Genetics of Style-Length in Oxalis

Fisher, Ronald Aylmer; Martin, V. C.

doi:10.1038/162533a0

Cited by 7 publications

(3 citation statements)

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“…Tristylous species are restricted to six flowering plant families, and populations are composed of long‐, mid‐ and short‐styled morphs (hereafter L‐, M‐ and S‐morphs), each with two stamen levels within a flower corresponding in height to stigmas in the remaining style morphs. Despite the polyphyletic origins of tristyly, a similar two‐locus diallelic model ( S and M loci) with dominance and epistasis between the two loci (reviewed in Lewis & Jones ; Barrett ) governs the inheritance of the floral polymorphism in Lythraceae (Barlow ; Fisher & Mather ; Eckert & Barrett ), Oxalidaceae (Von Ubisch ; Fisher & Martin ; Fyfe , ; Weller ; Bennett et al . ; Weller et al .…”

Section: Introductionmentioning

confidence: 99%

The genetic architecture of tristyly and its breakdown to self‐fertilization

et al. 2016

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The floral polymorphism tristyly involves three style morphs with a reciprocal arrangement of stigma and anther heights governed by two diallelic loci (S and M). Tristyly functions to promote cross-pollination, but modifications to stamen position commonly cause transitions to selfing. Here, we integrate whole-genome sequencing and genetic mapping to investigate the genetic architecture of the M locus and the genetic basis of independent transitions to selfing in tristylous Eichhornia paniculata. We crossed independently derived semi-homostylous selfing variants of the long- and mid-styled morph fixed for alternate alleles at the M locus (ssmm and ssMM, respectively), and backcrossed the F to the parental ssmm genotype. We phenotyped and genotyped 462 backcross progeny using 1450 genotyping-by-sequencing (GBS) markers and performed composite interval mapping to identify quantitative trait loci (QTL) governing style-length and anther-height variation. A QTL associated with the primary style-morph differences (style length and anther height) mapped to linkage group 5 and spanned ~13-27.5 Mbp of assembled sequence. Bulk segregant analysis identified 334 genes containing SNPs potentially linked to the M locus. The stamen modifications characterizing each selfing variant were governed by loci on different linkage groups. Our results provide an important step towards identifying the M locus and demonstrate that transitions to selfing have originated by independent sets of mating-system modifier genes unlinked to the M locus, a pattern inconsistent with a recombinational origin of selfing variants at a putative supergene.

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Section: Introductionmentioning

confidence: 99%

The genetic architecture of tristyly and its breakdown to self‐fertilization

et al. 2016

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“…The observed segregation of 86 short, 13 mid and 6 long is in good agreement with the frequencies 12 short:3 mid:1 long which would be expected with independent assortment (x2 = 299 with 2 df). There is no suggestion here of close linkage between S and M such as Fisher and Martin (1948) found with 0. valdiviensis. Indeed, if S and M were linked, then since the self-pollinated shorts must be in coupling we could estimate the recombination frequency as 044±009.…”

Section: Resultsmentioning

confidence: 81%

“…Indeed, if S and M were linked, then since the self-pollinated shorts must be in coupling we could estimate the recombination frequency as 044±009. Table 5 Genotypes for short-, mid-and long-styled plants according to Fisher and Martin's (1948) Table 6 Genotypes for short-, mid-and long-styled plants according to Fyfe's (1956) Fyfe's suggestion that short is recessive to nonshort in 0. articulata stemmed from her finding that on crossing a long and a mid, where both plants had one short parent, shorts reappeared in the progeny. Her total counts for the progeny of these crosses were 47 long, 107 mid and 76 short.…”

Section: Resultsmentioning

confidence: 99%

The inheritance of style length in Oxalis rosea

1986

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In Oxalis rosea it is found that some short-styled plants are dominant to non-short (mid-or long-styled plants) whilst others are recessive. Breeding experiments show that the short style form is under the control of two gene pairs (A, a and S, s) with shorts having either of the genotypes aaSS and aaSs. In plants segregating for A, a on an SS background, shorts appear as recessive whilst in plants segregating for S, s on an aa background, shorts appear as dominant. Among non-shorts, mids (MM, Mm) are dominant to long (mm). Genes at the three loci (i) A, a, (ii) S, a and (iii) M, m show independent assortment. These results are compared with previous suggestions of recessive short in 0. rosea by von Ubisch (1926) and in 0. articulata by Fyfe (1956). INTRODUCTIONFyfe (1956) first drew attention to the existence of two different genetic systems controlling style length inheritance in different tristylic species of Oxalis. In some species, the short-style form was found to be dominant to non-short (mid-or longstyle forms) whilst in other species short was recessive to non-short. Fyfe named four Oxalis species having a dominant short (0. valdiviensis, 0. hirta, 0. tragapoda, 0. boweii) and two other species in which short was said to be recessive (0. articulata and 0. rosea). She presented her own genetical data for 0. articulata indicating that short is recessive whilst for 0. rosea she referred to the work of von Ubisch (1926). Subsequently Mulcahy (1964) reported that Fyfe had stated in a personal communication that when she sent some of her specimens of 0. articulata to von Ubisch, the latter had replied that the material was taxonomically identical to what she, von Ubisch, had identified as 0. rosea. Mulcahy says that "the actual identity of the specimens variously referred to as 0. articulata or 0. rosea was not indicated by Fyfe" and he also comments that, "since it is extremely unlikely that a single species could possess two genetic systems, it is apparent that at least one and perhaps even both of the proposed systems may be incorrect". What Mulcahy here describes as "two genetic systems" are Fyfe's twolocus model and von Ubisch's three-locus model, which we shall discuss later. The present study was undertaken in the hope of removing some of the confusion as to the mode of inheritance of the short style form in 0. rosea. MATERIALS AND METHODSSeed of 0. rosea was obtained from the Royal Botanic Gardens, Kew, England. Following seed germination, plants of the three style forms were established and maintained in pots in a glasshouse. The plants of this species are clearly distinguishable from those of 0. articulata cultivated by Fyfe.Plants of all style forms in 0. 'rosea may readily be induced to set seed either by self-pollination or by intercrossing. Crosses of both kinds were used in this study. RESULTSThe foundation plants comprised four shorts, seven mids and one long. Crosses made between these shorts and mids gave the progenies shown in table 1. Whilst some of these progenies contain approximately h...

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The Breeding System of Oxalis Suksdorfii

Ornduff

1964

American J of Botany

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The Pacific Coast species Oxalis suksdorfii (section Corniculatae) is morphologically tristylous. Flowers of the 3 kinds of plants present in natural populations differ in style length, stamen length, pollen size, stigma size and orientation, and stylar pubescence. Experimental studies and field observations indicate that plants with long‐styled flowers are weakly self‐compatible and show little differentiation in size or compatibility relationships of pollen from the 2 sets of stamens. Plants with mid‐styled flowers have strongly differentiated pollen, but produce few capsules or seed after any artificial or natural pollinations. Plants with short‐styled flowers are self‐incompatible and show slight pollen differentiation. The data presented suggest that O. suksdorfii approaches functional dimorphism since the mid‐styled form contributes little pollen and few seeds in sexual reproduction. The species may be in the process of losing the mid‐styled form completely and provides a model of certain physiological and morphological changes which may have accompanied elimination of the mid‐styled form in other Oxalis species. The abundance of plants with mid‐styled flowers in natural populations suggests, however, that this form may be retained because it contributes to general population fitness, or because the genetic control of heterostyly in this species prevents its elimination.

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Genetics of Style-Length in Oxalis

Cited by 7 publications

References 3 publications

The genetic architecture of tristyly and its breakdown to self‐fertilization

The genetic architecture of tristyly and its breakdown to self‐fertilization

The inheritance of style length in Oxalis rosea

The Breeding System of Oxalis Suksdorfii

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