scholarly journals Inheritance of resistance to root-lesion nematode (Pratylenchus thornei) in wheat landraces and cultivars from the West Asia and North Africa (WANA) region

2011 ◽  
Vol 62 (1) ◽  
pp. 82 ◽  
Author(s):  
J. P. Thompson ◽  
N. P. Seymour
Keyword(s):  
North Africa ◽  
Doubled Haploid ◽  
Combining Ability ◽  
General Combining Ability ◽  
F1 Hybrids ◽  
Root Lesion Nematode ◽  
Components Of Variance ◽  
Pratylenchus Thornei ◽  
Lesion Nematode ◽  
Half Diallel

The root-lesion nematode Pratylenchus thornei causes substantial loss to bread wheat production in the northern grain region of Australia and other parts of the world. West Asia and North Africa (WANA) wheat accessions with partial resistance to P. thornei were analysed for mode of inheritance in a half-diallel crossing design of F1 hybrids (10 parents) and F2 populations (7 parents). General combining ability was more important than specific combining ability as indicated by components of variance ratios of 0.93 and 0.95 in diallel ANOVA of the F1 and F2 generations, respectively. General combining ability values of the ‘resistant’ parents were predictive of the mean nematode numbers of their progeny in crosses with the susceptible Australian cv. Janz at the F1 (R2 = 0.86, P < 0.001, 8 crosses), F2 (R2 = 0.83, P < 0.001, 9 populations) and F∞ (R2 = 0.71, P < 0.05, 5 doubled-haploid populations). The F2 and F∞ populations showed relatively continuous distributions. Heritability was 0.68 for F2 populations in the half-diallel of resistant parents and 0.82–0.92 for 5 ‘resistant’ parent/Janz doubled-haploid populations (narrow-sense heritability on a line mean basis). The results indicate polygenic inheritance of P. thornei resistance with a minimum of from 2 to 6 genes involved in individual F∞ populations of 5 resistant parents crossed with Janz. Morocco 426 and Iraq 43 appear to be the best of the parents tested for breeding for resistance to P. thornei. None of the P. thornei-resistant WANA accessions was resistant to Pratylenchus neglectus.

Resistance to root-lesion nematodes (Pratylenchus thornei and P. neglectus) in synthetic hexaploid wheats and their durum and Aegilops tauschii parents

2008 ◽  
Vol 59 (5) ◽  
pp. 432 ◽  
Author(s):  
J. P. Thompson
Keyword(s):  
Bread Wheat ◽  
Combining Ability ◽  
Aegilops Tauschii ◽  
General Combining Ability ◽  
F1 Hybrids ◽  
Pratylenchus Thornei ◽  
Lesion Nematodes ◽  
Synthetic Hexaploid Wheats ◽  
Synthetic Hexaploid ◽  
Root Lesion Nematodes

Root-lesion nematodes (Pratylenchus thornei Sher and Allen and P. neglectus (Rensch) Filipijev and Schuurmans Stekhoven) cause substantial yield loss to wheat crops in the northern grain region of Australia. Resistance to P. thornei for use in wheat breeding programs was sought among synthetic hexaploid wheats (2n = 6x = 42, AABBDD) produced through hybridisations of Triticum turgidum L. subsp. durum (Desf.) Husn (2n = 4x = 28, AABB) with Aegilops tauschii Coss. (2n = 2x = 14, DD). Resistance was determined for the synthetic hexaploid wheats and their durum and Ae. tauschii parents from the numbers of nematodes in the roots of plants grown for 16 weeks in pots of pasteurised soil inoculated with P. thornei. Fifty-nine (32%) of 186 accessions of synthetic hexaploid wheats had lower numbers of nematodes than Gatcher Selection 50a (GS50a), a partially resistant bread wheat. Greater frequencies of partial resistance were present in the durum parents (72% of 39 lines having lower nematode numbers than GS50a) and in the Ae. tauschii parents (55% of 53 lines). The 59 synthetic hexaploids were re-tested in a second experiment along with their parents. In a third experiment, 11 resistant synthetic hexaploid wheats and their F1 hybrids with Janz, a susceptible bread wheat, were tested and the F1s were found to give nematode counts intermediate between the respective two parents. Synthetic hexaploid wheats with higher levels of resistance resulted from hybridisations where both the durum and Ae. tauschii parents were partially resistant, rather than where only one parent was partially resistant. These results suggest that resistance to P. thornei in synthetic hexaploid wheats is polygenic, with resistances located both in the D genome from Ae. tauschii and in the A and/or B genomes from durum. Five synthetic hexaploid wheats were selected for further study on the basis of (1) a high level of resistance to P. thornei of the synthetic hexaploid wheats and of both their durum and Ae. tauschii parents, (2) being representative of both Australian and CIMMYT (International Maize and Wheat Improvement Centre) durums, and (3) being representative of the morphological subspecies and varieties of Ae. tauschii. These 5 synthetic hexaploid wheats were also shown to be resistant to P. neglectus, whereas GS50a and 2 P. thornei-resistant derivatives were quite susceptible. Results of P. thornei resistance of F1s and F2s from a half diallel of these 5 synthetic hexaploid wheats, GS50a, and Janz from another study indicate polygenic additive resistance and better general combining ability for the synthetic hexaploid wheats than for GS50a. Published molecular marker studies on a doubled haploid population between the synthetic hexaploid wheat with best general combining ability (CPI133872) and Janz have shown quantitative trait loci for resistance located in all 3 genomes. Synthetic hexaploid wheats offer a convenient way of introgressing new resistances to P. thornei and P. neglectus from both durum and Ae. tauschii into commercial bread wheats.

Resistance to the root-lesion nematode Pratylenchus thornei in wheat landraces and cultivars from the West Asia and North Africa (WANA) region

2009 ◽  
Vol 60 (12) ◽  
pp. 1209 ◽  
Author(s):  
J. P. Thompson ◽  
M. M. O'Reilly ◽  
T. G. Clewett
Keyword(s):  
Durum Wheat ◽  
Bread Wheat ◽  
North Africa ◽  
Economic Loss ◽  
Wheat Breeding ◽  
Root Lesion Nematode ◽  
Sources Of Resistance ◽  
The West ◽  
Pratylenchus Thornei ◽  
Lesion Nematode

Resistance to the root-lesion nematode Pratylenchus thornei was sought in wheat from the West Asia and North Africa (WANA) region in the Watkins Collection (148 bread and 139 durum wheat accessions) and the McIntosh Collection (59 bread and 43 durum wheat accessions). It was considered that landraces from this region, encompassing the centres of origin of wheat and where P. thornei also occurs, could be valuable sources of resistance for use in wheat breeding. Resistance was determined by number of P. thornei/kg soil after the growth of the plants in replicated glasshouse experiments. On average, durum accessions produced significantly lower numbers of P. thornei than bread wheat accessions in both the Watkins and McIntosh Collections. Selected accessions with low P. thornei numbers were re-tested and 13 bread wheat and 10 durum accessions were identified with nematode numbers not significantly different from GS50a, a partially resistant bread wheat line used as a reference standard. These resistant accessions, which originated in Iran, Iraq, Syria, Egypt, Sudan, Morocco, and Tunisia, represent a resource of resistance genes in the primary wheat gene pool, which could be used in Australian wheat breeding programs to reduce the economic loss from P. thornei.

Metabolomic profiling of wheat genotypes resistant and susceptible to root-lesion nematode Pratylenchus thornei

2021 ◽  
Author(s):  
Md Motiur Rahaman ◽  
Rebecca S. Zwart ◽  
Thusitha W. T. Rupasinghe ◽  
Helen L. Hayden ◽  
John P. Thompson
Keyword(s):  
Root Lesion Nematode ◽  
Wheat Genotypes ◽  
Metabolomic Profiling ◽  
Pratylenchus Thornei ◽  
Lesion Nematode

scholarly journals Using scab resistant donors in apple breeding

2017 ◽  
Vol 38 (SI 2 - 6th Conf EFPP 2002) ◽  
pp. 600-603
Author(s):  
B. Gelvonauskis ◽  
D. Gelvonauskienė
Keyword(s):  
Combining Ability ◽  
Apple Scab ◽  
General Combining Ability ◽  
Scab Resistance ◽  
Mean Square ◽  
Genetic Progress ◽  
Apple Cultivars ◽  
The Mean ◽  
Half Diallel ◽  
Selection Of

Apple cultivars were crossed according to the half-diallel and topcross mating design. Apple scab resistance of seedlings was estimated by using a 0–5 scale: 0 – no infection on leaves, 5 – more than 75% of leaf area infected. Percentage of scab resistant seedlings in crosses involving cultivars Prima varied from 35.8% to 67.6%, involving cultivars Florina and Arbat – 51.9–59.5% and 53.5–72.5%, respectively. Significant differences for resistance to scab were found among the crosses. Both general combining ability (GCA) and specific combining ability (SCA) were highly significant. The significance of GCA for scab resistance shows that genetic variability exists for this trait and selection should result in genetic progress, because the mean square for GCA was larger than that calculated for SCA. Therefore, selection of parents on its phenotype should be effective for development of resistant apple cultivars. The significant SCA estimates indicate that a large number of resistant seedlings from particular crosses should be selected.

Inheritance of anthracnose resistance in the tropical pasture legume Stylosanthes hamata

1995 ◽  
Vol 46 (7) ◽  
pp. 1353 ◽  
Author(s):  
N Iamsupasit ◽  
DF Cameron ◽  
M Cooper ◽  
S Chakraborty ◽  
LA Edye
Keyword(s):  
Combining Ability ◽  
Colletotrichum Gloeosporioides ◽  
Single Gene ◽  
General Combining Ability ◽  
Tropical Pasture ◽  
Gene Model ◽  
Stylosanthes Hamata ◽  
Moderately Resistant ◽  
Half Diallel ◽  
Pasture Legume

Eight tetraploid accessions of the tropical pasture legume Stylosanthes hamata with varying levels of response to the anthracnose pathogen (Colletotrichum gloeosporioides) were crossed in a half diallel scheme. Based on mean disease severity ratings (MDR), two parents, 55830 and 75164, were grouped as resistant (R), 55828 and 65365 were susceptible (S), and the remaining four, cvv. Verano and Amiga and 65371 and 75162 were moderately resistant (MR). Of these, the two resistant parents appear to carry different genes for resistance. The MDR of 20 of the 28 F2 populations was significantly different from their mid-parent MDR and the expression of resistance, in most cases, was recessive. Only a limited number of the F2 distributions for crosses between RxS, RxMR and MRxS parents conformed to a single gene model. The inheritance patterns observed were considered to be predominantly quantitative. Variation for general combining ability, was as large as or larger than that for specific combining ability suggesting that a large proportion of the genetic differences among the parents was additive. The finding that the resistance is inherited as a quantitative trait is consistent with results on the epidemiology of anthracnose in tetraploid S. hamata.

Fine mapping of root lesion nematode (Pratylenchus thornei) resistance loci on chromosomes 6D and 2B of wheat

2019 ◽  
Vol 133 (2) ◽  
pp. 635-652 ◽  
Author(s):  
Muhammad Shefatur Rahman ◽  
Katherine J. Linsell ◽  
Julian D. Taylor ◽  
Matthew J. Hayden ◽  
Nicholas C. Collins ◽  
...  
Keyword(s):  
Fine Mapping ◽  
Root Lesion Nematode ◽  
Pratylenchus Thornei ◽  
Lesion Nematode

GENOTYPE × ENVIRONMENT INTERACTIONS IN SMOOTH BROMEGRASS. I. YIELD

1979 ◽  
Vol 21 (1) ◽  
pp. 57-63 ◽  
Author(s):  
Wai-Koon Tan ◽  
Geok-Yong Tan ◽  
P. D. Walton
Keyword(s):  
Genetic Variation ◽  
Analysis Of Variance ◽  
Combining Ability ◽  
Significant Variation ◽  
Diallel Cross ◽  
General Combining Ability ◽  
Bromus Inermis ◽  
Smooth Bromegrass ◽  
Combining Ability Analysis ◽  
Half Diallel

Twenty-one progenies and the parents of a 7 × 7 half diallel cross of smooth bromegrass (Bromus inermis Leyss.) were evaluated at four locations in Alberta in each of two years, for genetic variation and genetic by environment interactions in the expression of their yield potentials. Years, locations and their interactions were highly significant in the combined analysis of variance. Combining ability analysis revealed that general combining ability (GCA) and specific combining ability (SCA) were both important in the expression of yield, including spring, fall and annual yield, whereas GCA was more important than SCA for yield per area. Although the genotype × environment interactions were all highly significant, variation accounted for by combining ability effects was generally higher than the interaction effects of GCA and SCA respectively, with environments. High average GCA effects for spring, fall and annual yield were demonstrated for the clones UA5, UA9 and B42. These together with the high average SCA effects suggested that the three clones could be included in a synthetic to develop high yielding cultivars. The results suggested that recurrent selections involving multi-location and multi-year testing seems necessary in breeding for high yielding bromegrass cultivars in Alberta.

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