Frost resistance of 'Chinese Spring'/'Cheyenne' chromosome substitution lines under short- and long-day hardening conditions

Investigations were carried out under phytotronic conditions to study the effect of daylength on the frost resistance of a ‘Chinese Spring’/‘Cheyenne’ chromosome substitution series. The frost resistance of the 5A, 7A, 4B, 5B, 1D and 5D lines was significantly better when raised and hardened with long-day (16 h) rather than short-day (8h) illumination. The frost resistance-increasing effect of daylength could be demonstrated after freezing lines 5A and 5D at both - 10°C and -12°C. An increase in the duration of illumination in the course of preliminary growth and hardening promoted the development of a higher level of frost resistance. This positive effect was most pronounced for chromosome substitution lines, where the frost resistance was significantly better than that of ‘Chinese Spring’ even with normal daylengths.     

Involvement of Chromosomes 5A and 5D in Cold-Induced Abscisic Acid Accumulation in and Frost Tolerance of Wheat Calli

The relationship between frost tolerance and abscisic acid (ABA) accumulation was studied in callus cultures of three wheat cultivars differing in the level of frost-tolerance, and of the 5A and 5D chromosome substitution lines from the frost-tolerant variety ‘Cheyenne’ into frost-sensitive ‘Chinese Spring’. Following cold hardening, the increase in ABA level in the calli of the two frost tolerant cultivars was significantly higher than in those of the frost-susceptible cultivar. Similarly, in 5A and 5D substitution lines, significantly higher ABA levels were detected than in the recipient ‘Chinese Spring’. One week-long ABA treatment at 26 °C induced a significantly higher level of frost tolerance than that achieved by cold hardening, irrespective of the frost sensitivity of the examined genotypes.     

The relationships of hardening period and the expression of frost resistance in chromosome substitution lines of wheat

Summary The highly frost resistant wheat variety Cheyenne (donor) and the poorly frost resistant variety Chinese Spring (recipient) were frozen at –9° C and –11° C at various stages of hardening, as were a number of substitution lines of these two varieties (CS/Ch 3A, CS/Ch 5A, CS/Ch 7A, CS/Ch 2B, CS/Ch 4B, CS/Ch 5B, CS/Ch 4D, CS/Ch 5D). Chromosomes 5A, 5B, 5D, 4B and 7A of Cheyenne increased the frost resistance of the recipient variety to varying extents. However, the frost resistance changed not only as a function of the different chromosomes, but also as a function of the duration of hardening, indicating that genes responsible for frost resistance are expressed differently during different phases of the hardening process.     

Chromosome location of genes affecting polyphenol oxidase activity in seeds of common and durum wheat

This study used cytogenetic stocks to investigate the chromosomal location of genes responsible for polyphenol oxidase (PPO) activity in common and durum wheat seeds. Substitution lines of chromosome 2A of hexaploid varieties ‘Cheyenne’, ‘Thatcher’ and ‘Timstein’ in ‘Chinese Spring’ showed significantly higher PPO activity than all other substitution lines of the same variety, with the exception of substitutions of ‘Cheyenne’ chromosome 3A and ‘Thatcher’ chromosome 4B. Substitution lines of chromosome 2A of Triticum turgidum var. dicoccoides and of chromosome 2D of ‘Chinese Spring’ into the tetraploid variety ‘Langdon’ showed a significant increase in PPO activity relative to all other substitution lines in Langdon. The gene(s) responsible for high PPO activity in chromosome 2D from ‘Chinese Spring’ was mapped on the long arm within a deletion that represents 24% of the distal part of the arm. This study shows that genes located in homoeologous group 2 play a major role in the activity of PPO in wheat.     

Plant survival after freezing in wheat 'Cappelle Desprez' ('Bezostaya 1') intervarietal chromosome substitution lines

The effect of individual chromosomes of the wheat variety ‘Bezostaya 1’ on plant resistance to low temperatures was studied using the available set of intervarietal ‘Cappelle Desprez’ (‘Bezostaya 1’) chromosome substitution lines. The number of plants surviving after freezing at ?12, ?15 and ?17°C was determined for both parents and lines in trials in 2004/2005 and 2005/2006. Significant differences between the three temperature treatments and between lines were found, implying that two factors, the level of temperature stress and chromosome substitutions, were influencing plant survival. Improved frost resistance in both trials was associated with genes located on five chromosomes: 5A, 2D, 4A, 5D and 6A. An increase in the plant frost resistance because of the effects of 7A and 1A chromosomes was also observed in the 2005/2006 trial, when the overall autumn and winter (January) temperatures were lower than in 2004/2005.     

Reciprocal substitutions analysis of freezing resistance in wheat (Triticum aestivum L.)

To investigate the effects of individual chromosomes on freezing resistance, as well as their interactions with the genetic background, reciprocal sets of chromosome substitution lines between two hard red winter wheat cultivars, ‘Cheyenne’ and ‘Wichita’, were used in this study. Duplicate lines for each chromosome were included to check background homogeneity. Two experiments were carried out in complete block designs with two replications for each duplicate. Crown and leaf water content and leaf wet weight were measured in the field experiments. Crown survival, electrolyte leakage and 50% lethality temperature (LT50) were measured in the laboratory. The results showed that ‘Cheyenne’ was more resistant than ‘Wichita’. Crown survival was significantly correlated with crown water content, crown wet weight and electrolyte leakage. Chromosomes 6A, 3B and 5D substituted from ‘Wichita’ into ‘Cheyenne’ (‘CNN‐WI’), decreased the crown survival, and increased membrane stability, crown water content and crown wet weight of ‘Cheyenne’. Thus, these chromosomes from ‘Wichita’ decreased freezing resistance in ‘Cheyenne’. Reciprocally, chromosomes 5A, 5D, 3B and 4D from ‘Cheyenne’ into ‘Wichita’ increased crown survival and decreased crown water content and crown wet weight of ‘Wichita’. It was concluded that these chromosomes from ‘Cheyenne’ cause freezing resistance in ‘Wichita’ and carry freezing‐resistance genes.     

Substitution Analysis of Plant Regeneration from Callus Culture in Wheat

The genetic determination of the plant regeneration ability of tissue cultures arising from immature embryos was studied using a ‘Chinese Spring’/‘Cheyenne’ substitution series. Plant regeneration proved to be polygenically determined. In tile current experiment the chromosomes 7B, 7D and ID were found to be effective, although the possibility of other chromosome effects cannot be excluded.     

Frost Resistance of Somaclones Derived from Triticum aestivum L. Winter Wheat Calli

Frost resistance was studied in SC₄ seedlings generated by self pollination from 31 (SC₄) plants of ‘GK Csongor’ winter wheat variety derived from resistance than ‘GK Csongor’. With respect to percentage survival, one family possessed significantly higher frost resistance as compared to the control at a temperature of -13°C In the case of regrowth analysis, 22 of the 31 families showed less growing capacity and 5 proved to be significantly better than ‘GK Csongor’. According to both testing methods, one family showed significantly higher frost resistance than the control.     

Genetic studies of antifreeze proteins and their correlation with winter survival in wheat

Antifreeze proteins (AFPs) accumulate in the leaves of winter cereals during cold acclimation, where they may inhibit ice recrystallization during freezing and thawing cycles and provide nonspecific disease resistance. In this study, 21 wheat chromosome substitution lines and the parental lines Chinese Spring and Cheyenne wheat were used to determine the heritability of AFPs and the relationship between the accumulation of AFPs and winter survival. In cold-acclimated lines, antifreeze activity in leaf apoplastic extracts ranged from 1 (low) to 5 (high) with an average value of 3.2, and the accumulation of apoplastic proteins ranged from 30 μg (g FW)^-1 to 115 μg (g FW)^-1 with a mean value of 70 μ (g FW)^-1. Examination of the individual lines revealed that Cheyenne chromosomes 5B and 5D carry major regulatory genes that increase both antifreeze activity and the accumulation of antifreeze proteins in plants grown at low temperature. Substitution lines carrying Cheyenne chromosomes 2A, 3A, 6B, and 7A exhibited lower freezing tolerance and also showed a marked decrease in the accumulation of specific AFPs during cold acclimation. Antifreeze activity and apoplastic protein content were not correlated with freezing tolerance (defined as % survival at -11 °C), but they were both significantly and positively correlated with winter field survival rates. Antifreeze activity (positively correlated) and total leaf fresh weight (negatively correlated) together accounted for about 55% of the variation in winter survival, indicating that high antifreeze activity and slow vegetative growth at low temperature are both important quantitative traits for winter survival. This revised version was published online in July 2006 with corrections to the Cover Date.     

Chromosomal location of genes affecting tissue-culture response in wheat

Six ‘Chinese Spring/Triticum spelta’ substitution lines for chromosomes 1A, 1D (duplicates), 3D (duplicates), 6D, and one ‘Chinese Spring/ Marquis’ substitution line for chromosome 2B were studied for tissue-culture response (TCR). The results reported here indicate that chromosomes 2B and 6D are critical for TCR, whereas chromosome ID affects callus weight only. Chromosomes 1A and 3D were not found to be critical, however, these chromosomes may carry genes with minor effects.     

Mapping of genes involved in glutathione, carbohydrate and COR14b cold induced protein accumulation during cold hardening in wheat

Using some of the chromosome substitution lines developed from thecrosses of the donor Cheyenne to Chinese Spring we showed that theaccumulation of water soluble carbohydrates during different stages ofhardening was time dependent. Moreover there was a significantcorrelation between the rate of carbohydrate accumulation and the frosttolerance. The expression and regulation of a wheat gene homologous tothe barley cold regulated cor14b gene was compared in frost sensitiveand frost tolerant wheat genotypes at different temperatures. Studies madewith chromosome substitution lines showed that the threshold inductiontemperature polymorphism of the cor14b wheat homologous genewas controlled by loci located on chromosome 5A of wheat, while cor14b gene was mapped, in Triticum monococcum, onto the longarm of chromosome 2A^m. Our study on the effect of cold hardeningon glutathione (GSH) metabolism showed that chromosome 5A of wheathas an influence on the GSH accumulation and on the ratio of reduced andoxidised glutathione as part of a complex regulatory function during coldhardening. In addition, the level of increase in GSH content duringhardening may indicate the degree of the frost tolerance of wheat.     

Resistance to barley yellow-dwarf-virus disease in derivatives of crosses between hexaploid wheat and species of Lophopyrum (Triticeae; Poaceae)

Among the wheatgrasses that are possible sources of genetic resistance for wheat to barley yellow-dwarf-virus disease (BYD) are those that have been commonly subsumed under the name Agropyron elongatum (Host) P. Beauv. Two of these wheatgrass species are the diploid Lophopymm elongatum (Host) Á. Löve (2n = 2x = 14) and the decaploid L. ponticum (Podp.) Á. Löve (2n = 10x = 70). These two species, the addition and substitution lines of L. elongatum chromosomes in hexaploid wheat (Triticum aestivum L.), and derivatives of hybrids between hexaploid wheat and L. ponticum, were screened for resistance to BYD, as defined by visual symptoms in field-grown plants. The two species, an amphiploid derived from L. elongatumבChinese Spring’ wheat, and the derivatives involving L. ponticum chromosomes were all highly resistant. The substitution and addition lines of L. elongatum chromosomes in ‘Chinese Spring’ revealed that the genetic control of resistance in L. elongatum must be complex, with more than one critical locus involved. Chromosomes 2E and 5E are involved and there are lesser contributions to resistance from the remaining wheatgrass chromosomes. One highly resistant derivative was determined to have only three pairs of L. ponticum chromosomes. It has a wheat-like morphology and shows promise for further characterization.     

The Transfer of Thinopyrum-Derived Leaf-rust Resistance from Common Wheat to Durum Wheat.

The leaf rust resistance gene on chromosome 7AL of ‘Chinese Spring’ transfer no. 12 derived from Thinopyrum ponticum, was transferred to durum wheat by standard backcrossing. In ‘Agatha’ and ‘Indis’ a leaf rust resistance gene from Thinopyrum ponticum and Thinopyrum ponticum respectively, is found on a translocated segment on chromosome arm 7DL. The use of the ‘Langdon’ disomic D-chromosome substitution lines for 7A and 7B resulted in the recovery of tetraploid leaf-rust resistant lines from the crosses with ‘Agatha’ in the B₂F₁ generation. Tetraploid lines carrying the ‘Indis’ translocation segment were recovered in the B₂F₂ generation. The F₂ segregation ratios for rust resistance after selfing or back-crossing generally fitted a 1: 1 ratio indicating non-transmission of the translocation segments in the male gametes. Homozygous resistant plants were not obtained. Meiotic instability was observed in 28 chromosome B₂ F₂ derivatives of the crosses between ‘Chinese Spring’ transfer no. 12 and durum wheat.     

Effects of Salinity on Growth, Ionic Relations and Physiological Traits of Wheat, Disomic Addition Lines from Thinopyrum bessarabicum, and Two Amphiploids

The effects of NaCl on the growth, ion relations and physiological characteristics at early stages of growth of bread wheat (Triticum aestivum) varieties ‘Chinese Spring’ and ‘Glennson 81’, ‘Chinese Spring’ lines tetrasomic for chromosomes 5A, 2B and 5B, ‘Chinese Spring’ disomic addition lines for chromosomes 2E^b and 5E^b from Thinopyrum bessarabicum (formerly Agropyron junceum), and amphiploids between ‘Chinese Spring’ and Thinopyrum bessarabicum and ‘Chinese Spring’ and Lophopyrum elongatum (formerly Agropyron elongatum) were examined. Plants were grown in a controlled environment cabinet, in nutrient solution with or without addition of 200 mol m^?3 NaCl. Growth in terms of leaf area, shoot and root weights was reduced by salt treatment. Salinity conditions gradually reduced the osmotic potential, though there was little effect on water potential. Turgor pressure was not much affected by salt. There was variation between genotypes for all the characteristics studied, especially in the extent of Na accumulation by leaves and roots. The amphiploids and 5E^b addition line accumulated the least Na in comparison with other genotypes. Generally roots accumulated lower quantities of Na than leaves. Genotype K contents were not affected by salt treatment. Stomatal conductance also declined whilst the ABA content increased in the salt treated seedlings. With respect to growth, the amphiploids and 5Eb addition line were most tolerant to salt while ‘Glennson 81’, tetrasomic 2B and tetrasomic 5B lines were most susceptible. The addition of homoeologous group 2 and 5 chromosomes reduced the tolerance to salt relative to ‘Chinese Spring’ euploid. It is concluded that chromosome 5E^b of Thinopyrum bessarabicum carries gene(s) for tolerance to salt and this tolerance may be due to the ability to exclude Na ions from the leaves and roots.     

Duplication of the Bx7 high-molecular-weight glutenin subunit gene in bread wheat (Triticum aestivum L.) cultivar'Red River 68'

SDS-PAGE analysis of seed proteins of the cultivar‘Red River 68’showed a considerably higher staining intensity of the band corresponding to HMW-GS Bx7 relative to the equivalent band in the cultivars‘Chinese Spring’and‘Cheyenne’. Southern blots of restriction enzyme fragments from DNA of these three cultivars were analyzed densitometrically to reveal that the band corresponding to the Bx7 gene of‘Red River 68’had a double staining intensity compared to the equivalent bands from the other two cultivars, which indicates that in‘Red River 68’a duplication of the Bx7 gene has occurred. Although the possibility of the gene copy being a pseudogene was not ruled out, the greater amount of protein corresponding to Bx7 in‘Red River 68’most likely is in accord with an increase in active gene number. SDSPAGE analysis of the proteins showed also that the mobility of Bx7 in‘Cheyenne’was slightly different from the mobilities of the Bx7 subunits of‘Red River 68’and‘Chinese Spring’. The same difference was observed at the gene level by PCR amplification of the genes encoding these subunits.     

Kernel hardness and baking quality of wheat — A genetic analysis using chromosome substitution lines

Summary An attempt was made to identify the chromosomal location of genetic control of a few components of wheat quality, using chromosome substitution lines of Cappelle Desprez, Cheyenne, Hope, and Timstein into the recipient variety Chinese Spring.Major factors for kernel hardness and increased baking absorption were found on chromosomes 5D of Cheyenne and Hope, and on 3B, 5D and 7D of Timstein. In Timstein, the presence of one of these chromosomes sufficed to make the wheat kernels hard.Factors for favourable dough properties were identified on a few other chromosomes, different in various varieties. These were 1A of Cappelle Desprez and Cheyenne, 3B of Hope, and 2D of Timstein. All but one of these chromosomes showed an increase in loaf volume to a level in-between those of the recipient variety Chinese Spring and the donor varieties. No relationship was found between kernel hardness and dough-making and baking properties.It was assumed that wheat quality is due to a combination of kernel hardness and favourable dough-making properties. As the genes for these factors are located on different chromosomes, it should not be too difficult to introduce both factors in existing varieties with poor baking properties. In a wheat breeding programme, the quality of new lines can be assessed in a rather simple way by determining kernel hardness and dough stability.     

Chromosomal Assignment of Three Enzyme Coding Loci (Icd1, Nad-Mdh1 and Aco1) Using Primary Trisomics in Beet (Beta vulgaris L.)

Resistance to Septoria nodorum was investigated in seedlings of an amphiploid generated from Triticum dicoccum Shübl. and Aegilops squarrosa Tausch, and in a series of substitution lines of single chromosomes from this synthetic hexaploid into Triticum aestivum cv. ‘Chinese Spring’ in three tests to determine the chromosomal location of resistance. From the Ae. squarrosa parent (D genome), chromosome 5D was found to confer a high level of resistance, reducing lesion cover to near that of the amphiploid in the three tests. Chromosomes 3D, and to a lesser extent, 7D were also found to confer significant resistance to the amphiploid. Three chromosomes, 2A, 3B and 5A, from the T. dicoccum parent (AB genomes) also conferred resistance but to a lesser extent than 7D. Two chromosomes, 2B and 2D, caused a significant decrease in resistance. ‘Chinese Spring’ may thus carry genes for resistance to S. nodorum on these chromosomes which are absent in the synthetic hexaploid.     

Rapid introduction of disease resistance from rye into common wheat by anther culture of a 6x triticale × nulli-tetrasomic wheat

Powdery mildew (caused by Erysiphe graminis) and yellow rust (caused by Puccinia striiformis) are the two most serious wheat diseases found in China. Rye chromosomes, carrying genes for resistance to these diseases, were introduced into common wheat in two generations using chromosome engineering and anther culture. The F₁ hybrids from a cross involving a hexaploid triticale (×Triticosecale Wittmack) בChinese Spring’ nulli‐tetrasomic N6DT6A wheat aneuploid line were anther cultured and doubled‐haploid plants were regenerated. Using genomic in situ hybridization, C‐banding and biochemical marker analyses, one of the anther‐cultured lines (ZH‐1)studied in detail, proved to be a doubled‐haploid with one rye chromosome pair added (1R) and a homozygous 6R/6D substitution (2n= 44). The line was tested for expression of disease resistance and found to be highly resistant to powdery mildew and moderately resistant to yellow rust.     

Genetic Control of Vernalization, Day-length Response, and Earliness per se by Homoeologous Group-3 Chromosomes in Wheat

To identify homoeologous group-3 chromosomes that carry genes for vernalization, day-length responses, and earliness per se, a series of aneuploid lines (mono-somics and tetrasomics) and chromosome-substitution lines in ‘Chinese Spring’ (CS) were surveyed under different vernalization and day-length regimes in controlled environments. The results indicated that genes on all three chromosomes of group 3 can have striking effects on ear-emergence time. The replacement of CS 3B by its homologues in ‘Lutescens 62’ and ‘Cheyenne’ produced an increased insensitivity to vernalization, while 3B homologues from ‘Ceska Presivka’ gave CS a remarkable sensitivity to vernalization. This provided evidence for multiple allelism at a new Vrn locus on chromosome 3B. A negative association between gene dosage and day-length response was found in CS 3D which was thought to carry a gene for promoting insensitivity to day-length. The behaviour of CS monosomic 3A and CS (Timstein 3A), in reducing numbers of days to heading independently of environmental stimuli, suggested the presence of earliness per se genes on this chromosome.     

Recessive genes controlling resistance to Helminthosporium leaf blight in synthetic hexaploid wheat

A study was conducted under controlled environment conditions in a phytotron to determine the nature of the inheritance of resistance Helminthosporium leaf blight (HLB) in a synthetic hexaploid wheat line, ‘Chirya‐3’, against the isolate KL‐8 of Bipolaris sorokiniana from the major wheat growing region of India. Crosses were made between two susceptible lines ‘WH 147’ and ‘Chinese Spring’. Analyses of F₁ and F₂ populations of these two crosses (‘WH 147’בChirya‐3’ and ‘Chinese Spring’בChirya‐3’) showed that resistance against the isolate in ‘Chirya‐3’ was governed by two recessive genes functioning in a complementary interaction giving an F₂ segregation pattern of 1 : 15 (resistant : susceptible). The segregation pattern of the resistant F₂ progenies in F₃ families from both crosses confirmed that two homozygous recessive genes were responsible for resistance to the isolate of Bipolaris sorokiniana in the synthetic line ‘Chirya‐3’. It is proposed that the genes be designated as hlbr1 and hlbr2.