GrainGenes

Clipping trials to test wheats for dual purposes aimed at establishing sustainable agrosystems.

I.J.A. del Duca and R.S. Fontaneli.

The no-till system, in addition to being a more powerful practice to prevent soil erosion, contributes greatly to the improvement of the physical, chemical, and biological properties of the soil and a reduction in production costs. However, to be feasible, the no-till system requires crop rotation and soil maintenance with a permanent cover of vegetation.

More than 6,000,000 ha are cultivated with crops such as soybean, corn, rice, and beans in the summer in the state of Rio Grande do Sul (R.S.), Brazil. In contrast, less than 1,000,000 ha are cultivated with the small, winter grains (wheat, oats, barley, triticale, and rye). This practice leaves a large area of land idle in the winter, with extremely negative results for the regional economy, leading to soil and revenue losses and unemployment, Furthermore, the possibility of better using native pasture areas in R.S.óabout 14,000,000 haóby incorporating them more efficiently into the productive system involving the grain crops must be contemplated.

On the other hand, in the traditional cattle-raising regions of R.S., there is a drastic shortage of forage in the winter months because of low temperatures. As a result, beef cattle finishing and milk production have increased during the winter in the middle plateau region of R.S. The need for crop rotation and cattle production has led to activities integrating crop-cattle production and may result in better use of farm potential.

During 1993-94, a clipping trial was carried out at Passo Fundo including four wheat lines with longer vegetative periods, two wheat checks (early) adapted to grain production, two cultivars of common oats, one wild oat (Avena strigosa), one barley, one rye, and one triticale. The trial was sown on 3 May, 1993, and 17 May, 1994, in a split-plot design with three replications. In order to simulate cattle grazing, each genotype was subjected to clippings (without clipping; first clipping 16 July, 1993, and 1 August, 1994; second clipping 13 August, 1993 and 25 August, 1994) 5-7 cm above the ground, when the plants reached a height of approximately 30 cm. The genotypes tested were: wheat (IPF 41004, IPF 55204, PF 86247, and PF 87451), early check wheats (BR 23 and EMBRAPA 16), oat (UPF 14 and UPF 15), an A. strigosa landrace, barley (MN 599, in 1993, and BR 2, in 1994), rye (BR 1), and triticale (BR 4).

The 1993-94 2-year averages of experimental data from the six wheats, compared with the other small grains, are shown in Table 4. Similarly, the effects of both one and two clippings on dry matter and grain yield, compared to the corresponding unclipped checks, are shown.

Table 4. Dry matter and grain yield average (kg/ha) and percent relative to the wheat

EMBRAPA 16, in the dual-purpose small grains trial during 1993-94.

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Cereal Dry matter Grain yield

kg/ha, % EMBRAPA 16 kg/ha, % EMBRAPA 16

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lC 2C 1C 2C WC1 1C WC1 1C

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Oats (UPF 14) 1,495 1,990 107 84 1,158 826 36 39

Oats (UPF 15) 1,332 2,790 95 118 1,040 1,422 32 67

Avena strigosa 1,524 2,348 109 99 222 590 7 28

Rye (BR 1) 1,754 2,343 125 99 1,829 774 57 36

Barley2 1,714 2,418 122 102 1,688 1,196 52 56

Triticale (BR4) 1,448 2,212 103 94 2,586 1,018 80 48

Wheat (IPF41004) 1,079 2,326 77 98 3,042 2,344 94 111

Wheat (IPF55204) 1,054 2,574 75 109 2,588 2,494 80 118

Wheat (PF 86247) 1,269 2,440 91 103 2,914 2,191 90 103

Wheat (PF 87451) 1,138 2,475 94 105 2,882 2,629 90 124

Wheat (BR 23) 1,327 1,958 95 83 2,474 702 77 33

wheat (EMBRAPA 16) 1,400 2,363 100 100 3,220 2,120 100 100

Average 1,393 2,353 2,137 1,526

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Sowing dates = 3 May, 1993, and 17 May, 1994.

1WC = without clipping; 1C (1 clipping = 16 July, 1993, and 1 August, 1994);

2C (2 clippings = 16 July, 1993 + 13 August, 1993, and 1 August, 1994 + 25 August, 1994).

2Barley MN 599 in 1993 and BR 2 om 1994.

C.V. % dry matter = 12 2 (1993), 10.9 (1994).

C.V. % grain yield = 16.0 (1993), 13.3 (1994).

The percent comparisons were made in relation to EMBRAPA 16 wheat, (the most cultivated wheat in R.S. at present and the highest-yielding wheat in each of the last 5 years). Another practical comparison could be made

relative to A. strigosa, the most cultivated winter cereal in R.S., for providing a soil cover and forage, especially during the autumn and winter months.

Considering the 2-year average of dry matter production with one clipping, the best cereal species were rye BR 1 and the barley lines, probably because of their early development, with 1,754 kg/ha and 1,714 kg/ha, respectively. Considering the sum of both clippings, the outstanding cereals were oat cultivar UPF 15 (2,790 kg/ha) and the wheat lines IPF 55204 (2,574 kg/ha) and PF 87451 (2,475 kg/ha).

No cereal surpassed the grain yield of EMBRAPA 16 (3,220 kg/ha) in the treatments without clipping for the 2-year average. Very low grain yields were obtained with two clippings over 2 years, probably making advancement of the sowing period (to April) of greater importance, so that grain yield would not be affected adversly when greater amounts of dry matter are desired. In the treatments with one clipping, the wheats were outstanding in relation to other cereals, especially the late early types. The varieties PF 87451, IPF 55204, and IPF 41004 yielded 2,629, 2,494, and 2,344 kg/ha of grain, respectively. EMBRAPA 16, with one clipping, yielded 2,120 kg/ha.

Early autumn sowing (April-May) for adequate late-flowering germplasms makes feasible a dual-purpose system, providing forage in the winter months without drastic reduction in grain yield. This system can provide greater stability to the wheat crop, when a flexible management depends on the prices of grain or animal products.

Plant health and agronomic and baking characteristcs of wheat cultivars and lines of the Paraná State Yield Trials, 1995.

L.J.A. del Duca, C.N.A. de Sousa, E.M. Guarienti, and W.I. Linhares.

Paraná is the most important Brazilian state with reference to wheat production. For this reason, a nursery including 95 cultivars and lines that were in intermediate and final yield trials in that state in 1995 was evaluated under field and greenhouse conditions at the Centro Nacional de Pesquisa de Trigo, Passo Fundo, in Rio Grande do Sul. Information regarding kernel note (KN) and disease complex on leaf (DCL) were obtained under field conditions, with natural infection (planting 13 June, 1995). For powdery mildew (PM), some data were obtained under artificial inoculation at the seedling stage in the greenhouse with a mixture of races. The average coefficient of infection (ACI) was obtained under field conditions with natural infection, after observation in different years.

For KN, the rating varied from 1 (excellent) to 5 (very poor). For the DCL and PM, the scale ranged from 0 (immune or without symptoms) to 5 (highly susceptible).

The nursery to evaluate effects of aluminum was seeded on 17 July, 1995 in acid soils (pH = 4.7-5 1; Al = 3.1-4.2 me/100 g soil) with two replications. The index of susceptibility (IS) varied from 0 50 (highly resistant) to 5.0 (highly susceptible). Because of strong dry periods, 1995 was favorable for reinforcing the negative effects of aluminum, leading to greater values when compared to years with normal rainfall.

Some information for baking quality from the alveograph method (W = deformation energy of dough) from EMBRAPA-CTAA and EMBRAPA-CNPT in 1990-94 are presented. These data represent the averages from a variable number of years for each genotype.

For each characteristic, the wheats below can be designated as outstanding:

Kernel note (< = 1+): IA 9113. IAPAR 41, IAPAR 42, IAPAR 46, LD 9lll, PG 9337, OC 935, OC 938, OC 9510, OC 9513, OCEPAR 21, Trigo BR 23, EMBRAPA 16, PF 86233, PF 86242, IDS 719-2, and ORL 9285;

DCL (< = 2): CEP 24, IA 9113, IAPAR 41, IAPAR 42, IAPAR 46, ID 9318, PG 9337, OC 956, OC 958, OC 959, OC 9513, EMBRAPA 16, PF 86242, PF 9122, PF 9127, PF 91204, and ORL 9285;

Aluminum tolerance (IS < = 1.5l): IAC 5-Maringa, IAPAR 41, IAPAR 53, OC 958, and Trigo BR 35, IS below 1.20; ORL 91274, PF 87410, and PF 88747, IS between 1.25 and 1.38; Trigo BR 23, IAPAR 46, OC 935, and OC 956, IS between 1.42 and 1.50;

W (> = 200): CEP 24, IA 9113, IA 948, IA 949, IA 9413, IA 9415, IA 9417, IAPAR 6, IAPAR 17, IAPAR 28, IAPAR 29, IAPAR 53, IAPAR 60, LD 9111, LD 937, OC 928, OC 935, OC 938, OC 939, OCEPAR 10, QCEPAR 16, OCEPAR 18, OCEPAR 19, OCEPAR 21, OCEPAR 22, ORL 9128, Trigo BR 40, EMBRAPA 10, EMBRAPA 16, PF 9099, PF 9127, PF 91205, PF 91420, PF 91450, PF 91627, Anahuac, Trigo BR 18, and IDS 723-2;

PM = IAPAR 42 and PF 87410 showed outstanding performance, considering their resistance under greenhouse and field conditions for 3 or more years. The following genotypes showed good performance in the year(s) and conditions: PG 9337, OC 954, OC 9511, PF 94120, PF 91627, and ORI 92141. Considering the ACI (< = 20 %), although they may show susceptibility in some years or in the greenhouse, the following cultivars can be mentioned: CEP 24, IAPAR 46, EMBRAPA 16, EMBRAPA 27, PF 86233, PF 86242, PF 9122, PF 91204, PF 91205, and ORL 91256.

Evaluations relating only to 1995 must be interpreted as preliminary information.

Distribution by state of the main Brazilian wheat cultivars in 1994-95.

L.J.A. del Duca and P.L. Scheeren.

As a result of political, social, and economic factors, Brazilian wheat production has fluctuated from almost self-sufficiency (6.1 million tons) in 1987 to the drastic reduction to nearly 1.5 million tons in 1995. However, consumption has increased to about 8 million tons, leading to importation of most of the domestically consumed wheat. Considering the reduction in world stocks and price elevation in the market, an increase in area in Brazil that can lead to 2.5 million tons of production is expected in 1996.

Paraná and Rio Grande do Sul are the states responsible for most of Brazilian wheat production and have a wide assortment of crop conditions, such as with or without irrigation, presence or absence of aluminum in the soil, and good or poor soil fertility. The commercial life span of cultivars is normally short. Some cultivars have broad adaptation (Trigo BR 13-Terena, Trigo BR 23, EMBRAPA 16, and CEP 24-Industrial), whereas others are more restricted in their growing area (IAC 60, Trigo BR 26, and Trigo BR 33).

The most important cultivated wheats, considering the three major ones at each state are detailed in Table 5 (p. 62), with additional information regarding pedigree, soil aluminum tolerance, and breadmaking quality. From these 16 listed genotypes, only four are tolerant to aluminum (EMBRAPA 16, CEP 24, IAC 60, and Trigo BR 35) and two are moderately tolerant (Trigo BR 23 and Panda). For breadmaking quality, nine cultivars are considered very good (EMBRAPA l0, Trigo BR 17, and Trigo BR 40) or good (Anahuac 75, Trigo BR 18, EMBRAPA 16, CEP 24, OCEPAR 16, and IAC 287).

At present, EMBRAPA 16 is the most cultivated Brazilian wheat accounting for much of the production areas of the three states, Rio Grande do Sul, Santa Catarina, and Paraná.

INSERT TABLE 5, Page 63.