ITEMS FROM BRAZIL

NATIONAL RESEARCH CENTER FOR WHEAT - EMBRAPA

Centro Nacional de Pesquisa de Trigo, BR 285, Km 174, Caixa Postal 451, 99001-970, Passo Fundo, Rio Grande do Sul, Brazil.

 

Wheat trials for double purpose in the Brazilian state of Rio Grande do Sul, 1999. [p. 30]

Leo de J.A. Del Duca, Osmar Rodrigues, Gilberto R. da Cunha, Luiz Hermes Svoboda, Dejair J. Tomazzi, Carlos F. Toescher, and Cleomar G. Ereno.

The aim of our work is to identify wheat genotypes that can be planted earlier than the normal sowing time in the Brazilian state of Rio Grande do Sul, are adapted to dual purpose use (forage and grain production), and are capable of promoting green cover under a no-till system because of their long vegetative cycle. The trials were grown at Embrapa Trigo, Passo Fundo (10 May, 1999); Fundacep Fecotrigo, Cruz Alta (4 May, 1999); PUC-Uruguaiana (14 May, 1999); Fepagro - S.Borja (14 May, 1999); and CAAL - Alegrete (6 June, 1999). Twenty-three early to late wheat cultivars were compared. Three early-wheat cultivars were used as checks for grain yield, Trigo BR 23, CEP 24-Industrial, and CEP 27-Missões, and one common black oat cultivar was the check for forage (dry matter) yield. The trial was arranged in a split-plot experimental design, with three replications and two clipping systems, one clipping (1C) and without clipping (NC). Clippings were made just prior to the jointing, and the dates varied according to the cycle of the genotypes.

Considering the average yield of all the local varieties, PF 960249, PF 940034, CEP 96227, BRS 177, CEPF 962, CEPF 974, PF 90132, and IPF 64758 exhibited outstanding performance, with 10-37 % higher dry matter yield production than the common black oat (1,476 kg/ha). In the NC system, PF 960263, CEPF 9715, PF 960262, PF 950136, BRS 177, CEP 96227, and IPF 55204 had outstanding grain production, yielding 31-48 % more than the average production of the early wheat check cultivars (2,753 kg/ha).

Outstanding grain yields were obtained at Passo Fundo in the NC system with the best eight genotypes varying from 6,022 kg/ha to 7,035 kg/ha. In the 1C system, PF 940034, PF 960243, PF 950136, PF 87451, PF 960249, PF 960262, IPF 55204, and CEPF 962 produced 10-34 % higher grain yields than the average of the early wheat checks (1,940 kg/ha).

Clippings reduced the average height of genotypes from 81 cm (NC) to 62 cm (1C), indicating that cereal grazing may have a potential advantage in lodging conditions. Clippings delayed the average cycle of genotypes by 8 days, from 107 days (NC) to 115 days (1C).

Testing wheat genotypes for double purpose in the Brazilian state of Paraná, 1999. [p. 31]

Leo de J.A. Del Duca, Rudimar Molin, and Itacir Sandini.

These trials were sown early at Fundação Agrária, Guarapuava, PR (5 May, 1999) and Fundação ABC, Castro, PR (13 May, 1999), Brazil. Seventeen early to late wheats were compared, with three early wheats used as checks for grain yield (BR 23, BR 35, and CEP 24), and the common black oat as dry-matter yield check. The trial was arranged in a split-plot experimental design, with three replications and two systems, without clipping (NC) and one clipping (1C). Clippings were made just prior to the jointing stage, varying the dates according to the cycle of the genotypes.

At Guarapuava, wheats PF 90134 and PF 940034 produced 1 % and 13 %, respectively, higher dry-matter yields than the common black oat check (1,028 kg/ha).

In the NC system, the wheats IPF 55204, PF 960243, PF 960239, PF 87451, PF 960249, PF 960262, and PF 950136 were outstanding for grain yield, being 53­89 % over the average of the three check varieties (3,329 kg/ha). In the 1C system, PF 87451, PF 960263, PF 960239, PF 960243, PF 960242, PF 950136, IPF 64758, and PF 960262 produced 57­80 % higher grain yields than the average of the early wheat checks (2,896 kg/ha).

Outstanding grain yields were obtained in the NC system at Castro. The best seven genotypes varied from 6,738 kg/ha to 7,984 kg/ha. In the 1C system, the best wheats varied between 6,336 kg/ha and 6,672 kg/ha.

Clippings reduced the height of the genotypes from 91 cm (NC) to 77 cm (1C) indicating that cereal grazing may have a potential advantage in lodging conditions.

Optimizing grain yield potential in the southern Brazilian wheat region. [p. 31-32]

Leo de J.A. Del Duca, Rudimar Molin, Itacir Sandini, Francisco Franco, Sérgio R. Dotto, Juliano Almeida, Eliana M. Guarienti, Osmar Rodrigues, Gilberto R. da Cunha, Luiz Hermes Svoboda, Dejair J. Tomazzi, and Carlos F. Toescher.

Different research results in the states of Paraná and Rio Grande do Sul indicate a greater yield potential with early planting dates, varying according to region. Nevertheless, considering that the recommended wheat cultivars are typically early genotypes, early planting may result in drastic losses from flowering in periods with a serious risk of frost.

Adapted lines should cover the soil and increase grain-yield potential with a greater chance of escaping frosts because of their longer emergence and flowering subperiod (late-early ecoideotypes). In order to identify adapted lines for early sowing, lines from Embrapa and Coodetec are being tested at four locations in Paraná by Embrapa, Soja and Coamo (Campo Mourão), Coodetec (Cascavel), Fundação ABC (Castro), and Fundação Agrária (Guarapuava). Early plantings were made in Rio Grande do Sul as well, testing lines from Embrapa and Fundacep Fecotrigo, by Embrapa Trigo (Passo Fundo), Fundacep Fecotrigo (Cruz Alta), Fepagro (São Borja), and PUC (Uruguaiana).

Outstanding grain yields were obtained in 1999, at Passo Fundo in Rio Grande do Sul, with the best eight genotypes varying from 6,022 kg/ha to 7,035 kg/ha (Table 1).

Table 1. Lines with the best performance in 1999 at Passo Fundo, Rio Grande do Sul, Brazil, in early sowing and without a fungicide disease control, as compared with conventional, early-wheat checks.

Cultivar	Cross	Grain yield (kg/ha)
BRS 177	PF 83899/PF 813//F27141	6,149
CEP 96227	PF 869114/CEP 8749//Curinda 'S'/YAV	6,072
IPF 55204	Florida 301/C 762	6,817
IPF 64758	Saluda/C 762//C80-28/FL 301	6,274
PF 950136	PF 8569/C 762	6,398
PF 960249	HLN/CNT 7//Amigo/CNT 7	6,022
PF 960262	C 762*2/CNT 8	7,035
PF 960263	C 762*2/CNT 8	6,855
BR 23 (early check)	CC/ALD SIB/3/IAS 54-20/COP//CNT 8	3,597
CEP 24 (early check)	BR 3/CEP 7887//CEP 7775/CEP 11	3,715
CEP 27 (early check)	CEP 8057/Butuí//CEP 8324	3,910
C.V. (%) 6.5

Outstanding grain yields were obtained in the state of Paraná in trials that were sown early at Fundação ABC, Castro, (13 May, 1999), with the best eight genotypes ranging from 6,543 kg/ha to 7,984 kg/ha (Table 2).

Table 2. Lines with the best performance in 1999 at Castro, Paraná, Brazil, in early sowing and without a fungicide disease control, as compared with conventional, early-wheat checks.

Cultivar	Cross	Grain yield (kg/ha)
BRS 177	PF 83899/PF 813//F27141	6,738
IPF 55204	Florida 301/C 762	6,992
IPF 64758	Saluda/C 762//C80-28/FL 301	6,543
PF 87451	C 762/BR 14	6,924
PF 950136	PF 8569/C 762	7,984
PF 960239	PEL 73101/BR 5//PF 79777/Oasis	6,872
PF 960243	Century/BR 35	6,725
PF 960262	C 762*2/CNT 8	7,631
BR 23 (early check)	CC/ALD SIB/3/IAS 54-20/COP//CNT 8	5,736
CEP 24 (early check)	BR 3/CEP 7887//CEP 7775/CEP 11	5,596
CEP 27 (early check)	CEP 8057/Butuí//CEP 8324	4,617
C.V. (%) 13.1

Without a fungicide disease control, the best results of over 7 t/ha in Rio Grande do Sul and nearly 8 t/ha in Paraná, confirm previous data obtained in these states and the possibility of exploiting a greater yield potential with a early-late ecoideotype in anticipated sowings.

Agronomic, baking, and plant health characteristics of wheat cultivars and lines from the Paraná State Yield Trials, 1999. [p. 32-33]

Leo de J.A. Del Duca, Cantídio N.A. de Sousa, Eliana M. Guarienti, Pedro L. Scheeren, Martha Z. de Miranda, and Márcio Sóe Silva.

Paraná is the most important wheat-producing state in Brazil. A nursery including 85 cultivars and lines tested in intermediate and final trials in that state in 1999 was evaluated under field conditions at Embrapa Trigo-National Wheat Research Center, Passo Fundo, RS. Information regarding complex diseases of the spike and grain yield was obtained under field conditions after natural infection (planting 25 June, 1999). The scale ranged from 0 (immune or without symptoms) to 5 (highly susceptible). For kernel note, the scale ranged from 1 (excellent) to 5 (very poor). Information on baking quality from the alveograph method (W = deformation energy of dough) at Embrapa, the National Wheat Research Center laboratory, between 1990-99 is shown. The data represent averages from a different numbers of years for each genotype. The nursery to evaluate the effects of aluminum toxicity was seeded into an acid soil with a high level of aluminum. The index of susceptibility (IS) varies from 0.5 (highly resistant) to 5.0 (highly susceptible).

The genotypes below had the best performance for the following characteristics.

Complex diseases of the spike (1 to < 2) = BRS 120, BRS 177, CEP 24, Embrapa 16, IPR 84, LD 975, and LD 984.

Kernel note (1 to < 2) = BRS 177, CD 994, CD 996, CD 997, CEP 24, Embrapa 16, Rubi, PF 940096, PF 950367, and WT 95032.

W (> 200) = Anahuac 75, BRS 49, CEP 24, COODETEC 101, COODETEC 102, COODETEC 103, COODETEC 104, Embrapa 16, FUNDACEP 29, IAPAR 6, IAPAR 17, IAPAR 28, IAPAR 29, IAPAR 53, IAPAR 78, IPR 84, IPR 85, Manitoba 97, OCEPAR 16, OCEPAR 21, OCEPAR 22, OR 1, Rubi, PF 93188, PF 940096, PF 940341, PF 940366, PF 940384, PF 950089, PF 950351, PF 950367, Tauro, Trigo BR 18, WT 95032, WT 95068, WT 96061, WT 96063, WT 96120, WT 96168, WT 97086, WT 97138, and WT 97189.

Grain yield (4,100 to 5,500 kg/ha): BRS 49, BRS 120, CD 994, CD 996, IPR 84, LD 975, OCEPAR 21, OC 9811, Rubi, PF 940096, PF 940341, PF 950367, and Trigo BR 35.

Soil aluminum toxicity = The following genotypes were considered as resistant: BRS 49, CIT 9644, Embrapa 16, IAPAR 53, IPR 84, IA 994, LD 969, LD 975, OC 968, OC 9811, OC 9812, PF 950351, PF 950367, Trigo BR 23, Trigo BR 35, WT 96061, and WT 97138. With a lower IS, the more resistant lines are BRS 49, OC 9811, PF 950367, WT 96061, and Trigo BR 35. The following germ plasms behaved as susceptibles Anahuac 75, CD 101, IAPAR 17, IAPAR 29, IA 981, and WT 95032. The remaining genotypes were included in the groups moderately resistant or moderately susceptible. In many cases, evaluations are related to data from only 1 or 2 years.

Data should be interpreted as preliminary considering that most of the information was from one year of evaluation.

BRS 194, a new wheat cultivar from Embrapa Trigo. [p. 33]

Cantídio N.A. de Sousa, João C.S. Moreira, Leo de J.A. Del Duca, Márcio Sóe Silva, and Pedro L. Scheeren.

BRS 194 was selected from the cross 'CEP 14/BR 23//CEP 17' made in Passo Fundo in 1987. The cross was made with the objective of combining the positive characteristics of three cultivars and be well-adapted in southern Brazil. Bulked in the F7 as line PF 92231 in 1992 using the pedigree method, BRS 194 was released for cultivation in the states of Rio Grande do Sul and Santa Catarina in 2000.

BRS 194 is an early, medium-tall cultivar with erect leaves and small spikes. The cultivar is resistant to SBMV, aluminum toxicity, and stem rust, has good resistance to leaf rust; is moderately resistant to Stagonospora blotch, tan spot, and powdery mildew; and susceptible to scab. BRS 194 has tolerance to sprouting in the spike and a tendency for good test weight. This cultivar has a protein content of 12.3 % (23 samples), an alveogram W value of 170 x 10-4 J (30 samples), and a Hagberg falling number of 357 (30 samples) based on data from 1994-98.

BRS 194 yielded 2,780 kg/ha in 62 trials conducted in the state of Rio Grande do Sul from 1966 to 1999. This yield represents a 117 % increase in relation to the check BR 23, one of its progenitors, and still an important cultivar in southern Brazil.

Results of tests for the reaction of wheat genotypes to Al toxicity in laboratory conditions and to soil acidity in the field. [p. 34]

Márcio Voss and Cantídio N.A. de Sousa.

Soil acidity and aluminum toxicity are present in many wheat-growing areas of Brazil. One hundred and sixty-three genotypes, including Brazilian and non-Brazilian cultivars and Brazilian experimental lines, were tested in the laboratory and the field in Passo Fundo, Brazil, in 2000. The genotypes were evaluated in the laboratory in a hydroponic solution with two rates of Al (1 and 2 mg/l). Roots were measured 4 days after the start of the test. The genotypes also were evaluated for sensitivity to soil acidity in a of pH between 4.4 and 3.8 cmolc Al/l. In these conditions, the susceptible check Anahuac 75 either did not produce spikes or the spikes were small with few spikelets. Data were recorded for reaction to soil acidity and a susceptibility index to aluminum toxicity (SIAL) was calculated (Plant Breed 117:217-221, 1998).

From the data for root length, the correlation value was 0.91 at both rates of Al in the laboratory test, and - 0.75 and - 0.77 between the SIAL data and root length at rates 1 and 2 of Al, respectively, in the laboratory test. The most susceptible genotypes, with roots less than 2-cm long in the laboratory test, at the two rates of Al and a SIAL greater than 3.50, were Anahuac 75 (Mexico), CD 104 (Brazil), Century (U.S.A.), Chagual (a Chilean durum wheat), Karl (U.S.A.), Neepawa (Canada), Sumai 2 (China), T50130 (Australia), and the durum lines Rascon 10, Sord 1, and Suranka 11 from Mexico.

The most outstanding genotypes with resistance/tolerance of Al and soil acidity that formed roots greater than 5-cm long at a rate of 1 mg/l of Al, more than 4-cm long at a rate of 2 mg/l of Al in the laboratory test, and a SIAL less than 1.51 were all Brazilian genotypes, including BH 1146, BRS 49, BRS 179, Embrapa 52, Frontana, IAC 5-Maringa, PF 8776, PF 950327, PF 970082, PF 980267, PG 1, Toropi, Trigo BR 15, and Trigo BR 23.

2000 Wheat Cultivar Yield Trials in Passo Fundo, State of Rio Grande do Sul (RS), Brazil. [p. 34-35]

João C.S. Moreira and Cantídio N.A. de Sousa.

Forty-seven yield trials testing nearly 850 spring genotypes of bread wheat were conducted at the National Wheat Research Center, of Embrapa, in Passo Fundo, RS, Brazil (Table 3). Climatic conditions during the wheat season in Passo Fundo (June to September) were good, with an excess of rainfall in October and November that favored the occurrence of disease. Scab was the main disease this year in Passo Fundo. In the field, the estimated average for the state of Rio Grande do Sul in 2000 was 1,700 kg/ha, whereas in 1998 it was 1,600 kg/ha and in 1999 it was 1,800 kg/ha.

The trials were conducted in a crop-rotation area. The check cultivars used in 1998, 1999, and 2000 were BR 23, CEP 24, and CEP 27. BRS 49 was the leading cultivar in hectares seeded in Rio Grande do Sul in 2000 (100,000 ha), followed by CEP 27 and BR 23 with 78,000 and 60,000 ha, respectively.

The three best genotypes and the best check in each trial in Passo Fundo in 2000 according with the trial are given in Table 3.

Haplodiploidization in the genetic analysis of disease resistance in wheat. [p. 34-35]

Sandra Patussi Brammer, Amarilis Labes Barcellos, Maria Irene Baggio de Moraes Fernandes, and Sandra Cristina Kothe Milach.

Double haploids are especially useful for genetic analysis of disease resistance in crop plants, mainly for complex inherited traits as was indicated to be the case of durable adult-plant resistance to wheat leaf rust. The Brazilian wheat cultivar Trigo BR 35, which has shown durable resistance to leaf rust, maintaining resistance for more than 10 years under the high inoculum pressure of the southern region, was crossed to the susceptible cultivar IAC 13-Lorena. Haplodiploidization via gymnogenesis was done by somatic elimination of the pollen-donor genome after maize pollination of the F1 plants. Genetic analysis for adult-plant resistance to leaf rust was made in 35 DH homozygous segregant lines infected with the MCG and LPG races. At the adult-plant growth stage, Trigo BR 35 expressed two resistance genes. Thirty-five DH lines are equivalent to 1,225 conventional F2 lines, allowing for economy of time and space and making it possible to perform further genetic analysis using the same completely homozygous population.

Monosomic analysis of adult-plant leaf rust resistance in the wheat cultivar Toropi. [p. 36]

Sandra Patussi Brammer, Amarilis Labes Barcellos, Anthony Worland, Maria Irene Baggio de Moraes Fernandes, and, Sandra Cristina Kothe Milach.

Chromosomal mapping of adult-plant leaf rust resistance was performed in the Brazilian wheat cultivar Toropi. Under the high-inoculum pressure of the southern region of Brazil, Toropi has maintained resistance for more than 30 years. Completely expanded flag leaves of the main tillers of F2 plants derived from the F1 monosomics of the cross Toropi with the monosomic series of Cappelle-Desprez were inoculated with one isolate of a P. triticina race MFT for analysis of the resistance reaction. The results indicated two main genes for adult-plant resistance in Toropi, which are located on chromosomes 1A and 4D and, previously, named Trp-1 and Trp-2, respectively. No reference was found on genes for adult-plant resistance to leaf rust on these chromosomes.

Molecular markers for adult-plant resistance to leaf rust in wheat. [p. 36]

Sandra Patussi Brammer, Sandra Cristina Kothe Milach, Greg Penner, Amarilis Labes Barcellos, and Maria Irene Baggio de Moraes Fernandes.

The completion of molecular genetic framework maps of all wheat chromosomes is among the recent accomplishments of biotechnology applied to the Triticeae species. Such technologies will have a major impact on the improvement of wheat varieties. The objective of this study was to identify DNA markers associated with adult-plant resistance to leaf rust that might be useful in breeding for this trait in wheat. The AFLP and BSA techniques were used to identify molecular markers associated with the adult-plant resistance gene present in the Brazilian wheat cultivar Toropi. Two independent markers, XPcgMac3 and XPcgMac6, were identified as associated with adult-plant, rust-resistance gene, confirmed by the analysis of an F7 inbred-line population from the 'Toropi/IAC13-Lorena' consensus map, and converted to a allele-specific cross. Both markers explained 71.5 % of the variation on the phenotypic data in a multiple linear regression model. Studies for the localization of these markers on wheat amplicons are under way and will contribute to the use of such traits for MAS of adult-plant, leaf rust-resistance genes in wheat.