Beneficios Tributarios

Department of Field Crops, Estonian Research Institute of Agriculture, Teaduse 13, EE 75501, Saku, Estonia, e-mail: [email protected]

Abstract

In the Department of Field crops of the Estonian Research Institute of Agriculture the factors influencing the quality of spring wheat were studied for a long time. The field trials were established on sod-calcareous soil, preceding crop was potato.

The protein content of different varieties in the grain yield remained from 11.5 % (‘Mahti’) to 13.2 % (‘Helle’) and gluten content from 23.2 % (‘Mahti’) to 28.1 % (‘Helle’) as the average of the compared years (1998…2003). Protein content in 6 ecologically grown spring wheat different varieties exceeded 11.3 % in 33 cases among 42 trials carried out in 11 years. The highest value was 15.3 %. In the same trials the gluten content was above 22.3 % in case of 32 trials.

Key words: spring wheat, grain quality, food, ecological farming

Wheat is a very old cultivated plant. The first data about wheat growing come from South- west Asia 7000-6000 B.C., from Danubian countries - 6000, from China, South Scandinavia and Denmark 3000 B.C. In Estonia wheat has been grown since 2000 B.C.

Under Estonian weather conditions spring wheat is of high food quality as a rule. Since we don’t have varieties bred especially for ecological cultivation the qualities of some mostly grown varieties have been compared below. In the Department of Field crops of the Estonian Research Institute of Agriculture the factors influencing the quality of spring wheat were studied for a long time. Since there was always an unfertilised variant in the trial, the results of 0 variant by different varieties have been used onward. The average humus content of soil was 2.8 %, P-93…128 mg kg-1 and K-73…132 mg kg-1. The field trials were established on

sod-calcareous soil, preceding crop was potato.

The trials with some varieties were carried out in different years, so the following data are incomparable in absolute figures but characterise the variety qualities to some extent. The spring wheat ‘Satu’ was in the trials for the longest period. The main demand for growing this variety was that the soil should not be acid. ‘Satu’ gave quite high yields even under

relatively low soil fertility conditions. The variety gave good assurance of yield, i.e. it gave satisfactory stable yields in both wet and dry years and quality indicators and baking qualities were at the same time satisfactory to good. The Figure 1 enables to assess the changes of gluten and protein content of the spring wheat ‘Satu’ by different years. Among these years there is not a single year where both the average air temperatures of these months and the amount of precipitation would be close to long-term averages. The observed trial years could conditionally be divided into the following groups:

o rainy and cool – ’93, ’96, ’98

o rainy and warm - ’95, ’97, ’01

o cool and dry - ’94, ’02, ‘03

o warm and dry - ’99

o cool, precipitation within the rate - ’00

Protein content of the spring wheat ‘Satu’ on the background of N0 varied between 9.5 % (1996) and 13.8 % (2003). The lowest gluten content was 17.1 % in 1997, the highest in the rainy and warm year of 2001 – 30.9 %. Among the observed years the gluten content remained below 20% only in three years. The yearly average protein content of the spring wheat ‘Satu’ was 11.7 % and gluten content 24.1 %. The grain yields of ‘Satu’ remained between 1867 kg ha-1 in 2003 and 3370 kg ha-1 in 1997, the trial years average being 2751 kg ha-1. 0 10 20 30 40

Figure 1 Gluten and protein content of spring wheat 'Satu'

Gluten 18,4 23,6 26 19,9 17,7 22,2 25 24,9 30,9 30,1 27,8 Protein 10,3 12,3 11,6 9,5 10,7 11,4 11 11,4 13,1 13,6 13,8 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003

The spring wheat ‘Manu’ was in the trials since 1995. Compared to the variety ‘Satu’ the advantage of the variety ‘Manu’ is the ability of standing also acid soils. In droughty years the grain remained fine but at the same time this variety had quite high quality indicators and baking qualities. The protein content of ‘Manu’ remained between 11.3 % (1996) and 15.3 % (2003) (Figure 2). The lowest gluten content was 23.1 % obtained in 1997 and the highest in 2003 – 30.0 %. In all trial years the gluten content of ‘Manu’ was above 23 %. The annual average gluten content was 26.7 %. The lowest grain yield - 1520 kg ha-1 _{was received in}

By years the protein content of the spring wheat ‘Helle’ was from 11.6 % (1998) to 14.5 % (2003). The annual average protein content was 13.2 %. The lowest gluten content was in 1998 – 18.6% and the highest in 2001 – 35.0%, the annual average being 28.1%.

Figure 3 Gluten and protein content of spring wheat 'Meri'

0 20 40 % Gluten 22,3 27,8 24,5 28,1 31,9 25,8 Protein 11,5 11,9 11,4 12,9 13,9 12,7 1998 1999 2000 2001 2002 2003

The grain yields of ‘Helle’ ranged from 1686 kg ha-1 _{in 2002 to 2870 kg ha}-1 _{in 1999, the}

annual average being 2349 kg ha-1_{. Finnish-Estonian joint varieties ‘Meri’ (Figure 3) and}

‘Helle’ were also in the trials. Both varieties were relatively indulgent to growth conditions. The variety ‘Mahti’ suitable also for growing on clay soils was also used in the trials. By years the protein content of the spring wheat ‘Mahti’ was from 9.4 % (1998) to 15.4 % (2002). The annual average protein content was 11.1 %. The lowest gluten content – 17.1 % was obtained in 1997 and the highest – 35.8 % in 2001, the annual average being 21.8 %. The grain yields of ‘Mahti’ ranged from 1308 kg ha-1 _{(2002) to 3630 kg ha}-1 _{(1997). The average yield of ‘Mahti’}

was 2716 kg ha-1_{, protein content 11.1 % and gluten content 21.6 %.}

Summing up, we can say that:

o When growing spring wheat without mineral fertilisers, the protein content of different varieties in the grain yield ranged from 11.5 % (‘Mahti’) to 13.2 % (‘Helle’) and gluten content from 23.2 % (‘Mahti’) to 28.1 % (‘Helle’) as the average of the compared years (1998…2003).

o Protein content of ecologically grown spring wheat of 6 different varieties was over 11.3 % in 33 cases among 42 trials carried out in 11 years, the highest being 15.3 %. In the same trials the gluten content was over 22.3 % in 32 cases. These indicators let us assume that ecologically grown spring wheat meets the requirements of food wheat quality sufficiently (Hagel, Schnug, 1997).

o The above-mentioned quality indicators (protein over 11.5 % and gluten more than 28.1 %) depended to some extent on weather conditions. These indicators were higher when the year was sunny, dry and warm.

References

Hagel, I., Schnug, E. (1997) Schwefelgehalte in biologisch-dynamischen Weizen, Auszug aus Publication Nr. 14.

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