Studies of genetic control of growth habit in Triticeae species: methods and problems

2004 ◽  
Vol 32 (3) ◽  
pp. 317-321
Author(s):  
Alexander Ju. Dudnikov
HortScience ◽  
1991 ◽  
Vol 26 (8) ◽  
pp. 1074-1075 ◽  
Author(s):  
Yonatan Elkind ◽  
Arie Gurnick ◽  
Nachum Kedar

The objective of this study was to elucidate the genetic control of the semideterminate growth habit in tomato (Lycopersicon esculentum Mill.). A semideterminate tomato line was crossed with determinate and indeterminate lines; their F1, F2, and backcrosses were grown; and the growth habit recorded and analyzed. Plants with six or more inflorescences on the main stem were defined as semideterminate, while those with fewer were defined as determinate. The F2 and backcross to determinate were bimodal, indicating a single recessive gene for semideterminate, which was denoted as sdt. The goodness-of-fit chi square for a single recessive gene model was 88% and 69% for F2 and backcross generations, respectively. In the cross between semideterminate and indeterminate types, the results indicated control by two genes, sp and sdt, with the sp+ indeterminate type epistatic over semideterminate. The goodness-of-fit to this model was 70% and 82% for F2 and backcross generations, respectively.


2002 ◽  
Vol 127 (2) ◽  
pp. 254-261 ◽  
Author(s):  
Ralph Scorza ◽  
Daniele Bassi ◽  
Alessandro Liverani

A study was conducted to determine genetic control of the columnar or pillar (PI) growth habit, and to evaluate the effects of interactions of various genes that influence peach [Prunus persica (L.) Batsch (Peach Group)] growth habit. The PI habit (brbr) examined in this study was inherited as a monogenic trait expressing incomplete dominance. The heterozygous Brbr derived from crosses between standard (ST) and PI genotypes was recognized as an upright (UP) tree with narrower branch angles than ST trees but wider than PI trees. The combination of brbr and brachytic dwarf (DW) (dwdw) produced dwarf-pillar (DWPI) trees. The effects of the heterozygous Brbr in combination with dw and/or compact (CT) (Ct) could not be recognized by visual observation. Compact pillar (CTPI) trees resulted from the expression of Ct_ brbr. These trees were distinguished from globe-shaped (GL) trees (Ct_Brbr) by the more upright growth habit of the CTPI trees. This genetic study highlights the genetic plasticity of tree growth habit in peach. The investigation of novel growth habits extends our concept of the peach tree. Some growth habits such as PI may have commercial potential for high-density peach production systems. Others, such as DWPI and CTPI may have potential as ornamentals.


HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 478g-479
Author(s):  
E.M.K. Koinange ◽  
S.P. Singh ◽  
P. Gepts

Cultivated plants and their wild progenitors show marked phenotypic differences regarding seed dormancy, the ability to disperse seeds, growth habit, phenology, photoperiod sensitivity, etc. We have used RFLP mapping to investigate the genetic control of these differences in a recombinant inbred population derived from across between a snap bean and a wild bean. Traits were scored either at Davis or in Colombia. Our results suggest that the genetic control is relatively simple. In particular, most of the phenotypic variation (>60%) in the population could be accounted for in genetic terms for all but two traits. The genetic control of many traits involved genes with major effect (>30%). Some regions of the genome had major effects on several traits. Our results suggest that evolution can proceed by macromutations, domestication could have taken place fairly rapidly and introgression of additional genetic diversity could be itrogressed relatively easily from wild beans into the cultivated bean gene pool.


Genome ◽  
1989 ◽  
Vol 32 (1) ◽  
pp. 19-23 ◽  
Author(s):  
A. L. Brule-Babel ◽  
D. B. Fowler

Rye (Secale cereale L.) is recognized as the most cold-tolerant winter cereal species. However, little is known of the genetic control of cold hardiness and its interaction with vernalization requirement in rye. In the present study, the modes of inheritance of cold hardiness and vernalization requirement were investigated in crosses among one spring and two winter rye cultivars that represented a wide range of winter survivability. Differences in growth habit were found to be determined by a single dominant gene for the spring growth habit. Multiple alleles, or modifiers, for this major gene may also have been present. Cold hardiness was controlled by genes with mainly additive effects, but other factors may also have been involved. Cytoplasmic effects were not detected. Broad-sense heritability estimates were generally high (48–82%), indicating that selection for cold hardiness should be effective in breeding programs.Key words: Secale cereale L., dominance, additive gene action, heritability, cytoplasmic effects.


HortScience ◽  
2004 ◽  
Vol 39 (3) ◽  
pp. 475-476 ◽  
Author(s):  
Shawn A. Mehlenbacher ◽  
Maxine M. Thompson

The style color of standard hazelnut (Corylus avellana L.) cultivars ranges from pink to dark purple. Styles with an unusual yellow color were first noted in seedlings of the progeny `Goodpasture' × `Compton', and the ratio was ≈3 red: 1 yellow. Controlled crosses were made to investigate the genetic control of style color. The same 3:1 ratio was observed in four additional crosses in which both parents had red styles. Two crosses of a red and a yellow parent gave ≈50% yellow styles, while a cross of two selections with yellow styles gave only seedlings with yellow styles. These segregation ratios indicate control by a single locus, with yellow style color recessive to red. Seedlings with yellow styles have green buds and catkins and a more upright growth habit than their siblings with red styles. Inspection of the pedigrees of these progenies shows that `Daviana', `Willamette', `Butler', `Compton', `Goodpasture', and `Lansing #1' are heterozygous. `Daviana' appears to be the original source of the allele for yellow styles, as it is a known or suspected parent or ancestor of the others. Ratios in a progeny segregating simultaneously for growth habit (normal vs. contorted) and style color indicated independence of the traits. However, in a progeny segregating simultaneously for leaf color (red vs. green) and style color, no redleaf seedlings had yellow styles. The S-alleles of eight genotypes with yellow styles were determined, and indicate a possible linkage between the yellow style locus and the S locus that controls pollen-stigma incompatibility. One explanation is that the yellow style trait is conferred by an allele (ays) at the anthocyanin (A) locus that controls leaf color. A second explanation is that there is a yellow style locus closely linked to the A locus. The A locus is known to be loosely linked to the S locus.


2014 ◽  
Vol 139 (5) ◽  
pp. 582-586 ◽  
Author(s):  
Khin Thida One ◽  
Narathid Muakrong ◽  
Chamnanr Phetcharat ◽  
Patcharin Tanya ◽  
Peerasak Srinives

Jatropha (Jatropha curcas) is one of the most popular tree crops for seed production as a source of oil for biodiesel. However, currently grown cultivars are too large in canopy size and thus have very low harvest index. Alteration of canopy height and size can lead to identification of a desirable plant architecture for jatropha. A study was conducted to determine genetic control of dwarfiness and erect growth habit in jatropha populations derived from an interspecific cross between J. curcas with tall-erect (TL-ER) plant type and J. integerrima with dwarf-spreading (DW-SP) plant type. Crosses were made between both species to develop F1, F2, BC1F1, and BC1F2 generations. The F2 plants segregated at a 1:2:1 ratio for tall (TL), intermediate (ID), and dwarf (DW) plant types as well as for spreading (SP), upright (UP), and erect (ER) canopy angles. Both characters segregated independently producing nine phenotypes including TL-ER, TL-UP, TL-SP, ID-ER, ID-UP, ID-SP, DW-ER, DW-UP, and DW-SP at a 1:2:1:2:4:2:1:2:1 ratio. The BC1F1 (J. curcas × F1) plant segregated into TL-ER, TL-UP, ID-ER, and ID-UP at a 1:1:1:1 expected ratio. Six BC1F2 lines were also evaluated to confirm the results by selfing two trees each of BC1F1 showing TL-ER, TL-UP, and ID-ER growth habits. The progenies of TL-ER trees were all TL-ER; the progenies of TL-UP trees segregated into TL-ER, TL-UP, and TL-SP at an expected 1:2:1 ratio, whereas the progenies of ID-ER trees segregated into TL-ER, ID-ER, and DW-ER at an expected 1:2:1 ratio. The results indicated that dwarfiness and erect growth habit were each controlled by independent genes with incomplete dominant action. The knowledge and progenies obtained from this study can be used in breeding jatropha for desirable canopy size and shape.


2014 ◽  
Vol 289 (3) ◽  
pp. 383-397 ◽  
Author(s):  
Lan Yun ◽  
Steve R. Larson ◽  
Ivan W. Mott ◽  
Kevin B. Jensen ◽  
Jack E. Staub

Author(s):  
F. Khoury ◽  
L. H. Bolz

The lateral growth habits and non-planar conformations of polyethylene crystals grown from dilute solutions (<0.1% wt./vol.) are known to vary depending on the crystallization temperature.1-3 With the notable exception of a study by Keith2, most previous studies have been limited to crystals grown at <95°C. The trend in the change of the lateral growth habit of the crystals with increasing crystallization temperature (other factors remaining equal, i.e. polymer mol. wt. and concentration, solvent) is illustrated in Fig.l. The lateral growth faces in the lozenge shaped type of crystal (Fig.la) which is formed at lower temperatures are {110}. Crystals formed at higher temperatures exhibit 'truncated' profiles (Figs. lb,c) and are bound laterally by (110) and (200} growth faces. In addition, the shape of the latter crystals is all the more truncated (Fig.lc), and hence all the more elongated parallel to the b-axis, the higher the crystallization temperature.


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