Showing papers in "Euphytica in 1983"
TL;DR: Current status of wide hybridization in wheat is considered in the light of the number of hybrids produced, theNumber of genes transferred to commercial cultivars and their use in world wide agricuture.
Abstract: Current status of wide hybridization in wheat is considered in the light of the number of hybrids produced, the number of genes transferred to commercial cultivars and their use in world wide agricuture. Some original results are presented and results of other authors are compiled to provide update information regarding wide crosses in wheat. Barriers to wide hybridization and progress made in overcoming such barriers are discussed. Areas requiring more research are indicated.
252 citations
TL;DR: It is argued that because most of the yield from such soils comes from the least saline areas, the best breeding strategy for improving the overall yield of crops growing on them is to select for high yield on non-saline soils.
Abstract: Saline soils are typically very patchy in their salinity. The yield of crops growing on them is similarly patchy. This paper argues that because most of the yield from such soils comes from the least saline areas, the best breeding strategy for improving the overall yield of crops growing on them is to select for high yield on non-saline soils. This conclusion derives from comparing the effects that four different breeding goals, namely: (1) a 10% increase in yield on non-saline soils, (ii) a 20% increase in the threshold salinity that first reduces yield, (iii) a doubling of yield at an electrical conductivity of the saturation extract (ECe) of 20 dS/m and (iv) a combination of (i) and (iii), would have on total yield. The effects of achieving these goals in barley, common wheat, durum wheat and triticale in fields exhibiting different salinities are predicted from actual yields of these species grown on different salinities in the field.
181 citations
TL;DR: The results suggest that linkage drag is a fairly common phenomenon in near isogenic lines of wheat and more research is needed to prove clearly that linkage is involved.
Abstract: To determine whether linkage drag had occurred during the breeding of near isogenic lines (NILs) of wheat, 176 lines involving 11 sets of NILs, their recurrent parents and some of their donors were tested for seedling reaction to stem rust (4 races), leaf rust (3 races) and yellow rust (3 races). From the results, six cases were identified in which linkage drag may have played a role. More research is needed to prove clearly that linkage is involved. Nevertheless, the results suggest that linkage drag is a fairly common phenomenon.
151 citations
TL;DR: Advanced high sugar and acid breeding lines of tomatoes (Lycopersion esculentumMill.) were rated higher in sweetness, sourness and overall flavor intensity than the standard cultivars Cal Ace or T3.
Abstract: Advanced high sugar and acid breeding lines of tomatoes (Lycopersion esculentum
Mill.) were rated higher in sweetness, sourness and overall flavor intensity than the standard cultivars Cal Ace or T3. Titratable acidity and soluble solids content were major contributors to differences in overall flavor intensity. The results demonstrate that significant improvement in tomato flavor can be attained by increasing sugar and acid contents in tomato fruits by genetic manipulation. Current evidence indicates that breeding for high soluble solids in horticulturally acceptable tomato cultivars is justified.
77 citations
TL;DR: Embryo yields were increased by subjecting excised inflorescences to a short term, high temperature shock prior to anther plating and by a ten-fold increase in the auxin level of the anther culture medium.
Abstract: Culture of broccoli (cv. Green Mountain) anthers at elevated temperatures (e.g. 35°C for two days) prior to maintenance at 25°C stimulated microspore embryogenesis. Embryo yields were also increased by subjecting excised inflorescences to a short term, high temperature shock (i.e. 45°C for one hour followed by 40°C for three hours) prior to anther plating and by a ten-fold increase in the auxin level of the anther culture medium.
76 citations
TL;DR: Desynaptic mutants of diploid potato were found to produce a fairly high frequency of fertile 2n pollen grains that may be expected to originate through an equational division of the entire chromosome complement, and therefore, of first division restitution (FDR) origin.
Abstract: Desynaptic mutants of diploid potato (2n=2x=24) were found to produce a fairly high frequency of fertile 2n pollen grains. Such 2n pollen grains may be expected to originate through an equational division of the entire chromosome complement, and therefore, of first division restitution (FDR) origin. Since second division restitution (SDR) gametes in desynaptic mutants are expected to abort, because of the imbalance of chromosome number, the fertile 2n gametes may constitute homogeneous populations of FDR gametes. Among a total of 306 progeny derived from six crosses 76 desynaptic mutants were detected. Of these, 23 mutants were found to have more than 20% pollen fertility. Some of these fertile mutants were successfully used as pollen parents. Almost all the fertile mutants derived from crosses involving parents both of which produced 2n pollen. On the other hand, two crosses in which one of the parents was normal (producing only n pollen), with the other being 2n pollen producer, almost all the mutants were either male sterile or had below 20% pollen fertility. Desynapsis was found to be controlled by a single recessive gene ds, but the inheritance of meiotic nuclear restitution appeared to be elusive. Despite certain drawbacks that may arise from the use of desynaptic gene in a breeding programme. there are certain advantages as well.
74 citations
TL;DR: The significance of major genes in monitoring response to vernalization, photoperiod and gibberellin reveals a more optimistic future for breeding programmes where simple genetic and physiologic studies are integrated within those programmes.
Abstract: Major changes in the behaviour of the Australian wheat crop over the last one hundred years have been associated with three major gene groupings. The significance of major genes in monitoring response to vernalization, photoperiod and gibberellin, reveals a more optimistic future for breeding programmes where simple genetic and physiologic studies are integrated within those programmes. A revised classification of growth habit is presented in the appendix.
73 citations
TL;DR: Crosses of resistant parents with JG-62 and C-104 with resistant cultivars provide further evidence that resistance in chickpea to Race 1 of Fusarium oxysporum f.sp.
Abstract: Tests of parents and F1, F2 and F3 generations of crosses of JG-62 (early-rilting) and C-104 (late-wilting) with resistant cultivars provide further evidence that resistance in chickpea (Cicer arietinum L.) to Race 1 of Fusarium oxysporum f.sp. ciceris is controlled by at least two genes, both of which must be present in homozygous recessive form for complete resistance. Singly, one of the genes delays wilting, as in C.104. The second has not yet been isolated but crosses of resistant parents with JG-62 suggest that it operates in similar fashion.
69 citations
TL;DR: Differences in time of wilting of chickpea (Cicer arietinum L.) in response to Race 1 of Fusarium oxysporum f.sp.
Abstract: Differences in time of wilting of chickpea (Cicer arietinum L.) in response to Race 1 of Fusarium oxysporum f.sp. ciceris, are confirmed. C-104 wilts later than JG-62 and the difference in time of wilting appears to be inherited as a single gene with early wilting partially dominant to late wilting. Considered in relation to earlier studies, the observations indicate that at least two genes are involved in the inheritance of resistance in chickpea to Race 1 and offer an explanation for previous difficulties in interpreting the inheritance of resistance.
63 citations
TL;DR: Evidence is presented that in general the bread-making quality of wheat cultivars containing the subunits 3+10 or the subunit 2* coded for by chromosome 1A is higher than that of cultivar containing their allelic counterparts the sub units 2+11 or subunit 1 and the null form respectively.
Abstract: The high-molecular-weight subunit composition of glutenin is regulated by genes on the long arm of the homoeologous group 1 chromosomes. Evidence is presented that in general the bread-making quality of wheat cultivars containing the subunits 3+10 coded for by chromosome 1D or the subunit 2* coded for by chromosome 1A is higher than that of cultivars containing their allelic counterparts the subunits 2+11 or subunit 1 and the null form respectively. Besides it is shown that the positive effects of the subunits 3+10 and subunit 2* are additive. ?? 1983 H. Veenman en Zonen B.V.
61 citations
TL;DR: Variation of virulence within a pathotype suggests different complements and frequencies of genes for virulence in populations of the same pathotype.
Abstract: Selection of potato cyst-nematode populations of several pathotypes on resistant Solanum vernei hybrids resulted in increased virulence in some populations. This increase is believed to be due to the selection of specific virulence genes in each population gene pool. Resistance based on S. vernei is race specific and its life in the field will probably be finite. Populations of Globodera pallida are conventionally classified into different pathotypes according to their response on resistant test plants. However, populations of the same pathotype did not all behave identically. Such variation of virulence within a pathotype suggests different complements and frequencies of genes for virulence. Many field populations may not fit simply into the current pathotype scheme but no alternative is at present available.
TL;DR: ‘Thornless Evergreen’ blackberry (Rubus laciniatusWilld.) is a periclinal chimera in which the epidermis has mutated to a thornless phenotype while the internal portions of the plant possess the wild thorny genotype.
Abstract: ‘Thornless Evergreen’ blackberry (Rubus laciniatus
Willd) is a periclinal chimera in which the epidermis has mutated to a thornless phenotype while the internal portions of the plant possess the wild thorny genotype Shoot tips were used to establish a source of experimental material Nine hundred plants of ‘Thornless Evergreen’ were proliferated and rooted in vitro in an effort to locate a chimeral rearrangement and/or a pure thornless plant When these tissue culture propagated plants were grown in the greenhouse, two predominant plant types were observed; about 53% of the propagules showed a normal vining growth habit while the other 47% of the plants were dwarfed due to shortened internodes Adventitious shoots from isolated root segments of the normal plants were thorny, while those from many of the dwarfed plants had developed from epidermal cells of the parent Such plants of epidermal origin are no longer chimeral but are of pure thornless genotype
TL;DR: Factor analysis indicated that pathogen-induced necrosis, related possiby to toxin susceptibility, and unit spore production were major components of partial resistance to S. nodorum.
Abstract: Components of partial resistance of wheat seedlings to Septoria nodorum were measured in a glasshouse. Incubation period, infection frequency, latent period, lesion size, lesion cover, necrosis and unit spore production were recorded on 41 Triticum genotypes. There was no clear evidence of associated variation in components and multivariate analyses were used to elucidate such relationships. Factor analysis indicated that pathogen-induced necrosis, related possiby to toxin susceptibility, and unit spore production were major components of partial resistance to S. nodorum. Principal component analysis was used to characterise genotypes: associated with a continuous general resistance could be a high level of pathogen-induced necrosis or a high unit spore production, but rarely both in the same genotype.
TL;DR: The application of a mixture of gibberellic acid, naphthaleneacetic acid and kintetin to the pollinated buds prevented early abscission of the pod and the abortion of the hybrid embryo in an otherwise incompatible cross involving blackgram and greengram.
Abstract: Interspecific hybrids have been obtained in an otherwise incompatible cross involving blackgram (Vigna mungo ♀) and greengram (V. radiata ♂). The application of a mixture of gibberellic acid, naphthaleneacetic acid and kintetin to the pollinated buds prevented early abscission of the pod and the abortion of the hybrid embryo. Hybrid embryos (11–17 days after pollination) excised from the young developing pods and cultured on modified Murashige & Skoogs' medium, supplemented with IAA, kinetin, casein hydrolysate or coconut water produced normal-looking plantlets. The younger embryos (less than 11 days after pollination) either proliferated to form callus, or occasionally produced plantlets which albino, spindly and weak. The F1 plants were partially fertile, late-maturing, and intermediate between the two parents with respect to characters such as leaflet size, plant height and number of branches. However, the setting percentage and the number of seeds per pod were highly reduced because of the meiotic irregularities. In the F2 generation, grown in the field as replicated rows, different combinations of desirable characters appeared and the setting percentage was also improved.
TL;DR: Interspecific crossability among four species of Vigna, namely, V. radiata (mungbean),V.
Abstract: Interspecific crossability among four species of Vigna, namely, V. radiata (mungbean),V. mungo (black gram), V. umbellata (rice bean) and V. angularis (adzuki bean), was investigated. Pod-set and percentages of pods harvested varied with the combinations of two parental cultivars of each species for most of the interspecific hybrid crosses. The use of intraspecific hybrids as parents was slightly superior to cultivars for interspecific hybridization. A remarkable increase in viable seed production was found for the interspecific cross,V. radiata x V. umbellata, by using intraspecific hybrid as parents. Furthermore, a successful interspecific hybrid of V. mungo x V. angularis was accomplished through the use of intraspecific hybrid parents. Reciprocal cross differences were common in all the interspecific combinations. Except for the cross between V. umbellata and V. angularis, all other reciprocal interspecific crosses were unsuccessful.
TL;DR: Polyacrylamide gel electrophoresis (PAGE) of storage proteins (prolamines) was used to screen 64 landraces of wheat and barley from Nepal and the YemenArab Republic and two cultivars for comparison to identify differences in ploidy levels.
Abstract: Polyacrylamide gel electrophoresis (PAGE) of storage proteins (prolamines) was used to screen 64 landraces of wheat and barley from Nepal and the YemenArab Republic and two cultivars for comparison. Altogether 3168 single seeds were examined and the advantages gained by using the vertical slab gel method were recognised. The extent of variation present within populations of landraces could be assessed easily and rapidly using the methods described. Differences in ploidy levels of wheats were detected by PAGE and investigated. Suggestions are made for improvements in sampling strategies in hilly terrain.
TL;DR: Increased interest for breeding for race-specific resistance in this host-pahtogen system is on the long term considered a wrong strategy as it will considerably hamper the selection for partical resistance.
Abstract: A range of leaf rust (Puccinia hordei) isolates was tested on a series of barley cultivars among which the differential series. No resistance to all isolates seems to exist in the cultivated barley. The barley cultivars appear to carry zero to two race-specific resistance (Pa) genes. The isolates carry from three to eight virulence factors from the eight or nine that could be evaluated. Isolates with wide virulence spectra were most common. The pattern with virulence to Pa, Pa2, Pa4, Pa5, Pa6, and Pa8, and avirulence to Pa3, Pa7 and Pa9 is very common and seems to have a near-global distribution. These isolates, however are not necessarily identical in genotype.
TL;DR: There was an interaction between certain genotypes when overall embryo culture rates were analysed and differences were found between the H. vulgare cultivars regarding rates of hybrid (VB) production and chromosome doubling whereas total plant regeneration was unaffected.
Abstract: Crosses were made between five cultivars of Hordeum vulgare and three genotypes of H. bulbosum and the influence of male and female partners on success rates up to the stage of haploid embryo culture was investigated. Both parents markedly affected seed setting and rates of embryo differentiation, whereas seed quality was mainly influenced by the female. There was an interaction between certain genotypes when overall embryo culture rates were analysed. Following embryo culture only the influence of the female partner was assessed but differences were found between the H. vulgare cultivars regarding rates of hybrid (VB) production and chromosome doubling whereas total plant regeneration was unaffected.
TL;DR: ‘m’ represents an objective and reliable statistical measure of cultivar performance and has been used to calculate two indexes: performance index, P=100 m/(n-1), giving the percentage of means which a particular cultivar exceeds significantly, and differentiation index, D=200 Σm/n (n- 1), giving a percentage of paired comparisons between cultivars that show significant differences.
Abstract: The number of means ‘m’, from which a particular cultivar differs significantly, is used to arrange cultivars in order of descending superiority. For n cultivars under study, the maximum ‘m’ value corresponding to the best cultivar is n-1, indicating that it exceeds significantly the n-1 other cultivars, and the minimum zero. Because ‘m’ represents an objective and reliable statistical measure of cultivar performance, it has been used to calculate two indexes: (1) performance index, P=100 m/(n-1), giving the percentage of means which a particular cultivar exceeds significantly, and (2) differentiation index, D=200 Σm/n (n-1), giving the percentage of paired comparisons between cultivars that show significant differences. Rating cultivars according to P across years (Py), sites (Ps), and years plus sites (Pys), gives an overall picture of the relative superiority of the entries. Rating trials according to D allows comparisons between trials and offers the possibility when the same sets of entries are compared each year across sites, to identify sites that give maximum differentiation.
TL;DR: In experimental lines with phenotypically normal heads but possessing the recessive supernumerary spikelet gene(s), increases in the number of nodes on the rachis and fertility and grain number per head were found, as well as in the ‘normal’ Australian and American wheat cultivar Phoenix.
Abstract: The inheritance of supernumerary spikelets was found to be controlled by two recessive genes with evidence for the possibility of a repressor(s) in crosses between normal and supernumerary spikelet wheats. In experimental lines with phenotypically normal heads but possessing the recessive supernumerary spikelet gene(s), increases in the number of nodes on the rachis (and hence the number of normal spikelets) fertility and grain number per head were found, as well as in the ‘normal’ Australian and American wheat cultivar Phoenix. This attribute has previously been suggested to be a way of increasing spikelet number in future wheat breeding.
TL;DR: Resistance to potato cyst-nematodes is predominantly found in some 17 species belonging to the series Tuberosa which have their geographical distribution mainly in the Andes.
Abstract: Numerous accessions maintained in the potato collection of the ‘German-Netherlands Potato Department of the Gene Bank in the Federal Research Center for Agriculture Braunschweig-Volkenrode’ have been evaluated for resistance to potato cyst-nematodes. The results of several years testing for resistance to both Globodera rostochiensis and G. pallida are presented in this paper. It is concluded that resistance is predominantly found in some 17 species belonging to the series Tuberosa which have their geographical distribution mainly in the Andes. The geographical distribution of species with G. pallida resistance is discussed and it is pointed out that this resistance is mainly concentrated on the eastern slopes of the Andes (Cordillera oriental).
TL;DR: Six segregating breeding populations were studied for inheritance of resistance to race 2 of the clubroot pathogen Plasmodiophora brassicae Wor, finding the single gene responsible for resistance toRace 2 transferred from B. oleracea is completely dominant over susceptibility.
Abstract: Six segregating breeding populations were studied for inheritance of resistance to race 2 of the clubroot pathogen Plasmodiophora brassicae Wor. The single gene responsible for resistance to race 2 transferred from B. napus is completely dominant over susceptibility. The diploid B. oleracea chromosome number of 2n=18 was restored in the B3 and B4 progenies derived from backcrossing a 26-chromosome B1 plant with 2x B. oleracea.
TL;DR: Indications are that selection for high bunch index would be more effective than selection for yield in giving palms capable of yielding well at high density.
Abstract: Three oil palm (Elaeis guineensis
Jacq.) experiments in West New Britain, Papua New Guinea, are discussed. The extent of heritable variation in growth parameters is estimated from parent-offspring correlations and from repeatabilities of successive measurements on the same palms. Heritability of vegetative measurements appears high. For yield of fruit, and growth parameters derived therefrom, the heritability is lower, but repeatabilities are improved when yield is averaged over three-year periods. In the early years of a planting density trial, when the level of interpalm competition was low, individual palms were selected on the basis of yield of fruit per palm and various growth parameters. The performance of the selected palms was then examined in later years, under more intense competition, to assess the possibilities of selection for high planting density. Indications are that selection for high bunch index (the proportion of total dry matter used for bunch production) would be more effective than selection for yield in giving palms capable of yielding well at high density. Selection for high leaf area ratio or for short leaf rachises was not effective.
TL;DR: Flowering behaviour and the morphology of flowers in white yam, Dioscorea rotundata Poir, is described in relation to hand pollination and fruit set is improved three-fold.
Abstract: Flowering behaviour and the morphology of flowers in white yam,Dioscorea rotundata Poir. is described in relation to hand pollination. Plants flowered between June and September with flowering intensity depending largely on factors associated with shoot vigour in genotypes. The high predominance of male plants coupled with irregular flowering necessitate the establishment of many plants to ensure sufficient flowering individuals for a hybridization programme. In order to achieve good fruit set and seed yields, pollen should be collected from open male flowers around 14.00 h and mature female flowers pollinated within a week after they are bagged particularly during the early flowering months. Low fruit set in white yam (12%) is primarily due to inefficient pollination by insects. With hand pollination fruit set is improved three-fold.
TL;DR: The chromosome bearing the gene(s) for resistance to the beet cyst nematode (Heterodera schachtiiSchm.), could be transferred from Beta patellaris to B. vulgaris by interspecific hybridization and repeated backcrossing by studying the nature of resistance in monosomic additions and growth cabinet experiments.
Abstract: The chromosome bearing the gene(s) for resistance to the beet cyst nematode (Heterodera schachtii
Schm.), could be transferred from Beta patellaris to B. vulgaris by interspecific hybridization and repeated backcrossing. A tetraploidized B. vulgaris originating from Anatolia (Turkey) was used as an intermediate. After several backcrosses with a number of different tetraploid and diploid beet cultivars, monosomic additions could be obtained which had the resistance bearing chromosome of B. patellaris. Cytological techniques were used for the study of this chromosome in resistant hybrids and monosomic additions. The analysis of pairing behaviour of the B. patellaris chromosome was hampered by the occurrence of non-specific stickiness of the chromosomes in meiocytes at pachytene and diakinesis. Moreover, the nature of resistance in monosomic additions was studied in growth cabinet experiments, revealing that the penetration rates of the larvae into the root system did not differ from the susceptible control plants. Among the F1B6 and F1B7 backcross derivatives, no plants with intermediate levels of resistance were found.
TL;DR: The authors' data suggest independent gene action with intragenic dominance in garden chrysanthemum siblings obtained through two generations of single-plant selfpollination, and one inbred expressed a high level of pseudo-self-compatibility (PSC).
Abstract: Eleven garden chrysanthemum siblings obtained through two generations of single-plant selfpollination were selfed and crossed in a complete diallel. Outcrosses to unrelated individuals were performed to test for male and female fertility. Since eleven crossing patterns were found inthe diallel, at least three genes must be assumed. Our data suggest independent gene action with intragenic dominance. One inbred, 77-AM3-3, expressed a high level of pseudo-self-compatibility (PSC) by giving some very low cross seed sets along with high self seed set. This inbred also exhibited variable PSC from season to season.
TL;DR: Testing of lines or families in an increasing number of replications increases the accuracy of evaluating the entries and thus enlarges the heritability as well as the expected response to selection, but the number of entries that can be evaluated is decreased.
Abstract: Testing of lines or families in an increasing number of replications increases the accuracy of evaluating the entries and thus enlarges the heritability as well as the expected response to selection. However, associated with this is a decrease in the number of entries that can be evaluated. This counterbalances the anticipated improvement in selection response due to more intensive testing. The mathematical background for deriving the optimal number of replications as well as illustrations of some calculations are elaborated.
TL;DR: Distribution and accumulation of dry matter (d.m.) and nitrogen (N) were investigated within ears of a semidwarf, a gigas, and a normal wheat genotype grown under controlled environments to suggest a pre-anthesis determination of the accumulation potential of grains in different spikelets.
Abstract: Distribution and accumulation of dry matter (d.m.) and nitrogen (N) were investigated within ears of a semidwarf, a gigas, and a normal wheat genotype grown under controlled environments. A high harvest index was linked with a small pre-anthesis N-storage (and vice versa) but this did not affect N amounts in grains because of compensation by prolonged N uptake during grain filling. N distribution within and between spikelets roughly paralleled that of d.m. Nevertheless, the two processes appeared to be rather independent as became evident from comparisons of the time courses in and between the genotypes. Final distribution of d.m. and N within and between spikelets mainly depended on different rates during the linear phases of accumulation and less on the duration. Maximum of d.m. and N weights per grain as well as maximum of grain number were observed in spikelets below the middle of the ear axis. This ‘submedian dominance’ suggested a pre-anthesis determination of the accumulation potential of grains in different spikelets. N percentage within spikelets disclosed that N accumulation was hampered more than that of d.m. in those positions unfavourable to the latter process. This principal pattern was not affected by genotypes in spite of considerable differences in numbers and weights of grains.
TL;DR: The phenetic relationships of 32 cacao clones were analysed with several multivariate statistical methods and the results were compared with their genetic relationships.
Abstract: The phenetic relationships of 32 cacao clones were analysed with several multivariate statistical methods and the results were compared with their genetic relationships. Also the relationships between 33 cacao characteristics were studied based on average measurements and observations from each of 294 clones. Some conclusions were drawn with respect to cacao breeding using simple correlations between characteristics.
TL;DR: There was some evidence to suggest that the presence of the now ‘overcome’ and ineffective major gene in Mostyn may have enhanced the level of partial resistance in this cross even in the absence of the corresponding virulence.
Abstract: In the cross Mostyn x (Mostyn x Maldwyn), 87 F6 lines with relatively high levels of adult resistance resulting from selection in previous generations, were field tested for severity to mildew infection in 1980 Of the 74 lines which proved to be homozygous regarding the Mostyn gene (AA or aa), 16 (including three lacking the Mostyn major gene-aa) proved to have significantly lower percentage leaf area infected than the most resistant parent at growth stages ranging from late ‘boot’ to ‘early milk’ ripeness of the grain Some lines showed 10–15% less mildew than the adult plant resistant parent Maldwyn There was some evidence to suggest that the presence of the now ‘overcome’ and ineffective major gene in Mostyn may have enhanced the level of partial resistance in this cross even in the presence of the corresponding virulence