• International Journal of Industrial Entomology and Biomaterials
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• v.10 no.1
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• pp.65-68
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• 2005

Growth and development of a plant over a growing season is closely related to the daily accumulation of heat. Heat unit measured by accumulated growing degree days (GDD) is becoming increasingly popular to estimate the growth of a plant or even in insect. GDD or heat accumulation per day is measured by calculating average daily temperature and then subtracting the base temperature below which growth does not occur. Heat accumulation per day is added for the desired period and accumulated GDD is determined. The present study was conducted in five seasons in an established garden with K-2, S-36 and V-1 mulberry varieties belonging to Morus indica L. grown under completely irrigated condition at the farm of CSRTI, Mysore during 2001 - 2002. Plants were pruned in each season and the growth of the plant measured by total shoot length and fresh leaf yield was recorded at an interval of 5 days starting from 30 days of pruning (DAP) to 70 days when all the plants were pruned. The accumulated GDD for the corresponding days were recorded and used for analysis. Accumulated growing degree days (GDD) have been found to be perfectly correlated with both growth and yield in all the seasons in all the varieties studied. The high $R^2$ values indicated a strong relationship between the accumulated GDD and, growth and yield of mulberry.

• Horticultural Science & Technology
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• v.29 no.6
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• pp.549-554
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• 2011

The effect of full bloom date and growing season weather on harvesting date of 'Niitaka' pear (Pyrus pyrifolia) in Naju province and the model of multiple linear regression for predicting the fruit growing days was studied. Earlier year in full bloom date, the harvesting date tended earlier but fruit growing days tended longer. Mean and coefficient of variation of fruit growing degree days (GDD) accumulated daily mean and maximum temperature at the base of $0^{\circ}C$ from full bloom date to harvesting date was 3,565, 2.9% and 4,463, 2.5%, respectively. Fruit growing days was not correlated with the fruit GDD accumulated daily mean and maximum temperature at the base of $0^{\circ}C$ in each month but highly correlated with GDD accumulated daily meteorological factors at days after full bloom date. Especially, it was highly negatively correlated with GDD accumulated daily mean and maximum temperature at the base of $0^{\circ}C$ from $1^{st}$ day after full bloom to $60^{th}$ day. The determination coefficient ($r^2$) of multiple linear regression model by full bloom date, GDD accumulated daily mean and maximum temperature from $1^{st}$ day after full bloom to $60^{th}$ day for predicting fruit growing days was 0.7212. As a result, the fruit growing days of 'Niitaka' pear in Naju province can predict with 72% accuracy by the model of multiple linear regression.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.2
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• pp.122-125
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• 1990

Pearl millet (Pennisetum americanum (L.) Leeke) has been detected as an excellent and new forage crop in Korea. Thus the objective of the study was to determine optimum planting season, growing degree days and productivity by shifting the planting season of pearl millet. Days to emergence of Australia pearl millet inbred line were shortened from 12 days to 3 days by delaying planting season from April 15 to July 15 in Suwon, 1986, but their growing degree days remained relatively constant 32.1$^{\circ}C$ in average. Days to heading also were shortened from 96 days to 54 days by shifting the planting season, but their growing degree days varied little being 697$^{\circ}C$ in average. For grain crop, economic planting season was from early May to late June, and their harvest index also did not varied much, but suddenly reduced in the July 15 planting plot. For forage crop, economic planting season was from mid-May to mid-June with optimum planting time of mid-May. Particularly, when planted in early July, 1987 and 1988, green fodder yields of Suwon 1 pearl millet hybrid were very low being 54 percent as compared with optimum planting season's yield 10.8t/10a.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.28 no.2
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• pp.173-183
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• 1983

To evaluate growing degree days(GDD) as an index of growth duration of rice plants, 30 days old seedlings of 16 japonica and 14 indica/japonica varieties were transplanted six times from May 10 at the 10-day intervals at Gyeongsan in 1982. The number of days from transplanting to heading decreased as transplanting dates delayed in all japonica varietie and 4 indica/japonica varieties but that of 10 indica/japonica varieties decreased up to June 9 or June 19 transplantings and then it levelled off or increased with further delay of transplanting. However, GDD requirement was similar among transplanting dates at appropriate base temperatures; GDD could be better than calendar day system to classify maturity of varieties especially grown in a wide range of climatic conditions. Required GDD from transplanting to heading of all indica/japonica and early japonica varieties showened a smaller coefficient of variation (CV) compared to longer season japonica varieties. Among GDD methods, an accumulation of daily Max + Min temp./2 -$l0^{\circ}C$ showed the smallest CV for the duration from transplanting to heading, but for ripening period GDD calculated with adjusted maximum temperature when it was higher than $30^{\circ}C$ showed the best results. Heading date did not affect required GDD for maturity of japonica varieties, but in indica/japonica varieties GDD decreased as heading date delayed; at late transplantings ripening period of indica/japonica varieties was less extended compared to japonica varietes due to a decrease in grain weight.

• Proceedings of the Korean Society of Crop Science Conference
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• 2005.04a
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• pp.168-169
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• 2005

• Journal of Climate Change Research
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• v.7 no.4
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• pp.493-498
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• 2016

This study was conducted to investigate the effect of environment factors on full bloom stage and fruit width in four peach cultivars. The average temperature in March was the main factor to determine the date of full bloom in 'Kurakatawase'($-0.6871^*$) and 'Changhowon Hwangdo'($-0.5270^*$). The fruit growth curve after 35 days from full bloom was the double sigmoid shape in 'Changhowon Hwangdo' cultivar. Environmental factors affecting fruit width were mean diurnal range(BIO2) and temperature annual range(BIO 7) in 'Kurakatawase', growing degree days(GDD) after 30 days from full bloom and July precipitation in 'Yumyeong', and annual mean temperature(BIO1), BIO7, and July precipitation in 'Kawanakajima Hakuto'. Of these, major environmental factors affecting fruit width in more than two cultivars were BIO7 and July precipitation.

• Korean Journal of Environmental Agriculture
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• v.35 no.4
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• pp.302-305
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• 2016

BACKGROUND: The northeast district of China, especially Liaoning province, Jilin province, and Heilongjiang province, is one of the largest agricultural production regions in China. These regions play a significant role in ensuring food security. Accumulated temperature such as growing degree days (GDD) is an important environmental factor for plant growth and yield. Therefore, in this study, temporal and spatial distribution of GDD for maize was examined as a basis to estimate the growth and yield of maize in these regions. METHODS AND RESULTS: Meteorological date produced by NASA (MERRA-2) was used to estimate GDD of maize at this study sites. The GDD was calculated from sowing (May 1) to harvesting (Sep. 30). The average GDD of this region between 2010 and 2015 was $1323.0^{\circ}C$ day (595.3-1838.9). The spatial distribution of GDD showed a similar pattern during the different years surveyed. Double cropping for maize could be in only Liaoning province, northwestern Jilin province, and western and eastern Heilongjiang province where the GDD was over $1600^{\circ}C$day. However, The GDD in eastern Heilongjiang province was varied by year. CONCLUSION: The GDD of maize in northeast district of China was varied spatially, but similar among recent six years at the same region. This result can be used to predict growth stage and yield of maize at these regions.

• Proceedings of the Korean Society of Crop Science Conference
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• 1989.02a
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• pp.122-123
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• 1989

• Journal of Ecology and Environment
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• v.33 no.1
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• pp.37-45
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• 2010

I conducted extensive analyses of daily weather data of precipitation and temperature monitored from the Surface Synoptic Meteorological Station in Seoul from 1 October 1907 to 31 December 2009 to understand how the climate is changing and the ecological implications for Seoul, Korea. Statistical analyses of the data, including the lengths of seasons and growing degree-days (GDD), showed a clear warming trend in the Seoul area over the study period. The mean daily temperature in Seoul increased by $2.40^{\circ}C$ over the period of one hundred years, which was about three times faster than the global trend and it was striking to notice that mean daily temperature in Seoul in recent 30 years was increasing with the rate of $5.50^{\circ}C$ per hundred years, which is an extremely fast rate of increase in temperature. In the last 100 years, an increase in the number of summer days was apparent, coupled with a reduction in the average number of winter days for about 27 to 28 days based on the analysis of mean daily temperature. Although the lengths of spring and autumn have not changed significantly over the century, early initiations of spring and late onsets of autumn were quite apparent. Total annual precipitation significantly increased at the rate of 2.67 mm/year over the last 100 years, a trend not apparent if the analysis is confined to periods of 30 to 40 years. The information has the potential to be used not only for better understanding of ecological processes and hydrology in the area, but also for the sustainable management of ecosystems and environment in the region.

• Journal of Bio-Environment Control
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• v.27 no.4
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• pp.424-430
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• 2018

This study was carried out to estimate growth characteristics of hot pepper and to develop predicted models for the production yield based on the growth parameters and climatic elements. Sigmoid regressions for the prediction of growth parameters in terms of fresh and dry weight, plant height, and leaf area were designed with growing degree days (GDD). The biomass and leaf expansion of hot pepper plants were rapidly increased when 1,000 and 941 GDD. The relative growth rate (RGR) of hot pepper based on dry weight was formulated by Gaussian's equation RGR $(dry\;weight)=0.0562+0.0004{\times}DAT-0.00000557{\times}DAT^2$ and the yields of fresh and dry hot pepper at the 112 days after transplanting were estimated 1,387 and 291 kg/10a, respectively. Results indicated that the growth and yield of hot pepper were predicted by potential growth model under plastic tunnel cultivation. Thus, those models need to calibration and validation to estimate the efficacy of prediction yield in hot pepper using supplement a predicting model, which was based on the parameters and climatic elements.