leveillula taurica (Lév.) Arnaud) in pepper

“…To record the reaction at two different DAI allowed us to select accessions with a consistent response of low infection over the time, such as Ag-01, Ag-02, A-06, A-23, belonging to C. annuum and C-05, from C. chinense. On the contrary to other authors (Blat et al, 2005 and2006;McCoy and Bosland, 2019), our findings did not identified sources of resistance from the C. baccatum accessions tested here.…”

“…The biotroph nature of the fungus requires to maintain infected plants as a source of inoculum and limits the evaluation of accessions for resistance (Daubeze et al, 1995;Lefebvre et al, 2003;Blat et al, 2005 and2006). Evaluation usually is done in open fields at the fruiting stage, but it also can be done under controlled conditions (greenhouses or growth chambers) during early plant stages, where inoculation of accessions is done from 3-4 true leaves up to the fruiting stage (de Souza and Café-Filho, 2003;Zheng et al, 2013).…”

“…High tolerances have been found in other Capsicum species like C. baccatum L., C. chinense Jacq., C. frutescens L., and C. pubescens Ruiz & Pav. (Lee et al, 2001;de Souza and Café-Filho, 2003;Blat et al, 2005 and2006). Despite C. chinense and C. frutescens are grouped within the C. annuum botanical complex, sexual incompatibility (both pre and postzygotic) has been reported on many occasions, depending on the accession (Manzur et al, 2015).…”

Molecular Mapping of PMR1, a Novel Locus Conferring Resistance to Powdery Mildew in Pepper (Capsicum annuum)

“…The dominant resistance sources in ‘VK515' and ‘PM Singang' are different from other known powdery mildew resistance factors reported. Overall, previous findings and the results presented here indicate that the nature of genetic resistance to powdery mildew in pepper genotypes is highly variable, and it is likely that different genes are involved in conferring the powdery mildew resistance in different genetic backgrounds (Daubèze et al, 1995 ; Murthy and Deshpande, 1997 ; Lefebvre et al, 2003 ; Blat et al, 2005 , 2006 ).…”

“…Powdery mildew resistance in pepper is reported to be a dominant and polygenic trait (Anand et al, 1987 ; Murthy and Deshpande, 1997 ; Blat et al, 2005 ). Genetic analyses have also indicated that relatively few genetic factors with significant additive and epistatic effects confer resistance to powdery mildew in different pepper genetic backgrounds (Daubèze et al, 1995 ; Murthy and Deshpande, 1997 ; Blat et al, 2005 , 2006 ). At least three pairs of incompletely dominant genes are thought to confer resistance to powdery mildew in the C. frutescens line ‘IHR 703' (Anand et al, 1987 ).…”