Semigamy Gene Is Associated with Chlorophyll Reduction in Cotton

Abstract

currently the only feasible means for production of haploids in cotton is via semigamy. Haploids produced by semigamy can be used to facilitate selectionSemigamy is a type of facultative apomixis in which in cotton (Gossypium barbadense L.) breeding and gene mapping. The the male sperm nucleus does not fuse with the egg objectives of the present study were to detail the genetic mechanism of nucleus after penetrating the egg in the embryo sac. Subsemigamy and its relationship with reduction in chlorophyll content. Pima 57-4, a semigametic line isolated as a doubled haploid (DH) sequent development can give rise to an embryo confrom Pima S-1, produced 46 to 50% haploid progeny when selfed.taining haploid chimeral tissues of paternal and mater-Compared with its natural isogenic line S-1, 57-4 had lower leaf chloronal origins. In cotton, the semigametic phenomena was phyll content, photosynthetic rate (Pn), and boll weight, and had first reported by Turcotte and Feaster (1963), who dehigher lint percentage, seed index, and shorter and coarser fiber.veloped the Pima line 57-4 that produced haploid seeds Three segregating populations (F 2 and two BC 1 F 1 ) from a cross of at a high frequency. The semigametic line was a DH 57-4 ϫ S-1 were progeny tested to investigate the genetic basis of from a natural haploid mutant found in a field of Pima semigamy. Haploid production in F 1 , F 2 , and backcrosses were also S-1. In two presentations, Turcotte and Feaster (1974, recorded. The results verified that semigamy in cotton is controlled 1975) indicated that semigamy in Pima appeared to be by one gene, previously designated Se. The gene functions sporophytcontrolled by one dominant gene (Se). Despite wide ically and gametophytically, resulting in incomplete dominance nature. A generation-mean analysis for the cross of 57-4 ϫ S-1 identified acceptance by the cotton research community (Kohel one gene responsible for the parental differences in chlorophyll conand Lewis , 1984;Smith and Cothren, 1999), no compretent. Consistent with the difference between the two parental isogenic hensive genetic data have been published. Semigametic lines, semigametic F 2.3 lines had significantly lower chlorophyll contentlines can produce 30 to 60% haploids when self pollithan nonsemigametic F 2.3 lines, an observation that was confirmed by nated, and about 0.7 to 1.0% androgenic haploids when a significant association between haploid production and chlorophyll used as female parents in crosses with normal nonsemicontent. The Se gene and the gene for reduced chlorophyll content gametic cottons (Chaudhari, 1978(Chaudhari, , 1979; Turcotte and could be either the same or closely linked. The elucidation of the Feaster, 1967). A unique feature of semigamy is that relationship between semigamy and fiber development will help charthe inheritance of the gene is conveyed by both male acterize the molecular function of the semigametic gene. and female gametes, but expression of the trait in terms of haploid production occurs only in the female parent.

Genetic Mapping in Cotton

“…Mapping populations are obtained using two contrasting parents for the desired trait. In self-pollinated crops; usually mapping populations include F 2 [56,57]; F 2:3 [58,59], recombinant inbred lines (RILs) [60,61], backcross (BC) [62,63], Backcross inbred lines (BILs) [64], near isogenic lines [65,66], doublehaploids [67,68], chromosome substitution lines (CSILs) [69,70]. F 2 , BC, RILs and doublehaploids have been highly used for linkage mapping studies in cotton.…”

Identification of differentially expressed genes associated with semigamy in Pima cotton (Gossypium barbadenseL.) through comparative microarray analysis

“…Subsequent breeding and genetic experiments revealed that semigamy was an inheritable trait and controlled by a single incompletely dominant gene, denoted Se [7,8]. A unique feature of semigamy in cotton is that expression of the trait in terms of haploid production is controlled by the genotype of both male and female gametes [8].…”

“…In cotton, semigamy was first observed by Turcotte and Feaster [ 5 ] through recovery of a doubled haploid mutant 57-4 from a commercial non-semigametic Pima S-1, which produced haploids at a high frequency, ranging from 25 to 61% when self pollinated. Subsequent breeding and genetic experiments revealed that semigamy was an inheritable trait and controlled by a single incompletely dominant gene, denoted Se [ 7 , 8 ]. A unique feature of semigamy in cotton is that expression of the trait in terms of haploid production is controlled by the genotype of both male and female gametes [ 8 ].…”

“…Subsequent breeding and genetic experiments revealed that semigamy was an inheritable trait and controlled by a single incompletely dominant gene, denoted Se [ 7 , 8 ]. A unique feature of semigamy in cotton is that expression of the trait in terms of haploid production is controlled by the genotype of both male and female gametes [ 8 ]. Zhang and Stewart [ 8 ] reported that the semigametic line 57-4 produced 44% haploids when both gametes carried the semigametic gene Se by self pollination, but produced only 11% haploids when crossed as female to its nonsemigametic isoline Pima S-1.…”

Molecular mapping of quantitative trait loci controlling chlorophyll content at different developmental stages in tetraploid cotton

“…The authors proposed that the complementary function could be due to a non‐diploidized function of homoeologous loci in the G. hirsutum allotetraploid. Zhang and Stewart (2004) identified a gene responsible for lower chlorophyll content and photosynthetic rate of a semigamy mutant compared to the wild‐type, and suggested this gene could be either the same or closely linked with the semigamy gene ( Se ).…”