scholarly journals Unilateral Incompatibility as a Major Cause of Skewed Segregation in the Cross between Lycopersicon esculentum and L. pennellii

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 625d-625
Author(s):  
M.R. Foolad
Keyword(s):  
Lycopersicon Esculentum ◽  
Selection Model ◽  
Interspecific Crosses ◽  
Unilateral Incompatibility ◽  
Skewed Segregation ◽  
Selective Elimination ◽  
Backcross Populations ◽  
Isozyme Loci ◽  
The Cross ◽  
Incompatibility Reactions

Skewed segregations are frequent events in segregating populations derived from different interspecific crosses in tomato. To determine a basis for skewed segregations in the progeny of the cross between Lycopersicon esculentum and L. pennellii, monogenic segregations of 16 isozyme loci were analyzed in an F2 and two backcross populations of this cross. In the F2, nine loci mapping to chromosomes 1, 2, 4, 9, 10, and 12 exhibited skewed segregations and in all cases there was an excess of L. pennellii homozygotes. The genotypic frequencies at all but one locus were at Hardy–Weinberg equilibria. In the backcross populations, all except two loci exhibited normal Mendelian segregations. No postzygotic selection model could statistically or biologically explain the observed segregation patterns. A prezygotic selection model, assuming selective elimination of the male gametophytes during pollen function (i.e., from pollination to karyogamy) adequately explained the observed segregations in all three populations. The direction of the skewed segregations in the F2 was consistent with that expected based on the effects of unilateral incompatibility reactions between the two species. In addition, the chromosomal locations of five of the nine markers that exhibited skewed segregations coincided with the locations of several known compatibility-related genes in tomato. Multigenic unilateral incompatibility reactions between L. esculentum pollen and the stigma or style of L. pennellii (or its hybrid derivatives) are suggested to be the major cause of the skewed segregations in the F2 progeny of this cross.

Molecular Mapping of Segregation Distortion Loci in Aegilops tauschii

Genetics ◽  
1998 ◽  
Vol 149 (1) ◽  
pp. 319-327 ◽  
Author(s):  
J D Faris ◽  
B Laddomada ◽  
B S Gill
Keyword(s):  
Segregation Distortion ◽  
Molecular Mapping ◽  
Aegilops Tauschii ◽  
Distorted Segregation ◽  
F2 Population ◽  
Male Gametes ◽  
Skewed Segregation ◽  
Segregation Ratios ◽  
Backcross Populations ◽  
Intraspecific Hybrids

Abstract Distorted segregation ratios of genetic markers are often observed in progeny of inter- and intraspecific hybrids and may result from competition among gametes or from abortion of the gamete or zygote. In this study, 194 markers mapped in an Aegilops tauschii F2 population were surveyed for distorted segregation ratios. Region(s) with skewed segregation ratios were detected on chromosomes 1D, 3D, 4D, and 7D. These distorter loci are designated as QSd.ksu-1D, QSd.ksu-3D, QSd.ksu-4D, and QSd.ksu-7D. Three regions of segregation distortion identified on chromosome 5D were analyzed in two sets of reciprocal backcross populations to analyze the effect of sex and cytoplasm on segregation distortion. Extreme distortion of marker segregation ratios was observed in populations in which the F1 was used as the male parent, and ratios were skewed in favor of TA1691 alleles. There was some evidence of differential transmission caused by nucleo-cytoplasmic interactions. Our results agree with other studies stating that loci affecting gametophyte competition in male gametes are located on 5DL. The distorter loci on 5DL are designated as QSd.ksu-5D.1, QSd.ksu-5D.2, and QSd.ksu-5D.3.

scholarly journals Inheritance and Linkage Relationships of Isozymes in Easter Cactus

1998 ◽  
Vol 123 (1) ◽  
pp. 98-103
Author(s):  
Maureen C. O'Leary ◽  
Thomas H. Boyle
Keyword(s):  
Interspecific Hybrids ◽  
Triosephosphate Isomerase ◽  
Recombination Frequency ◽  
Polyacrylamide Gel Electrophoresis ◽  
Interspecific Crosses ◽  
Germplasm Collections ◽  
Segregation Ratios ◽  
Isozyme Loci ◽  
Linkage Relationships ◽  
Aberrant Segregation

Polyacrylamide gel electrophoresis was used to study inheritance and linkage of isozymes in Easter cactus (Hatiora species and interspecific hybrids). Five isozyme systems were analyzed: aspartate aminotransferase (AAT), glucose-6-phosphate isomerase (GPI), malate dehydrogenase (MDH), phosphoglucomutase (PGM), and triosephosphate isomerase (TPI). F1, F2, BC1, and S1 progeny were used for inheritance studies. Six polymorphic loci (Aat-1, Gpi-1, Mdh-1, Pgm-1, Pgm-2, and Tpi-2) were identified. Aat-1 and Pgm-1 were linked (recombination frequency = 26% ± 7%), but the other isozyme loci assorted independently. Aberrant segregation ratios were observed in at least one segregating family for all six isozyme loci. We hypothesize that segregation distortion was due to linkage between isozyme loci and other genes subject to pre- or postzygotic selection. The existence of five additional isozyme loci (Aat-2, Gpi-2, Mdh-2, Mdh-3, and Tpi-1) was inferred from segregation patterns and by comparison of isozyme profiles from phylloclades and pollen. These isozyme loci may prove useful for confirming hybridity in intra- and interspecific crosses, determining parentage of cultivars, and assessing genetic diversity in germplasm collections.

TRANSFER OF COMMON BLIGHT (Xanthomonas campestris pv phaseoli) RESISTANCE FROM Phaseolus coccineus Lam. TO P. vulgaris L. THROUGH INTERSPECIFIC HYBRIDIZATION

1987 ◽  
Vol 67 (3) ◽  
pp. 685-695 ◽  
Author(s):  
S. J. PARK ◽  
B. N. DHANVANTARI
Keyword(s):  
Phaseolus Vulgaris ◽  
Xanthomonas Campestris ◽  
Growth Habit ◽  
Interspecific Backcross ◽  
Leaf Blight ◽  
Phaseolus Coccineus ◽  
Interspecific Crosses ◽  
Blight Resistance ◽  
White Bean ◽  
Backcross Populations

Four interspecific backcross populations derived from hybridizations between Phaseolus vulgaris × (P. vulgaris × P. coccineus) were produced to transfer common blight (Xanthomonas campestris pv phaseoli) resistance from a blight–resistant accession of P. coccineus to P. vulgaris white bean cultivars and to determine the association between blight resistance and some agronomic characteristics. Frequency distribution of leaf blight resistance ratings in the BCF2 and BCF3 generations and of percent pod blight infection in the BCF3 generation appeared to be continuous, ranging between the respective parental resistance reactions. This indicated that the transfer of common blight resistance from P. coccineus to P. vulgaris was feasible. Scores for leaf and pod blight were not associated indicating differential blight resistance reactions of the two plant organs. Leaf blight was negatively correlated with days to blossom but was not correlated with growth habit and pod set except for one cross in which leaf blight and pod set were associated. Percent pod blight was negatively correlated with days to blossom in two crosses. Pod blight was not associated with growth habit and pod set except for one cross in which it was associated with pod set. Days to blossom and pod set were associated. Implications of these findings in the breeding of blight resistant white bean cultivars are discussed.Key words: Interspecific crosses, Phaseolus coccineus, Phaseolus vulgaris, Xanthomonas campestris pv phaseoli, common blight, correlation

scholarly journals Cross Compatibility Analysis to Identify Suitable Parents of Tagetes erecta and T. patula for Heterotic Hybrid Breeding

2019 ◽  
Vol 47 (3) ◽  
Author(s):  
Huali ZHANG ◽  
Haibo XIN ◽  
Richen CONG ◽  
Zijing LI ◽  
Lina SONG ◽  
...  
Keyword(s):  
Plant Height ◽  
Male Parent ◽  
Hybrid Breeding ◽  
Interspecific Crosses ◽  
Tagetes Erecta ◽  
Seed Setting ◽  
Cross Compatibility ◽  
Ray Florets ◽  
The Cross ◽  
Seed Setting Rate

Seven interspecific crosses of Tagetes erecta × T. patula were conducted in this study. The cross compatibility index, seed setting rate, germination rate, phenotype, ploidy level, heterosis over male parent and field performance were tested. The results showed that different cross compatibility indices of Tagetes vary greatly, from 10.44~114.41, which is far less than that of the intraspecific hybridization S-121 × I-506 index. The seed setting rate of each cross ranged from 15.67% to 49.0%, and the cross S-121 × TP-512 scored the highest seed setting rate, which was higher than that of the intraspecific cross S-121 × I-506 (35.85%). Compared with the male parent, F1 has higher plant height, wider crown width, larger flower diameter and more ray florets and earlier bloom with two exceptions. The S-121 of T. erecta was diploid. All of the male parents of T. patula were tetraploids, and the combinations were triploids. The traits of plant height, plant width, flower size and number of ray florets showed positive heterosis over the male parents, and the days leading to flowering showed both positive and negative ones. Finally, S-121 × TP-379 and S-121 × TP-512 were selected as the two best combinations. This study confirmed that the two species of marigold could be crossed for better F1 varieties with improved performance.   ********* In press - Online First. Article has been peer reviewed, accepted for publication and published online without pagination. It will receive pagination when the issue will be ready for publishing as a complete number (Volume 47, Issue 3, 2019). The article is searchable and citable by Digital Object Identifier (DOI). DOI link will become active after the article will be included in the complete issue. *********

Unveiling of suppressed genes in interspecific and backcross populations derived from mutants of Cicer species

2019 ◽  
Vol 70 (3) ◽  
pp. 254 ◽  
Author(s):  
F. Oncu Ceylan ◽  
Alper Adak ◽  
Duygu Sari ◽  
Hatice Sari ◽  
Cengiz Toker
Keyword(s):  
Seed Size ◽  
Yield Components ◽  
Transgressive Segregation ◽  
Interspecific Crosses ◽  
Large Seed ◽  
Cicer Species ◽  
Yield And Yield Components ◽  
F1 Progeny ◽  
Backcross Populations ◽  
Transgressive Segregations

Although many interspecific crosses in Cicer species have successfully been carried out to improve the population in cultivated chickpea (Cicer arietinum L.), interspecific and backcross populations derived from mutants of Cicer species have not been studied for revealing suppressed genes responsible for heterotic effects and transgressive segregations. Therefore, the study aimed (i) to estimate heterosis (here, offspring superior to mid-parent value) and heterobeltiosis (offspring superior to better parent) for yield and yield components in the F1; (ii) to decipher transgressive segregation (extreme phenotypes) in F2 and backcross populations; and (iii) to reveal suppressed genes in interspecific and backcross populations (C. arietinum × F1 and C. reticulatum Ladiz.× F1) derived from interspecific crosses between a mutant of C. arietinum and a mutant of C. reticulatum. Heterobeltiosis was found for seed and biological yields, number of branches, and number of pods per plant in F1 progeny; heterosis was determined for the additional traits of 100-seed weight and harvest index. Heterobeltiosis and heterosis for yield and yield components in F1 progeny prompted transgressive segregation for these traits in F2 and backcross populations. In the backcrosses, C. arietinum × F1 crosses produced greater seed size and more pods per plant than C. reticulatum × F1, suggesting that C. arietinum × F1 backcrossing could improve yield components and lead to large seed size. Most of the high-yielding progeny in F2 and C. arietinum × F1 populations had double-podded nodes. It was concluded that the suppressed genes in a mutant of C. reticulatum or a mutant of C. arietinum played a crucial role in increasing transgressive segregations and allowing the cultivated chickpea to gain increased yield and yield components as well as large seed size.

scholarly journals Genetic Analysis of the Green Cotyledon Trait in Southernpea [Vigna unguiculata (L.) Walp.]

1994 ◽  
Vol 119 (5) ◽  
pp. 1054-1056 ◽  
Author(s):  
Richard L. Fery ◽  
Philip D. Dukes
Keyword(s):  
Genetic Analysis ◽  
Vigna Unguiculata ◽  
Genetic Relationship ◽  
Recessive Gene ◽  
Field Studies ◽  
Single Recessive Gene ◽  
Green Cotyledon ◽  
Backcross Populations ◽  
The Cross

A series of greenhouse and field studies were conducted to determine the inheritance of the green cotyledon trait exhibited by the recently released southernpea `Bettergreen' and to elucidate the genetic relationship between the green cotyledon trait and the green testa trait exhibited by `Freezegreen'. Evaluation of parental, F1, F2, and backcross populations of the crosses `Bettergreen' × `Carolina Cream' and `Bettergreen' × `Kiawah' indicated that the green cotyledon trait is conditioned by a single recessive gene. Evaluation of parental and F2 populations of the cross `Bettergreen' × `Freezegreen' indicated that this gene is neither allelic to nor linked with the gt gene that conditions the green testa trait in `Freezegreen'. The color of seeds harvested from plants homozygous for both the green cotyledon and green testa genes was superior and more uniform than the color of seeds harvested from either `Bettergreen' or `Freezegreen' plants. We propose that the newly discovered gene be designated green cotyledon and symbolized gc. Seeds containing embryos homozygous for the gc gene are easily identified. The ability to select in the seed stage should greatly facilitate efforts to backcross the gc gene into cream-, pinkeye-, and blackeye-type cultivars.

Inheritance of three agronomic characters in Lycopersicon interspecific crosses

1988 ◽  
Vol 110 (3) ◽  
pp. 471-474
Author(s):  
T. E. Yassin
Keyword(s):  
Lycopersicon Esculentum ◽  
Wild Species ◽  
Selection Criterion ◽  
Fruit Weight ◽  
Interspecific Crosses ◽  
Agronomic Characters ◽  
Yield Improvement ◽  
Plant Yield

SummaryCrosses between two cultivars of tomato (Lycopersicon esculentum Mill.), and two accessions of the wild species L. pimpinellifolium (Jusl.) Mill, were made and F1, F2 and backcross generations were developed and studied. Significant differences in number of fruits per plant, yield per plant and fruit weight were found between means of the different generations. Variation in number of fruits per plant and yield was also found between plants within generations. Number of fruits per plant was a highly heritable character (average h2 = 73·6%) and closely correlated with yield per plant, indicating that it may be a suitable selection criterion for yield improvement in tomato crosses.

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