Plant Density and Location: Optimization of Growth and Quality of Cut Sunflower in Tropical and Subtropical Environments.

The cultivation of sunflower (Helianthus annuus L.) as a cut flower stands out in floriculture due to its aesthetic beauty and commercial value. Understanding how cut sunflower genotypes adapt to different edaphoclimatic regions and management practices is essential to optimize flower quality and productivity. This study aimed to evaluate the effect of plant density and location on the development, growth, and quality of cut sunflower in tropical and subtropical environments. Plant densities of 10, 20, 30, 40, and 50 plants/m2 were evaluated in tropical climate and subtropical climate using a randomized block design in a factorial scheme. Results showed significant differences between locations for plant height, capitulum and stem diameter, final number of leaves, leaf area, leaf area index, phyllochron, and the developmental cycle. Plant density significantly influenced these variables except for plant height and developmental cycle. The interaction between location and plant density was significant only for capitulum diameter and final leaf number. The findings indicate that both planting density and location significantly influence the developmental cycle of cut sunflowers, with lower densities favoring more robust plants at harvest. A density of 30 plants/m2 is recommended for efficient space use without significantly compromising floral stem quality. All produced stems are marketable, suggesting that adjusting planting density can optimize production without compromising quality, adapting to specific regional conditions.

Farming system impacts the bioactive compounds, microbial diversity, aroma and color in edible red mini-roses (Rosa chinensis Jacq.).

Mini-roses (Rosa chinensis Jacq.) is largely used in salty dishes and desserts. This study evaluated instrumental color, sugars, organic acids, phenolics, volatiles, and the indigenous microbiota (fungi and bacteria) in edible mini-roses farmed in discarded fruits biocompost and animal manure systems. A descriptive sensory analysis of flowers was also performed. Mini-roses farmed in biocompost had higher luminosity and intensity of instrumental red color, a higher concentration of phenolic compounds, including anthocyanins related to red color, and fructose than mini-roses farmed in animal manure (p < 0.05). Furthermore, mini-roses farmed in biocompost had higher concentrations of various volatiles (p < 0.05), including hexyl acetate and cis-3 -hexenyl butyrate related to the fruity aroma. Bacterial groups related to plant growth-promoting such as Stenotrophomonas and endophilic fungal groups such as Eurotiales sp, Pleosporales sp were found in higher abundance (p < 0.05) in mini-roses farmed in biocompost. Mini-rose farmed in biocompost also received higher score (p < 0.05) for fruity aroma and red color than mini-rose mini-roses farmed in animal manure. Results indicate that farming mini-roses using biocompost from discarded fruits impacts the synthesis of phenolics and volatiles, resulting in a more intense fruity aroma and red color. Findings also suggest that the microbiota of mini-roses farmed in biocompost or animal manure do not represent a major risk for the safety of these products.

Assessing climate change effects on gladiola in Southern Brazil

Gladiola ( Gladiolus × grandiflorus Hort.) is an important cut flower for small farmers in Brazil. While the El Niño Southern Oscillation, which causes interannual variability to air temperature in Southern Brazil, can shift the optimum planting window of gladiola, an increase in temperature due to climate change can accelerate gladiola flowering and cause injuries by heat. The objective of this study was to assess the potential climate change effects on gladiola optimum planting date for specific market dates and investigate injuries occurrence on spikes in the Rio Grande do Sul State, Brazil. Field experiments were conducted from 2016 to 2018 at four different locations across the Rio Grande do Sul State to evaluate the performance of the PhenoGlad model in simulating the developmental stages of gladiola. The PhenoGlad model was run on climate scenarios of the Coupled Model Intercomparison Project Phase 5 (CMIP5) named RCP2.6, RCP4.5 and RCP8.5 scenarios. The climate change scenarios caused a delay in the optimum planting date to harvest gladiola for All Souls’ Day across the Rio Grande do Sul State. For harvesting spikes for Mother’s Day, negative anomalies (earliest planting date) occurred in the warmest regions, because the very high temperature extended the crop development. Injuries by heat on spikes reached positive anomalies in 70 % of the years in the warmest regions for scenario RCP8.5. To harvest spikes for Mother’s Day, heat injury did not exceed 20 % of the years. Mitigation strategies for farmers to deal with climate change and keep their gladiola production include adjusting the optimum planting date.

Assessing climate change effects on gladiola in Southern Brazil

Gladiola ( Gladiolus × grandiflorus Hort.) is an important cut flower for small farmers in Brazil. While the El Niño Southern Oscillation, which causes interannual variability to air temperature in Southern Brazil, can shift the optimum planting window of gladiola, an increase in temperature due to climate change can accelerate gladiola flowering and cause injuries by heat. The objective of this study was to assess the potential climate change effects on gladiola optimum planting date for specific market dates and investigate injuries occurrence on spikes in the Rio Grande do Sul State, Brazil. Field experiments were conducted from 2016 to 2018 at four different locations across the Rio Grande do Sul State to evaluate the performance of the PhenoGlad model in simulating the developmental stages of gladiola. The PhenoGlad model was run on climate scenarios of the Coupled Model Intercomparison Project Phase 5 (CMIP5) named RCP2.6, RCP4.5 and RCP8.5 scenarios. The climate change scenarios caused a delay in the optimum planting date to harvest gladiola for All Souls Day across the Rio Grande do Sul State. For harvesting spikes for Mothers Day, negative anomalies (earliest planting date) occurred in the warmest regions, because the very high temperature extended the crop development. Injuries by heat on spikes reached positive anomalies in 70 % of the years in the warmest regions for scenario RCP8.5. To harvest spikes for Mothers Day, heat injury did not exceed 20 % of the years. Mitigation strategies for farmers to deal with climate change and keep their gladiola production include adjusting the optimum planting date.(AU)

Scheduling optimum planting window for gladiola based on El Niño Southern Oscillation

Gladiola is an important cut flower worldwide and scheduling field gladiola production is largely dependent on planting at the correct time since its development is controlled by the air temperature. The aim of this study was to configure a planting window of gladiola in order to harvest spikes to be sold on All Souls' Day and Mother's Day holidays in the state of Rio Grande do Sul, Brazil, taking into account the El Niño Southern Oscillation (ENSO) phases. The PhenoGlad model, a dynamic process-based simulation model that simulates gladiola phenology on a daily time step was used in this study. Daily minimum and maximum temperatures over 55 years (1961-2015) from 18 weather stations across Rio Grande do Sul state, Brazil, were used as input data in the PhenoGlad model. The optimum planting window was simulated for each maturity group, location and ENSO phase. For harvesting on All Souls' Day, the optimum planting window had greater variation among the different ENSO phases. For Mother's Day, only Very Strong El Niño events affected the development of gladiola, indicating the weak signal of the phenomenon at this time of the year. A case study in a commercial farm demonstrated the importance of these results for farmers. The planting window for production on Mother's Day in a Neutral year was successfully configured. Determining the optimum planting window by considering the ENSO effect led to a more precise scheduling of gladiola production in southern Brazil.

Scheduling optimum planting window for gladiola based on El Niño Southern Oscillation

Gladiola is an important cut flower worldwide and scheduling field gladiola production is largely dependent on planting at the correct time since its development is controlled by the air temperature. The aim of this study was to configure a planting window of gladiola in order to harvest spikes to be sold on All Souls' Day and Mother's Day holidays in the state of Rio Grande do Sul, Brazil, taking into account the El Niño Southern Oscillation (ENSO) phases. The PhenoGlad model, a dynamic process-based simulation model that simulates gladiola phenology on a daily time step was used in this study. Daily minimum and maximum temperatures over 55 years (1961-2015) from 18 weather stations across Rio Grande do Sul state, Brazil, were used as input data in the PhenoGlad model. The optimum planting window was simulated for each maturity group, location and ENSO phase. For harvesting on All Souls' Day, the optimum planting window had greater variation among the different ENSO phases. For Mother's Day, only Very Strong El Niño events affected the development of gladiola, indicating the weak signal of the phenomenon at this time of the year. A case study in a commercial farm demonstrated the importance of these results for farmers. The planting window for production on Mother's Day in a Neutral year was successfully configured. Determining the optimum planting window by considering the ENSO effect led to a more precise scheduling of gladiola production in southern Brazil.(AU)

Estimating cassava yield in future IPCC climate scenarios for the Rio Grande do Sul State, Brazil / Produtividade simulada de mandioca em cenários climáticos futuros do IPCC para o Rio Grande do Sul, Brasil

The objective of this study was to simulate the yield of two cassava cultivars in two IPCC future climate scenarios, the SRES-A1B (Cmip3) and the RCP4.5 (Cmip5), for the state of Rio Grande do Sul, Brazil. The Simanihot model, with the Thornthwaite and Mather water balance sub-model, and the SRES-A1B (Cmip3 - Third Coupled Model Intercomparison Project) and RCP4.5 (Cmip5 - Fifth Coupled Model Intercomparison Project) scenarios of the Fourth and Fifth IPCC Assessment Report, respectively, was used. Cassava cultivars used in this study were "Fepagro - RS13" (forrage) and "Estrangeira" (human consumption). In both cultivars, there was an increase in tuberous roots yield in future climate scenarios. The cultivar for human consumption benefits more roots yield in the scenario with higher CO2 (Cmip3 scenario); whereas, the forage cultivar benefits more the Cmip5 scenario. Among the three future periods (2010-2039, 2040-2069 e 2070-2099), changes in tuberous roots yield are more evident in the end of the century period (2070-2099) and for early planting dates (01 September and 01 October). The northeastern region of the state has the greatest changes in tuberous roots yield in future climates, because this is the coldest region, with winter minimum temperature during between 6 and 8ºC.

O objetivo deste trabalho foi simular a produtividade de duas cultivares de mandioca em dois cenários climáticos futuros do IPCC, o SRES-A1B (Cmip3) e o RCP4.5 (Cmip5), para o Rio Grande do Sul. Foi utilizado o modelo Simanihot, com o submodelo de balanço hídrico do solo diário sequencial de Thornthwaite e Mather, e os cenários SRES- A1B (Cmip3 - 3o Projeto de Intercomparação de modelos globais) e o RCP4.5 (Cmip5 - 5o Projeto de Intercomparação de modelos globais) do 4o e 5o relatório do IPCC, respectivamente, regionalizados por downscaling dinâmico com modelo RegCM3 e RegCM4 (Modelo Climático Regional), respectivamente. As cultivares utilizadas no estudo foram a 'Fepagro - RS13' (uso forrageira) e 'Estrangeira' (uso para mesa). Em ambas há aumento na produtividade de raízes em cenários climáticos futuros. A cultivar de mesa se beneficia mais na produtividade de raízes no cenário com maior concentração de CO2 (cenário Cmip3), enquanto a cultivar forrageira, se beneficia mais no cenário Cmip5. Nos três períodos futuros (2010-2039, 2040-2069 e 2070-2099), as mudanças na produtividade são sempre mais expressivas no último período (2070-2099) e nas primeiras datas de plantio (01/09 e 01/10). A região do Rio Grande do Sul com maiores mudanças na produtividade é a nordeste, a qual, no clima atual é a mais fria do Estado, com temperatura mínima do ar no inverno entre 6 e 8°C.

Estimating cassava yield in future IPCC climate scenarios for the Rio Grande do Sul State, Brazil / Produtividade simulada de mandioca em cenários climáticos futuros do IPCC para o Rio Grande do Sul, Brasil

The objective of this study was to simulate the yield of two cassava cultivars in two IPCC future climate scenarios, the SRES-A1B (Cmip3) and the RCP4.5 (Cmip5), for the state of Rio Grande do Sul, Brazil. The Simanihot model, with the Thornthwaite and Mather water balance sub-model, and the SRES-A1B (Cmip3 - Third Coupled Model Intercomparison Project) and RCP4.5 (Cmip5 - Fifth Coupled Model Intercomparison Project) scenarios of the Fourth and Fifth IPCC Assessment Report, respectively, was used. Cassava cultivars used in this study were "Fepagro - RS13" (forrage) and "Estrangeira" (human consumption). In both cultivars, there was an increase in tuberous roots yield in future climate scenarios. The cultivar for human consumption benefits more roots yield in the scenario with higher CO2 (Cmip3 scenario); whereas, the forage cultivar benefits more the Cmip5 scenario. Among the three future periods (2010-2039, 2040-2069 e 2070-2099), changes in tuberous roots yield are more evident in the end of the century period (2070-2099) and for early planting dates (01 September and 01 October). The northeastern region of the state has the greatest changes in tuberous roots yield in future climates, because this is the coldest region, with winter minimum temperature during between 6 and 8ºC. (AU)

O objetivo deste trabalho foi simular a produtividade de duas cultivares de mandioca em dois cenários climáticos futuros do IPCC, o SRES-A1B (Cmip3) e o RCP4.5 (Cmip5), para o Rio Grande do Sul. Foi utilizado o modelo Simanihot, com o submodelo de balanço hídrico do solo diário sequencial de Thornthwaite e Mather, e os cenários SRES- A1B (Cmip3 - 3o Projeto de Intercomparação de modelos globais) e o RCP4.5 (Cmip5 - 5o Projeto de Intercomparação de modelos globais) do 4o e 5o relatório do IPCC, respectivamente, regionalizados por downscaling dinâmico com modelo RegCM3 e RegCM4 (Modelo Climático Regional), respectivamente. As cultivares utilizadas no estudo foram a 'Fepagro - RS13' (uso forrageira) e 'Estrangeira' (uso para mesa). Em ambas há aumento na produtividade de raízes em cenários climáticos futuros. A cultivar de mesa se beneficia mais na produtividade de raízes no cenário com maior concentração de CO2 (cenário Cmip3), enquanto a cultivar forrageira, se beneficia mais no cenário Cmip5. Nos três períodos futuros (2010-2039, 2040-2069 e 2070-2099), as mudanças na produtividade são sempre mais expressivas no último período (2070-2099) e nas primeiras datas de plantio (01/09 e 01/10). A região do Rio Grande do Sul com maiores mudanças na produtividade é a nordeste, a qual, no clima atual é a mais fria do Estado, com temperatura mínima do ar no inverno entre 6 e 8°C. (AU)

Estimating cassava yield in future IPCC climate scenarios for the Rio Grande do Sul State, Brazil / Produtividade simulada de mandioca em cenários climáticos futuros do IPCC para o Rio Grande do Sul, Brasil

ABSTRACT: The objective of this study was to simulate the yield of two cassava cultivars in two IPCC future climate scenarios, the SRES-A1B (Cmip3) and the RCP4.5 (Cmip5), for the state of Rio Grande do Sul, Brazil. The Simanihot model, with the Thornthwaite and Mather water balance sub-model, and the SRES-A1B (Cmip3 - Third Coupled Model Intercomparison Project) and RCP4.5 (Cmip5 - Fifth Coupled Model Intercomparison Project) scenarios of the Fourth and Fifth IPCC Assessment Report, respectively, was used. Cassava cultivars used in this study were 'Fepagro - RS13' (forrage) and 'Estrangeira' (human consumption). In both cultivars, there was an increase in tuberous roots yield in future climate scenarios. The cultivar for human consumption benefits more roots yield in the scenario with higher CO2 (Cmip3 scenario); whereas, the forage cultivar benefits more the Cmip5 scenario. Among the three future periods (2010-2039, 2040-2069 e 2070-2099), changes in tuberous roots yield are more evident in the end of the century period (2070-2099) and for early planting dates (01 September and 01 October). The northeastern region of the state has the greatest changes in tuberous roots yield in future climates, because this is the coldest region, with winter minimum temperature during between 6 and 8oC.

RESUMO: O objetivo deste trabalho foi simular a produtividade de duas cultivares de mandioca em dois cenários climáticos futuros do IPCC, o SRES-A1B (Cmip3) e o RCP4.5 (Cmip5), para o Rio Grande do Sul. Foi utilizado o modelo Simanihot, com o submodelo de balanço hídrico do solo diário sequencial de Thornthwaite e Mather, e os cenários SRES- A1B (Cmip3 - 3o Projeto de Intercomparação de modelos globais) e o RCP4.5 (Cmip5 - 5o Projeto de Intercomparação de modelos globais) do 4o e 5o relatório do IPCC, respectivamente, regionalizados por downscaling dinâmico com modelo RegCM3 e RegCM4 (Modelo Climático Regional), respectivamente. As cultivares utilizadas no estudo foram a 'Fepagro - RS13' (uso forrageira) e 'Estrangeira' (uso para mesa). Em ambas há aumento na produtividade de raízes em cenários climáticos futuros. A cultivar de mesa se beneficia mais na produtividade de raízes no cenário com maior concentração de CO2 (cenário Cmip3), enquanto a cultivar forrageira, se beneficia mais no cenário Cmip5. Nos três períodos futuros (2010-2039, 2040-2069 e 2070-2099), as mudanças na produtividade são sempre mais expressivas no último período (2070-2099) e nas primeiras datas de plantio (01/09 e 01/10). A região do Rio Grande do Sul com maiores mudanças na produtividade é a nordeste, a qual, no clima atual é a mais fria do Estado, com temperatura mínima do ar no inverno entre 6 e 8°C.

Estimating cassava yield in future IPCC climate scenarios for the Rio Grande do Sul State, Brazil

ABSTRACT: The objective of this study was to simulate the yield of two cassava cultivars in two IPCC future climate scenarios, the SRES-A1B (Cmip3) and the RCP4.5 (Cmip5), for the state of Rio Grande do Sul, Brazil. The Simanihot model, with the Thornthwaite and Mather water balance sub-model, and the SRES-A1B (Cmip3 - Third Coupled Model Intercomparison Project) and RCP4.5 (Cmip5 - Fifth Coupled Model Intercomparison Project) scenarios of the Fourth and Fifth IPCC Assessment Report, respectively, was used. Cassava cultivars used in this study were 'Fepagro - RS13' (forrage) and 'Estrangeira' (human consumption). In both cultivars, there was an increase in tuberous roots yield in future climate scenarios. The cultivar for human consumption benefits more roots yield in the scenario with higher CO2 (Cmip3 scenario); whereas, the forage cultivar benefits more the Cmip5 scenario. Among the three future periods (2010-2039, 2040-2069 e 2070-2099), changes in tuberous roots yield are more evident in the end of the century period (2070-2099) and for early planting dates (01 September and 01 October). The northeastern region of the state has the greatest changes in tuberous roots yield in future climates, because this is the coldest region, with winter minimum temperature during between 6 and 8oC.

RESUMO: O objetivo deste trabalho foi simular a produtividade de duas cultivares de mandioca em dois cenários climáticos futuros do IPCC, o SRES-A1B (Cmip3) e o RCP4.5 (Cmip5), para o Rio Grande do Sul. Foi utilizado o modelo Simanihot, com o submodelo de balanço hídrico do solo diário sequencial de Thornthwaite e Mather, e os cenários SRES- A1B (Cmip3 - 3o Projeto de Intercomparação de modelos globais) e o RCP4.5 (Cmip5 - 5o Projeto de Intercomparação de modelos globais) do 4o e 5o relatório do IPCC, respectivamente, regionalizados por downscaling dinâmico com modelo RegCM3 e RegCM4 (Modelo Climático Regional), respectivamente. As cultivares utilizadas no estudo foram a 'Fepagro - RS13' (uso forrageira) e 'Estrangeira' (uso para mesa). Em ambas há aumento na produtividade de raízes em cenários climáticos futuros. A cultivar de mesa se beneficia mais na produtividade de raízes no cenário com maior concentração de CO2 (cenário Cmip3), enquanto a cultivar forrageira, se beneficia mais no cenário Cmip5. Nos três períodos futuros (2010-2039, 2040-2069 e 2070-2099), as mudanças na produtividade são sempre mais expressivas no último período (2070-2099) e nas primeiras datas de plantio (01/09 e 01/10). A região do Rio Grande do Sul com maiores mudanças na produtividade é a nordeste, a qual, no clima atual é a mais fria do Estado, com temperatura mínima do ar no inverno entre 6 e 8°C.

Desenvolvimento e crescimento foliar e produtividade de cana-de-açúcar em cultivo de cana-planta e de cana-soca / Leaf development and growth, and yield of sugarcane clones from plant crop and ratoom crop

Os objetivos deste trabalho foram determinar o filocrono, as relações alométricas entre crescimento e desenvolvimento foliar e a produtividade de três clones de cana-de-açúcar em cultivo de cana-planta e cana-soca de um ano em ambiente subtropical. Um experimento de campo foi conduzido durante dois anos (2008 a 2010), em Santa Maria, RS. Os clones de cana-de-açúcar utilizados foram: IAC 822045 (ciclo precoce), SP 711406 (ciclo médio) e CB 4176 (ciclo tardio). O delineamento experimental foi Blocos ao Acaso com quatro repetições. Calculou-se o filocrono (°C dia folha-1) com número de folhas (NF) menor que 15 (FILO≤15), maior que 15 folhas (FILO>15) e com todas as folhas (FILOtotal). Ajustaram-se modelos não lineares do tipo potência para a área foliar acumulada (AF) versus o NF no colmo. O filocrono variou durante o ciclo de desenvolvimento da cana-de-açúcar aumentando na sequência FILO≤15 > FILOtotal > FILO>15. O filocrono da cana-planta é menor que o filocrono da cana-soca de um ano para as primeiras 15 folhas. O modelo potência é apropriado para caracterizar a relação alométrica entre a evolução da área foliar verde acumulada a partir do número de folhas acumulado no colmo principal. O clone de ciclo médio tem maior produtividade em cultivo de cana-soca.

The objectives of this study were to determinate the phyllochron, allometric relationships between leaf growth and development, and crop yield of three sugarcane clones in plant and first year ratooning crop in subtropical environment. A two-year field experiment was conducted at the experimental area of Santa Maria, RS, during 2008-2010. Three sugarcane clones were used: IAC 822045 (early), SP 711406 (medium) and CB 4176 (late). Experimental design was a complete randomized block with four replications. Phyllochron (°C day leaf-1) was calculated considering leaf number (LN) lower than 15 (PHYLearly), greater than 15 leaves (PHYLlate) and for the entire LN (PHYLentire). A power-type nonlinear model was fit for cumulative leaf area (LA) versus LN. Phyllochron varied during the development cycle of sugarcane increasing in the sequence PHYLearly>PHYLentire>PHYLlate. The phyllochron of plant crop is lower than phyllochron of ratoon crop for the first 15 leaves. The power model is appropriate to characterize the allometric relationship between the evolution of accumulated green area as a function of accumulated main stem leaf number. The medium clone has a higher productivity in the ratoon crop.

Desenvolvimento vegetativo e reprodutivo em gladíolo / Vegetative and reproductive development in gladiolus

A caracterização das etapas ou fases do ciclo de desenvolvimento das culturas agrícolas é importante para realização de práticas de manejo e, para o gladíolo, essas etapas ainda não foram bem caracterizadas em cultivos a campo no Rio Grande do Sul. Este trabalho teve como objetivo determinar a duração das fases vegetativa e reprodutiva do ciclo de desenvolvimento e as relações entre estas com a emissão de folhas em cultivares de gladíolo. Dois experimentos foram realizados a campo, em Santa Maria, RS, um na primavera/verão 2010/11, com as cultivares: 'Priscila', 'Peter Pears', 'Sunset', 'T704', 'Traderhorn', 'Rose Supreme' e 'Jester' e outro no outono/inverno 2011 com as cultivares 'T704', 'Traderhorn' e 'Jester'. O delineamento experimental foi inteiramente casualizado com duas repetições de cinco plantas de cada cultivar. Foram determinadas as datas do espigamento e final de florescimento e o ciclo de desenvolvimento foi dividido em duas fases: vegetativa (do plantio ao espigamento) e reprodutiva (do espigamento ao final do florescimento). Os resultados indicaram que a duração da fase vegetativa é a que determina a duração do ciclo total da parte aérea e que a duração da fase vegetativa é influenciada pela velocidade de emissão das folhas e pelo número final de folhas. Assim, cultivares precoces têm maior velocidade de emissão de folhas e menor número final de folhas do que cultivares tardias.

The characterization of the developmental phases of agricultural crops is important for management practices and for gladiolus in the field this characterization has not been made in Rio Grande do Sul State. The goal of this study was to determine the duration of vegetative and reproductive phases of the developmental cycle, and the relationships between them and with leaf appearance in gladiolus cultivars. Two field experiments were conducted in Santa Maria, RS, Brazil, one during the Spring/Summer 2010/11 with the cultivars 'Priscila', 'Peter Pears', 'Sunset', 'T704', 'Traderhorn', 'Rose Supreme' and 'Jester', and another during the Fall/Winter 2011 with the cultivars 'T704', 'Traderhorn' and 'Jester'. The experimental design was a completely randomized with two replications of five plants per cultivar. The date of heading and end of flowering was determined and the developmental cycle was divided into vegetative (from planting to heading) and reproductive (from planting to and of flowering). Results showed that the duration of the vegetative phase determines the duration of the developmental cycle and the duration of the vegetative phase is affected by leaf appearance rate and by final leaf number. Thus, early cultivars have greater leaf appearance rate and lower final leaf number than late cultivars.