Australian Varieties Research Articles

Genetic improvement of early vigour in wheat

Grain yield potential of Australian wheat crops is often limited because of inadequate water for crop growth and grain filling. Greater early vigour, defined here as the amount of leaf area produced early in the season, should improve the water-use efficiency and yield of wheat crops grown in Mediterranean-type climates such as occurs in southern Australia. In order to maximise selection efficiency for early vigour in breeding programs, the magnitude and form of genetic variation for early vigour and its components was investigated for 2 contrasting wheat populations. The first population comprised 28 Australian and overseas wheat varieties evaluated in a serial sowing study in Canberra. The second population contained 50 random F 2:4 and F 2:6 families derived from a convergent cross of elite CIMMYT wheat lines evaluated in Canberra, and in the field at Condobolin, New South Wales. For the first population, environmental effects on leaf breadth and length, and to a lesser extent, phyllochron interval, produced significant (P < 0.05) changes in leaf area. Large and significant (P < 0.05) differences were observed among Australian and overseas wheats for early vigour and its components. Australian varieties were among the least vigorous of the lines tested, with a number of overseas varieties producing about 75% greater leaf area than representative Australian wheats. Increased leaf area was genetically correlated with increases in leaf breadth and length, and a longer phyllochron interval. Significant (P < 0.05) genotype ´ environment interaction reduced broad-sense heritability (%) for early vigour (H ± s.e., 87 ± 26) compared with leaf breadth (96 ± 25) and length (97 ± 27). Narrow-sense heritability (%) in the second population was small for leaf area (h2 ± s.e., 30 ± 6) and plant biomass (35 ± 7), but high for leaf breadth (76 ± 14) and length (67 ± 16). Genetic correlations were strong and positive for leaf area with plant biomass, leaf breadth and length, specific leaf area and coleoptile tiller frequency, whereas faster leaf and primary tiller production were negatively correlated with leaf area. The high heritability for leaf breadth coupled with its strong genetic correlation with leaf area (rg = 0.56-0.57) indicated that selection for leaf breadth should produce genetic gain in leaf area similar to selection for leaf area per se. However, the ease with which leaf breadth can be measured indicates that selection for this character either by itself, or in combination with coleoptile tiller production, should provide a rapid and non-destructive screening for early vigour in segregating wheat populations. The availability of genetic variation for early vigour and correlated traits should enable direct or indirect selection for greater leaf area in segregating wheat populations.

Genetic variation of β‐amylase thermostability among varieties of barley, Hordeum vulgare L., and relation to malting quality

AbstractTo investigate variation in the thermostability of β‐amylase among varieties of barley, Hordeum vulgare L., crude enzyme was extracted from the seeds, and the relative remaining activity was calculated after heat treatment. Our results indicated that the varieties tested were divided into three groups (types A, B and C). All the latest Japanese malting varieties showed high themostability (type A), while European, North American and Australian varieties showed intermediate (type B) or low thermostability (type C). Isoelectric focusing (IEF) of β‐amylase was also investigated. Type B varieties divided into two subtypes (types B1 and B2) based on two different IEF patterns (types I and II), whereas those of types A and C showed only one IEF pattern (type II). We also examined their thermostability in the varieties based on the pedigrees of the Japanese malting barley. Our results indicated that the thermostability of β‐amylase had a close relationship to fermentability for the production of beer. This fact suggests that the thermostability of β‐amylase has a significant influence on the malting quality of barley.

Temperature effects on node appearance in sugarcane

Plants of the Australian commercial sugarcane varieties Q117 and Q138 were grown to 6 months age in a controlled environment at temperatures of 14, 18, 22 and 26˚C. The rate of node appearance, which equates to the rate of leaf appearance, was significantly correlated with temperature across the temperature range examined. Analysis of the varietal rates of node deposition as a function of time allowed determination of both base temperature for node (hence leaf) appearance and phyllochron. The base temperatures for node appearance were 7.8˚C for Q117 and 7.6˚C for Q138, significantly lower than previously published base temperatures for leaf appearance in sugarcane. During the developmental stages covered by this study, phyllochron differed between the two varieties with Q117 requiring 108.7˚Cd per node, whilst Q138 required 126.6˚Cd per node. This work reinforces the value of controlled environment research as a way of elucidating basic functions of plant growth and development.

Variability for quantitative traits in exotic hybrid germplasm of sugarcane

The foreign hybrid collection of sugarcane germplasm comprising 399 clones representing 10 geographical groups, was evaluated for nine yield and quality characters, in relation to their place of origin. Discriminant function analysis showed that all the nine variables contributed significantly to the discrimination of the groups, the maximum contribution being cane height. The overall percentage of correct classification was only 48%, with a range from 32% to 73% with respect to individual groups. This suggests an underlying genetic similarity among the groups, which stem largely from their common genetic base. The exceptions were the Hawaii and Mauritius groups, which had distinct identities. The Hawaii group was the most productive group, having maximum yield and sucrose potential. The Puerto Rico group was the best source for juice sucrose. Australian varieties bred for high juice quality did not show the expected level of juice sucrose in the present study. The use in breeding programmes of Hawaiian varieties, which have a broader genetic base and high yield and quality potential, might impart better productivity to commercial varieties.

Transformation of an Australian Variety of Carica papaya Using Microprojectile Bombardment

We have developed a method for the stable transformation and regeneration of a dioecious Australian cultivar of Carica papaya (papaw or papaya) by microprojectile bombardment. This method was developed after investigation of both zygotic and somatic embryos as target tissue and optimisation of a number of parameters using transient expression of the uidA reporter gene. The tissue culture regime prior to bombardment was critical in optimisation of transformation. Factors such as age of embryos and various treatments prior to bombardment, increased transient expression by up to 22-fold. Highest uidA transient expression results were obtained when somatic embryos 3 weeks since last subculture on solid medium were given a 3 day treatment in liquid medium, and a 2 h osmotic treatment pre- and post-bombardment. Stably transformed plants were obtained 6 months after bombardment using this system. Transformation efficiency was high with two experiments yielding 45% and 37.5% of bombarded plates regenerating plantlets on media containing kanamycin. The presence of both the uidA and aphA genes, (selectable marker) which code for the enzymes β-glucuronidase (GUS), and neomycin phosphotransferase II (NPTII) respectively, was confirmed in regenerated plantlets by Southern hybridisation.

Genetic distance detected with RAPD markers among selected Australian commercial varieties and boron-tolerant exotic germplasm of pea (Pisum sativum L.)

The optimisation of polymerase chain reaction (PCR) for random amplified polymorphic DNA (RAPD) analysis in pea was investigated and the results were applied to an analysis of five representative Australian varieties and five selected boron-tolerant accessions derived from different geographical regions. Genotypes were compared using 34 random primers (Operon Technologies, Alameda, CA) which generated 180 polymorphic bands. Genetic similarity among genotypes was estimated on the basis of the percentage of common bands between genotypes and a dendrogram was constructed by the unweighted pair grouping method. A pattern of RAPD reaction corresponding to two main groups was discerned. The genetic divergence between Australian varieties and the boron-tolerant accessions suggests an intensive back-crossing programme would be required to transfer boron tolerance to a locally adapted genetic background. Our results show RAPD to be useful for clarifying phylogenic relationships within a species and also to provide useful genetic markers for varietal identification in pea.

Indoor Plants and Pollution Reduction

Preliminary experiments by Wolverton et al., first with NASA, and then for the US Interior Plantscape Division of ALCA, have shown that selected indoor potted plants, in test chambers, can reduce concentrations of volatile indoor pollutants such as formaldehyde or benzene by up to 90%. This paper outlines plans to take this pilot work further in new directions, under Australian conditions, by: •testing the efficacy of local varieties of indoor foliage plants to reduce concentrations of volatile organics in a 'real-world' situation, namely a selected air-conditioned office building in the Sydney area; •extending Wolverton's methodology, using Australian pot-plant varieties •carrying out a series of studies on the mechanisms of absorption and assimilation by plants and soil microorganisms; •initiating selection and breeding programs for the varieties tested. This work has enormous potential world-wide across the full range of indoor environments, m which the population of modern cities spend most of their t...

Identification of navy bean varieties using a random amplification of polymorphic DNA

Random amplification of polymorphic DNA (RAPD-PCR) was applied to the identification of Australian navy bean varieties. A total of 296 markers were generated from 29 primers. Three new navy bean varieties that were difficult to distinguish by visual characteristics could be uniquely identified by RAPDPCR. The varieties were distinguished from their parents and from 3 commercially available varieties. The overall level of polymorphism between all varieties was low (about 15%). However, 3 lines (Campbell-11, CH33-8D, Spearfelt) were more distinct genetically from the other genotypes (e.g. similarity of only 75%). Analysis using RAPD-PCR molecular markers may allow distinction of varieties for plant variety rights and will provide information on the genetic relationships of these varieties for breeding purposes.

Effect of Environment and Genotype on the Fermentability of Malt Produced from Four Australian Barley Varieties

The new Australian two-row malting barley varieties, Franklin and Tallon, which were derived from Triumph, were compared with two existing varieties, Schooner and Weeah. Samples of each variety, gr...

Analysis of a genomic DNA segment carrying the wheat high-molecular-weight (HMW) glutenin Bx17 subunit and its use as an RFLP marker

A genomic fragment containing the Bx17 high-molecular-weight (HMW) glutenin gene was isolated from a wheat genomic library. The fragment contains a coding region of 2.82kb with 1.98-kb downstream and 12.8-kb upstream flanking regions. The fragment was sequenced and compared with previously published glutenin genes from chromosomes 1A, 1B and 1D using a computer alignment package. The Bx17 gene shows marked similarity to the Bx7 gene sequence. A phenetic tree derived from the alignments is presented. Also shown are restriction fragment length polymorphisms (RFLPs) at the glutenin loci in a set of Australian and international wheat varieties using different regions of the glutenin clone as probes. The RFLPs correlated well with the protein composition in all cultivars analysed.

Effect of Environment and Genotype on the Fermentability of Malt Produced from Four Australian Barley Varieties

Effect of Environment and Genotype on the Fermentability of Malt Produced from Four Australian Barley Varieties

Note: The correct names for two Australian varieties of Ficus L. (Moraceae)

Note: The correct names for two Australian varieties of Ficus L. (Moraceae)

Response of Cotton to Damage by Insect Pests in Australia: Pest Management Trials

Twenty pest management experiments were done between 1985 and 1988 at 11 sites in the Namoi valley of NSW, Australia, on four varieties of cotton, Gossypium hirsutum L. In every experiment, the control treatment, consisting of the standard action thresholds for the common insect pests of the region, was compared with higher early season thresholds Lower thresholds were tested at one site for three seasons and at three other sites for the last season. The Australian-bred okra leaf variety Siokra consistently outyielded normal leaf variety, DP90 and required fewer sprays. 'Siokra', with higher early season pest thresholds, had yields similar to or better than the control treatment. DP90 compensated less for early-season damage and was therefore more susceptible to early season damage than 'Siokra', often resulting in a lower yield for the treatments with higher thresholds. There was no threshold treatment that was always the best, but there was a trend for treatments with higher early-season thresholds to be more profitable than the control with the Australian varieties 'Siokra' and 'Sicala', but not with 'DP90'. Higher thresholds early in the season, and the resultant less stringent pest control, did not consistently delay the crop or lead to more late-season applications of costly insecticides. The less exhaustively tested treatment with low thresholds always yielded well. It was the most profitable only 1 yr in 3 with Siokra but 2 yr in 3 with 'DP90'.

Tolerance of Australian wheat varieties to aluminium toxicity

Abstract This paper reports the reaction of 24 Australian wheats and 16 overseas cultivars to high aluminium (Al) in solution culture. These results are compared with those from a rapid haematoxylin stain test. The relationship between the haematoxylin stain test results and performance in the field was also determined. The dry matter yields in solution culture confirmed tolerances previously reported for the non‐Australian cultivars, with only two exceptions. The Australian varieties vary in tolerance but none were as tolerant as those from Brazil. The tolerances of the Australian varieties were not related to the breeding origins of the varieties. Exposure to Al in solution differentially reduced the concentration of calcium (Ca), magnesium (Mg), and phosphorus (P) in both shoots and roots. The more Al‐tolerant varieties were less affected. The results obtained in solution culture and in the haematoxylin stain test generally agreed, but more differences between varieties were noted in solution culture r...

Response of annual medics (Medicago spp.) and field peas (Pisum sativum) to high concentration of boron: genetic variation and the mechanism of tolerance

The genetic range and mechanism of tolerance to high concentrations of B were examined for field peas and annual medic species. Both genera showed a wide range in response to B. The most tolerant Australian varieties of pea included Early Dun, Partridge, Dun, Derrimut, Dundale, Alma and Maitland, while Parraggio, Ghor and Cyprus were the most tolerant of the Australian medics. Accessions more tolerant than the Australian varieties were identified for both species. The highest percentage of tolerant accessions of medics originated from the central and western Mediterranean regions, while the two tolerant peas identified originated from India. The mechanism of tolerance consisted of exclusion of B from the roots and shoots of tolerant lines, and was therefore consistent with previous results for wheat and barley.

Yield, plant characteristics, and relative tolerance to bunch loss of four banana varieties (Musa AAA Group, Cavendish subgroup) in the semi-arid subtropics of Western Australia

The yield, plant characteristics (pseudostem height and girth), and relative tolerance to bunch loss of 4 banana varieties (Musa AAA Group, Cavendish subgroup) were studied over 2 crops in the semi-arid subtropics at Carnarvon, Western Australia. The varieties were New Guinea Cavendish, Chinese Cavendish, Hsien.Jen Chiao, and the most widely grown Australian variety, Williams. The marketable yield of Williams was higher (P<0.05) than the mean of the other varieties in the parent crop (70.2 v. 50.7 t/ha) and ratoon 1 crop (65.8 v. 34.4 t/ha). This was the result of lower (P<0.05) bunch loss, about 41% less over the 2 crops, than for the other varieties. Resistance to bunch loss-pseudostem breakage and bunch peduncle snap was not associated with the shorter varieties (New Guinea Cavendish and Chinese Cavendish), but resistance to choke throat was associated with the taller varieties (Williams and Hsien Jen Chiao).

Heterosis in F1 hybrids derived from crosses of adapted Australian wheats

Data on the level of heterosis for grain yield under Australian dryland wheat growing conditions is essential before any decision can be made to commit resources to hybrid wheat breeding. Experiments were conducted at Narrabri, N.S.W., to determine the level and stability of heterosis for grain yield expressed by F1 hybrids derived from crosses of adapted Australian varieties. The hybrids and their parents were grown in hill plots in replicated experiments at three sowing times for two years (six environments). The hybrids outyielded their parents in each of the six environments with levels of mid- and high-parent heterosis up to 31.5 and 26.8%, respectively. The best hybrid outperformed the best check variety by an average yield margin of 18.2%. The hybrids were marginally but not significantly more stable in their yield performance across environments than their parents. While heterosis for grain protein content was generally negative, some hybrids were superior to the check varieties for both grain yield and protein content. Yield component analysis revealed no consistent pattern by which the best hybrids obtained their yield advantage over their parents. The levels of heterosis and the absolute yield advantage displayed by the hybrids over the best pure line check varieties were sufficient to sustain the commercial production of hybrid wheats in northern N.S.W.

A rapid (< 10 minute) electrophoresis method for identification of wheat varieties

Conventional procedures for electrophoretic identification of grain samples according to variety are too slow to permit checking at the time of delivery. The method described permits electrophoretic identification within an hour. It involves extraction of gliadin proteins from crushed grain with 6% urea solution or ethylene glycol, cathodic electrophoresis for 9 min at 300 V in a Micrograd gel (MG 315 from Gradipore Ltd, Sydney, Australia) using sodium lactate buffer (pH 3.1), and staining in Gradipore (at about 50 degrees C). Distinction between a set of Australian varieties was similar to that obtainable with the Australian Standard Procedure.

Seed yield and seed quality of subterranean clover (Trifolium subterraneum L.) in growing conditions of Finland

Seed yield and overwintering of seeds of 22 Australian subterranean clover varieties were investigated in 1986 and 1987 at the Viikki Experimental Farm of the University of Helsinki. The seed yield varied remarkbly according to the variety and weather conditions of the two summers. Some varieties, such as Seaton Park, Woogenellup and Karridale, and during the summer of 1987 also the early variety Dalkeith, produced lots of seed. Some late varieties, e.g. Treeton, Tallarook and Esperance, produced very few seeds or no seeds at all. A considerable proportion of the seeds degenerated during the wet autumn conditions, by the end of October. Many seeds showed embryo dormancy, but complete dormancy or hard seeds were found only exeptionally. In spring 1988, some seedlings which had developed from overwintered burrs were found. There seems to be little hope of finding self-seeding subterranean clovers suitable for Finnish growing conditions.

The extent of similarity between near-isogenic lines of the Australian spring wheat variety Triple Dirk with their recurrent parent

The near-isogenic lines of the wheat variety Triple Dirk supposed to differ only for Vrn genes have been investigated for their similarity to Triple Dirk and for purity. The NILs were found to differ from Triple Dirk. It was also discovered that Triple Dirk and the NILs each exist of more than one genotype. It is recommended that each NIL is tested for its Vrn-genotype and purified. New sets of Vrn NILs can only be made with these checked NILs and with one-plant progeny of the newly used recurrent parents.