Genetic modifications of dimorphic incompatibility in the Turnera ulmifolia L. complex (Turneraceae)

1986 ◽  
Vol 28 (5) ◽  
pp. 796-807 ◽  
Author(s):  
J. S. Shore ◽  
S. C. H. Barrett

Diploid and tetraploid populations of Turnera ulmifolia are distylous and exhibit a strong self-incompatibility system. Distyly is governed by a single locus with two alleles. Several self-compatible variants were, however, obtained and the nature and genetic control of self-compatibility was assessed using controlled crosses. The study documented the occurrence of self-compatible variants in four contrasting situations. These included the following. (i) Self-compatibility in a diploid short-styled variant. The gene(s) governing self-compatibility interact with the distyly locus and are expressed only in short-styled plants. When tetraploids carrying the genes were synthesized, self-incompatibility reappeared. (ii) Self-compatibility occurred in a cross between geographically separate diploid populations. Self-compatibility appeared sporadically in the F1. Crosses revealed that self-compatibility is likely under polygenic control. (iii) Low levels of self-compatibility occurred in a tetraploid population. Crosses revealed that self-compatibility was under polygenic control. A small response to selection for increased self-compatibility was observed, (iv) Hexaploids were synthesized from crosses between distylous diploids and tetraploids. All hexaploids obtained were long- or short-styled indicating that hexaploidy per se does not cause homostyly. A single long-styled plant showed aberrant pollen behaviour, resulting in a moderate degree of self-compatibility. All of the variants studied exhibited either aberrant pollen or stylar incompatibility responses. In no instance was the genetic control of self-compatibility solely the result of segregation at the distyly locus.Key words: Turnera, dimorphic incompatibility, polyploidy, self-compatibility, distyly.

1955 ◽  
Vol 33 (2) ◽  
pp. 149-155 ◽  
Author(s):  
W. H. Cram

Self-compatibility (% of 'tripped' flowers setting pods) for 218 selections of Caragana arborescens varied continuously from 0.0 to 99.5%. The frequency distribution of the compatibility data in terms of percentage was positively skewed by an excess of low self-compatibility plants and had a mean of 36.9%. However, angular transformation of the data resulted in a distribution which approached normality. Pollen abortion, which ranged from 0 to 24%, had little if any influence upon self-compatibility. Selection for high plant vigor was accompanied by a minor reduction in compatibility. Self-incompatibility of three trees could be explained by the action of several compatibility [Formula: see text] factors.


Genetics ◽  
1974 ◽  
Vol 76 (1) ◽  
pp. 45-50
Author(s):  
M E Nasrallah

ABSTRACT Single radial immunodiffusion was used to study the self-incompatibility (S) proteins present in stigmas of two inbred lines of Brassica oleracea: a self-incompatible line and a self-compatible mutant derived from it. The genetic basis of observed quantitative differences in S proteins between the two inbreds was shown to be determined by a single gene with dosage effects. Self-pollination of individual plants with high, intermediate and low levels of S protein in the stigmas, respectively, resulted in low, intermediate and high seed set.


2021 ◽  
Author(s):  
Marta B Bianchi ◽  
Thomas R Meagher ◽  
Peter E Gibbs

Abstract Background and Aims Genetically controlled self-incompatibility (SI) mechanisms constrain selfing and thus have contributed to the evolutionary diversity of flowering plants. In homomorphic gametophytic SI (GSI) and homomorphic sporophytic SI (SSI), genetic control is usually by a single multi-allelic locus S. Both GSI and SSI prevent self pollen tubes reaching the ovary and so are pre-zygotic in action. In contrast, in taxa with late-acting self-incompatibility (LSI), rejection is often post-zygotic, since self-pollen tubes grow to the ovary where fertilization may occur prior to floral abscission. Alternatively, lack of self fruit set could be due to early-acting inbreeding depression (EID). The aim of our study was to investigate mechanisms underlying lack of selfed fruit set in Handroanthus heptaphyllus in order to assess the likelihood of LSI versus EID. Methods We employed four full sib diallels to study the genetic control of LSI in Handroanthus heptaphyllus using a precociously flowering variant. We also used fluorescence microscopy to study the incidence of ovule penetration by pollen tubes in pistils that abscised following pollination or initiated fruits. Key Results All diallels showed reciprocally cross-incompatible full-sibs (RCI), reciprocally cross compatible full-sibs (RCC), and non-reciprocally compatible full-sibs (NRC) in almost equal proportions. There was no significant difference between the incidence of ovule penetrations in abscised pistils following self- and cross-incompatible pollinations, but those in successful cross pollinations were around twofold greater. Conclusions A genetic model postulating a single S locus with four s alleles, one of which, in the maternal parent, is dominant to the other three, will produce RCI, RCC and NRC situations each at 33 %, consistent with our diallel results. We favour this simple genetic control over an early-acting inbreeding depression (EID) explanation since none of our pollinations, successful or unsuccessful, resulted in partial embryo development, as would be expected under a whole genome EID effect.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ling Ma ◽  
Chunzhi Zhang ◽  
Bo Zhang ◽  
Fei Tang ◽  
Futing Li ◽  
...  

AbstractPotato is the third most important staple food crop. To address challenges associated with global food security, a hybrid potato breeding system, aimed at converting potato from a tuber-propagated tetraploid crop into a seed-propagated diploid crop through crossing inbred lines, is under development. However, given that most diploid potatoes are self-incompatible, this represents a major obstacle which needs to be addressed in order to develop inbred lines. Here, we report on a self-compatible diploid potato, RH89-039-16 (RH), which can efficiently induce a mating transition from self-incompatibility to self-compatibility, when crossed to self-incompatible lines. We identify the S-locusinhibitor (Sli) gene in RH, capable of interacting with multiple allelic variants of the pistil-specific S-ribonucleases (S-RNases). Further, Sli gene functions like a general S-RNase inhibitor, to impart SC to RH and other self-incompatible potatoes. Discovery of Sli now offers a path forward for the diploid hybrid breeding program.


1970 ◽  
Vol 12 (4) ◽  
pp. 905-913 ◽  
Author(s):  
T. Swamy Rao

The correlated response with changes in self-compatibility in three varieties of brown sarson subjected to gamma irradiation was examined. Selection for improved seed set in the irradiated populations showed that substantial correlated response can result for a constellation of other characters in which the self-compatible and self-incompatible forms differ. The correlated response was in a direction opposite to that of the previous history of selection.


1998 ◽  
Vol 46 (4) ◽  
pp. 421 ◽  
Author(s):  
Ross L. Goldingay ◽  
Susan M. Carthew

There has been a significant increase in the number of studies investigating plant breeding and mating systems over the past 10 years. The family Proteaceae, in particular, has dominated such research conducted in Australia. Thus it is now timely to present a critical review of the breeding and mating systems of the Australian Proteaceae. It is hoped that this will stimulate further research. The review covers key events between pollen deposition on stigmas through to fruit set. The genus Banksia, although not the most diverse of the family, has received a disproportionate amount of attention. It has featured in nine published studies of self-compatibility compared to 13 studies spanning the other 45 genera and has featured in eight genetic studies of the mating system compared to just two on other genera. Few studies have assessed the timing of stigma receptivity despite the intriguing situation in most Proteaceae of auto-deposition of self-pollen on or near stigmas at anthesis. Studies suggest that stigmas are not receptive until 0.5–4 days after anthesis. Banksia species appear to show low levels of self-compatibility although one subspecies shows high levels of selfing and evidence of selective fruit development. Self-compatibility may be more common in other genera, although a dearth of studies precludes generalisation. Assessment of mating systems indicates almost complete outcrossing for most species, lending support to the idea of selective fruit development. It is clear that many further studies of all topics are required but particularly across a wide range of genera because many have not been studied at all.


Author(s):  
Scott H. Brainard ◽  
Shelby L. Ellison ◽  
Philipp W. Simon ◽  
Julie C. Dawson ◽  
Irwin L. Goldman

Abstract Key message The principal phenotypic determinants of market class in carrot—the size and shape of the root—are under primarily additive, but also highly polygenic, genetic control. Abstract The size and shape of carrot roots are the primary determinants not only of yield, but also market class. These quantitative phenotypes have historically been challenging to objectively evaluate, and thus subjective visual assessment of market class remains the primary method by which selection for these traits is performed. However, advancements in digital image analysis have recently made possible the high-throughput quantification of size and shape attributes. It is therefore now feasible to utilize modern methods of genetic analysis to investigate the genetic control of root morphology. To this end, this study utilized both genome wide association analysis (GWAS) and genomic-estimated breeding values (GEBVs) and demonstrated that the components of market class are highly polygenic traits, likely under the influence of many small effect QTL. Relatively large proportions of additive genetic variance for many of the component phenotypes support high predictive ability of GEBVs; average prediction ability across underlying market class traits was 0.67. GWAS identified multiple QTL for four of the phenotypes which compose market class: length, aspect ratio, maximum width, and root fill, a previously uncharacterized trait which represents the size-independent portion of carrot root shape. By combining digital image analysis with GWAS and GEBVs, this study represents a novel advance in our understanding of the genetic control of market class in carrot. The immediate practical utility and viability of genomic selection for carrot market class is also described, and concrete guidelines for the design of training populations are provided.


1976 ◽  
Vol 87 (2) ◽  
pp. 315-323 ◽  
Author(s):  
Elizabeth M. Tucker ◽  
L. Kilgour ◽  
J. D. Young

SummaryFinnish Landrace sheep with low red cell GSH concentrations resulting from a defective transport system for certain arnino acids were crossed with Tasmanian Merino sheep with a red cell GSH deficiency due to impaired activity of the enzyme γ-glutamyl cysteine synthetase. Inheritance data showed that the two types of GSH deficiency were under independent genetic control. In the Finnish Landrace breed, the gene coding for the transport defect (Trn) was inherited as an autosomal recessive and sheep homozygous for this gene had high red cell concentrations of lysine and ornithine (Ly ×) as well as low levels of GSH. In the Tasmanian Merino breed the GSH deficiency behaved as if controlled by an autosomal dominant gene (GSHL). Backcross breeding experiments resulted in lambs which had inherited both types of GSH deficiency. Evidence suggested that such ‘double low’ GSH lambs had an impaired viability. In Tasmanian Merinos the GSH deficiency was established prior to birth. Newborn Finnish Landrace lambs were clearly separable into two types on the basis of their red cell lysine and ornithine content but not on their GSH concentrations.


1982 ◽  
Vol 73 (4) ◽  
pp. 308-309 ◽  
Author(s):  
R. L. Hummel ◽  
P. D. Ascher ◽  
H. M. Pellett

2016 ◽  
Vol 23 (2) ◽  
pp. 61-65
Author(s):  
V. Soorya ◽  
V. Radhakrishnan ◽  
K. Mohanan

Curcuma aeruginosa Roxb., the pink and blue ginger is an underutilized rhizomatous herb used in the Indian as well as Thai and Malaysian systems of traditional medicine.Its antioxidant and nutraceutical properties have also been explored recently. However, no effort has been made to study the genetic variability and genetic control of the agronomic morphometric characters of this species. Hence the present study was carried out to analyse the genetic variability and genetic control of such characters in the species.All the fifteen morphometric characters showed continuous distribution indicating their polygenic control. Among the growth characters, plant height, leaf length, leaf breadth and leaf area showed accumulation of higher number of dominant alleles in their gene pool and number of tillers and number of leaves per tiller showed higher accumulation of recessive factors. Among the yield characters, length of primary fingers and length of secondary fingers showed a balanced distribution of genotypes, number of primary fingers, number of secondary fingers, diameter of primary tillers, length of mother rhizome and yield per plant showed skewness towards the assembly of higher number of recessive factors and diameter of primary fingers and diameter of secondary fingers showed skewness towards the assembly of dominant contributing factors. However, all the characters under study showed comparatively wide distribution of factor combinations, indicating the broad genetic base of the population under study. However, most of the agronomically important characters showed very low frequency of genotypes with higher number of dominant factors indicating the necessity of selecting superior genotypes to develop improved varieties.


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