Norman L. Darvey

Mixing Properties, Baking Potential, and Functionality Changes in Storage Proteins During Dough Development of Triticale-Wheat Flour Blends

ABSTRACT Flours from advanced lines or cultivars of six triticales and two prime hard wheats, along with triticale-wheat blends, were investigated for mixing, extension (excluding blends), and baking properties using microscale testing. Percentage total polymeric protein (PPP) and percentage unextractable polymeric protein (UPP) of flours and doughs, including blends, mixed to optimal dough development were estimated using size-exclusion HPLC to determine the changes in protein solubility and association with blend composition (BC), mixing properties, and loaf height. Each triticale was blended with flours of each of the two wheat cultivars (Hartog and Sunco) at 0, 30, 40, 50, 60, 70, and 100% of wheat flour. Nonlinear relationships between BC and mixograph parameters (mixing time [MT], bandwidth at peak resistance [BWPR], and resistance breakdown [RBD]) were observed. A linear relationship between BC and peak resistance (PR) was predominant. PPP of triticale flours was mostly higher than PPP of wheat cul...

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 colchicine on triticale anther-derived plants: Microspore pre-treatment and haploid-plant treatment using a hydroponic recovery system

In cereals, chromosome doubling of microspore-derived haploid plants is a critical step in producing doubled haploid plants. This investigation was undertaken to study the effect of incorporation of colchicine in the induction medium for anther culture, and the effect of colchicine on anther culture-derived plants of triticale grown under controlled greenhouse conditions. In the latter case, chromosome doubling of adult sterile plants derived from anther culture of fourteen triticale populations was attempted, where androgenetic plants with non-dehiscent anthers were cloned and subjected to the colchicine treatment, and then grown with the aid of hydroponics. The hydroponic system provided optimal conditions for recovery of the affected haploids from the toxic effects of colchicine treatment and all colchicine-treated plants survived. A topcross-F1 (TC1F1) population with timopheevii cytoplasm produced the highest percentage of plants with seed-set either due to chromosome doubling by colchicine (98%) or spontaneous doubling of chromosome number (15%). Colchicine-treated anthers performed inferior than control in both induction and regeneration phases. One of the key observation of this study was the reversal from reproductive stage back to the vegetative stage which in turn enabled further cloning of haploid plants under hydroponic conditions once they were identified as sterile. The one hundred percent survival rate of in vitro-derived plants, 100% survival rate of colchicine treated haploid plants and the high chromosome doubling success rate (X = 82.3) observed in this study imply that a temperature-controlled greenhouse with an hydroponic system provides an efficient environment for inducing chromosome doubling of haploid plants in cereals.

Influence of selected wheat and rye genotypes on the direct synthesis of hexaploid triticale

SummaryIn the synthesis of primary hexaploid triticale, a cross-incompatibility barrier exists when tetraploid wheat (4X) is crossed with diploid (2X) rye. Fertilization may occur, however, abnormal endosperm development usually leads to premature embryo death. Four selected tetraploid wheat lines were crossed as females with seven open-pollinated rye lines and the resulting embryos were rescued in vitro 13–16 days after pollination. The wheat genotypes showed a major influence on crossability (seed set), embryo development and plant recovery. The highest efficiency of amphihaploid plant recovery (18.3 plants per 100 pollinated florets) was obtained from one 4X wheat line originally selected from the cross T. carthlicum × T. dicoccoides. Some of the 3X amphihaploid plants (ABR) derived from two wheat lines showed relatively high level of partial fertility presumably as a result of meiotic restitution. Correlation analysis showed that crossability (seed set), normal hybrid embryo development in vivo and embryo culturability were independent of each other.

Androgenetic response of heterozygous triticale populations using a greenhouse hydroponic system

Production of haploids, followed by chromosome doubling to produce doubled haploids (DH) represents the most rapid means of achieving complete inbreeding. In order to improve the androgenetic responses and maximize the production of green regenerants from selected plants of twenty-five triticale (× Triticosecale, Wittmack) populations (BC1F1, TC1F1, and F2) we used a uniform and optimal growth environment for anther donor plants within a greenhouse hydroponic system. Non-orthogonal analysis of deviance showed highly significant differences (p < 0.001) among populations for both induction and regeneration. The overall induction response of the populations was very high with a mean of 50.4 embryoids per 100 anthers plated. Among all tested-populations, M86-6068/TW179//EP80 (TC1F1) was the most responsive for both induction and regeneration which could be associated to its Triticum timopheevii cytoplasm. On the other hand, although populations 80465/II83-194 both as BC1F1 and F2 had a high level of induction response, only a few green plants were regenerated. These populations probably possess a partial Secale montanum genome, which could be contributing to the low regeneration ability. In conclusion, the need for optimization of donor plant growth conditions to effectively assess the androgenetic ability of individual populations/lines would be emphasized.

Development of the components of a cytoplasmic male sterility hybrid system in rye through anther culture

Anther culture was applied as a method to develop the essential components of a cytoplasmic male sterility hybrid system in rye (Secale cereale L.). These components are the male sterile seed parent (A line), its isogenic maintainer counterpart (B line) and the restorer pollen parent (R line). Australian rye cultivars were crossed reciprocally to the cultivar ‘Luchs’ which carries the Pampa male sterile cytoplasm (cms-P). Anthers of the F1s in the cms-P cytoplasm (primary cross) and their reciprocals in the normal cytoplasm (reciprocal cross) were cultured in a modified C17 medium. Male sterile and male fertile doubled haploids were obtained from the anther culture of the F1s in the cms-P cytoplasm. Testcrosses indicated that the male sterile doubled haploids were A lines and the male fertile doubled haploids were R lines (restorers). The anther culture of genotypes in the normal cytoplasm (reciprocal cross) gave all male fertile doubled haploids. Testcrosses indicated that the male fertile doubled haploids were R lines (restorers) in the normal cytoplasm. The expected maintainer B lines were not identified because of the limited number of doubled haploids obtained from the anther culture of reciprocal crosses. Experimental single cross hybrids between male sterile and restorer male fertile doubled haploids showed high levels of heterosis. The results of this study have significant economic implications especially in the production of hybrids in several species.

Comparison of doubled haploid lines and their mid-generation progenitors in forage and dual-purpose triticales under greenhouse hydroponic conditions

A doubled haploid method (DH) has been used to rapidly advance generations intriticale, and selections then made for high yielding homozygous lines. This study aimed at comparing the forage performance of DH populations produced from the BC1F1, TC1F1 and F2 generations with superior mid-generation progenies (BC1F3,TC1F3 and F4) derived from field selection. One hundred and sixty eight DH lines derived from anther culture of eight populations were used. The results of analysis of variance for plant weight (PW), and dry matter yield (DM) of triticale lines developed by the method of doubled haploidy and field selections showed that the differences between the two methods were not significant. Differences among the three type crosses(BC1F3, TC1F3, F4/BCF∞, TCF∞ and F∞), method × cross interaction, and among populations within methods × cross were significant for PW and DM. Unlike forage characters, no significant differences were obtained for grain yield (GY) in all sources of variations. However, DH lines generally had wider ranges for PW, DM, GY and total biomass (TB) than lines derived from field selections. The observations of higher forage and grain performances of several DH lines compared to their corresponding field-derived populations show that the forage and dual-purpose breeding of triticale DH lines by means of hydroponics and anther culture of individual-plant selections in early generation under greenhouse conditions is highly beneficial.

Positive Effect of Timopheevi Cytoplasm on Anther Culture Response of Triticale

The influence of Triticum timopheevi cytoplasm on the anther culture response in triticale was investigated using four reciprocal crosses. Significant differences were observed between and among reciprocal crosses for induction and regeneration, with the positive effect of timopheevi cytoplasm.

Establishment of a Network for Genetic Resources

Systematic germplasm creation and deployment is the basis for the establishment of the ITA’s first ‘Co-operative Network’. Membership of the network will normally require an active contribution by an individual or organisation in the development of germplasm resources. Membership will also be afforded to organisations with a mandate for the development of regionally adapted germplasm. The germplasm centre at CIMMYT is willing to take a leadership role in the documentation, maintenance and distribution of newly developed germplasm. Germplasm will be freely interchanged among members of the co-operative, and all materials held in the CIMMYT collection will be available on request. The management committee will be subject to election by participating members of the co-operative during a meeting to be held at each International Triticale Symposium. The management committee is responsible for approving and amending membership lists and for co-ordinating various aspects of germplasm research. The genetic resources will initially include primary triticales, selected progenies from primary (or amphihaploid) times primary or secondary triticale crosses, standard wheats and ryes for triticale production or standard triticales with special attributes (eg. good GCA, disease resistance, spontaneous doubling genes for haploid producing systems, good green/albino ratio for anther culture derived regenerants, male sterility for germplasm deployment and recurrent selection, etc.). The network objectives, methodologies (strategies for germplasm production and evaluation/deployment), data and communication bases and contributions of the authors are presented along with membership and nomination lists for completion by intending participants.

Development of a Dominant Male-Sterile Triticale (MS3) for Recurrent Selection and Hybrid Seed Production

With the reports of dominant male sterility (DMS) in wheats such as cv. Taigu (Ms2) and cv. Selkirk (Ms3) interest has developed in the transfer of the male sterility genes into triticales for utilization in breeding programs. This paper presents the steps involved in the manipulation of chromosome 5A (Ms3) of cv. Selkirk to incorporate relevant marker genes into it via recombination so as to enable the identification of the seeds prior to sowing or plants prior to anthesis. Furthermore, the synthesis of dominant male-sterile triticale and its application and relevance to triticale breeding are described and discussed.