Identification of Cytoplasmic Male Sterility (CMS) and Maintainer Line through Testcross and Self-Pollination in Chili Peppers (Capsicum annuum L.)

Hybrid seed production in chili is more efficient when using male-sterile plants. Cytoplasmic male sterility (CMS) produces 100% male sterile progeny and eliminates the need for emasculation, making it highly advantageous for hybrid seed production and enhancing the genetic purity of hybrid seeds. Indonesia possesses a wide range of commercial hybrid chili pepper varieties that can serve as alternative sources of CMS genetic resources. Although CMS germplasm is available from the World Vegetable Center (AVRDC), the utilization of commercial hybrid varieties as CMS sources is more practical because their seeds are widely available domestically. In this study, nine commercial hybrid chili varieties were used as female parents and testcrossed with IPB379 as a candidate maintainer line and self-pollination was performed for each hybrid. The resulting progenies were evaluated based on segregation patterns of male sterility, floral morphology, and correlation among flower traits and fertility status. This study reports that the chili pepper hybrids IPB432, IPB433, IPB434, IPB435, IPB436, IPB437, IPB439, and IPB440 are presumed to carry a CMS gene based on the 1:1 segregation ratio observed in the testcross populations and the 3:1 segregation ratio observed in the self-pollinated populations. In addition, the chili pepper line IPB379 has the potential to serve as a maintainer line because it consistently produced a 1:1 testcross segregation ratio across the eight hybrid genotypes. Furthermore, CMS chili pepper plants exhibited smaller anther length and width than fertile plants due to reduced pollen production.