Capsicum annuum with causal allele of hybrid weakness is prevalent in Asia

Abstract

Reproductive isolation, including hybrid weakness, plays an important role in the formation of species. Hybrid weakness in Capsicum, the cessation of plant growth, is caused by two complementary dominant genes, A from C. chinense or C. frutescens and B from C. annuum. In the present study, we surveyed whether 94 C. annuum accessions had B or b alleles by crossing with C. chinense having the A allele. Of the 94 C. annuum accessions, five had the B allele, three of which were native to Latin America and two were native to Asia. When combined with previous studies, the percentage of B carriers was 41% in Japan, 13% in Asia excluding Japan, 6% in Latin America, and 0% in Europe and Africa. In addition, 48 accessions of C. annuum from various countries were subjected to SSR analysis. Clades with high percentages of B-carriers were formed in the phylogenetic trees. In the principal coordinate analysis, most B-carriers were localized in a single group, although the group also included b-carriers. Based on these results, we presumed that the B allele was acquired in some C. annuum lines in Latin America, and B-carriers were introduced to the world during the Age of Discovery, as along with the b-carriers.

Understanding and overcoming hybrid lethality in seed and seedling stages as barriers to hybridization and gene flow

“…The general symptoms of hybrid lethality are apparent death of seedlings and are typically observed in interspecific hybridizations in Nicotiana ( Yamada et al., 1999 ; Tezuka, 2012 ; Tezuka, 2013 ). Hybrid weakness is characterized by the weak growth of seedlings compared to both parents and is typically observed in Oryza ( Chu and Oka, 1972 ; Chen et al., 2013 ; Nadir et al., 2019 ; Shiragaki et al., 2019 ), Capsicum ( Shiragaki et al., 2020b ; Shiragaki et al., 2021 ; Shiragaki et al., 2022 ), and Phaseolus ( Koinange and Gepts, 1992 ; Reiber and Neuman, 1999a ). Hybrid necrosis may refer to both types and is mainly used for the Triticum - Aegilops complex ( Tsunewaki and Kihara, 1962 ; Toxopeus and Hermsen, 1964 ; Mizuno et al., 2010 ; Zhang et al., 2022b ) and Arabidopsis ( Bomblies et al., 2007 ; Świadek et al., 2017 ).…”

Genetic Diversity, Production, and Trade of Chili With Special Reference to Nepal

“…A study reported a wider range (2%-91%) of outcrossing, with chili as suggested as a crosspollinating crop species (Ritonga et al, 2018). Natural and artificial selection (variety development by breeder) can bring diversity to the chili gene pool (Shiragaki et al, 2022). Moreover, interspecific cross-compatibility between cultivated capsicum species (Barchenger et al, 2019) may have developed interspecific hybrids (Bosland and Baral, 2007), contributing to the genetic diversity.…”

Genetic Cause of Hybrid Lethality Observed in Reciprocal Interspecific Crosses between Nicotiana simulans and N. tabacum

“…A typical example of postmating-prezygotic barriers is the cross-incompatibility between pollen and pistils [4][5][6][7][8][9][10][11]. Postzygotic barriers include hybrid seed abortion [4,, hybrid weaknesses [37][38][39][40][41][42][43][44][45][46][47], hybrid lethality [32,[48][49][50][51][52][53][54][55][56][57][58][59][60] or necrosis [61][62][63][64][65][66][67][68][69][70][71], and hybrid sterility [72][73][74][75][76]…”