SMALL GRAIN INSTITUTEPrivate Bag X29, Bethlehem, 9700, South Africa. http://www.arc-sgi.agric.za
M. Craven.
The main aim of the preharvest-sprouting program is the routine evaluation of wheat cultivars for their preharvest sprouting susceptibility. Wheat breeding material from the Small Grain Institute's Plant Breeding Division also is screened for PHS resistance to ensure that cultivars released within the program has the required PHS resistance. Aside from this routine screening, the possibility was investigated that cultivars might show a different PHS score when the cultivars are subjected to various fertilizer levels.
Because PHS is closely associated with falling number (FN), an intensive research program was maintained for the past few years that investigated FN and cultivar response regarding FN to various external factors. The factors investigated focused on the implementation of an FN-management system within a general wheat-production practice. The effect of kernel moisture content, fertilizer application, and glyphosate treatments to enhance the drying period of wheat and reduce the occurrence of green kernels are projects that were finalized during the 2004-05 season at Small Grain Institute. Because FN is an important quality factor evaluated within the wheat grading regulations, the possibility of managing FN within various wheat production practices would add enormously to the wheat industry.
In April 2004, an extreme temperature trial was initiated in
collaboration with the University of the Free State. The effect
of extreme high (35 C) and low (-4 C) temperatures during various
grain-filling stages on specified quality parameters on selected
cultivars will be investigated over a 2-year period. Some of the
quality parameters investigated include FN, protein composition,
starch damage, yield, and hectoliter mass. All temperature simulations
are based on actual temperatures recorded over approximately 6
years. We hope that this research will shed light on cultivars
that might respond better to such extreme 'freak' temperature
occurrences. The data generated could be used either in breeding
programmes or serve as guidelines on general production practices
in risk areas that might be prone to such extreme temperature
occurrences.
A. Barnard, W.M. Otto, and T. Walsh.
There are three dominant production systems in South Africa, under dryland conditions in both summer and winter rainfall regions and under irrigation conditions on a country wide basis. Almost 50 % of the South African wheat production is accounted for by cultivation under dryland conditions in the Summer Rainfall Region, whereas wheat production in the Winter Rainfall Region and under irrigation accounts for the remaining production in South Africa. A national cultivar evaluation program is conducted each year at Small Grain Institute that entails the evaluation and characterization of all newly classified and released wheat cultivars of all seed companies on an objective and scientific basis.
The objectives of this program are mainly to characterize cultivars in terms of yield performance and yield stability, hectoliter mass, falling number, and protein content, and other grain quality parameters, over environments and years. Another major objective is to compare cultivars in terms of agronomic characteristics, such as growth period, straw strength, shattering, and yield components and to make reliable and scientifically sound recommendations to producers and other role-players for all production regions of South Africa.
The results of the program enable producers, including small-scale farmers, to make well-informed production decisions in terms of cultivar choice. Cultivar choice is a critical production decision that will greatly affect the profitability of the producer's enterprise.
Dryland production. Almost half of the South African wheat production is accounted for by cultivation under dryland conditions in the Summer Rainfall Region. Because of the large variation in climatic conditions and soil types existing in this region, wheat production is very challenging. Not only are good cultivation and management practices essential for successful wheat production, but also the correct cultivar choice. The dryland production area is divided mainly into four homogenous areas where different cultivars, mainly winter and intermediate types, are planted. Cultivar evaluation trials were planted at 17 sites throughout the Western, Central, and Eastern Free State, and parts of Mpumalanga. The trials were successfully carried out and were reported. Twenty entries were included in the trials, of which eight were from Small Grain Institute, five from Monsanto, and seven from PANNAR.
Production under irrigation. Wheat produced under irrigation amounts to about 20 % of the total wheat production of South Africa, and has a stabilizing influence on the total production. There are currently six major irrigation regions, although irrigation farming is expanding into new production regions.
Mainly spring wheat cultivars are planted in a total of 60
evaluation trials at 31 localities in the different irrigation
areas. Entries in these trials originated from Small Grain Institute
(6) and from Monsanto (6). Two advanced breeding lines also were
included. Analyses of variance, AMMI analysis, and biplots are
used in the interpretation of results, and identifying cultivar
adaptation and stability in the different production regions.
Results from these trials are available in a detailed report.
There are mainly two wheat producing areas in the Winter Rainfall Region:
The Winter Rainfall Region is well suited to the production of spring wheats, which do not require the same amount of cold to break their dormancy, as that of the winter wheat cultivars grown in the rest of South Africa. Cultivar choice in the Winter Rainfall Region is of extreme importance due to the varied climatic differences between cultivation areas. The cultivars available differ in their yield reaction to the changing yield potential conditions that exist in the Winter Rainfall Region. Other important factors which have also to be taken into consideration are grain quality, hectoliter mass and disease susceptibility.
The Cultivar Evaluation Program in the Winter Rainfall Region
is run jointly by the Small Grain Institute and The Directorate
of Agriculture of the Western Cape. The program consists of 13
sites in the Swartland and 14 sites in the Rûens, with 14
cultivars included in the trials. The cultivars, from ARC-Small
Grain Institute, Monsanto, and PANNAR, are tested annually for
yield potential, quality, disease resistance, and adaptability.
S. Ramburan.
As part of the National Cultivar Evaluation Programme the Small Grain Institute has introduced a related programme in 2003 that involves the screening of wheat cultivars suitable for production in resource limited agriculture. The differences in production practices and resources of small-scale enterprises in comparison to commercial situations necessitated the introduction of cultivar evaluation work in the resource limited areas of the country. A large proportion of resource limited farmers in the major wheat producing regions of South Africa have the potential for commercialization and correct cultivar choice is sure to assist them in reaching this ultimate goal.
Cultivar evaluation trials were planted at various small-scale farms which were representative of specific wheat producing regions in 2004. A total of five dryland trials (20 cultivars) and four irrigation trials (15 cultivars) were planted. Cultivars originated from three different institutes, Small Grain Institute, Pannar, and Monsanto. During the season the adaptability of the cultivars to the production environments were evaluated through observations of emergence problems, growth period and disease damage. Statistical analyses were utilized to determine the yield and quality performance of the cultivars in the different environments.
The data obtained from the project will be used to ultimately characterize the different cultivars in terms of their suitability for production in different resource limited areas. These results, together with those expected in 2005 and 2006 will eventually be used to assist small-scale wheat producers with reliable recommendations that are based on applicable scientific research.
H. Hatting.
Seed plays a vital role in the potential crop yield of each small grain producer. Small grain seed must comply with legal requirements with regard to the purity and germination percentage before it can be marketed. The Small Grain Institute has a registered Seed Testing Laboratory in which international methodology [viz. ISTA (International Seed Testing Association) methods] is used to determine the quality characteristics of seed. The germination and purity testing over the past year resulted in 474 analyses, in which the quality of each seed lot was tested to ensure that poor quality seed would not be planted. The laboratory provides a unique service. Having the infrastructure and experience, seed analyses are conducted objectively on a commercial and need driven basis for the seed industry.
The laboratory was visited by several schools. This work contributes
favorably to the income of the Seed Testing Laboratory. The services
are client specific and extended the commercial services of the
laboratory.
C.W. Miles.
The Wheat Quality Laboratory plays an integral part in the breeding process and accurate and reliable data for researchers must be ensured. To accomplish accuracy and reliability, the laboratory takes part in ring tests sent out by Sasko, monthly, and the South African Grain Laboratory, quarterly.
During the past year, a total of 70,033 analyses were performed
for researchers at Small Grain Institute and 5,373 analyses were
performed for external clients such as Omnia Fertilizer, PANNAR,
and SENWES Co-operation.
Spring wheat varieties are grown in these two regions. These varieties do not require the same amount of cold to break dormancy as do the winter and wheat varieties grown in the rest of South Africa. Cultivar choice in the winter-rainfall region is of extreme importance because of the varied climatic differences between cultivation areas. The cultivars available differ in their reaction to the changing yield-potential conditions that exist in the winter-rainfall region. Other important factors that also have to be taken into consideration are grain quality, hectoliter mass, and disease susceptibility.
In the winter-rainfall region, the Cultivar Evaluation Program is run jointly by The Small Grain Institute and The Directorate Agriculture of the Western Cape. The program consists of 12 sites in the Swartland and 12 sites in the Rûens, with 14 cultivars included in the trials. Cultivars from ARC-Small Grain Institute, Monsanto, and PANNAR are tested annually for yield potential, quality, disease resistance, and adaptability.
A. Barnard, C.W. Miles, K.B. Majola, M.L.T. Moloi, M.M. Radebe, N.E.M. Mtjale, C.N. Matla, M.M. Mofokeng, M.L. Dhlamini, and N.M. Mtshali.
One of the main objectives of the Quality Laboratory is to maintain a cost-effective, highly scientific, and objective quality assessment of Small Grain Institute breeding lines; incorporate contract work for milling and baking industries and private companies; and provide an objective service to wheat producers. To ensure accurate data to researchers and external parties, the laboratory takes part in quarterly and monthly ringtests. A total of 40,341 analyses were made during 2001.
H. Hatting.
Seed plays a vital role in the potential crop yield of each
small grain producer. Small-grain seed must comply with legal
requirements with regard to the purity and germination percentage
before it can be marketed. The Small Grain Institute has an accredited
Seed Testing Laboratory in which international methodology (i.e.,
ISTA (International Seed Testing Association) methods) is used
to determine the quality characteristics of seed. The laboratory
provides a unique service. Having the infrastructure and experience,
seed analyses are conducted objectively on a commercial and need-driven
basis for the seed industry.
L. Visser.
The Soil Analyses Laboratory provides an important service to researchers, farmers, advisors, and representatives of different fertilizer companies. In addition to reliable and accurate analysis results, clients who visit the laboratory also have the benefit of exposure to research information generated at the Institute. At present, the laboratory is actively involved in a research project to evaluate the fertility status of soils from resource limited farms. There is a huge need for more information, specifically on the soils of Qwa-Qwa and the Eastern Cape.
The external income of the laboratory increased by nearly 30
% during the past year. A total of 75,532 tests were performed
on 430 plant and 9,947 soil samples. Fifty-five percent of these
samples were internal research samples. The laboratory aims to
improve these figures in the following year.
Klaus Pakendorf joined Small Grain Institute as a wheat breeder in Stellenbosch, and Solomon Fekybelu, a researcher handling the irrigation program, at Plant Breeding in Bethlehem. Tholi Mazibuko was appointed as a researcher at Crop Science and manages the falling number and preharvest-sprouting programs. Eric Morojele was appointed as a researcher at Soil Management. Brian de Villiers from Plant Protection resigned and was replaced by Hestia de Wet. Lucas Serage also resigned from the Soil Management section.
UNIVERSITY OF STELLENBOSCH
Department of Genetics, Stellenbosch 7600, South Africa
G.F. Marais, H.S. Roux, A.S. Marais, W.C. Botes, K.W. Pakendorf,
and J.E. Snyman.
Our breeding program continued and promising new lines were
selected. The 2004 growing season was abnormally dry and in the
elite trials the six commercial triticale cultivars, USGEN 19,
Rex, Kiewiet, Bacchus, Tobie, and Ibis, on average, outyielded
the leading wheat cultivars by about 20 %. Of the released cultivars,
Tobie had the best yield and hectoliter mass.
A large-scale, recurrent mass selection program based on hydroponic culture of cut male sterile (Ms3ms3) tillers was continued. In the summer of 2004-05, some 500 F4 inbred lines (2003 crosses) and 1,800 F6 inbreds (2002 crosses) were developed using field planting and single-seed descent in the off-season. Approximately 60,000 new F1 were produced. The program is continuously being refined and strong selection pressure is maintained for mildew, rust and Septoria resistance. In 2004, we began to experiment with MAS of four gene complexes, i.e., the Ae. ventricosa-derived Lr37/Sr38/Yr17 cluster, the S. cereale-derived Sr31/Lr26/Pm8/Yr9 cluster (without Sec1 locus), the Th. ponticum-derived Lr19 gene (without yellow pigment locus), and the Sr24/Lr24 complex (Th. elongatum). Currently, published marker systems for the Lr21, Lr34/Yr18, and Sr2 genes are being evaluated for their utility in recurrent selection. In 2005, we will implement routine MAS directed at the Lr37 complex, which will supplement rather than replace conventional seedling and field resistance screening and will be kept up for 2-3 seasons when the frequency of the gene complex in the base population should have reached a level of 0.70-0.80. At this point, a new gene(s) will be targeted for MAS.
In our program aimed at the transfer of rust resistance genes from wild relatives, linked leaf rust (Lr53) and stripe rust (Yr35) resistance genes introgressed from T. turgidum subsp. dicoccoides were found to be located on chromosome arm 6BS of the cross derivative, 98M71. We also translocated (centric break and fusion) linked leaf rust (Lr54) and stripe rust (Yr37) resistance genes from Ae. kotschyi to wheat chromosome arm 2DL. The latter resistance genes appear to be associated with an Rht-gene as well as a gene affecting daylight sensitivity. Attempts to determine the chromosome location of genes that were introgressed from Ae. sharonensis and Ae. peregrina were continued. Experiments were initiated to disrupt meiotic chromosome pairing through Ph1b deficiency in hybrids carrying disease resistance genes on translocation/ addition chromosomes from Ae. speltoides, Ae. biuncialis, and Ae. caudata. Test cross derivatives from these material are being screened for useful recombinants. A recombined Lr19 translocation, Lr19-149-299, was used in an attempt to shorten it still further through use of ph1b-induced homoeologous pairing. Testcross progeny, which may have lost the segregation distortion gene, Sd2, are being characterized in segregation and GISH analyses.
A program aimed at transferring salt tolerance from Th.
distichum to triticale was continued. Backcrosses to develop
disomic additions for the remaining three of five target chromosomes
were made, as were attempts to find PCR-based markers for each
critical chromosome.