Influence of winter and spring wheat genetic backgrounds on haploid induction parameters and trait correlations in the wheat × maize system

The interactive influence of winter and/or spring wheat genetic background on haploid induction parameters and trait correlation was studied by hybridizing five elite and diverse genotypes each of winter and spring wheat and their F₁s (winter × winter, spring × spring, and winter × spring, generated in a diallel design excluding reciprocals) with a single genotype of maize. Data were recorded with respect to per cent seed formation, embryo formation, and regeneration. High genetic variability was present among the wheat genotypes (parents + F₁s) for the three haploid induction parameters. Significant differences were obtained within and between different groups viz., spring wheats, winter wheats, spring × spring wheats, winter × winter wheats, and winter × spring wheats with respect to the three haploid induction parameters based on ANOVA. The winter genotypes (winter parents and winter × winter wheat hybrids) responded better than the spring groups (spring wheat parents, spring × spring and winter × spring wheat hybrids) with respect to embryo formation and winter × spring wheat hybrids yielded significantly the highest numbers of regenerants. Correlation studies amongst the haploid induction parameters indicated that the genes controlling seed formation and haploid plantlet regeneration are negatively correlated when the genetic backgrounds of both ecotypes are combined in winter × spring hybrids. Haploid embryo formation had no association with seed formation and regeneration in all genetic backgrounds, suggesting independent inheritance.     

Evidence for genetic control and media effect on haploid regeneration in the anther culture of hexaploid wheat (Triticum aestivum L.)

Crosses were made between seven hexaploid wheat genotypes. Twenty-one F₁ hybrids and their parents were grown in a greenhouse with 16 h day/8 h night at 25°C and 15°C, respectively. The experiment was a complete randomized block design with three replications. Each replication consisted of one pot with three plants. Anther culture was performed in two different induction media (CHB and W14) and androgenetic traits were studied. Statistical analysis was carried out separately for each induction medium. Genetic variation was highly significant for androgenetic traits and the best parent (IBPT 19) produced 68 embryos and 9.3 green plants per 100 anthers in CHB medium. Genetic components were affected by induction media and some components were significant in one medium and non significant in the other. General combining ability (GCA) was significant for all androgenetic traits, except for albino plant regeneration in both media and total plant regeneration in CHB medium, whereas specific combining ability (SCA) was not significant for the traits studied. Narrow sense heritability was high for embryo induction frequency and green and total plant regeneration. All our results indicate that androgenetic parameters can be improved in hexaploid wheat by genetic means.     

Doubled haploid production in winter wheat and triticale genotypes,using the Hordeum bulbosum system

Summary An attempt was made to produce doubled haploids on 16 winter wheat and six spring and winter triticale genotypes thought to carry genes for interspecific incompatibility. The potential for haploid production was maximized by the use of Hordeum bulbosum genotypes selected for high crossability on crossable wheat genotypes, the use of two post-pollination applications of gibberellic acid and by the pollination of immature florets.A low frequency of seed was set on both the wheat and the triticale genotypes, having mean seed sets of 0.20 per cent and 0.27 per cent respectively. Although the frequency of embryos (seed quality) was high, doubled haploid production was further limited by poor embryo differentiation and regeneration. Haploid plantlets were obtained from the wheat cultivars Moulin and Renard, although successful chromosome doubling and doubled haploid production was achieved in Moulin only.     

Anther callus induction and green plant regeneration at high frequencies from an interspecific rice hybrid Oryza sativa Linn. x O. rufipogon Griff

Summary Callus induction and green plant regeneration at high frequencies from an interspefic hybrid, Oryza sativa L. x O. rufipogon Griff. has been achieved by simply coordinating the growth regulators in the induction medium. The study was conducted with two different basal media (Potato-2 and N₆) and seven different combinations of growth regulators 2,4-D, NAA and kinetin. Synergistic effects of the two auxins in enhanced anther response to callus induction and subsequent green plant regeneration were observed in both media. The highest frequency of callus induction was obtained on Potato-2 medium supplemented with 1 mg/12,4-D, 2 mg/l NAA and 1 mg/l kinetin. The same combination of growth regulators which yielded higher frequencies of callus induction also induced higher mean number of calli per anther. Although the calli formed on N₆ medium showed high regenerability, there was a concomitant increase in the number of albinos among the regenerants. The auxins in the induction media had considerable influence on the regeneration capacity of the calli. The regeneration frequencies were higher from calli formed in the presence of both auxins in the induction media. The levels of growth regulator combinations seem to influence the green plant regeneration especially for calli induced on Potato-2 medium. Among the pollen grain derived plants the majority were either haploids or double haploids and very few were chromosomal variants.     

Medium-Genotype-Interaction on Androgenetic Haploid Production in Wheat

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.     

Regeneration of fertile doubled haploid plants from colchicine-supplemented media in wheat anther culture

The effect of colchicine added to induction medium for the production of fertile doubled haploid plants after in‐vitro anther culture was studied in wheat, Triticum aestivum L. For this, one winter and two spring wheat varieties were used. Anther cultures of the three genotypes were treated with 0.03% colchicine for 3 days at the beginning of microspore induction. Colchicine had no significant effect on anther response and embryoid production of the genotypes examined. However, in the winter wheat genotype ‘Mv Szigma’, colchicine caused a significant reduction in microspore‐derived structures. A significant decrease was also observed in plant regeneration ability of two genotypes (‘Vergina’ and ‘Acheloos’) after colchicine treatment. In addition, a significant reduction of the albinos produced was observed in all genotypes after olchicine treatment. In contrast, the regenerants obtained from the colchicine‐supplemented induction media produced significantly higher percentages of fertile plants in all genotypes. However, the level of fertility, was significantly different among the fertile plants obtained. This, together with the observation that in the case of the winter wheat variety the colchicine treatment resulted in 100% completely fertile plants with a high seed‐setting ability indicate that there is space for further improvement of the method when it is applied to spring cultivars. Finally, the increased number of seeds per 100 plated anthers obtained from all three genotypes after colchicine treatment, clearly demonstrates that the addition of colchicine to induction medium was superior to the conventional anther culture method and it could therefore be introduced into wheat breeding programmes.     

Callus induction and plant regeneration from immature and mature embryos of winter durum wheat genotypes

Seven genotypes of winter durum wheat (Triticum durum Desf.) were cultured to establish an efficient method of callus formation and plant regeneration from mature embryo culture, and to compare the responses of immature and mature embryo cultures. Immature embryos were aseptically dissected from seeds and placed, with the scutellum upwards, in dishes containing Murashige and Skoog's (MS) mineral salts and 2mg 2,4- dichlorophenoxyacetic acid (2,4-D) per litre. Calli and regenerated plants were maintained on 2,4-D-free medium. Mature embryos were moved slightly on the imbibed seeds. For callus formation, the seeds with moved embryos were placed, furrow downwards, in dishes containing 8 mg 2,4-D per litre. The developed calli and regenerated plants were maintained on the MS medium. Plants regenerated from both embryo cultures were vernalized and grown to maturity in soil. Variability was observed among the wheat genotypes tested for various culture responses in both explant cultures. Callus induction rate and regeneration capacity of callus were independent of each other. Mature embryos have a low frequency of callus induction but a high regeneration capacity. Considering availability, rapidity and reliability, this form of mature embryo culture can be used as an alternative method for immature embryo culture.     

固体培养基上浸润培养提高花粉植株诱导率的研究

在30×170mm的试管内,倒入25～30ml加琼脂固化的C_(17)培养基,接种冬小麦花药后注入2ml左右不加琼脂而浓度相同的C_(17)培养液浸润培养,冬小麦花药愈伤组织诱导率可从固体培养基的13.94％提高到29.95％,愈伤组织的绿苗分化率还比固体培养基提高10.2％,分化绿苗丛数占接种花药的10.94％,是固体培养的2.37倍。     

Die Nutzung der Antherenkulturmethode im Zuchtprozeß von Winterweizen

Anther culture in the breeding process of winter wheat. I. Ability of 1B—-1R wheat-rye translocation forms for androgenesis 45 winter wheat varieties or F₁ hybrids, F₂ populations and lines with 1B—1R wheat-rye translocation were tested for their anther culture ability. A total of 48058 anthers was cultured on Potato-2 medium. When averaged over all genotypes and the two experimental years frequencies of embryoid formation of 5.4—6.8 per 100 anthers were observed. Plant regeneration efficiency from embryoids ranged from 5.3—9.1 % or a mean of 4—5 green plants per 1000 anthers plated. The results confirmed the preferential regeneration frequency of gametes with the 1BL—1RS chromosome compared to the gametes with the 1BL—IBS chromosome. Multiple peroxidase were used as marker. The effect of cold pretreatment or of media on the androgenetic response and productivity was not important. On the contrary the variability between the anther response from single ears of the same genotype was noticeable. Examples are presented for the transferability of the androgenetic ability to breeding material. Most green plants obtained were haploid or spontaneous doubled haploid. By cloning it was guaranteed, that progenies were obtained from most of the haploids after colchicine treatment.     

Somatic in vitro culture response of Lolium perenne L.: genetic effects and correlations with anther culture

Summary Genotypic effects on callus induction and plant regeneration in callus, suspension and protoplast culture, and their correlations with both phenotypic and GCA-values for anther culture response, were studied using 21 genotypes of perennial ryegrass. Differences between genotypes accounted for approximately 40% of the total variation for callus induction and initial callus growth, and 59 and 83% of the variation in callus culture for regeneration percentage and percentage of green plants. Effects of genotypes were less pronounced in suspension culture, where suspensions from the same genotype often behaved differently. Some suspension cultures retained their capacity for green plant regeneration for almost two years, repeatedly producing 80–100% green regenerants during this period. Genotypes with high regeneration percentage and a large proportion of green plants from callus culture were also superior in suspension culture for both regeneration performance and longevity. Regeneration percentage and percentage of green plants were uncorrelated, and probably under different genetic control. While capacity for green plant formation from the different genotypes showed no correlation between anther culture and somatic in vitro culture, a positive correlation was observed between the regeneration percentages in somatic in vitro culture and anther culture (r=0.44^*–0.85^***), suggesting some common genetic control of the two systems.     

Genetic analysis for haploid-regenerations responses of the hexaploid-wheat anther cultures

Genetic variability in response to anther culture was investigated in 49 winter hexaploid wheats, comprising 33 pure lines (F₁₀) derived from a composite cross programme and their 16 parental genotypes. All genotypes were grown in a randomized block design with three replications in a controlled greenhouse. The number of embryoids and total plant regeneration per 100 anthers, as well as the numbers of green and albino plants regenerated per 100 embryoids, were measured. Significant genetic variability was observed among the 49 genotypes for all the traits studied. All traits showed high heritability. Among the genotypes compared, DC²30N and 1BPT-40 gave the best results for the production of embryoids and IBPT-78 had the highest value for the production of green plants. The genotype IBPT-34 developed a large number of albino plants, and it should be useful as a parent in studies to determine the genetic control of albino plants in wheat.     

Winter × spring wheat hybridization - a promising avenue for yield enhancement

Introgression of the winter gene pool into spring wheat is being considered as one of the strategies to break through the yield plateau. However, little information is available on the combining ability of these two important but distinct groups of wheats in Indian conditions. Therefore, the present study was undertaken to determine the combining ability and gene action of yield and yield attributes in winter × spring wheat crosses. Seventy F₁ progenies developed by 14 winter and five spring wheat lines using a line × tester design were evaluated, along with their parents, for yield and yield attributes in a randomized complete block design under field conditions. The mean squares for all the characters studied showed highly significant differences. The mean squares due to female × male interactions were significant for all the characters studied except for grains per ear and grain weight per ear. Additive genetic effects were found to play a key role in controlling the expression of days to heading, plant height and spikelets per ear.‘MV 19’ and ‘Stepniak’/‘Karvuna’ among winter and ‘PBW 65’ among spring wheats were good general combiners for most of the yield attributes studied. The estimates for specific combining ability effects suggested that, although general combining ability (GCA) effects of most winter wheats are either average or poor, their combination can give desirable genotypes with spring wheat parents possessing a high GCA.     

Genetic variation for resistance to Fusarium head blight in bread wheat

Summary During a four year period, a total of 258 winter and spring wheat genotypes were evaluated for resistance to head blight after inoculation with Fusarium culmorum strain IPO 39-01. It was concluded that genetic variation for resistance is very large. Spring wheat genotypes which had been reported to be resistant to head blight caused by Fusarium graminearum were also resistant to F. culmorum. The resistant germplasm was divided into three gene pools: winter wheats from Eastern Europe, spring wheats from China/Japan and spring wheats from Brazil. In 32 winter wheat genotypes in 1987, and 54 winter wheat genotypes in 1989, the percentage yield reduction depended on the square root of percentage head blight with an average regression coefficient of 6.6. Heritability estimates indicated that for selection for Fusarium head blight resistance, visually assessed head blight was a better selection criterion than yield reduction.     

Inheritance of culm number in two uniculm x multiculm wheat crosses

Summary Effective utilization of uniculm wheat (Triticum aestivum L.) germplasm in breeding programs requires an understanding of the inheritance of the uniculm character. The parents, F₁, F₂, and first generation backcrosses (B₁ and B₂) of two crosses, each utilizing a uniculm spring wheat line and a locally adapted winter wheat cultivar, were space planted in an experiment to acquire information regarding the genetic control of culm number. Significant F₁ deviations from midparent values revealed the presence of substantial non-additive gene effects. The scaling tests of Mather and the joint scaling test detected the presence of epistasis. Hayman's six-parameter model revealed that a negative dominance effect provided the major contribution to variation in culm number, while additive x additive and dominance x dominance gene effects were of considerable importance.     

小麦（Triticum aestivum L.）品种的组培特性和转基因受体选择

本研究分析了西南地区地方品种资源的几个组培特性的变异及优良转基因受体小麦品系选育的可能性。研究指出,小麦幼穗的脱分化能力和愈伤组织再分化能力具有基因型间的广泛变异,农家品种和育成品种中的变异趋势一致。在不同的品种中,半愈期和成愈率分别分布在6～28 d以上和15.85%～100%,半愈期呈现了连续的分布,并在12 d     

Development of a technique for in vitro unpollinated ovary culture in rice, Oryza sativa L.

A simple and efficient technique for in vitro unpollinated ovary culture in rice which is also applicable for indica genotypes was developed for breeding and genetic studies. Sampling explants at the auricle distance of 7–12 cm between the two uppermost leaves of a tiller, providing a chilling pretreatment and ovaries with 1/3 of the hulls intact gave optimum response to culture. For callus induction with the spontaneous breaking of ovaries, N₆ media supplemented with NAA (2 mg/l) and DMSO (0.6–0.8%) gave a mean PCI value of 3.8% and range of 0.8–12.5% among genotypes. Media combining 2,4,5-T or 2,4-D with NAA in N₆ medium also has reasonably good callus induction. For calli induced inside, 2,4-D (0.2–0.5 mg/l), NAA (2 mg/l) and KT (1 mg/l) contained media were superior. The maximum green plant regeneration (PPR) of 77.3% was found with the medium containing NAA 0.25 mg/l, IAA 0.5 mg/l and KT 2.0 mg/l. Significant genotype, medium and their interaction effects for per cent ovary survival and callus induction were observed. This revised version was published online in August 2006 with corrections to the Cover Date.     

Optimization of culture conditions for improved plant regeneration efficiency from wheat microspore culture

The production of haploid plants through microspore culture is a very important tool for plant breeding. However, progress in microspore culture for many species has been hampered by a number of factors that have resulted in low recovery of regenerated green plants. In this study, a series of experiments were conducted to increase the regeneration of haploid green plants from isolated wheat microspores. The use of different basal media and variations in media components resulted in the increased recovery (approximately double) of regenerated haploid wheat plants. Our findings demonstrate that CHB medium, in combination with 2,4-d, was a better medium for embryoids induction and plant regeneration than medium MC17 with either 2,4-d or PAA growth hormones. Wheat microspores cultured without ovary co-cultivation did not respond. Furthermore, high efficiency of microspore derived embryoids (up to 296 MDEs per 100 anthers) and green plant regeneration (up to 71 green plants per 100 anthers) were achieved by the use of gelrite instead of agarose as a gelling agent, and by the addition of media additives such as spent medium or MET.     

The Effect of Sugars and Growth Regulators on Embryoid Formation and Plant Regeneration from Barley Anther Culture

The influence of carbon source and growth regulator composition in induction medium on anther culture response was investigated using spring barley genotypes. Anthers were cultured on BAC3, Ficoll-containing medium, supplemented with one of the following carbohydrates: sucrose, maltose, cellobiosc and melibiose (6 % w/v). The use of either maltose or cellobiose resulted in a significantly higher anther response, calli and/or embryoid production and green plant regeneration compared to the incubation of anthers on a medium containing sucrose. Contrary to these results, the replacement of sucrose by melibiose in BAO medium, drastically reduced the efficiency of anther culture. As an average for the three genotypes tested, the frequency of green plants per 100 anthers plated was 9- to 22-fold higher on medium supplemented with sucrose or cellobiose than on medium containing melibiose as a sole carbohydrate. Among the growth regulators tested, the combination of auxin NAA (2 mg/l) and cytokinin BAP (1 mg/1) performed much better than the employment of auxin 2,4-D combined either with zeatin riboside or BAP as cytokinins. The beneficial effect of medium supplemented with NAA and BAP was associated with better embryoid formation compared to the other growth regulator combinations tested. The hormone-free combination gave a similar anther response and production of calli as any medium supplemented with growth regulators, but the regeneration capacity of calli produced on hormone-free medium was much lower, resulting in the drastic reduction of the number of both total and green regenerants.     

小麦花药培养的基因型差异与亲本选配分析

对104份不同基因型材料进行花药培养,结果表明：F1代愈伤组织诱导率为13.28%,高于F3代的6.02%; 绿苗产率F1代为2.88%,F3代为1.10%,F1相当于F3的2.6倍。同样的培养条件下,不同基因型材料间花药培养力差异很大,愈伤诱导率在 0～111.43% 之间、绿苗产率在 0～49.29% 之间;愈伤诱导率、绿苗分化率与绿苗产率三者之间成正相关关系。同时筛选出了一批如宁春4号等具有高培养力、高产和优质基因的花培桥梁亲本,为有目的配制杂交组合提供依据。     

Anther Culture in Rye: Improved Plant Regeneration Using Modified MS-Media

The use of androgenetic doubled haploids in rye breeding is still limited by low regeneration rates. In this study we tested the influence of two modified MS-media on the number of reacting anthers and on plant regeneration. Picloram and 2,4-D were used as auxin components in the induction media. The highest induction rates (reacting anthers per 100 cultivated anthers) and the highest regeneration rates (number of green plants per 100 cultivated anthers) were reached on a modified MS-medium containing Picloram as auxin source, regardless of the donor plant material. The comparison of the results obtained with the single cross ‘SC 35’ which contains genes of Secale vavilovii and the true Secale cereale donor forms clearly show the genotypic influence of donor plant material on induction and regeneration ability.