Maataloustieteellinen A ikakauskirja Vol. 62: 227—236, 1990 The effect of climatic factors on production of spring wheat quantity to quality ratio in southern Finland JARI PELTONEN*, TUOMO KARVONEN* and ERKKI KIVI** * University ofHelsinki, Department ofCrop Husbandry, Viikki, SF-00710 Helsinki, Finland ** Hankkija Plant Breeding Institute, SF-04300 Hyrylä, Finland Abstract. Interrelationships between climatic factors and spring wheat yield and quality were examined with 21 years field experiments. The formation of gluten was less at dry condi- tions (total precipitation under 50 mm) and total precipitation exceeded 130—140 mm. The optimum daily temperature for gluten production was some 15—17°C during grain filling. The gluten content decreased if daily minimum and maximum temperatures exceeded 11 —12°C and 21—22°C, respectively. The effect of temperature and rainfall were not, however, signifi- cant in early maturing varieties. The climatic factors and grain yield did not correlate. Grain yield and protein yield had strong positive relationship, which was perhaps a consequence of supply and utilization of nitrogen. It is concluded that climatic factors affecting yield to quali- ty ration in wheat may be excessive rains before heading and high temperature during grain filling. Interaction between weather and nitrogen are discussed to optimize correct timing of nitrogen fertilization for amount and quality of economic wheat yield. Index words: Spring wheat, climatic factors, grain yield, protein content Introduction The wheat processing industry needs high quality wheat for milling. The flour mills in Finland have, however, limited access to im- ported high quality wheat to compensate crop of poor technological quality. There was lit- tle annual variation in protein content of wheat grain before 1974 (Suomela et ai. 1977), however since 1974 there has been a de- crease in the protein content. An explanation for this could be increased cultivation of late high-yielding wheat varieties. However, the ef- fect of the choice of wheat variety on the de- crease in protein content was only 0.5—0.6 % and does not alone explain the declining trend in protein amount (Juuri 1985). Another factor causing the decrease in pro- tein content may be weather conditions dur- ing the growing season. Excessive rains in June has been observed to decrease grain pro- tein content (Rekunen and Juuri, unpub- 227 JOURNAL OF AGRICULTURAL SCIENCE IN FINLAND https://www.c-info.fi/en/info/?token=mzXbDRX4FTC54VAP.UKpJV64h3mcq4ct0rB0Jzw.v9ObjcyfJwHjAzFUxY3UKDyYoTrCT3CSsjcR6zhmWelaNhZOClTet-jwiy0eu1zusgt2DvKWeF8VuwFQbGHdKtRyRuKzRc3CZTeNIQToJvYq_8Ffq-s0uJD45S0OlSn5efCJaxobMoxiYmDrUNZqNQ-XYaHl-SncbpYAVa7-Yyh4Sy38VJedNdPtRnvCrHct8B18KMXJVBSOVw lished data), however, according to Kontto- ri (1979) sufficient rainfall and high radiation during early summer seemed to increase pro- tein content. This may be attributed to better uptake of nitrogen by wheat (Kaila and Elo- nen 1970). Rain during harvesting activates enzymes that split starch and proteins, but the protein quality only decreases when sprouting of the ear is advanced (Lallukka 1971). The effect of climatic factors on the yield of wheat has been studied by many research- ers in 1960—1970’s (e.g. Lipsett 1963,Asana and Williams 1965, Stoy 1966, Campbell and Read 1968, Lallukka 1971, Peters et al. 1971, Bremner 1972, Horhikawa ref. Evans et al. 1975, Kontturi 1979), but the role of weather in the yield quantity quality ratio in spring wheat has not yet been carried out un- der northern growing conditions. The object of the present study was to evaluate the role of climatic factors in the relationship between wheat quantity and quality. Material and methods Test material The study period covered the years from 1968 to 1988. The material was cultivated at Tammisto 1968—72 and Anttila 1973—88, at experimental farms of Hankkija Plant Breeding Institute. Both are located in South- ern Finland, some 20 km apart, at latitudes 60° 16' N, and 60° 25' N, respectively. Test varieties used were; ‘Ulla’ and ‘Heta’ with growing time less than 100 days; and late cul- tivars ‘Ruso’, ‘Kadett’, ‘Drabant’, and ‘Tähti’ which need over 100 days to ripe. ‘Ulla’ and ‘Heta’ are characterized as low yielding varieties with high protein content, while ‘Drabant’ and ‘Kadett’ are cultivars of high yield potential, but low protein content lower than the average for wheat varieties of Finnish origin (Mustonen et ai. 1987). Data of the spring wheat varieties in official trials are given in Table 1. The soil type was predominantly sandy clay. Fertilization was applied according to analysis of soil nutrient status: 50 kg N/ha in 1968, 60 kg N/ha in 1969, 90 kg N/ha in 1970, and during 1971 1988 the standard nitrogen application was 110 kg N per hectare. Plot-based observations were made for the days to heading, at growth stage (GS) 54 (Zadoks et al. 1974) and days to yellow ripeness (GS 85). The plots were con- sidered to be fully ripened (GS 91) 5—7 days after the yellow ripeness. This was dependent on daily temperature after yellow maturation. Grain yield and thousand grain weight were measured from harvested yield. The protein content was determined by using the common Kjeldahl procedure and multiplied by nitro- gen conversion factor of 5.7. From 1983 Near Infrared Reflectance (NIR) analyser was used to measuring the protein content. Wet gluten content was used to estimate the quantity of storage protein. Measured grain yield and quality are given in Table 2. Table 1. Data of spring wheat varieties in the results of official trials in Finland 1979—1986 (Mustonen et ai. 1987). Variety Ruso Ulla Heta Tähti Drabant Kadett Breeder Hja Hja Hja Jo WW WW Year of release 1967 1975 1988 1972 1972 1981 Days to ripeness 102 98 99 109 108 106 Grain yield (kg/ha) 3768 3403 3693 3559 3931 4068 1000 grain weight (g) 37.2 35.2 34.0 34,3 35.2 36.6 Protein (Vo) 14.0 15.9 15.9 14.7 13.2 13.4 Hja = Hankkija Plant Breeding Institute, Finland Jo = Plant Breeding Institute of the Agricultural Research Centre, Jokioinen, Finland WW = Weibullsholm Plant Breeding Institute, Sweden 228 Table 2. Data of grain yield, protein content, and wet gluten amount in examined wheat varieties in study period 1968—88. Year Variety Ruso Tähti Ulla Drabant Heta Kadett 1968 a 5450 5360 b 15.8 17.8 1969 a 4950 4670 b 13.8 14.6 1970 a 2700 2250 b 17.8 17.9 1971 a 4350 4900 b 14.1 16.2 1972 a 5180 5010 b 11.2 11.6 1973 a 3520 3680 b 15.3 16.4 1974 a 5630 6250 b 17.5 17.4 1975 a 3380 4380 b 13.8 15.9 1976 a 5180 5260 b • 1977 a 2550 2910 b 11.8 13.4 1978 a 4450 3960 b 12.8 12.0 1979 a 2530 2450 b 9.5 10.3 1980 a 4180 4450 b 10.7 10.6 1981 a 2630 1910 b 10.5 11.1 c 19.0 22.5 1982 a 3570 4760 b 14.3 15.3 c 35.9 37.0 1983 a 4550 3660 b 11.9 14.3 c 25.3 34.4 1984 a 4460 3740 b 11.3 12.7 c 27.8 27.2 1985 a 3530 4110 b 14.3 12.7 c 34.4 31.8 1986 a 3520 3250 b 10.8 11.2 c 23.4 31,4 1987 a 3380 2460 b 11.0 10.7 c 0.0 0.0 1988 a 2960 2910 b 10.1 10.8 c 19.7 22.4 2180 19.6 4300 16.0 4280 13.5 3340 18.2 4800 6760 18.315.2 3990 4890 16.314.4 6000 6620 * * 3350 2510 3570 4630 13.212.1 14.612.6 4500 4910 4220 5610 15.011.5 15.012.0 3380 3070 3560 5000 12.110.5 10.111.6 4950 5330 4820 5170 11.010.2 14.210.3 2430 2230 2900 2770 11.19.5 11.68.8 23.219.8 27.817.9 4420 5330 4250 4880 15.413.2 14.813.3 35.629.5 38.729.1 4510 4640 4100 5550 12.111.0 13.511.9 25.322.8 34.326.2 3920 4640 4070 4870 12.710.0 12.110.6 25.123.0 30.722.3 3040 4340 3270 4060 14.512.4 15.412.7 34.730.0 44.339.8 2800 3590 3460 3670 13.511.0 11.910.2 34.830.8 36.327.5 3470 • 3690 3640 11.8 * 11.29.0 24.7 • 27.90.0 2500 3380 2740 3420 13.09.7 12.39.7 28.721.2 27.520.3 a = grain yield (kg/ha), b = protein %, c = wet gluten % * = result not determined 229 Table 3. The climatic data of air temperature, precipitation, global radiation, and the lenght of growing period in 1968—1988. Year Mean air temp. (°C) Precipit. sum Mean glob, rad. (MJ m-2 ) Lenght of period (d)(mm) SH HR SH HR SH HR SH HR 1968 12.014.9 12.716.3 14.115.9 13.217.2 14.419.6 15.519.4 12.515.2 13.518.3 13.314.7 12.814.5 14.414.9 15.815.8 14.316.8 14.815.3 12.616.8 13.618.4 15.215.5 14.116.2 14.917.3 13.511.5 16.519.4 115 129 93 37 59 128 39 45 19.115.8 20.721.8 22.417.2 21.120.1 21.521.4 22.920.7 20.014.4 21.520.6 19.715.2 17.314.0 21.915.9 22.415.5 19.317.1 19.312.4 19.917.8 18.821.2 20.416.4 19.013.9 21.219.1 19.110.8 22.118.8 65 51 1969 60 45 1970 56 45 1971 56 45 1972 75 94 62 47 81 144 54 27 119 120 152 101 63 122 123 105 246 107 151 172 93 115 110 39 98 107 81 153 59 98 149 215 57 35 1973 53 34 1974 65 57 1975 59 40 1976 60 54 1977 76 43 1978 52 55 1979 57 46 1980 54 47 1981 57 48 1982 64 46 1983 60 41 1984 51 53 1985 53 52 1986 51 41 '987 58 70 1988 44 89 49 33 SH = period between sowing and heading HR = period from heading to yellow ripening Data of climatic factors The basic daily climatic data for each year and locality was obtained from the Finnish Meteorological Institute. The following cli- matic factors were used; mean, maximum, and minimum daily air temperature (°C), precipitation (mm d-1)> and daily global radiation (MJ m-2), measured at the Hel- sinki-Vantaa Airport, located between Tam- misto and Anttila experimental farms. Data given in table 3. The statistical analysis was carried out using regression analysis in order to clarify sig- nificance of individual climatic factor on proportion of grain yield, grain size and pro- tein properties. Results and Discussion individual climatic factors explained poor- ly the variation in grain yield per hectare and grain weight. The coefficient of determina- tions (R 2) between climatic factors and both grain yield and grain weight ranged 0.01 0.25, and 0.02—0.27, respectively (Table 4). Grain yield is the end-result of interaction of climatic factors and several plant characteris- tics (Miedema 1984). Thus any individual fac- tor does not necessarily explain such a com- plex system as yield. The coefficient of determination (R 2 ) be- tween protein yield per hectare and minimum air temperature after sowing was 0.53 for early maturing varieties, and 0.51 for late matur- ing varieties, respectively. The lower the mini- mum air temperature was, the higher was the protein yield per hectare (Fig. 1). Nitrogen absorption from the soil depends on soil moisture content (e.g. Kaila and Elo- nen 1970, 1971,Elonen et ai. 1975). Accord- ing to figure 2a, it seemed that excessive rains before heading caused leaching of nitrogen which was followed the decrease in gluten con- 230 Table 4. Coefficient of determination (R2 ) in climatic data versus grain yield, thousand grain weight, protein con- tent, protein yield, and wet gluten content in study period 1968—88. Grain yield 1000 grain Protein Protein Wet gluten (kg/ha) weight content yield (%) (g) (%) (kg/ha) Average air temperature (°C) SH e 0.20 0.17 0.14 0.31 0.11 1 0.20 0.17 0.32 0.38 0.02 HR e 0.05 0.17 0.05 0.05 0.13 1 0.06 0.11 0.08 0.08 0.76 Average min. air temperature (°C) SH e 0.19 0.27 0.44 0.53 0.20 I 0.25 0.24 0.50 0.51 0.05 HR e 0.21 0.20 0.07 0.19 0.14 1 0.06 0.11 0.08 0.08 0.72 Average max. air temperature (°C) SH e 0.14 0.05 0.08 0.21 0.09 1 0.14 0.08 0.20 0.28 0.00 HR e 0.04 0.18 0.07 0.06 0.16 1 0.07 0.10 0.06 0.08 0.79 Precipitation sum (mm) SH e 0.10 0.05 0.28 0.04 0.42 1 0.01 0.17 0.12 0.07 0.54 HR e 0.08 0.03 0.05 0,12 0.13 1 0.06 0.04 0.06 0.04 0.55 Average global radiation (MJ m~2 ) SH e 0.10 0.02 0.04 0.07 0.02 1 0.13 0,10 0.02 0.10 0.02 HR e 0.03 0.08 0.09 0.10 0.13 1 0.09 0.10 0.06 0.05 0.54 SH = period between sowing and heading HR = period from heading to yellow ripening e = early maturing varieties, 1 = late maturing varieties tent. When total precipitation exceeded 130— 140 mm, the gluten content decreased to be- low 25 %, and thus below that regular from bread wheat quality (Salovaara 1983). The heavy rains during grain filling contributes the decrease in wet gluten amount, too (Fig. 2b). Rain fall under 50 mm before heading may cause the same type decrease in wet gluten content (Fig. 2a). The reason for this was per- haps that in dry soils the uptake of nitrogen was decreased (Kaila and Elonen 1971). The mean daily temperature during grain filling was below 20°C for the whole study period (Table 3). The optimum daily mean temperature for gluten formation appeared to be some 15—17°C in all wheat varieties (Fig. 3). The wet gluten amount decreased if daily minimum and maximum temperatures exceeded 11—12°C and 21 —22°C, respec- tively (data not shown). Temperatures ex- ceeding 25—30°C have been found to cause decreases in grain yield and grain size (e.g. Asana and Williams 1965,Peters et al. 1971 and Hoshikawa ref. Evans et al. 1975). Ac- cording to Lawlor et al. (1988), the high temperature decreases protein synthesis more 231 than it decreases carbon assimilation. It is con- cluded that high temperature during grain filling affects quantity to quality ratio in wheat. The effect of temperature and precipitation on formation of wet gluten content was not significant in early maturing varieties ‘Ulla’ and ‘Heta’ (cf. Figs. 2 and 3), perhaps due to their better ability to utilize nitrogen effecient- ly and an advantageous weather during grain Fig. 1. The effect of minimum air temperature on protein yield from sowing to heading. Fig. 2a. The effect of precipitation on wet gluten content from sowing to heading. 232 filling. Conversely, the late cultivars (‘Ruso’, ‘Kadett’, ‘Drabant’, ‘Tähti’) were more sus- ceptible to lose their quality in unfavourable growing conditions (cf. data at Table 2, e.g. year 1987). It has been suggested that grain yield and amount of protein in grain have a negative phenotypic relationship in Finnish cultivation conditions (e.g. Konttori 1979). This type of relationship was not, however, observed in Fig. 2b. The effect of precipitation on wet gluten content from heading to ripening. Fig. 3. The effect of mean air temperature on wet gluten content from heading to ripening. 233 our examination (Fig. 4a). The present study showed that there was a strong positive corre- lation between grain yield and protein yield (Fig. 4b). According to Kramer (1979), with- in a wheat genotype the correlation between grain yield and grain protein content can be either close to zero, positive, or negative, de- pending on the level of fertilization. But be- tween genotypes the correlation is strongly negative. It has also been suggested that grain Fig. 4a. Relationship between grain yield and protein content of spring wheat. Fig. 4b. Relationship between grain yield and protein yield of spring wheat. 234 protein content can be used as an indicator to evaluate if nitrogen fertilization was sufficient (Goos et al. 1982 and Goos 1984). Perhaps, supply and utilization of nitrogen by wheat are the main factors changing quantity and qual- ity proportion in wheat and the utilization of nitrogen is dependent of weather e.g. precipi- tation. However, more detailed experimental data is required to understand: the interaction between weather, nitrogen supply and quan- tity and quality of wheat yield. This would lead to a more efficient use of nitrogen in agricultural systems to optimize correct tim- ing of nitrogen supply for amount and quali- ty of economic wheat yield in Finland. References Asana, R.D. & Williams, R.F. 1965.The effect of tem- perature stress on grain development in wheat. Aust. J. agric. Res. 16: I—l 3.1—13. Bremner, P.M. 1972. The accumulation of dry matter and nitrogen by grains in different positions of the wheat ear as influenced by shading and defoliation. Aust. J. biol. Sci. 25: 657—681. Campbell, C.A. & Read, D.W.L. 1968. Influence of air temperature, light intensity and soil moisture on the growth, yield and some growth analysis characteris- ticsof Chinook wheat grown in grown chamber. Can. J. Plant Sci. 48: 299—311. Elonen, P., Rinne, S.L. & Suomela, H. 1975. Influence of irrication and nitrogen fertilization on grain yield and some baking quality characteristics of spring wheat. J. Scient. Agr. Soc. Finl. 47: 166—180. Evans, L.T., Wardlaw, I.F. & Fischer, R.A. 1975. Wheat. In Crop Physiology. Ed. Evans, L.T. Pp. 101 —149. Cabridge. Goos, R.J., Westfall, D.G., Ludwick, A.E. & Goris, J.E. 1982. Grain protein content as an indicator of N sufficiency for winter wheat. Agron. J. 74: 130 —133. Goos, R.J. 1984. Post-harvest evaluation of nitrogen management a new approach for “selling soil test- ing to wheat farmers. J. Agron. Educ. 13: 103—106, Juuti, T. 1985. Kevätvehnä. Siemenjulkaisu, 1985. Hankkijan kasvinjalostuslaitos. Pp. 46—53. (In Finn- ish) Kaila, A. & Elonen, P. 1970. Influence of irrigation and supply of available nitrogen on growth and nutrient content of spring wheat. J. Scient. Agric. Soc. Finl. 42: 205—215. Kaila, A. & Elonen, P. 1971. Effect of irrigation on fer- tilization nitrogen in arable clay soil. Acta Agr. Fenn. 123: 126—135. Konttori, M. 1979. The effect of weather on yield and quality of spring wheat in Finland. Ann. Agric. Fenn, 18: 263—273. Kramer, T. 1979. Environmental and genetic variation for protein content in winter wheat (Triticum aesti- vum L.). Euphytica 28: 209—218. Lallukka, U. 1971. 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Ms received March 26, 1990 235 SELOSTUS Säätekijöiden vaikutus kevätvehnän jyväsadon ja valkuaisen muodostumiseen Jari Peltonen,* Tuomo Karvonen* ja Erkki Kivi** * Helsingin yliopisto, Kasvinviljelytieteen taitos, Viikki, 00710 Helsinki ** Hankkijan kasvinjalosluslailos, 04300 Hyrylä Tutkimuksessa tarkastellaan, 21 vuoden mittaisen jak- son perusteella, säätekijöiden vaikutusta kevätvehnän jy- väsadon ja valkuaisen määrän muodostumiseen. Tutki- musaineistona olivat kevätvehnät: Ulla, Heta, Ruso, Ka- dett, Drabant sekä Tähti peruslannoitetuissa kenttäko- keissa. Yksittäiset säätekijät eivät selittäneet jyväsadon muo- dostusta. Kostean sitkon muodostusta kuitenkin rajoitti alkukesän kuivuus (sade alle 50 mm) tai liiallinen yli 130— 140 mm sade, jonkaseurauksena vehnän typenotto heik- keni. Yli 15—17°C keskilämpötila jyvän täyttymisjaksolla aiheutti vehnäsadon alhaisen sitkopitoisuuden. Sääteki- jät eivät kuitenkaan vaikuttaneet voimakkaasti aikaisin tuleentuviin lajikkeisiin. Kevätvehnän jyväsadon sekä val- kuaissadon välillä oli voimakas positiivinen korrelaatio, mikä osoitti ilmeistä lisätyppilannoituksen tarvetta sellai- sina kasvukausina, jolloin säätekijät vaikeuttavat perus- lannoituksen hyväksikäyttöä. 236