QTL mapping of anthracnose (Colletotrichum spp.) resistance in a cross between Capsicum annuum and C. chinense

Abstract

Anthracnose fruit rot is an economically important disease that affects pepper production in Indonesia. Strong resistance to two causal pathogens, Colletotrichum gloeosporioides and C. capsici, was found in an accession of Capsicum chinense. The inheritance of this resistance was studied in an F(2) population derived from a cross of this accession with an Indonesian hot pepper variety ( Capsicum annuum) using a quantitative trait locus (QTL) mapping approach. In laboratory tests where ripe fruits were artificially inoculated with either C. gloeosporioides or C. capsici, three resistance-related traits were scored: the infection frequency, the true lesion diameter (averaged over all lesions that actually developed), and the overall lesion diameter (averaged over all inoculation points, including those that did not develop lesions). One main QTL was identified with highly significant and large effects on all three traits after inoculation with C. gloeosporioides and on true lesion diameter after inoculation with C. capsici. Three other QTL with smaller effects were found for overall lesion diameter and true lesion diameter after inoculation with C. gloeosporioides, two of which also had an effect on infection frequency. Interestingly, the resistant parent carried a susceptible allele for a QTL for all three traits that was closely linked to the main QTL. The results with C. capsici were based on less observations and therefore less informative. Although the main QTL was shown to have an effect on true lesion diameter after inoculation with C. capsici, no significant QTL were identified for overall lesion diameter or infection frequency.

Mapping for Axillary Shooting, Flowering Date, Primary Axis Length, and Number of Leaves in Pepper (Capsicum annuum)

“…Hence, the inheritance of these traits has been extensively studied and the quantitative trait loci (QTLs) that contribute to disease resistance and fruit traits have been reported (Ben Chaim et al, 2001a, 2001bLefebvre et al, 2003;Minamiyama et al, 2005Minamiyama et al, , 2007Popovsky and Paran, 2000;Thabuis et al, 2003;Voorrips et al, 2004). In addition to the above-mentioned traits, axillary shooting, flowering date, primary axis length, and number of leaves are also important for pepper production.…”

Resistance in Capsicum spp. to anthracnose affected by different stages of fruit development during pre- and post-harvest

“…The presence of a recessive gene controlling anthracnose resistance has also been described in Capsicum chinense (Pakdeevaraporn et al, 2005). Voorrips et al (2004) used quantitative trait loci (QTL) mapping and identified a highly significant main QTL with major effect on three evaluated traits (frequency of infection, lesion true diameter and overall diameter of lesion) after the inoculation of C. gloeosporioides in plants from crosses between Capsicum annuum and C. chinense. In this study, tests to assess resistance were performed only in ripe fruit.…”

A major recessive gene associated with anthracnose resistance to Colletotrichum capsici in chili pepper (Capsicum annuum L.)

“…Disease evaluation was conducted using the disease incidence (percentage of infected sites per total inoculated sites), overall lesion diameter (averaged over all inoculation points, including those that did not develop lesions), and true lesion diameter (averaged over all lesions that actually developed) method at 7 days after inoculation (DAI), as described previously (Voorrips et al 2004). A chi-squared goodness-of-fit test was used for statistical analysis.…”

“…In these countries, the causal pathogens are C. gloeosporioides, C. capsici, and C. acutatum. The primarily causal pathogens in Thailand and Indonesia are C. gloeosporioides and C. capsici (Lin et al 2002, Voorrips et al 2004. C. gloeosporioides attacks pepper fruits at both the green and red stages, while C. capsici mainly attacks pepper fruits at the red stage (Park et al 1990a).…”

“…Several sources of resistance to C. capsici have been reported (Cheema et al 1984, Lin et al 2002, Pakdeevaraporn et al 2005, Park et al 1990b, Voorrips et al 2004) and, using these resources, researchers have studied the inheritance of anthracnose resistance (Lin et al 2002, Pakdeevaraporn et al 2005, Park et al 1990b, Voorrips et al 2004. However, inheritance patterns vary depending on the source of resistance and the Colletotrichum isolate.…”