Showing papers in "Plant Breeding in 1990"
TL;DR: The current and potential uses of molecular markers in breeding for oligogenic resistance traits and advantages of marker-facilitated selection for resistance genes under a variety of special circumstances are discussed.
Abstract: In several plant species, genetic maps have recently been developed for restriction fragment length polymorphisms (RFLPs). Together with isozymes, they offer alternative solutions to many breeding problems. This review deals with the current and potential uses of molecular markers in breeding for oligogenic resistance traits.
In the first part, segregation analyses and analyses of near-isogenic lines are collated with respect to the mapping of resistance genes. Also, various types of populations are compared for the amount of information obtained in segregation analyses. In the second part, theoretical and numerical results are presented dealing with the number of individuals required for marker-facilitated selection of a resistance gene in a backcross program. Both the use of a single marker and a marker bracket are considered and the influence of the following parameters is investigated: (a) recombination frequency between the resistance gene and marker(s), (b) size of backcross families, (c) number of backcross generations, and (d) number of carriers of the resistance gene to be recovered in the final backcross generation. The results provide information with regard to the optimum design of marker-facilitated selection programs and the required expenditures compared to direct selection of the resistance trait. In the third part, applications of molecular markers are discussed with respect to (1) advantages of marker-facilitated selection for resistance genes under a variety of special circumstances, (2) pyramiding of resistance genes, (3) selection against the genetic background of a donor parent, and (4) their use as a starting point for chromosome Walking.
247 citations
TL;DR: High molecular weight glutenins were found in general to be poor indicators of viscoelastic properties, although band 20 showed a negative influence on quality, in relation to development of cultivars with good gluten strength.
Abstract: An electrophoretic study of gliadin and glutenin proteins, mainly low-molecular-weight (LMW) Glutenin Subunits, was undertaken to investigate possible assoeiations between these proteins and gluten strength. Thirty-eight durum wheat cultivars having different origins and currently grown in Spam were analysed. Different electrophoretic methods were used to analyse the seed storage proteins. Protein grain content was estimated and gluten strength was measured by the SDS-sedimentation test. New patterns for LMW glutenins were observed. Besides the known patterns of LMW-1, associated with γ-gliadin 42, and LMW-2 associated with γ-gliadin 45, six cultivars had LMW-2− associated with γ-gliadin 43, one cultivar showed LMW-2* associated with γ-gliadin 44, and another cultivar, null for γ-42 and γ-45, had LMW-1−. Significant differences for gluten strength were found among groups of cultivars with different LMW patterns. High molecular weight glutenins were found in general to be poor indicators of viscoelastic properties, although band 20 showed a negative influence on quality. The results are discussed in relation to development ol cultivars with good gluten strength.
98 citations
TL;DR: The experiments proved that one single gene was capable in potato to affect substantially the manifestation of vieldmg attributes and supported the conclusion that the gene product of the ml C gene interacts with the hormonal status of the plant.
Abstract: Diploid and tetraploid potato clones were transformed with the rol C gene from Agrobacterium rhizogenes under the control of the cauliflower-35-S promoter. Parameters proper to the sink and source attributes and hormone treatments have been considered to study the effect of the gene on yield physiology of the potato plant. The expression of the rol C gene in diploid and tetraploid potato lines induced drastic developmental abnormalities like dwarfism and increased tillering. Hormonal treatments revealed a different behavior of rol C transformams and controls. This supports the conclusion that the gene product of the ml C gene interacts with the hormonal status of the plant. Grafting experiments showed the non-ditfusable nature of rol C gene product. Tuberization was studied in-vitro and in-planta. Relevant differences in tuber shape and eye number were noted between rol C transfonnams and controls. Tuber yields in-planta in greenhouse or in growth chamber resulted higher in the controls; a significant increased number of tubers per plant was found, however, in both diploid and tetraploid rol C transformants. The effect of the rol C gene was apparently too drastic for diploid and tetraploid potatoes; weaker and tissue specific promoters may be necessary to induce only those modifications which are wanted for this crop. The experiments nevertheless proved that one single gene was capable in potato to affect substantially the manifestation of vieldmg attributes.
87 citations
TL;DR: These landraces are a useful source of breeding material, which also widens the genetic base of the present breeding program, and the largest gains for variety improvement for the Syrian steppe area are expected from direct selection under stress conditions.
Abstract: Homozygous lines from six Syrian and two Jordanian landrace populations were tested under highly productive growing conditions in Tel Hadia (1982/83), under drought stress in Breda (1983/84), and under dryland salinity stress in Hegla (1982/83/84) in Syria. Mean grain yield levels ranged between 260 kg/ha and 4850 kg/ha. Under drought and salinity stress, the majority of the landrace lines out-yielded the best cheeks significantly. In Tel Hadia the check cultivars mostly outyielded the landrace lines, but not always significantly. In all environments the harvest index of the landrace lines was near the optimum for barley. They expressed intermediate plant height and time to flowering, high lodging susceptibility under favorable growing conditions, high protein content, and a wide range of yield component combinations.
In the stress environments highly significant genetic variation among the landrace lines was found. The heritabilities for gram yield were high in these trials. The correlations between performance under stress and under favorable growing conditions were poor. Therefore, the largest gains for variety improvement for the Syrian steppe area are expected from direct selection under stress conditions.
Unique responses in proline accumulation and germination patterns in saline solution indicated specific adaptation in this material. These landraces, thus, are a useful source of breeding material, which also widens the genetic base of the present breeding program.
70 citations
TL;DR: It is suggested that in maize, improvement in salt tolerance could be obtained through further cycles of selection and breeding.
Abstract: Genetic variation for NaCl tolerance at the vegetative stage was assessed in nutrient solution culture in maize (Zea mays L.). Shoot growth, and plant fresh and dry weight of the two cultivars, Akbar and Sadat were severely reduced after three weeks growth in 120, 150, and ISO mol m−3 NaCl. There was however considerable variability between seedlings. Ten-thousands seeds of cv. Akbar were therefore screened for shoot growth at 180 mol m−3 NaCl after four weeks growth in sand culture. A selection intensity of 0.42 % was achieved. Eighteen selected plants were polycrossed for estimation of narrow-sense heritability based on female parent-progeny regression. A narrow-sense heritability estimate of 0.54 was obtained.
The progeny of the salt-tolerant selection line and selfed progeny plants of the unselccted control lines of cvs Akbar and Sadat were grown for six weeks in 0, 30, 60, 90, 120, 150, and 180 mol m−3 NaCl in sand culture. The tolerant line produced significantly greater fresh and dry biomass and had greater shoot length than the unselected cv. Akbar, but the selection line derived from cv. Akbar was equal to the salt tolerant cv. Sadat in all the growth parameters measured.
These data suggest that in maize, improvement in salt tolerance could be obtained through further cycles of selection and breeding.
70 citations
TL;DR: Eighty-three third backcross lines which comprise a set of near isogenic lines (NIL's) of the barley cultivar ‘Clipper’ but each carrying a different chromosomal segment from Hordeum spontaneum, marked with a distinct isozyme, were tested for resistance to three races ofThe barley leaf rust pathogen (Puccmia hordei).
Abstract: Eighty-three third backcross lines which comprise a set of near isogenic lines (NIL's) of the barley cultivar ‘Clipper’ but each carrying a different chromosomal segment from Hordeum spontaneum, marked with a distinct isozyme, were tested for resistance to three races of the barley leaf rust pathogen (Puccmia hordei). Fourteen lines showed resistance to at least one race and three showed resistance to all three races. The resistance in two of these lines was controlled by separate, single partially dominant genes. In one case the resistance gene named Rph1O was on chromosome 3 and linked (r = 0.15 ±0.05) with the isozyme locus Est2. In the second case, the gene (Rph11) was on barley chromosome 6 and linked (r = 0.07±0.02) with the isozyme locus Acp3 and (r = 0.11±0.02) with Dip2.
69 citations
TL;DR: Six lines resistant to Tomato Leaf Curl Virus (TLCV) have been developed with controlled introgression of L. hirsutum f.
Abstract: Six lines, i.e., H-2, H-11, H-17, H-23, H-24, and H-36, resistant to Tomato Leaf Curl Virus (TLCV) have been developed with controlled introgression of L. hirsutum f. glabratum into Lycopersicon esculentum. The disease incidence, 120 days after inoculation, of those lines derived from L. hirsutum f. glabratum ranged from 8.3 to 35.0 %, whereas in susceptible varieties it ranged from 95.0 to 100 %. The coefficient of infection (CI) values in the resistant lines were very low, ranging from 0.25 to 4.55, whereas in susceptible varieties CI values ranged from 60.56 to 88.96. Line H-2 had the highest resistance by showing the least disease incidence and CI values. The fruit size and days to maturity in resistant lines were close to those of cultivated susceptible varieties. These lines have the scope for being used as varieties in the TLCV infested areas or as foundation lines for further genetic improvement.
68 citations
TL;DR: The culture of unpollinated ovules is shown to be a suitable system for the production of haploid sugar beet (Beta vulgaris L.) and the majority of the haploids isolated maintained the haploid genome level during the in vitro culture and propagation.
Abstract: The culture of unpollinated ovules is shown to be a suitable system for the production of haploid sugar beet (Beta vulgaris L.). The yield of haploids depended upon the genotype and varied between 0 and 13 % with a mean of 1.0 %. Haploid plants could be produced from approximately 50 % of all genotypes examined.
The majority of the haploids isolated (about 90%) maintained the haploid genome level during the in vitro culture and propagation; 10% of the haploid clones showed a spontaneous doubling to the diploid genome level.
65 citations
TL;DR: The occurrence in the backcross offspring of plants having a morphology similar to A. cepa without showing symptoms of downy mildew opens perspectives for breeding P. destructor-resistant onion varieties.
Abstract: Allium roylei Stearn and both reciprocals of the interspecific hybrid between Allium cepa L. and A. roylei displayed no symptoms of Peronospora destructor (Berk.) Casp. after artificial or natural inoculations, whereas A. cepa was susceptible. In the offspring from the backcross A. cepa× (A. roylei ×A. cepa) resistant and susceptible plants segregated after artificial inoculations, fitting a 1: 1-ratio. This suggests that resistance is controlled by a single, dominantly-inherited locus (designated Pd1) from the nuclear genome of A. roylei. During a severe epidemic in the field, plants from the same backcross segregated resistant and susceptible individuals in a 3: 1-ratio. Escapes may explain the deviation from the 1: 1-segregation, but the presence of a second resistance locus segregating independently from Pd1 cannot be excluded, implicating possible differences in virulence between populations of P. destructor. The occurrence in the backcross offspring of plants having a morphology similar to A. cepa without showing symptoms of downy mildew opens perspectives for breeding P. destructor-resistant onion varieties.
60 citations
TL;DR: Preliminary cytological analyses of pollen mother cells of hybrid plants suggests the possibility of genetic exchange between the two species, as well as the need for further research on this topic.
Abstract: Embryo rescue techniques were used to obtain hybrids between Sinapis alba L. (white mustard) and Brassica napus L. (oilseed rape) with the goal of improving the disease tolerance of oilseed rape. Hybrid plants with 31 or 43 chromosomes were only recovered, when S. alba, was used as the female parent. One hybrid was obtained from the cross S. alba L. cv. ‘Kirby’×B. napus L. cv. ‘Topas’, while 26 hybrids were obtained, when various S. alba L. cultivars were pollinated with the rapid cycling B. napus line CrGC 5006. All F1, hybrid plants were male sterile; however, the first generation backcross to B. napus L., also obtained by embryo rescue, produced plants with 50 chromosomes and 61–84 % pollen viability. Second backcross generation seed was produced by normal sexual crossing. Preliminary cytological analyses of pollen mother cells of hybrid plants suggests the possibility of genetic exchange between the two species.
60 citations
TL;DR: A list with information about named host genes controlling resistance to rust in both cultivated and wild flax has been compiled and will be useful for genetic, physiological and biochemical research as well as breeding for resistance.
Abstract: A list with information about named host genes controlling resistance to rust in both cultivated and wild flax has been compiled. These will be useful for genetic, physiological and biochemical research as well as breeding for resistance. Information regarding mutation, temperature sensitivity and the effect of inhibitor/avirulence gene interaction on expression of certain host genes is included.
TL;DR: The application of GMS in hybridization intended for the introduction of alien genes is discussed as well as factors affecting the pollination of genie male steriles.
Abstract: The possible applications of genie male sterility (GMS) in plant breeding arc reviewed and discussed. The basic contribution of GMS is that it provides a means of genetic emasculation which can be applied for the massive production of hybrids. There are two main fields of application: (1) the production of hybrid varieties and (2) inter- and intraspecific hybridization and back-crossing programmes for the introduction of genetic variation into crop varieties. Several schemes have been proposed for using GMS in hybrid breeding in different crops. These are discussed under four headings: genetic methods, cy-togenetic methods, temporary restoration of fertility and manual pollination. The application of GMS in hybridization intended for the introduction of alien genes is discussed as well as factors affecting the pollination of genie male steriles.
TL;DR: Within the resyn and further extensive breeding materias, screening for low indolyl GSL contents resulted in finding one genotype with an extremely low 4-hydroxy-gluco-brassicin and glucobrassicin content.
Abstract: The glucosinolate (GSL) pattern of 93 resynthesized (resyn) repeseed lines was examined over three years, and five stable genotypes with distinct GSL profiles were identified. Typically the resyn B. napus profile exhibited progoitrin as the main GSL, but contained sinigrin. The different GSL patterns of the four deviating lines are discussed with respect to the proposed biosynthetic pathway. Within the resyn and further extensive breeding materias, screening for low indolyl GSL contents resulted in finding one genotype with an extremely low 4-hydroxy-gluco-brassicin and glucobrassicin content. Furthermore, other lines were identified, over a wide range of indolyl GSL contents. The values were stable over two years.
TL;DR: Electrophoretic profiles of denatured albumin, globulin, prolamin, and glutelin solubility fractions demonstrated that quinoa seed polypeptides could be classified as either albumin or globulin with most predominant polypePTides in the globulin fraction.
Abstract: Quinoa (Chenopodium quinoa Willd) is an important domesticated food crop of the Andean highlands with potential as an alternative crop elsewhere. Among its most attractive characteristics are the quantity and favorable amino acid balance of the seed proteins. The objective of this study was to characterize quinoa seed proteins by electrophoretic mobility, solubility fractionation, and genetic variability from a wide genetic base. Electrophoretic profiles of denatured albumin, globulin, prolamin, and glutelin solubility fractions demonstrated that quinoa seed polypeptides could be classified as either albumin or globulin with most predominant polypeptides in the globulin fraction. Insignificant amounts of protein were present in the prolamin fraction and all polypeptides in the glutelin fraction had identical electrophoretic mobilities to albumins and globulins. Three globulin polypeptides of 34.3, 35.6, and 36.2 kilodaltons in size were highly variable within and among the accessions examined and appear to be coded by at least two loci. Two-dimensional peptide mapping revealed that these three polypeptides were homologous. These highly variable markers could be used for identification and classification of germplasm and elucidation of systematics and genetic variability within the quinoa germplasm pool. All other major polypeptides were electrophoretically invariant among the accessions examined.
TL;DR: Preliminary small scale field trials indicate that the selfed hybrid of Eruca sativa and Brassica campestris is comparable in yield with a high yielding commercial variety of B. juncea.
Abstract: Allied species of crop Brassicas have potential value as donors of useful nuclear/organelle genomes. Eruca sativa, a member of subtribe Brassicineae, is resistant to white rust and well adapted to drought. Attempts to hybridize it with Brassica campestris by conventional methods were unsuccessful. However, hybrids were obtained by embryo rescue and the hybrid embryos were found to produce numerous secondary embryos in upto 7 to 8 subcultures. Plantlets developed from them exhibited morphological characteristics of both parents. The chromosome number of 2n = 42 showed that they were amphidiploids. The plants were allotctraploids (2n = 42) and showed 21 bivalents at M1 of meiosis. Hybridization of total DNA of the hybrids with two probes, a B. campestris tandem repeat DNA and 18s ribosomal DNA of wheat showed that it was derived from the genome of both parents. The hybrids are self-fertile and show the same high fertility even in A3 generation. They were selfed or crossed with B. juncea, B. campestris and B. nigra to screen for useful agronomical traits. Six more embryos of E. saliva × B. campestris have been obtained and their growth is being studied. Preliminary small scale field trials indicate that the selfed hybrid is comparable in yield with a high yielding commercial variety of B. juncea.
TL;DR: In an attempt to generate more variation of the type represented by the rugosus loci, r and rb, putative seed development mutants have been isolated from peas following chemical mutagenesis of a round-seeded (RRRbRb) genotype.
Abstract: In an attempt to generate more variation of the type represented by the rugosus loci, r and rb, putative seed development mutants have been isolated from peas (Pisum sativum L.) following chemical mutagenesis of a round-seeded (RRRbRb) genotype. The populations segregating for wrinkled seeds at the M3 generation were examined for their starch, lipid and protein content. The starch content of the wrinkled-type variants was between 0 and 55 % with an amylose content between 0 and 80 %, compared with 51 % and 30 %, respectively, for the round-seeded parent. When the range of compositions of the wrinkled-type seed was grouped, the values indicated that similar phenotypic groups to the wild type (RRRbRb) and the rugosus types (rrRbRb, RRrbrb and rrrbrb) existed in the population. The lipid content of the putative mutants supported this conclusion. Furthermore, some of the values for starch content and composition, and for lipid content indicated that new mutants had been induced. The material represents the first report on chemically-induced mutants of legumes with altered storage product composition.
TL;DR: The heterosis of Pol CMS hybrids is evident and common in some of the characters tested, especially in plant seed yield and siliqua number, and the cytoplasm has no deleterious effects on the FI characters tested.
Abstract: Polima CMS lines can be divided into three groups according to the sensitivity of male sterility to temperature: 1) high temperature CMS lines (62.9%), 2) low temperature CMS lines (28.6 %) and 3) stable CMS lines (8.5 %). The heterosis of Pol CMS hybrids is evident and common in some of the characters tested, especially in plant seed yield and siliqua number. The cytoplasm has no deleterious effects on the FI characters tested.
TL;DR: Results show that the cultivars ‘Banteng’ and ‘Arrivate’, the Ethiopian line CI 5791, and the Syrian line 79 SIO-10, had a high partial resistance in all experiments and could be successfully used for breeding purposes.
Abstract: Reciprocal crosses were made between 9 different barley genotypes with high genetic variability for net blotch resistance. Parents and 72 F1 plants were used to determine the inheritance of partial resistance to net blotch. Four experiments, one in a growth chamber on seedlings and 3 others in the field on adult plants, were undertaken using a randomised complete block design. An isolate of net blotch from local cultivars was used for inoculation. Non-inoculated plants of one of the field experiments were used for the detached leaf test in petri dishes.
Results show that the cultivars ‘Banteng’, and ‘Arrivate’, the Ethiopian line CI 5791, and the Syrian line 79 SIO-10, had a high partial resistance in all experiments. Diallel analysis showed high significant general and specific combining ability when maternal and reciprocal effects were not significant. As the resistance genotypes have a high additive genetic effect, they could be successfully used for breeding purposes.
TL;DR: The present study investigates the effects of media on the rate of green plantlet formation from anther cultures of five different winter and spring wheat cultivars with strong effect on the formation of plantlets, but the developed procedure allows also the regeneration of recalcitrant genotypes.
Abstract: The present study investigates the effects of media on the rate of green plantlet formation from anther cultures of five different winter and spring wheat cultivars. An increased number of embryos and calli were produced on Ficoll-containing liquid potato-2 medium, whereas the addition of 0.2 M/l maltose increased the rate of regeneration. The genotypes had strong effect on the formation of plantlets, but the developed procedure allows also the regeneration of recalcitrant genotypes. On the best medium sequence, a total of 2430 anthers over all genotypes were plated which developed 1325 macroscopic structures (55 %) of which 159 green plants have developed, i.e. 12 % from the structures and 7 % from the plated anthers, respectively.
TL;DR: Phenotypic differentiation of durum wheat, and probably many other crops, on a geographic basis is more pronounced in areas where plant breeding has had little impact.
Abstract: Flag leaf in wheat (Triticum spp.) is a major source of photosynthate for the developing grain and its size contributes to interplant competition. Flag leaf length, width, and area in a sample of 778 entries of durum wheat (T. turgidum L. durum group) germplasm obtained from the U.S. National Small Grains Collection showed considerable phenotypic variation. Correlations between flag leaf and eight spike quantitative characters showed significant values greater than 0.30 for kernel weight per spike with all three flag leaf measurements and for awn length with flag leaf length and area. Larger flag leaf area appeared to be associated with accessions having a history of some deliberate plant breeding for high grain yield. A multivariate approach was used to assess how discrimination among 26 countries of origin obtained with spike characters in a previous study was affected by reducing the sample size from about 3,000 to 735 and by the addition of flag leaf measurements to the analysis. The reduced sample size had little impact on the results of the previous analysis on the whole collection of about 3,000 entries. The addition of flag leaf characters to the analysis caused a rearrangement in the clusters of countries, mostly from Asia, where less germplasm modified by plant breeding was included in the collection. Five clusters were identified: (1) 11 Mediterranean basin countries, (2) USA, UdSSR, and Yugoslavia, (3) four Near East Countries and Bulgaria, (4) three Middle East countries and Greece, India and Ethiopia, and (5) Afghanistan. Phenotypic differentiation of durum wheat, and probably many other crops, on a geographic basis is more pronounced in areas where plant breeding has had little impact.
TL;DR: An effective method of incorporating germplasm of wild 2x Solanum species into the cultivated potato is through hybridization with haploids of 4x S. tuberosum Group Tuberosum for the introduction of desirable traits and genetic diversity from wild species into potato.
Abstract: An effective method of incorporating germplasm of wild 2x Solanum species into the cultivated potato is through hybridization with haploids of 4x S tuberosum Group Tuberosum This procedure provides for the introduction of desirable traits and genetic diversity from wild species into potato Haploid and wild species genotypes can be evaluated for parental value based on the presence of good tuberization, desirable traits, fertility, and 2n gametes in their hybrid progeny Haploid-wild species hybrids may be intercrossed and evaluated at the 2x level to take advantage of diploid genetic ratios Selected 2x genotypes may then be brought to the 4x level through sexual polyploidization with 2n gametes
TL;DR: The changes of morphological properties of 13 Finnish oat varieties released between 1921 and 1988 and 13 Hankkija's breeding lines were evaluated in field trials and there was a significant positive linear relationship between year of cultivar release and size and weight of the flag leaf, and mean panicle filling rate.
Abstract: The changes of morphological properties of 13 Finnish oat varieties released between 1921 and 1988 and 13 Hankkija's breeding lines were evaluated in field trials. Twenty-two characteristics of oat stands were measured. The relationship between years of cultivar release and characteristics of oats was studied by using the linear regression analyses and Spearman's rank correlation analyses.
In both years of experiment there was a significant positive linear relationship between year of cultivar release and size and weight of the flag leaf, and mean panicle filling rate. The correlation was significant, but negative between year of release of cultivar and plant height. Also other relationships arc discussed.
TL;DR: Hyperploid derivatives of Diplotaxis erucoides × Brassica nigra hybrids were used to extract seven out of the eight possible monosoinic addition lines for B. nigra, and the plants carrying extra chromosomes were slower in development than diploid D. emcoides.
Abstract: Hyperploid derivatives of Diplotaxis erucoides × Brassica nigra hybrids were used to extract seven out of the eight possible monosoinic addition lines for B. nigra (genome B). The fertility and transmission of the lines varied depending on the added chromosome. However, these parameters were high enough to assure the maintenance of the addition lines. Although no phenotypic changes were observed, the plants carrying extra chromosomes were slower in development than diploid D. emcoides. Each of the B. nigra chromosomes was recognizable cytologically by size and heterochromatin distribution. Seven of these were characterized by a series of isozymes and RFLP markers. Ribosotnal DNA sequences were detected in two independent B. nigra chromosomes. Two probes disclosed fragments dispersed in more than one chromosome.
TL;DR: 39 lines derived front direct crosses to determine the effects of Ac.
Abstract: Direct introgression of genes from diploid Aegilops squarrosa L into hexaploid wheat (Tnticum aestivumL.) is an efficient way of developing stable, hexaploid lines with unique, useful genes. 39 such lines derived front direct crosses to determine the effects of Ac. squarrosa germplasm were field-tested on productivity. Whereas some lines were agronomically inferior to the recurrent parent, others periormed at an equall or better level. In addition to the larget traits (Hessian-fly and leaf-rust resistance), other traits, including soilborne-mosaic-virus resistance and protein concentration, were improved.
TL;DR: The segregation of isozyme markers has been examined in the green and albino androgentic progenies of two plants of Lolium perenne and overall the pooled data for the loci PG1/2 and GOT/2 does not deviate from expectation, but there is considerable heterogeneity between families and between green and algae plants.
Abstract: The segregation of isozyme markers has been examined in the green and albino androgentic progenies of two plants of Lolium perenne. Overall the pooled data for the loci PG1/2 and GOT/2 does not deviate from expectation, but there is considerable heterogeneity between families and between green and albino plants. Specific alleles predominate in the different progeny sets. The results may be accounted for by possible linked loci affecting anther culture response or of linked lethal genes.
TL;DR: The highest yielding cultivar was superior over a wide range of environments and the seed yield of the poorest cultivars was on average only 64% of that of the best cultivar, while there were no significant cultivar differences for yield stability.
Abstract: In perennial ryegrass seed yield is low and unreliable and little is known about the seed-yielding capacity of different cultivars. Therefore, genetic variation for seed yield was studied for therefore, genetic variation for seed yield was studied for three years at two locations. Twelve trials consisting of drilled plots of nine diploid, late-flowering cultivars in four replications were harvested for seed. Significant gentic differences for seed yield and seed weight weight were detected. The ranking of the cultivars for seed yield differed from that for seed weight. The levels of seed yield and seed weight were affected by such environmental factors as year, soil type and crop production year, but interactions of these factors with cultivars were generally not significant. Variation in seed yield was more related to variation in seed number than to variation in seed weight. There were no significant cultivar differences for yield stability. The highest yielding cultivar was superior over a wide range of environments and the seed yield of the poorest cultivar was on average only 64% of that of the best cultivar.
TL;DR: Morphology, cytology and DNA analysis confirmed the hybrid nature of Raphanus sativus and Brassica napus and the potential for developing B. napus with resistance to shattering.
Abstract: Intergeneric hybridization is one of the effective methods to broaden the genetic base of cultivated species. Raphanus sativus, a member of the subtribe Raphaninae, has very hard pods at threshing time. In an attempt to transfer shattering resistance to Brassica napus, Raphanobrassica was used as the male parent in crosses with Brassica napus. Plantlets were obtained by embryo rescue and were further multiplied in vitro by micropropagation of nodal segments. Morphology, cytology and DNA analysis confirmed the hybrid nature of these plants. They were backcrosscd with Brassica napus and the progeny was raised. Plants of BC1 and BC2 generations showed wide variation in morphology, chromosome number and pollen fertility. Some of the plants showed up to 95 % pollen fertility and resistance to shattering, indicating the potential for developing B. napus with resistance to shattering.
TL;DR: The results indicate that monosomic wheat/rye addition lines may be directly used as an effective means to transfer genetic material from rye into bread wheat.
Abstract: Hybrid plants with 21 pairs of wheat chromosomes and with a haploid rye genome were produced by backcrossing a primary octoploid triticale with its parental hexaploid wheat. Upon a second backcrossing or selfing, the rye chromosomes were eliminated rapidly. Added rye chromosomes, in varying numbers, affected the transmission rate of wheat chromosomes significantly. Loss of wheat chromosomes ranging from 0.06 to 0.35 per plant in different populations was observed. In these plants a remarkably high incidence of wheat/rye and rye/rye translocations occurred. Translocations were identified by using the C-banding technique. Among 837 analyzed plants 64 wheat/rye and 256 rye/rye translocations were identified. In different generations of backcrossing or selfing the frequency of wheat/rye translocations varied between 4.23 % and 14.67 %. All 14 rye chromosome arms were involved in translocations but with different frequencies. BC1F3 plants with homozygous wheat/rye translocations were isolated The results indicate that monosomic wheat/rye addition lines may be directly used as an effective means to transfer genetic material from rye into bread wheat.
TL;DR: Effects of incubation temperature and developmental stage of microspores on polyhaploid production in three wheat cultivars and one triticale cultivar were studied using a one-step medium, finding cultivar-by-developmental-stage interaction was significant for frequency of callus induction.
Abstract: Effects of incubation temperature and developmental stage of microspores on polyhaploid production in three wheat cultivars‘Pavon 76′, ‘Kitt’, and ‘Chris’ and one triticale cultivar, ‘T81′, were studied using a one-step medium. Calli failing to differentiate on the one-step medium were placed on a medium containing 1 mg/l indole-3-acctic acid (IAA) and 2 mg/1 6-furfurylaminopunne (KIN). Anthers containing either early- or late-uninucleate microspores were incubated in dark at 26, 28 or 32°C lor 3 days prior to transfer to 26°C. Averaged over temperatures and microspore stages, frequency of calli and green plantlets were 8.9 % and 3.4 %, respectively, for wheat cultivar‘Pavon 76′, 8.4 % and 1.6 % for cultivar ‘Kitt’, 4.5 % and 0.25 % for cultivar ‘Chris’, and 2.9 % and 0.12 % for the triticale cultivar‘T81′. However, cultivar-by-developmental-stage interaction was significant for frequency of callus induction. Temperature had no significant effects on callus induction and plantlet regeneration. Anthers containing early-unmucleate microspores produced no polyhaploids.
TL;DR: Anthers containing microsporcs at miduninucleatc stage from live wheat cultivars and two octoploid trilicale lines were tested mainly for callus induction and polyhaploid production on each of the 11 media.
Abstract: Homozygous doubled-haploid plantlets derived from anther culture of wheat (Triticum aestivum L.) and triticale (×Triticosecale Wittmack) are useful breeding materials. However, efficiency of an-drogenesis needs improvement. We used media (basic components, are the same as 85DI2) each containing one of the seven auxins [2,4,5-trichlorophenoxyacetic acid (2,4,5–T), P-chloraphenoxyacetic acid (pCPA), 3,6-dichloro-o-anisic acid (dicamba), 4-amino-3,5,6-trichloropicolinic acid (picloram), indole-3-butrytic acid (IBA), indole-3-acctic acid (IAA), and 2,4-dichlorophenoxyacetic acid (2,4-D) as a control] in combination with 6-furturyl-aminopurine (kinetin). In addition, each of the four cytokinins [6-benzylaminopurine (6-HA), 2-isopenlylnyl adenine (2-ip), 6-(4-hydroxy-3-meihylbut-2-enylamino) purinc (zeatin), and kinetin as a control] was tested in combination with 1-naphthalene acetic acid (NAA). Anthers containing microsporcs at miduninucleatc stage from live wheat cultivars (Angus, Centurk, Chris, K.itt, and Pavon 76) and two octoploid trilicale lines (T81, T82) were tested mainly for callus induction and polyhaploid production on each of the 11 media. The cultivar × medium interaction was not significant, When averaged over all growth regulators, Pavon was (he best cultivar which produced 14.4 % calli and 23 % polyhaploid plantlets. Averaged over all cultivars, the medium containing 2, 4-U produced the highest calli (13.9 %). Undifferentiated calli were regenerated on 87T1 medium, which contained IAA (1 mg/1) and kinetin (2 mg/1).