Contents lists available at ScienceDirect Scientia Horticulturae journal homepage: www.elsevier.com/locate/scihorti Review CMS system and its stimulation in hybrid seed production of Capsicum annuum L. B.N. Swamy ⁎ ,1 , N.K. Hedau 1 , Chaudhari G.V., Lakshmi Kant, A. Pattanayak Crop Improvement Division, ICAR-VPKAS, Almora, India ARTICLE INFO Keywords: Capsicum CMS GMS fertility restorer marker ABSTRACT Cytoplasmic male sterility (CMS) is maternally inherited trait; its phenotypic expression generally is due to interaction between sterile cytoplasm and recessive nuclear genes. Presently, commercial hybrid seed production of Capsicum relies on hand emasculation and pollination resulting in higher seed production cost to the seed producers. However, exploitation of CMS in hybrid seed production could significantly diminish its production cost and has capability to provide genetically pure seed. The best CMS approach is a 3-line hybridization method involving male sterile line (A-line), Maintainer line (B-line) and Restorer of fertility line (C-line). Availability and identification of Restorer of fertility (Rf) line in sweet pepper for suppressing male sterile phenotype in F 1 plants is difficult task. Thus identification of reproducible, co-dominant molecular markers linked to nuclear (Rf) and mitochondrial (S-cytoplasm) genes offers fast and reliable detection of parental lines during F 1 hybrid seed production. In this review, we tried to present the possibilities of exploiting CMS in Capsicum with their merits and drawbacks. 1. Introduction Among the five domesticated Capsicum species, Capsicum annuum L. is an important vegetable crop grown in temperate and tropical regions of the world. It is rich in vitamin C and B-complex, minerals, essential oils, carotenoids and capsaicin. In India, sweet pepper and hot pepper are important commercial crops, cultivated for vegetable, spice and value-added processed products. Capsicum occupies an area of 30 thousand hectares and produces 172 thousand tonnes of Capsicum fruits. In contemporary farmers thrust for hybrid seeds in Capsicum cultivation has magnified manifold owing to their excellence in quality, yield and biotic stress management. It is forecasted hybrid seeds in Capsicum cultivation will covers more than 80% of the total cropped area. At present, commercial hybrid seed production shouldered on hand emasculation and pollination which intern enhances resultant seed cost. Genic male sterility (GMS) and cytoplasmic male sterility (CMS) offer good opportunities to forbid escalating cost of hybrid seed production. Male sterility refers to inability of flowering plant to produce functional pollen grain. GMS is governed by one or more nuclear genes and follows Mendelian inheritance; whereas CMS is governed by interaction between nuclear genes and sterile cytoplasm, and it does not follow Mendelian inheritance. Male sterility, i.e. nuclear genetic male sterility (GMS) first time reported in Capsicum by Martin and Grawford (1951), it is monogenic and controlled by recessive nuclear (ms) alleles. Several spontaneous or induced ms mutants have been characterized by Shifriss (1997), and some are presently exploited for hybrid seed production. However genetic male sterility (GMS) has not been widely exploited, due to the segregation into 50% male fertile and 50% male sterile, and it consumes more space, labour and other inputs in crossing block. Peterson (1958) first time distinguished cytoplasmic male-sterility (CMS) in Capsicum accession introduced from India (USDA P.I. 164835) at United States of America (USA), and he found that trait was controlled by major recessive nuclear gene interacting specifically with the sterile (S) cytoplasm. Cytoplasm is maternally inherited resulting in 100% sterility in the female parent, and remains the best system for hybrid seed production if sterility is stable and restorer genes are available. Shifriss (1997) reported that manifestation of cytoplasmic male sterility in pepper due to interaction of a single recessive nuclear gene, designated as rf 1 , with sterile (S) cytoplasm; and the restorer dominant allele Rf 1 controls the fertility restoration. However, Peterson (1958) and Novak et al. (1971) in separate investigation reported that a few genotypes apparently carried a second recessive nuclear gene, designed as rf 2 , which was needed in addition to rf 1 in order to produce complete sterility in Capsicum. Zhang et al. (2000), Kim and Kim (2005) and Kumar et al. (2007) reported CMS which is now commercially exploited http://dx.doi.org/10.1016/j.scienta.2017.05.023 Received 15 December 2016; Received in revised form 4 May 2017; Accepted 8 May 2017 ⁎ Corresponding author. 1 These authors contributed equally. E-mail addresses: bandelasravanthi@gmail.com, swamy.horti07@gmail.com (B.N. Swamy). Scientia Horticulturae 222 (2017) 175–179 0304-4238/ © 2017 Published by Elsevier B.V. MARK