Comparison of chili pepper breeding populations for agronomic traits and polygenic resistance to Phytophthora blight

Comparação de populações melhoradas de pimenta para características agronômicas e resistência poligênica à queima das folhas por Phytophthora

ABSTRACT

Belonging to the Oomycete class, Phytophthora capsici has wide range of host profile and is responsible for many devastating diseases in many countries. In addition to time consuming problem for transferring resistance to susceptible varieties, backcrossing method causes losing of genes providing resistance to susceptible varieties. In this study transferring P. capsici resistance genes to susceptible chili pepper lines was aimed during the extensive breeding period and resistant lines were confirmed by marker assistance. Two different breeding populations from CM334 and PM217 were compared by stem inoculation test to determine receptivity, inducibility, and stability resistance component. CM334 was found more effective for transferring all resistance components while PM217 was found suitable for keeping agronomic traits along with two important resistance component inducibility and stability. These two resistant components were found highly correlated to length of stem necrosis. C-29 and C-18 have been improved from CM334 as resistant as CM334; P-73 and P-77 have been improved satisfactorily resistant and yielded lines from PM217. Marker assisted selection proved that resistance of lines differentiated phenotypically despite the genotypes have the same genes.

Keywords:
Capsicum annuum; Phytophthora capsici; resistance component; molecular markers; crop breeding