Sweet Pepper Cultivars Research Articles

Effect of pre-anthesis temperature on the size and shape of sweet pepper ( Capsicum annuum L.) fruit

The effects of pre-anthesis temperature on the size and shape components of fruits from three bell and two pointed-fruit type cultivars of sweet pepper were investigated in growth chambers, glasshouses and the field. Three temperature regimes of constant 18°C (low), 25°C/18°C, day/night (intermediate) and constant 35°C (high) were applied to plants at the third leaf stage through the third branching node formation. Thereafter, plants were allowed to grow either in a glasshouse maintained at 25°C/18°C, day/night temperature or in the open field until harvest. Large, medium and small fruits were obtained at the intermediate, high and low pre-anthesis temperatures, respectively. A high temperature increased the mean number of locule per fruit (shape component), in the five cultivars as compared with intermediate temperature. In the bell types, the number of four-loculed (tetralocular) fruits significantly increased, while that of three-loculed (trilocular) fruits decreased. A low temperature also resulted in a minor increase in the mean number of locules as a result of a slight increase in the number of tetralocular fruits; yet most fruits were unmarketable because they were short and blunt. The increase in the number of locules per fruit was associated with improvement in the blockiness of the bell type fruits, but not the pointed type fruits. Medium size blocky fruits, which meet the high market standards, were obtained at high pre-anthesis and intermediate post-anthesis temperatures.

The effects of interfruit competition on the size of sweet pepper ( Capsicum annuum L.) fruits

Two cultivars of sweet pepper were used to study the effect of interfruit competition on the components of fruit size under glasshouse and field conditions. Variation in interfruit competition was artificially simulated by removal of flower buds, flowers and set fruits on the first three flowering nodes of the pepper plant. The inhibitory effect of old fruits on the increase in weight, length, diameter and pericarp thickness of the younger ones was significant only from flower bud inception through Weeks 2 and 4 after fruit set in the glasshouse and field, respectively. Thereafter, the effect was not significant. Histological investigations revealed less cell multiplication activity and formation of fewer cell tiers, in the ovary wall of flower buds and small fruits under competition stress, than those under no competition. These results suggest that maintenance of vigorous vegetative growth from flower bud formation throughout fruit development might ensure sufficient organic nutrient supply to alleviate the stress on growth processes in developing buds, thereby reducing the variations in fruit sizes on upper nodes of pepper plant.

Varietal difference among some sweet pepper cultivars against frogeye leaf spot

Varietal difference among some sweet pepper cultivars against frogeye leaf spot

ピーマンの生育, 果実発育と収量に及ぼす仕立本数, 育苗日数と栽植密度の影響

The effects of shoot number and raising period of seedlings on growth, fruiting and yield of sweet pepper were investigated. In Experiment I, 30-day or 45-day seedlings of ‘California-Wonder’, ‘Shin-sakigake’ and ‘Shishito’ were planted in the plastic house. In Experiment II, 33-day seedlings of ‘Eiko’ were used. The plants were trained with two or four shoots in Experiment I and one, two or four shoots in Experiment II. The total number of shoots in each plot (9m2) were kept in same number by changing the plant number.The more the 2-training shoot plant is in plot, the more the fruit number and yield per plot were increased. The increase in fruit number and yield in ‘California-Wonder’ and ‘Shinsakigake’ was more notable than in‘Shishito’. Except for ‘California-Wonder’, the fruit number and yield of 30-day seedlings were higher than those of 45-day seedlings.The fewer the training shoot number is, the more the top and root dry weights were increased. The total dry weight of 30-day seedlings was increased as the number of training shoots increased. The 30-day seedlings had thicker roots than the 45-day seedlings except for the 2-training shoot plants of ‘California-Wonder’. Highly signicant correlations were recognized between the yield and the number of thick roots or the total leaf area in each cultivar.The percentage of normal fruits, the mean fruit weight and fruit thickness were increased as the number of training shoots decreased. The percentage of normal fruits and the mean fruit weight in 30-day seedlings were higher than those in 45-day seedlings.Results of this study on four sweet pepper cultivars showed that with more plants, each with fewer training shoots, harvestable fruit and the total yield per plot increased. Fewer training shoots resulted in an increase in the number of thick roots, total dry weight and total leaf area per plot, thus the enhancement of photosynthesis.

ピーマンの花芽形成ならびに果実発育に関する研究（第７報） ピーマンの花芽形成と発育に及ぼす温度と日長の影響

The effects of growing temperatures and day length on flower bud initiation and development were investigated. Three sweet pepper cultivars, ‘California Wonder, ’‘Shin-sakigake’and‘Shishito’were transferred to the phytotron and exposed to temperatures of 15°C, 20°C, 25°C and 30°C at the unfolding time of the cotyledons (Exp. 1) or at the time of flower bud initiation (Exp. 2) . The plants were grown at these temperatures under natural, (short) day and also under long day.As the growing temperature rose, the number of nodes on the 1st flower bud decreased (except 15°C) . The flower bud was initiated at only 15°C and under long day. Comparing the number of nodes in the three cultivars at the budding, the lowest was 10.9 of ‘Shin-sakigake’ and the others were 11.3 and 14.5 for ‘California Wonder’ and‘Shishito, ’respectively. The higher the growing temperature, the fewer the number of days for the initiation of the 1st flower bud.The number of days for the initiation of the 1st flower bud decreased more under long day than short day in the three cultivars. The difference of these days under long day and short day was smaller as the growing temperature rose and the flower buds were formed almost at the same time under both day lengths at 30°C. The effect of day length on the number of nodes on the 1st flower bud was not clear. Though the budding of the three cultivars was promoted as the temperature rose, the budding at 25°C and 30°C occurred alsmost simultaneously.From these results, it is deduced that the 1st flower bud of the three cultivars used is formed earlier and at a lower node as the growing temperature rises. It seems that the 1st flower bud is formed earlier under long day than that of short day but the effects of day length on the number of nodes to the 1st flower bud was not clear.

The effects of air humidity on flowering, fruit set, seed set and fruit growth of glasshouse sweet pepper ( Capsicum annuum L.)

The effects of day and night humidity on flowering, fruit set, seed set and fruit growth of sweet pepper ( Capsicum annuum L.) cultivar ‘Delphin’ were investigated in a glasshouse experiment. A continuously high or low humidity and alternating high and low humidities by day and night were applied during the early post-planting period from early December until mid-April. The vapour pressure deficit (VPD) of the glasshouse air varied from 0.33 to 0.66 kPa by day, from 0.27 to 0.86 kPa by night and the 24-h average from 0.30 to 0.75 kPa. Numbers of flowers and fruits showed a significant positive correlation with VPD by night. Fruit set and number of seeds per fruit were increased by low VPD by day. No significant effect of VPD was found on fruit shape ( length width ratio), number of cavities per fruit, pericarp thickness, dry matter content and fruit maturation rate.

Título en español

Se evaluó el efecto de varios niveles de fósforo y azufre y aplicaciones foliares o al suelo de oligoelementos sobre el rendimiento de dos cultivares de pimiento sembradas en un suelo Santa Isabel arcilloso con un pH inicial de 8.0. Ninguno de los tratamientos alteró significativamente la producción de pimientos. Las aplicaciones de azufre al suelo aumentaron la acidez del suelo señaladamente. Las aplicaciones de fuentes de nitrógeno con efectos residuales ácidos usados en estos experimentos, y que son los más recomendables para suelos alcalinos, bajaron el pH del suelo en la zona de las raíces a 7.4. A este nivel de acidez los pimientos pudieron utilizar el fósforo y los oligoelementos. Por lo tanto, si se usan abonos con residuos ácidos, la nutrición del pimiento y otras hortalizas con fósforo y oligoelementos en suelos como los utilizados en estos experimentos no debe constituir un problema.

Effect of Polyethylene Glycol-6000 on Pepper Seed1

Abstract Seeds of 2 cultivars of sweet pepper (Capsicum annuum L.) were invigorated by presoaking in a −8 bar solution of polyethylene glycol-6000 (240 g/liter H2O) at 15°C for 5 days. Invigorated seed germinated and emerged faster than noninvigorated in the greenhouse and laboratory, but not in the field. In the last field planting, yield from invigorated ‘Yolo Wonder L.’ was significantly greater than the control seed. Various seed treatments (KC1, KNO3, indoleacetic acid and gibberellic acid) in combination with the osmoticum did not affect invigoration.

Título en español.

En el primer ciclo de un programa de evaluación de variedades de pimiento de 1970 a 1973 se evaluaron 10 variedades (8 del tipo campana y 2 del tipo largo), en siembras mensuales en diferentes épocas. En unas se sembró la semilla directamente en el campo y en otras plantitas de semilleros. Los meses de noviembre a abril son los mejores para la siembra directa de pimiento en la zona noroeste. Junio es el mejor mes para la siembra por trasplante. En el segundo ciclo se evaluaron cuatro variedades de pimiento seleccionadas por sus altos rendimientos, resistencia a enfermedades y preferencias del consumidor. En este ciclo de siembras se lograron los rendimientos más elevados durante los meses de octubre, diciembre y febrero. Las variedades Blanco del País y Puerto Rico Wonder superaron en rendimientos a la Yolo Wonder Y y a la Cubanelle. Las siembras del segundo ciclo (cada 2 meses) confirmaron los resultados del primer ciclo. En el análisis combinado de todas las siembras, las variedades Puerto Rico Wonder y Blanco del País, la primera de las cuales fue desarrollada por la Estación hace muchos años, superaron a las otras ocho variedades en rendimiento. Se confirmó que estas dos variedades se adaptan bien a la región noroeste de Puerto Rico y que pueden producir buenas cosechas aún bajo condiciones adversas para otras variedades. En términos generales, se obtuvieron mejores rendimientos cuando la semilla se sembró directamente en el campo que cuando se trasplantó. En la siembra directa las plantas se desarrollaron más rápidamente, lográndose así una cosecha inicial más temprana.

Development and karyology of the tapetal layer of anthers in sweet pepper (Capsicum annuum L.)

The tapetal layer of anthers inCapsicum annuum L. is differentiated from the archesporial complex during the early development stage of the anthers. Further development of tapetum proceeds according to the scheme of the cellular polynuclear type. The high rate of polyploidy is characteristic of the whole layer (from 4n to 8n). Cytokinesis does not follow karyokinesis which conditions the inception of two or three-nuclear cells. The majority of the mononuclear cells show the typical plant endomitosis without the chromosome spiralization, accompanied by the structural nuclear change-over. In other cells chromosome spiralization in the prophase and, after passing through the metaphase, restitution of the cell nuclei were observed. The tapetum development has been studied in 12 cultivars of sweet pepper which did not differ in the course of the karyological processes. The subtle differences during the temporal course of degeneration of the whole layer in the postmeiotic period of development were observed.