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Unlike edaphic factors, it is difficult to control climatic conditions and their changes that affect plant growth and development. To deal with such posture, farmers have to cultivate their crops at the right time. From this point, over two–year of 2014 and 2015, a field experiment was performed at El-Nubaria region, El-Behaira Governorate, Egypt, to assess the response of sunflower to different combinations between sowing dates (early, mid and delayed) and ascorbic acid treatments (with ascorbic acid and without ascorbic acid). Ascorbic acid was sprayed at 30, 40 and 50 days after sowing. The results showed that sowing sunflower in mid sowing (May 21) achieved the highest values of cumulative heat units utilization efficiency as well as all growth and yield traits, while the lowest values were recorded under the delayed sowing date (June 21). Application of ascorbic acid was effective for promoting growth and yield traits under all studied sowing dates. Ascorbic acid achieved 11.6, 10.1, 10.7 and 12.9% increases under early sowing, and 9.5, 6.6, 8.6 and 10.3% increases under delayed sowing in head diameter, seed weight plant−1, seed yield and oil yield, respectively. Comparing to mid sowing × without ascorbic acid, application of ascorbic acid alleviated seed yield losses associated early sowing from 15.7–6.6% and from 23.0–16.4% with delayed one. In conclusion, for remediating the thermal stressful impacts of early or late sowing of sunflower, farmers are advised to treat crop plants with ascorbic acid to avoid yield losses.

Haden, Kent, Palmer, and Keitt mango varieties were studied to establish the relationship of harvest time to 1) seasonal accumulated day-degrees or heat units (˚C), 2) daily rainfall amount (mm), and 3) physical fruit development attributes in order to fix maturity standards for export and local markets. Randomized Complete Block Design with four replications was used. In each case of Haden, Kent, Palmer, and Keitt varieties, physical fruit development attributes established as standard harvest maturity values were: weight (640 g, 836 g, 837 g, and 1104 g, respectively), length (16.31 cm, 16.19 cm, 21.22 cm, and 19 cm, respectively), width (30.97 cm, 33.47 cm, 30.86 cm, and 35.91 cm, respectively), volume (598 cm3, 807 cm3, 772 cm3, and 959 cm3, respectively), density (1.147 g/cm3, 1.076 g/cm3, 1.084 g/cm3, and 1.189 g/cm3, respectively), and indentation (0.25 cm, 0.49 cm, and 0.50 cm, respectively). The intensity of grooves around the stylar-scar end of Palmer fruits was studied and used as maturity index. Index values of 0.075 mls, 0.150 mls, 0.425 mls, and 0.116 mls, respectively, for Haden, Kent, Palmer, and Keitt varieties were recorded as latex exuded at harvest since these values tallied with the other physical harvest maturity index values, and also with those of rain fall and temperature values. Temperature, rainfall, and physical characteristics are therefore important non-destructive criteria for fixing maturity index values for mango fruits.

Buah naga merah adalah buah non klimakterik dengan lintasan fotosintesis crassulacean acid metabolism. Kematangan optimum ditandai dengan warna kulit buah merah 100%. Tujuan percobaan adalah mempelajari perubahan warna kulit terkait dengan kesegaran dan daya simpan buah naga merah untuk menentukan kriteria panen optimum. Bahan percobaan disiapkan di kebun Sabisa Farm, Sindang Barang, Bogor (60 35’ 16” LS, 1060 46’ BT; elevasi 219 m di atas permukaan laut). Percobaan menggunakan rancangan kelompok lengkap teracak dengan perlakuan 5 taraf umur panen, yaitu 30, 32, 34, 36, dan 38 hari setelah antesis (HSA) dengan 5 ulangan. Hasil percobaan menunjukkan bahwa kulit buah naga merah 30 HSA memiliki skala warna 2 (1-25% merah), buah 32 HSA memiliki skala warna 4 (26-50% merah), dan buah 34, 36, dan 38 HSA telah mencapai skala warna 6 (100% merah) ketika dipanen. Kulit buah 30 HSA memerlukan waktu 6 hari setelah panen (HSP) dan buah 32 HSA memerlukan waktu 3 HSP untuk mencapai warna merah 100%. Pada saat warna merah 100%, buah 30 - 38 HSA memiliki kandungan padatan terlarut total 11.7 hingga 13.5 oBrix yang masih memenuhi standard pemasaran buah naga sebesar 11.0 oBrix. Kandungan asam tertitrasi total menurun, tetapi kandungan vitamin C meningkat dengan meningkatnya umur panen. Kata kunci: CAM, kematangan pascapanen, kesegaran buah, satuan panas, tanaman hari-panjang

Waktu panen dapat berpengaruh terhadap umur simpan dan kualitas buah selama penyimpanan, sehingga dibutuhkan metode yang tepat dalam menentukan kriteria panen. Percobaan ni bertujuan untuk mengoptimasi akumulasi satuan panas sebagai kriteria panen pisang Barangan dan pengaruhnya terhadap kualitas buah. Percobaan dilakukan di PTPN VIII Parakan Salak, Sukabumi, Jawa Barat pada Oktober 2018 hingga Februari 2019 dengan menggunakan Rancangan Acak Kelompok (RAK) faktor tunggal dengan perlakuan lima waktu antesis. Antesis 1 (13 Oktober 2018), antesis 2 (20 Oktober 2018), antesis 3 (27 Oktober 2018), antesis 4 (3 November 2018) antesis 5 (10 November 2018). Hasil penelitian menunjukkan bahwa satuan panas 1 234.50±2.76 0C hari dapat digunakan sebagai kriteria panen pisang Barangan dengan umur panen 72 -73 HSA dan umur simpan 16-17 hari. Waktu antesis tidak berpengaruh terhadap ukuran buah saat dipanen, umur simpan, susut bobot, kualitas fisik dan kualitas kimia buah. Kata kunci: kualitas buah, kematangan, umur simpan, suhu, susut bobot

‘Yu Her Pau’ is one of the most dominant litchi (Litchi chinensis Sonn.) cultivars grown in Taiwan and China. However, the extremely large inflorescences often result in the production of early- and late- flowering female flowers (“two-sequence inflorescence”), thereby leading to the production of late-maturing fruit within the same cluster. This asynchronous maturity, often being regarded as a nuisance by growers and the impact of this trait requires further clarity. To document the alteration of growth and characteristics of fruits that mature asynchronously inside a cluster, 10-year-old field grown plants were used in the present study. Four categories of fruit: early- or late-maturing fruit in the presence of single cluster; and early- or late-maturing fruit in the presence of two-sequence cluster on trees were selected. The fruit growth curves and patterns, liquid endosperm retention in the embryo sac, primary (apparent) sink strength quantity and harvested quality were analyzed. The accumulated heat unit from fruit set to maturity was estimated. Flowering dates were noted to be three weeks apart, whereas harvest dates were noted to be only one week apart between the early- and late-maturing fruit because of the two-week longer maturity period of the early-maturing fruit. All categories of fruit exhibited single sigmoid curve and have commercial value at harvest. Early-maturing fruit from the early-maturing two-sequence inflorescence were approximately 50% heavier and matured two weeks earlier than the late-maturing fruit and exhibited significantly higher quality. The larger fruit from the early-maturing two-sequence clusters was associated with smaller seeds, higher absolute and relative fruit growth rates, longer fruit development periods in response to lower air temperatures pertaining at that time, greater primary sink strength quantity, longer retention of liquid endosperm, and higher accumulated heat units that were amassed during the pulp growth stage. In the meantime, the earlier dissipating of liquid endosperm in late-maturing fruit and in early-maturing two-sequence fruit was associated with decreased seed size. Late-maturing fruit in two-sequence clusters increased the primary sink strength quantity of early-maturing fruit in the same cluster. The results from our research should prompt a re-assessment of the physiological significance of the second-sequence of female flowers in litchi cultivars with extremely large inflorescence.

Flower bud development of apricot cultivars can be studied during dormancy period by different methods (forcing of shoots, measuring of bud weight and water content, observing of pistil elongation, study of microsporogenesis). In our 24-year experiment, the phenological process of microsporogenesis of three apricot cultivars ('Cegledi biborkajszi', 'Gonci magyar kajszi' and 'Rozsakajszi C.1406') was studied. We could find great differences in the process of microsporogenesis between three cultivars and between years as well. During this long-term period, the string stage (end of endodormancy) occurred gradually later (more than half a day later per year), but tetrad stage and blooming time occurred gradually earlier. As a trend of 24 years, tetrad stage shifted 8–19 days earlier, and the beginning of blooming time is 3 days earlier. The reason for the observed trends is probably due to the regional warming of the climate, which has a strong effect in the Carpathian Basin. Because of regional warming, winters are getting milder at our site as well. In the milder winters, it takes longer time to collect the necessary chilling units, thus the end of endodormancy occurs later. But the heat unit accumulation is faster during ecodormancy, which means that the phenological processes are accelerated and blooming occurs earlier.

A halofita Salicornia neei Lag. apresenta ciclo de vida perene e elevada tolerância a salinidade intersticial. Este trabalho objetivou caracterizar a fenologia e as exigencias termicas da Salicornia neei Lag. cultivada no semiarido cearense. O monitoramento ocorreu em area de cultivo de 200 m 2 em Ocara-CE, semiarido cearense. Foram marcadas 20 plantas aleatoriamente (10 femininas e 10 masculinas), e irrigadas uma vez ao dia por 30 minutos. Foram observadas as fenofases de enfolhamento, queda foliar, floracao e frutificacao, no periodo de junho de 2014 a maio de 2015. O enfolhamento predominou durante todo o periodo monitorado, e apresentou uma baixa intensidade de queda foliar. A floracao ocorreu de setembro de 2014 a marco de 2015, e a frutificacao ocorreu de setembro de 2014 ate abril de 2015. Os resultados indicaram que a energia exigida por S. neei desde a marcacao da planta ate a flor em antese foi de 1.139,2 unidades de calor (UC). Para a frutificacao, a partir da flor em antese ate o estadio de fruto maduro foi de 1.282,4 UC. Conclui-se que a S. neei teve uma boa adaptacao ao semiarido, alcancando todas as fenofases de seu ciclo perene, com uma irrigacao diaria. A falta de sincronia na floracao e frutificacao dificulta a colheita das plantas quando maduras, podendo induzir a erros, levando a uma subestimativa na producao de flores e frutos quando estimadas. A B S T R A C T The Halophyte Salicornia neei Lag. features perennial life cycle and high tolerance to salinity of interstitial. This work aimed to characterize the phenology and the thermal requirements of Salicornia neei Lag. grown in the semiarid. The monitoring occurred in growing area of 200 m 2 in Ocara-CE, Ceara semiarid. 20 plants were marked at random (10 female and 10 male), and irrigated once a day for 30 minutes. Observed the phenophases of leafiness, fall foliage, flowering and fruiting in the period June 2014 to May 2015. The leafiness prevailed throughout the period monitored, and presented a low intensity of leaf fall.Flowering occurred September 2014 and March 2015, and fruiting occurred September 2014 until April 2015. The results indicated that the energy required by S. neei since marking of the plant until the flower anthesis was 1,139.2 heat units (HU). For the fruiting, from the flower anthesis until the mature fruit stage was of 1,282.4 HU.It is concluded that S. neei had a good adaptation to the semi-arid, reaching all the phenophases of your perennial cycle, with a daily irrigation. The lack of synchrony on flowering and fruiting difficult to harvest plants when mature, and may induce errors, leading to an underestimate in the production of flowers and fruit when estimated. Keywords: Phenophase, halophytic vegetation, salinity

Budbreak is one of the most observed and studied phenological phases in perennial plants. Two dimensions of exposure to temperature are generally used to model budbreak: accumulation of time spent at low temperatures (chilling); and accumulation of heat units (forcing). These two effects have a well-established negative correlation: the more chilling, the less forcing required for budbreak. Furthermore, temperate plant species are assumed to vary in amount of chilling required to complete endodormancy and begin the transition to breaking bud. Still, prediction of budbreak remains a challenge. The present work demonstrates across a wide range of species how bud cold hardiness must be accounted for to study dormancy and accurately predict time to budbreak. Cold hardiness defines the path length to budbreak, meaning the difference between the cold hardiness buds attain during the winter, and the cold hardiness at which deacclimated buds are predicted to open. This distance varies among species and throughout winter within a species. Increases in rate of cold hardiness loss (deacclimation) measured throughout winter show that chilling controls deacclimation potential – the proportion of the maximum rate response attained at high chill accumulation – which has a sigmoid relationship to chilling accumulation. For forcing, rates of deacclimation increase non-linearly in response to temperature. Comparisons of deacclimation potential show a dormancy progresses similarly for all species. This observation suggests that comparisons of physiologic and genetic control of dormancy requires an understanding of cold hardiness dynamics and the necessity for an update of the framework for studying dormancy and its effects on spring phenology.

Artificial lighting given in plant-factory planting system is inseparable from uniformity problem. Spatial variation in the catch of light (radiation) will occur due to the position of the plant against the lamp. The purpose of this research was; a) to determine the relationship between biomass growth and the intensity of artificial irradiation in plant-factory systems, and b) to apply the mechanical model of plant growth based on radiation interception and temperature. Six boxes containing red spinach plants were placed on plant factory system in the form of two racks (each rack is placed 3 boxes). In each box, intercepted light was measured and then converted to radiation value. The air temperature in plant-factory space was measured during growth to harvest. Observations showed that there was a difference in light interception in plantfactory growing spaces that caused variations in plant biomass growth. Mathematical models were used to predict the relationship between light interception and biomass growth. This research concludes that the variation of light occurring in plant-factory planting cannot be ignored, as this leads to markedly different plant-end biomass differences. Modeling can be applied to design optimal lighting to improve plant biomass. Abstrak Pencahayaan buatan yang diberikan dalam sistem penanaman dalam ruang (plant factory) tidak terlepas dari masalah keseragaman. Variasi spasial dalam tangkapan cahaya (radiasi) akan terjadi karena posisi tanaman terhadap lampu. Tujuan dari penelitian ini adalah; a) untuk mengetahui hubungan antara pertumbuhan biomassa dan intensitas penyinaran buatan dalam sistem plant-factory, dan b) menerapkan model mekanik pertumbuhan tanaman berdasarkan intersepsi radiasi dan temperatur. Enam buah kotak berisi tanaman bayam merah diletakkan pada sistem plant factory berupa dua buah rak (masing-masing rak ditempatkan 3 buah kotak). Pada masing-masing kotak diukur cahaya terintersepsi yang kemudian dikonversi menjadi nilai radiasi. Suhu udara dalam ruang plant-factory diukur selama pertumbuhan hingga panen. Pengamatan menunjukkan bahwa dalam ruang tumbuh plant-factory terdapat perbedaan intersepsi cahaya yang menyebabkan adanya variasi pada pertumbuhan biomassa tanaman. Model matematika digunakan untuk memprediksi hubungan antara intersepsi cahaya dan pertumbuhan biomassa. Kesimpulan menunjukkan bahwa variasi cahaya yang terjadi dalam penanaman sistem plant-factory tidak dapat diabaikan, karena menyebabkan terjadinya perbedaan biomassa akhir tanaman yang cukup tajam. Permodelan dapat diterapkan untuk merancang pemberian cahaya yang optimal untuk meningkatkan biomassa tanaman.

The method for determining the appropriate time to harvest banana could affect the shelf life and quality of banana fruits during storage. The objectives of this study were to establish the heat unit as harvesting criteria of banana “Mas Kirana” and to evaluate how heat unit affects fruit shelf life and postharvest maturity characteristics. The research was conducted at PTPN VIII Parakansalak Plantation, Sukabumi, West Java, Indonesia, in November 2017 to February 2018. Laboratory analysis was conducted in Postharvest Laboratory, Department of Agronomy and Horticulture IPB in February to April 2018. The experiment was organized in a completely randomized design with a single factor of eight different flower tagging times after anthesis. Each treatment was replicated five times totaling 40 experimental units. The results showed that the different times of anthesis did not affect fruit size, weight per hand, number of fruits per hand and weight per fruit. Different time of anthesis did not affect respiration rate, fruit shelf life, physical and chemical quality. The minimum heat unit of 650ºC degree days can be used as harvesting criteria for banana “Mas Kirana”. The number of day after anthesis was 39 to 43 with fruit shelf life of 12 to 16 days.

Purpose: This study was conducted at Crop Physiology and Ecology Department, Hajee Mohammad Danesh Science and Technology University, Dinajpur to identify phenology, growing degree days, phenothermal index and heat use efficiency of wheat genotypes in response to heat stress.Research Method: Eight wheat genotypes viz., Pavon-76, Prodip, BARI Gom-25, BARI Gom-26, BAW-1143, BAW-1146, BAW-1147 and BAW-118 were used and seeding them at November 27 (normal), December 17 (late) and January 7 (very late growing condition) over two successive years of 2011-12 and 2012-13. The experiment was laid out in a split plot design and main plot treatments were sowing time and sub plot design was wheat genotypes.Findings: The number of days for attaining different phenological stages, the requirement of heat unit (GDD), phenothermal index (PTI) and heat use efficiency (HUE) was higher for normal growing condition compared to late and very late growing condition and higher in heat tolerant genotypes than the heat sensitive genotypes in each sowings of every year. The heat tolerant (HT) genotype BAW-1143 needed highest number of days whereas, HS genotype Pavon-76 required the lowest number of days for attaining all the phenological stages .Under normal growing condition, HT genotype BAW-1143 had the significantly highest HUE (2.22 and 2.37 for first and second year, respectively). But HS genotype Pavon-76 had the lowest HUE (1.71 and 2.16 for first and second year, respectively).Limitations: The limitations of the research are apparent to the fact that it was done in a single location.Originality/Value: This research helps the researcher to identify heat tolerance genotypes for further investigation.

During cold seasons, in order to ensure good plant growth, the internal temperature of greenhouses is kept within certain levels. However, this causes increased heating costs due to the increase in global energy price. Thus, greenhouse growers prefer unheated production in the Mediterranean Region with a mild climate. In order to have a high quality yield, greenhouses should be heated when average daily temperature drops below 12°C. Due to today's continuous increase of energy costs, greenhouse insulation and minimizing heating requirements are equally important as heating itself. Heating energy requirements in greenhouses are calculated based on the average daily temperature which leads to errors in determining the actual heat requirements. In order to calculate more accurate heating requirements, the calculation should be based on hourly climate data. The aim of this study is to calculate the heat energy requirements as well as the energy that can be saved. The technical approach utilized "long-period mean hourly temperatures, radiation and wind speed values". The study was carried out for greenhouses having different types of cladding material in Mersin (Turkey) in the Eastern Mediterranean Region where intensive greenhouse production exists. © 2017 ISHS.

Olive phenology is a sensitive indicator of climate change and especially the climatic warming of areas where olives are grown. Flowering occurs after being exposed to chilling and subsequent accumulation. The Mediterranean region is characterized by a changeable climate, especially in spring when temperature varies quickly from year to year. In this context, a study was carried out on local ('Meski' and 'Chemlali') and foreign ('Picholine' and 'Koroneiki') olive cultivars grown in southern Tunisia to calculate the heat requirements for flowering during the period 2008-2012. The aim of the present work is to compare flowering full bloom dates for the different cultivars and to calculate the heat requirement until flowering. Heat units were expressed in growing degree day (GDD). For the GDD accumulation, the results indicated a large inter-annual variation. The GDD began being recorded when the calculations of chilling accumulation were stopped. There were differences in flowering dates among cultivars. During the springs of 2008, 2009 and 2010, 'Chemlali' began blooming on 16 April, just after accumulation of 173.85, 100.7 and 160.65 GDD after the end of chilling respectively. 'Koroneiki' was in full bloom on 12 April in 2010-2011 after accumulation of 133.33 GDD. For the year 2011-2012, 'Meski' entered to bloom on 12 April after accumulation of 182.56 GDD while the other cultivars entered into bloom after receiving heat requirements ranging between 169.45 and 267.6 GDD.

OAC Bruton is an indeterminate large-seeded food-grade soybean [Glycine max (L.) Merr.] cultivar with high yield potential, high seed protein concentration, and resistance to soybean cyst nematode (SCN). OAC Bruton is developed and recommended for soybean growing areas in southwestern Ontario with 2950 or greater crop heat units. OAC Bruton is classified as a maturity group 1 (MG1) cultivar with a relative maturity of 1.8.

OAC Ramsay is an indeterminate large-seeded food-grade soybean [Glycine max (L.) Merr.] cultivar with high yield potential, high seed protein and oil concentrations, and resistance to soybean cyst nematode. OAC Ramsay is developed and recommended for soybean growing areas in southwestern Ontario with 3050 or greater crop heat units and has a relative maturity of 2.2 (MG 2.2).

Chili peppers are widely used in many cuisines all around the world for enhancing dishes hotness. For this reason, a fast, reliable, non-destructive and not-invasive method is needed to measure and control the content of hotness in red chili peppers could be quite useful in respect of their use. Visible - Near InfraRed Spectroscopy (Vis-NIRS) fits well this purpose. The work explores the possible utilization of a portable spectroradiometer, to evaluate the spiciness of dried red chili peppers, along others important properties such as moisture content and ash content. An ASD FieldSpec 4™ Standard-Res able to acquire reflectance spectra on “spot” bases in the electromagnetic region (350-2500 nm) was utilized to reach this goal. Different specimen of ground dried chili peppers (i.e. powder) and crushed dried chili peppers, of different characteristics, were analyzed. The collected spectra have been correlated with the pungency, reported in Scoville Heat Units (SHU), of the powder and crushed samples. To reach these goals, a chemometric approach, finalized to set up Partial Least Square (PLS) regression models able to predict red chili peppers characteristics (i.e. ash content, moisture and SHU) was preliminary applied, then a Partial Least Square - Discriminant Analysis (PLS-DA) classification model was calibrated and validated by using reflectance spectra in order to specifically recognize the pungency of the examined samples. Results have been framed in a proximity sensing perspective and in a “on-line” food quality control logic.

Breeding for capsaicinoid content is one of the major objectives for chile pepper breeding programs due to its culinary, agricultural, and medicinal uses. The objectives of the current study were to determine the Scoville Heat Units (SHU) of select New Mexico State University (NMSU) chile pepper varieties and ‘superhot’ genotypes using high-performance liquid chromatography, and to verify the feasibility of using capsaicinoid content as a taxonomic indicator for the ‘superhot’ varieties. Significant variation (P

Determining of the harvest of onion in the peat soil can be done by using physiological harvest criteria, but calculating the appropriate of harvest time can support the quality of harvesting of the onion plant. This study was conducted by using polybags in research and experiment gardens of the Faculty of Agriculture and Forestry of the University of Muhammadiyah Palangkaraya from April to June in 2016. The given fertilization was an organic fertilizer in peat soil by using stall fertilizer like chicken feces with dosages of 15-30 tons ha-1 (PK) and bokashi of stall fertilizer of chicken feces with a dosage of 2-5 tons ha-1 (BK). The observation was done to the calculation of daily temperature (�C), the average of daily temperature (�C), and the unit of heat (heat unit) (�C day) as long as the cultivation of onion plant. The results showed that the harvest time that appropriate to the harvest physiological criteria in the treatment of BK at the age of 57 days after planting is relatively accurate and appropriate because it has a heating unit for 947,17oC day, and the harvest time that appropriate to the harvest physiological criteria of PK treatment at the age of 59 days after planting is relatively late because it has a heating unit for 978,09oC day.

Se analizaron cinco genotipos de amaranto; cuatro de la especie Amaranthus hypochondriacus L.,153-5-3, 655, 653 y Criollo Tlaxcala y uno de la especie Amaranthus cruentus L., 33 en cuatro ambientes, contrastantes en clima y topografía ubicados en el norte de México. Los estudios se efectuaron entre el 15 de agosto de 2000 y el 15 de noviembre de 2002. El objetivo del presente trabajo fue: determinar la interacción genotipo por ambiente (A x G) en el requerimiento de unidades (UC) calor en el desarrollo fenológico del cultivo y el rendimiento de grano (RG). Se utilizó un diseño experimental de bloques completos al azar con tres repeticiones para diferentes ambientes. Los resultados indican que para MC (Madurez comercial), Criollo Tlaxcala de A. hypochondriacus fue el de mayor requerimiento con 977 UC en el ambiente A1, en A2; 655, 33,653 presentaron comportamientos estadísticos similares con un requerimiento de 1475 UC cada uno, superando a Criollo Tlaxcala y 153-5-3 que requirieron de 1133 y 1473 UC, en A3 Criollo Tlaxcala fue el de menor requerimiento con 1384 UC, los demás genotipos estadísticamente fueron similares en el requerimiento de UC en promedio con 1568, para A4 los genotipos en estudio presentaron requerimientos en promedio de 315 UC. Los genotipos de mayor RG (p< 0.05) fueron 153-5-3 de A. hypochondriacus en el ambiente A1 con 2144 kg ha-1, en los ambientes A2 y A3 el genotipo 33 con 1637 y 1283 kg ha- 1, para A4 los genotipos 153-5-3 y 653 con y 1539 y 1562 kg ha-1 respectivamente.

An integral model was developed to compute the growing degree-days easily and rapidly.The model was applied to about 12,000 meteorological stations worldwide.The developed model was found to have excellent fit with the original method.The model is available for all readers as two module-free excel workbooks (attached). The concept of heat units is used in several phenological studies like the prediction of sowing and harvesting dates, crop yield, length of plant stages, and maturity state. However, calculation of heat units as growing degree-days requires a summation process that is not easily performed like direct-substitution equations. The aim of this work was to develop a simple integral model to calculate the heat units as growing degree-days. The development involved two steps; the first step was applying a non-iterative sinusoidal fit to the discrete temperature data to get a fitting equation of each station in the two datasets, CLIMWAT 2 and FAOCLIM 2. The second step was to integrate each temperature equation to calculate the heat units, either by the average temperature or by both the minimum and maximum temperatures. The results showed that the sinusoidal model properly fits the temperature profiles in most of the studied stations (Most of the stations got the fit with R295% and 98.4% of the stations had

A copious quantity of pollen production is desirable from the male parent in hybrid maize (Zea mays L.) seed production. However tassel size and presumably pollen production varies across environments. This research was conducted to better understand if variation in pollen production is due to stress during initiation of specific pollen production components. If component compensation for pollen production occurs, then components that form later should show plasticity with reduced production of earlier formed components. This was also investigated. To conduct such studies, a pollen production measurement technique was devised since current methods do not adequately quantify total pollen produced per tassel. In addition, knowledge of the morphological development of tassel components that lead to pollen production is critical for these studies. Thus tassel morphological development was characterized relative to plant development and heat units. To develop best management practices for high pollen production, a reliable pollen production measurement tool is necessary. A new method was developed involving extraction of pre-shed pollen from tassels through grinding tassels, wet sieving to separate pollen from tassel debris, and counting pollen. This technique compared favorably with other established pollen yield measurement techniques. Benefits of the new technique include the quantification of all pollen produced by a single tassel, a direct count of pollen grains, and a comparatively low CV. This technique is resource intensive compared to other methods. Tassel developmental events leading to pollen production were characterized in relation to plant development and heat unit accumulation in two modern dent inbreds. Tassel initiation occurred from fourth leaf stage, six leaf tips (V4:T6) to V5:T7. Branch meristems appeared promptly after tassel initiation. Pollen mother cells entered meiosis from V9:T14 to V12:T15. In this study the rate of tassel development relative to leaf emergence was the same between inbreds, but the rate of plant development relative to accumulated heat units

There are little information in the scientific literature on flowering and fruiting of ‘Ubá’ mango trees. These information enables to know the proportion of hermaphrodite flowers in inflorescence, fruit set percentage and developmental stages of the fruit. In this study evaluations on inflorescence and fruit development of the ‘Ubá’ mango tree (Mangifera indica L.) were carried out, as well as the determination of the required number of heat units for full fruit development. Thirty branches whose terminal buds were swollen were selected from five mango trees. With the aid of a camera and a caliper, the panicle and fruit development were evaluated weekly until full fruit development. A digital thermometer was used to record ambient temperatures during fruit development in order to estimate the number of heat units required for complete development of the fruits. Male and hermaphrodite flowers of the panicles were also identified and counted. The developmental cycle of ‘Ubá’ mango from the beginning of apical bud swelling to commercial harvest of the fruit lasted 168 days in 2011 and 154 days in 2012. The number of hermaphrodite flowers and the percentage of fruit set in the inflorescence in 2011 were 32.3 and 0.066%, respectively; and 122.1 and 0.099% in 2012, respectively. There was accumulation of 3,173 heat units from flower bud swelling to full development of the ‘Ubá’ mangoes. Resumo Há poucas informações na literatura científica sobre florescimento e frutificação da mangueira ‘Ubá’. Essas informações permitem conhecer a proporção de flores hermafroditas na inflorescência, a porcentagem de fixação e as fases de desenvolvimento do fruto. Neste trabalho, foram realizadas avaliações do desenvolvimento da inflorescência e do fruto da mangueira ‘Ubá’ (Mangifera indica L.), além da determinação do número de unidades térmicas necessário para o completo desenvolvimento do fruto. Foram selecionados 30 ramos de cinco mangueiras, em estádio de intumescimento da gema terminal. Com o auxílio de câmara fotográfica e paquímetro, avaliou-se semanalmente o desenvolvimento da panícula e do fruto até o completo desenvolvimento do mesmo. Com o auxílio de um termômetro digital, registraram-se as temperaturas ambientes durante o desenvolvimento dos frutos, com o objetivo de estimar o número de unidades térmicas necessárias para o completo desenvolvimento dos mesmos. Foram realizadas ainda a contagem e a identificação do número de flores masculinas e hermafroditas das panículas. O ciclo de desenvolvimento da manga ‘Ubá’, desde o início do intumescimento da gema apical até à colheita comercial do fruto, teve a duração de 168 dias em 2011 e 154 dias em 2012. O número de flores hermafroditas e a percentagem de fixação dos frutos na inflorescência no ano de 2011 foram de 32,3 e 0,066%, respectivamente; e em 2012, de 122,1 e 0,099%, respectivamente. Houve acúmulo de 3.173 unidades térmicas a partir do intumescimento da gema floral até ao completo desenvolvimento da manga ‘Ubá’.

Climate change could profoundly affect the status of agricultural insect pests. This study is a predict of the two-spotted spider mite in potato and tomato cops annual generation peaks under current and expected future climate by using the relationship between the accumulated thermal heat units expressed as degree-days unit (DDU) and the population fluctuations. The results indicate the population of the predicate annual generation number and duration of T. urticae of tomato and potato crop under current and expected future climatic changes and their relationship with accumulated thermal units (degree-days units), at Beheira, Bani sweif and Sohag governorates. Under current climate mean generation numbers of T. urticae (10-12 and 12) and mean numbers days per generate (21-19 and 19) and mean degree-days units for T. urticae (170.7- 170.9 and 167.4) at Beheira, Bani sweif and Sohag governorates, respectively were highly recorded compared with expected future climate in 2050s and 2100s. Meanwhile, future predicate in 2050s and 2100s, mean generation numbers (15-17 generation) were highly recorded, but mean degree-days units (165.2-172.3 unit) were highly recorded and days numbers per generate (14-17 days per generate) were less recorded compared with data of current climate, respectively.

Bueckert, R. A., Wagenhoffer, S., Hnatowich, G. and Warkentin, T. D. 2015. Effect of heat and precipitation on pea yield and reproductive performance in the field. Can. J. Plant Sci. 95: 629–639. Pea (Pisum sativum L.) is important globally as a cool season crop. Pea cultivars are heat-sensitive so our goal was to investigate how weather impacted growth and yield in recent cultivars in the Co-operative pea yield trials (2000 to 2009) for a dryland (Saskatoon) and an irrigated (Outlook) location. We explored relationships between days to maturity, days spent in reproductive growth (flowering to maturity), yield and various weather factors. Yield and the length of reproductive growth increased with seasonal precipitation. Pea was sensitive to heat but heat units did not satisfactorily describe growth and yield in all environments. Strong relationships were observed between crop growth and mean maximum daily temperature experienced during reproductive growth, and between crop growth and mean minimum temperature. The greater the mean maximum temperature (>25.5°C), the fewer the number of days (

Chile peppers (Capsicum sp.) are one of the most important spices in the world and a significant vegetable, providing substantial amounts of vitamins A and C. Chile peppers are also used as a medicinal and lachrymator plant because of the characteristic burning sensation they cause when consumed by mammals. This sensation is caused by capsaicinoids that are alkaloids produced in vesicles inside the fruit. A novel class of chile peppers known as “super-hots” having greater than 1 million Scoville heat units have generated much interest. We compared the morphological structure of fruit pericarp and placental tissue of “super-hot” chile peppers to those of jalapeno and bell pepper. Most chile peppers including jalapenos, only produce the capsaicinoids in secreting vesicles found on the placenta. We report on the novel discovery that these “super-hot” chile peppers have developed accessorial vesicles on the pericarp tissue in addition to the vesicles on the placental tissue, thus leading to exceedingly high Scoville heat units for these plants.

Thermal time models have been used to predict the development of many different species, including grapevine (Vitis vinifera L.). These models normally assume that there is a linear relationship between temperature and plant development. The goal of this study was to estimate the base temperature and duration in terms of thermal time for predicting veraison for four grapevine cultivars. Historical phenological data for four cultivars that were collected in the Pacific Northwest were used to develop the thermal time model. Base temperatures (T b) of 0 and 10 °C and the best estimated T b using three different methods were evaluated for predicting veraison in grapevine. Thermal time requirements for each individual cultivar were evaluated through analysis of variance, and means were compared using the Fisher’s test. The methods that were applied to estimate T b for the development of wine grapes included the least standard deviation in heat units, the regression coefficient, and the development rate method. The estimated T b varied among methods and cultivars. The development rate method provided the lowest T b values for all cultivars. For the three methods, Chardonnay had the lowest T b ranging from 8.7 to 10.7 °C, while the highest T b values were obtained for Riesling and Cabernet Sauvignon with 11.8 and 12.8 °C, respectively. Thermal time also differed among cultivars, when either the fixed or estimated T b was used. Predictions of the beginning of ripening with the estimated temperature resulted in the lowest variation in real days when compared with predictions using T b = 0 or 10 °C, regardless of the method that was used to estimate the T b.

HS-151 is a lipoxygenase free food grade soybean line (Glycine max. L.) with large seed size, high protein content, yellow hilum, and satisfactory food processing quality. It is adapted to areas of southwest Ontario with 3100 or more crop heat units and has a relative maturity of 2.2 (MG 2.2).

Plum curculio, Conotrachelus nenuphar (Herbst), feeding and oviposition on apples during spring was measured for 3 yr in a heavily infested orchard in New York State. A logistic model was formulated to relate cumulative fruit injury to cumulative heat units (degree-days base 10°C [DD10]) following petal fall. Cumulative plum curculio injury was well described by the model in the trees from which data for the model were collected. However, injury progressed faster and ended earlier in smaller trees at the same site and at a different site, probably because of differences in tree architecture. Field trials showed that protection of the fruit via insecticide residue was no longer necessary after the model predicted that 40% of the cumulative plum curculio oviposition and feeding cycle had been completed (171 DD10 after petal fall). Based on historical weather records, use of the model to schedule insecticide treatments would save 1 insecticide application nearly half the time compared with a standard of 3 insecticide applications. A delay between initial plum curculio feeding and oviposition, which coincides with the petal fall, phenophase, and steadily increasing damage, which is influenced by temperatures after petal fall was observed. The effectiveness of delaying insecticide treatments until the rate of plum curculio damage was rapidly increasing was compared with treatments applied at petal fall. Delaying the 1st insecticide application resulted in higher levels of damage compared with making the 1st treatment immediately after petal fall.

HS-172 is a black-seeded food-grade soybean line [Glycine max (L.) Merr.] suitable for use to make douchi or fermented, salt-preserved black soybean. It is adapted to the areas of southwest Ontario with 3100 or more crop heat units and has a relative maturity rating of 2.5.

HS-171 is a large-seeded edamame food-grade soybean genotype [Glycine max. (L.) Merr.] with yellow hilum, low oil, and high protein and sucrose concentrations. It is adapted to the areas of southwest Ontario with 3100 or more crop heat units and has a relative maturity rating of 2.6.

We have studied 15 different cultivars of chillies (Capsicum var.) grown in temperate climate Denmark and determined the contents of the four major capsaicinoids: capsaicin, dihydrocapsaicin, nordihydrocapsaicin, and homocapsaicin. From these contents we have, as commonly done for chillies, calculated the so-called pungency in Scoville heat units in order to compare with previous studies from other climatical zones. For three of the investigated cultivars, Serrano, Habanero and BIH Jolokia, for which reliable pungencies has previously been reported, we have found pungencies of 34,000 ± 1400, 247,000 ± 24,000 and 665,000 ± 4000, respectively, which are all in the same ranges as found earlier for chillies grown in more traditional chilli growing areas. Furthermore we have found that the relative distribution of the four capsaicinoids in the 15 different cultivars is highly variable, with the content of capsaicin ranging from 31% to 71% of the total capsaicinoid content.

An experiment was conducted at Siwa Oasis Research Station, Matrooh Governorate, Desert Research Center in two consecutive winter seasons, 2012 and 2013 to determine the effects of four planting dates (1st of Jan., mid of Jan., 1st of Feb. and mid. of Feb.) and three potato seed tuber sources of spunta cultivar (imported certified seed tubers, local seed tubers and recently harvested seed tubers which treated with GA3 ) on growth and yield under Siwa conditions. The results showed that planting on mid. of Jan. (date2) and 1st of Feb. (date 3) , generally, produced the highest growth and total yield and its components values. On the other hand, 1st of Jan. (date 1) and mid. of Feb. (date 4) gave the lowest values. Base temperature calculation for potato revealed that it was 5.99 oC and accumulated heat units above base temperature were 191.56 ± 12.4 degree-days during emergence period. The results showed , also, that Imported seed tubers (source 1) showed superiority in most studied characters of vegetative growth and yield parameters , followed by local seed tubers (source 2) as compared with recently harvested seed tubers (source 3). Generally, satisfactory characters were obtained when imported seed tubers were planted on mid. of Jan. (date 2) or first of Feb. (date 3) in both two seasons. Highly significant positive correlations were found between yield/fe d. and either yield/plant or average tuber weight. On the contrary, significant negative correlation was found between yield/fed. and number of tuber /plant. Correlation and regression revealed ,also, that increasing number of plant leaves led to increasing of plant fresh weight and average of tuber weight. While increasing number of plant shoots led to increasing number of tubers and decreasing tuber weight.

The ripeness at harvest of stone fruit should ensure the best balance between consumer satisfaction and ease logistic management, even if this compromise is not easy to achieve. In fact, as consequence of too early harvesting, an increased consumer dissatisfaction with peach and nectarine fruit is frequently observed. The use of the new non-destructive vis/NIR based, ripening index of absorbance difference (IAD) in planta, may help to overcome this problem. In our experiments, the IAD gave an objective measure of the nectarine ripening stage and showed a linear trend during stage 3 (S3) of fruit development, that did not appear affected nor by the climatic conditions of different years, neither by the training systems. The combined field monitoring of fruit ripening (IAD) and growth (mm) during stage 3 of nectarine development allowed two-three weeks advance predictions for harvest date and yield with low errors. The new approach also appeared a more reliable method in predicting harvest date than the till now used growing degree heat unit accumulation at 30 days after full bloom (growing degree days GDD30). The model developed in the present work offers promises for future real applications under field conditions, to obtain early objective and precise predictions for harvest date and yield. Moreover, taking into account fruit ripening stage at harvest, would allow an increase in fruit quality and improve fruit management during post-harvest.

The present study was conducted in Beni-Suef Governorate under field conditions during the seasons of 2005 and 2006. Results indicated that the population of the American bollworm moths, Helicoverpa armigera (Hubner) had four peaks starting from the 3rd week of May until the 2nd week of September during the two tested seasons. The highest number of moths was recorded during the end of July and the whole August which being 120 & 154 moth/trap/35 days and 150 days after cotton planting in both seasons, respectively. The predicted peaks of generations could be detected when the accumulated thermal units recorded 558.18 DD’s. The predicted peaks for the detected four generations varied from +2 to -3 days from the observed peaks. For better prediction of the American bollworm the period between the observed and expected peaks should be positive and as short as possible when early preparation of pest control materials are of great important, consequently it could be helpful when IPM control tactics are considered.

The aim of this work was to compare methods to predict the time of anthesis in tomato (Solanum lycopersicum L.). Two independent experiments were carried out using seeds of the Tauro commercial hybrid. Daily maximum and minimum air temperatures were measured by means of an electronic thermometer with data storage; the photoperiod was calculated using a mathematical procedure. The moment at which each inflorescence presented 50% of its flowers in anthesis was recorded. The use of calendar days (CD) had a high dispersion, which was measured with a variation coefficient (VC) higher than 3.70% for all inflorescences. The method that considered both a base temperature and the photoperiod allowed the highest prediction uniformity for the conditions of this assay, since its VC was lower than 0.30%.

Ecodormancy is a state in which the growth of a tree is inhibited by external environmental conditions. In this study, the concept of temperature range-based growth inhibition during the ecodormancy period was applied to estimate the heat requirements of the Niitaka oriental pear. Hourly temperature and flowering data from 12 regions of South Korea from 1999 to 2014 were analyzed, and the results were validated by flowering data from 2015–2017. Temperature ranges equal to 7 °C or higher had a heat accumulation effect that advanced flowering, whereas temperatures below 6.0 °C delayed flowering and negated the heat accumulation effect. In particular, 1 h at −2.0 to 6.0 °C and below −2.0 °C negated the heat accumulation effects of 1 and 8 h at temperatures of 7.0 °C or higher, respectively. Due to these negating effects, a ‘limited heat accumulation period’ occurred that maintained the heat accumulation values at 0. Furthermore, this period was consistent with the basic concept of ecodormancy because it indicated that the heat effect required for bud burst and flowering could not be achieved under low-temperature environmental conditions. The ‘limited heat accumulation period’ exempted the heat requirements from being confounded by errors in the estimation of the ecodormancy starting point, even though this point varied by up to 19 days depending on the chilling requirement model. The developed model was validated in terms of the consistency of the heat requirements and the accuracy of the flowering prediction. The heat requirement of Niitaka pear from 1999 to 2014 was 334.0 heat units (Hus), and the values were similar in 2015, 2016 and 2017 when this was not inputted into the model. The developed model presented errors of 2.5–2.8 days between the actual and estimated flowering dates.

Yu, K., Woodrow, L. and Poysa, V. 2015. AAC 26-15 soybean. Can. J. Plant Sci. 95: 441–443. AAC 26-15 is a high-yielding, high-protein, SCN resistant, food grade soybean cultivar with yellow hila and acceptable processing quality for foreign and domestic tofu and soymilk markets. It was developed at Agriculture and Agri-Food Canada (AAFC), Greenhouse and Processing Crops Research Centre (GPCRC), Harrow, Ontario. AAC 26-15 is adapted to areas of southwest Ontario with 3100 or more crop heat units and has a relative maturity of 2.3 (MG 2.3).

Olive cultivars differed significantly concerning the number of buds per shoot, percentage of burst buds, and floral buds borne on one-year-old shoot. Time of flowering varied in the cultivars studied differently in two successive years of investigation. It is uncertain whether chilling hours or the number of heat units influenced this phenomenon more. Sex expression depended as well on cultivar as on climatic conditions of the year.

The chili pepper is a very important plant used worldwide as a vegetable, as a spice, and as an external medicine. In this work, eight different varieties of Capsicum annuum L. have been characterized by their capsaicinoids content. The chili pepper fruits were cultivated in the Comarca Lagunera region in North of Mexico. The qualitative and quantitative determination of the major and minor capsaicinoids; alkaloids responsible for the pungency level, has been performed by a validated chromatographic procedure (HPLC-DAD) after a preliminary drying step and an opportune extraction procedure. Concentrations of total capsaicinoids varied from a not detectable value for Bell pepper to 31.84 mg g(-1) dried weight for Chiltepín. Samples were obtained from plants grown in experimental field and in greenhouse without temperature control, in order to evaluate temperature effect. Analysis of the two principal capsaicinoids in fruits showed that the amount of dihydrocapsaicin was always higher than capsaicin. In addition, our results showed that the content of total capsaicinoids for the varieties Serrano, Puya, Ancho, Guajillo and Bell pepper were increased with high temperature, while the content of total capsaicinoids and Scoville heat units (SHU) for the varieties De árbol and Jalapeño decreased. However, the pungency values found in this study were higher for all varieties analyzed than in other studies.

A field experiment was conducted with sunflower hybrid KBSH- 1 parental lines with six monthly sowings to predict the number of days to be staggered between the parental lines to achieve a synchronized flowering based on meteorological parameters. The regression study was made using the different heat unit concepts. The regression co-efficient between the phenophases and the derived weather parameters growing degree days (GDD), relative temperature disparity (RTD), helio thermal units (HTU) and photo thermal units (PTU) clearly indicated the variability between male and female lines with reference to the three phenophases studied. Among the phenophases, highly significant co-efficient was obtained for days to button formation and 50% flowering. Hence, from the study it was concluded that the computed regression equation could be employed to adopt suitable staggering to achieve proper synchronization to get higher seed filling and yield in sunflower hybrid KBSH-1 seed production. Key words: Sunflower, hybrid parental lines, heat unit concepts, synchronization, flowering, equation.

Xie, M., Tremblay, N., Tremblay, G., Bourgeois, G., Bouroubi, M. Y. and Wei, Z. 2013. Weather effects on corn response to in-season nitrogen rates. Can. J. Plant Sci. 93: 407–417. The response of corn yield to in-season nitrogen rate (ISNR) fertilizer applications in a temperate humid climate is conditioned to a great extent by prevailing weather conditions, which affect nitrogen use efficiency and raise the level of uncertainty for making management decisions. A better understanding of the effects of temperature, expressed as accumulated corn heat units (CHU), and precipitation would help to ensure that a “closer-to-optimal” nitrogen rate is supplied at side-dressing. A meta-analysis was performed using a database of nitrogen response trials conducted from 1997 to 2008 in 60 locations in the corn grain production area of Québec, in conjunction with a weather database. Meta-analysis is a statistical procedure for combining results from a series of studies that is used in many fields of research. It is used to assess treatment effect (also called effect size) in a group of studies or experiments. Corn yield response to ISNR was negatively correlated with overall CHU accumulation, but positively correlated with CHU accumulation before side-dressing. Responses also showed a stronger relationship with cumulative precipitation (PPT) before side-dressing than after side-dressing. High and evenly distributed precipitation before side-dressing tended to increase responses to ISNR. It can be concluded that low CHU, low precipitation and low precipitation evenness before side-dressing reduce the impact of ISNR on corn yield.

Accumulated heat unit and phenology of a full season open pollinated and three specialty corn (Zea mays L.) cultivars (Hybrid, QPM and Pop) were studied by growing them on three different planting dates (September 1, October 1 and November 1) in RCB design at Rampur Chitwan, Nepal during the winter season of 2009-10. The results indicated that the number of days required to attain different phenological stages were short for the early winter and gradually long for late winter plantings. For all the phenological studies, plants of normal sowing condition (September 1) recorded comparatively higher heat units than the late planting (October 1 and November 1) for all cultivars. Both early and late plantings recorded the higher helio-thermal units at advanced growth phases than at the early stages. The pheno-thermal indices at the earlier growth stages were significantly higher for early planting than the late plantings. The heat use efficiency (HUE) was found to be higher under normal planting as compared to the late plantings. Popular maize variety Rampur Composite was found to be the most suitable to produce stable HUE than the other varieties tested. The specialty corn cultivars could not show stable yield in late planting conditions suggesting their planting could be better for September sowing during early winter seasons. DOI: http://dx.doi.org/10.3126/ajn.v2i0.7526 Agronomy Journal of Nepal (Agron JN) Vol. 2: 2011 pp.111-120

Thermal accumulation ('degree day') methods are routinely used to predict plant and insect phenology. Depending on the data available, prediction may involve three separate steps with associated errors: estimating daily heat units from maximum and minimum temperatures; interpolating daily maxima and minima from monthly averages; and predicting future monthly averages from past climate, potentially including climate change. This research investigated the potential error in thermal accumulation totals arising from each of these factors at nine New Zealand sites. Ten simple heat unit calculations were tested, including two little-known and three new methods. Those utilising the true daily mean temperature performed best, followed by 4-step, triangle and sine approximations. Interpolating between monthly mean temperature extremes introduced much error into daily estimates, and the use of predicted, rather than observed, monthly normals further increased error. Speciic recommendations are made for thermal accumulation methods depending on what temperature data are available.

Optimum crop yield is greatly affected by proper planting and sowing times. The objective of this research was to develop an algorithm that uses the heat unit concept to determine the most suitable planting times for vegetable crops. The developed algorithm was programmed in a database environment with sample climatic data for the Kingdom of Saudi Arabia. The model was tested by validation (comparison to experts' estimations), verification (statistical comparison to formal published data), and evaluation (by professionals, landowners, and farmers). The overall results of the model were highly acceptable. The model needs more verification and validation in different environments and with various crops.

OAC Prosper is a semi-determinate food-grade soybean (Glycine max (L.) Merr.) cultivar with high yield potential, high seed protein concentration, and resistance to soybean cyst nematode. OAC Prosper is developed and recommended for soybean growing areas in southwestern Ontario with 2950 or greater crop heat units. OAC Prosper has a relative maturity of 1.8.