Showing papers in "Journal of Agriculture of The University of Puerto Rico in 1969"

En memoria: miguel a. lugo lopez 1921-2005

Abstract: Miguel A. Lugo López falleció en junio de 2005 en Isabela, Puerto Rico. Le sobrevive su esposa la Sra. Aurora de Menkini de Lugo, su hijo Peter, sus nietos y su biznieta. El doctor Lugo López nació el 21 de julio de 1921 en Mayagüez, Puerto Rico, ciudad donde también cursó estudios elementales y superiores. En 1943 se graduó con honores de Bachiller en Ciencias Agrícolas, con una concentración en Agronomía, del Colegio de Agricultura y Artes Mecánicas de la Universidad de Puerto Rico en Mayagüez. Profesionalmente se inició trabajando como Auxiliar de Investigaciones en la Estación Experimental Federal en Mayagüez. Sin embargo, pronto partió hacia la Universidad de Cornell en Ithaca, Nueva York, donde en 1945 obtuvo el grado de Maestro en Ciencias, especializado en Ciencias del Suelo. Allí continuó estudios post-graduados hasta 1946. A su regreso a Puerto Rico sirvió por dos años como Catedrático Auxiliar en el Colegio de Agricultura y Artes Mecánicas de Mayagüez. De allí pasó a ocupar el puesto de Científico Auxiliar de Suelos en la Estación Experimental Agrícola (EEA) de la Universidad de Puerto Rico, en Río Piedras. Posteriormente continuó sus estudios graduados y en 1950 obtuvo el grado de Doctor en Filosofía, en Ciencias del Suelo, en la Universidad de Cornell. Del 1950 al 1957 fue Científico Asociado de Suelos y Director Interino del Departamento de Suelos en la EEA en Río Piedras. Del 1957 al 1960 trabajó en la Subestación de Gurabo como Científico Asociado de Suelos y Científico de Suelos a Cargo; del 1960 al 1961 ocupó el puesto de Director Auxiliar de la EEA a cargo de la Subestación de Gurabo. De la Subestación de Gurabo pasó a la EEA en Río Piedras, donde ocupó los puestos de Director Auxiliar, Director Interino, Director Asociado y Científico de Suelos. Del 1969 al 1972 fue Profesor y Científico de Suelos, además de Director de la Oficina de Programas y Planes y Decano Asociado del Colegio de Ciencias Agrícolas, en el Recinto Universitario de Mayagüez (RUM). Ocupó el puesto de Decano de Estudiantes del RUM del 1972 al 1974. En 1974 regresa a la investigación como Científico de Suelos y Líder del Proyecto de Investigaciones en

The Phytoseiidae (Acarina: Mesostigmata) of Puerto Rico

Abstract: This is a faunal summary of the phytoseiids of Puerto Rico in which three new species are described: Typhlodromips plumosus, Typhlodromalus higuilloae, and Amblydromella deleoni. Fourteen other species are recorded from the island for the first time, bringing the total to 48 species.

Steinernema puertoricensis n. sp. (Rhabditida: Steinernematidae), a new entomopathogenic nematode from Puerto Rico

Abstract: Steinernema puertoricensis n. sp., isolated from sand collected from a coconut plantation, can be distinguished from S. glaseri , its most closely related species, by characteristics of the first generation adults. The female has a greater body length (8.6 mm) and width (375 µm). Males have the excretory pore anteriad or posteriad to the nerve ring. Spicules are arcuate and lack a hook at the ventral side of the spicule tip. Infective third-stage juveniles are over 1 mm in length. This appears to be the first species of Steinernema described from the Caribbean islands and adapted to a hot humid environment.

Banding of oedionychina (coleoptera : alticinae) chromosomes : c - and ag - bands

Abstract: Banding of chromosomes was studied in about 40 species of Brazilian Oedionychina. Long sex chromosomes and large germ line cells of these fleabeetles facilitate such studies. Because the sex chromosomes comprise about 50% of the total karyotype length and do not pair in male meiosis, the spermatogenesis serves unusually well for the banding purposes. Abundant mitoses are obtained from colchicinized embryos (eggs). Conventional tapping and smearing techniques are catastrophic, because the large spermatocytes are so perishable. Squashes of Kahle-Smith-fixed tissues are safest and good for silver staining, but the fixative tends to slow down the formation of C-bands. Teasing the testes with pins on the slide saves about 25% of the Ml cells. C-bands mark procentric heterochromatin in most chromosomes, and intercalary heterochromatin of variable amount and location in the sex chromosomes. Insufficient treatment in Ba(OH) 2 induces G-band-like marking of the sex chromosomes (especially of Y) in some species. Failure of C-banding can be corrected by rebandings up to 6 times. A prolonged Giemsa staining is necessary for rebanded chromosomes. Silver staining marks kinetochore dots in most chromosomes, and intercalary bands in male diplotenic sex chromosomes. Strongest of these bands are still present at Mil. The active sites they mark are presumably related to a synthesis (through gene amplification?) of a material structurally similar to chromatoid bodies. Band differences between species show that C- and Ag-bands are powerful tools for the cytotaxonomy of these beetles. Ag-bands must be compared with care, because their number is reduced from diplotene to Ml.

Sources of resistance to early blight, Alternaria solani, and transfer to tomato, Lycopersicon esculentum

Abstract: Tomato entries reported as early blight resistant were collected and evaluated under severe early blight infection in the warm rainy summer months of 1982-1985 in Mayaguez, Puerto Rico to identify sources with useful resistance in Puerto Rico. Of the common tomato lines, 84B 510-4 was the closest in resistance to the best wild tomato species, which are less susceptible to early blight than common tomatoes. Useful field resistance was found in the minority of cases, but one or more entries of L. esculentum f. cerasiforme, L. pimpinellifolium, L. esculentum X L. pimpinellifolium , and L. hirsutum var. typicum showed useful early blight resistance. Lowest disease ratings were found in varieties of L. hirsutum , which also showed the lowest yield. Better fruiting was found in L. pimpinellifolium although resistance levels were slightly less. Crosses of L. pimpinellifolium and L. hirsutum with useful early blight resistance to susceptible L. esculentum were followed in F 1 , F 2 , and F 3 generations. Resistance appeared partially dominant from F 1 disease ratings, and segregation in F 2 suggested that many modifying genes both dominant and recessive were probably involved in conditioning early blight resistance. Generally, common tomatoes appear much more susceptible to early blight than wild species. To enlarge the pool of early blight resistence genes, F 2 selection and progressive back crosses are suggested. Susceptible tomatoes were defoliated by early blight within one month after first flower during the warm rainy months; whereas, entries with useful resistance defoliated from 6 weeks to 2 months after the same stage.

A Catalogue of the Bloodsucking Midges of the Americas (Culicoides, Leptoconops, and Lasiohelea) with Keys to the Subgenera and Nearctic Species, a Geographic Index, and Bibliography

Abstract: This catalogue dealing with the bloodsucking Ceratopogonidae of the Western Hemisphere includes 198 subspecific and specific names in Culicoides , 12 in Leptoconops and 12 in Lasiohelea , together with most of the literature references to them which had appeared up to June 1954. A subgeneric system in Culicoides based particularly on the male genitalia is proposed and eight subgenera are described or redescribed: Macfiella (new subgenus), Hoffmania , Fox, Avaritia (new subgenus), Culicoides Latreille, Selfia Khalaf, Monoculicoides Khalaf, Oecacta Poey, and Beltranmyia Vargas. The species are placed in the appropriate subgenera, as far as possible, and a key is given to the males and females of the Nearctic forms. The Geographic Index lists the species reported from the geographic units of the Western Hemisphere as well as each of the states of the United States. A brief review of the literature on biology, control, and medical importance is also included.

A survey of puerto rican soils for entomogenous nematodes which attack diaprepes abbreviatus (l.) (coleoptera : curculionidae)

Abstract: A survey was conducted to determine the presence of entomogenous nematodes which might parasitize Diaprepes abbreviatus (L.) larvae in Puerto Rican soils. One larva (2.3%) was parasitized with Heterorhabditis sp. Poinar when 4-month-old larvae were placed in the soil at eight different sites throughout the Island. Soil samples, taken from sugarcane fields and pasture lands in five geographical regions during July and September 1980, and January and April 1981, and inoculated with D. abbreviatus larvae did not reveal entomogenous nematodes. In the laboratory, when Neoaplectana carpocapsae Weiser was introduced into sterile soil from these regions, 40% of the exposed D. abbreviatus larvae became infected. We believe this is the first report of the entomogenous nematode, Heterorhabditis sp., occurring in Puerto Rico.

Crop response to soil acidity factors in ultisols and oxisols in puerto rico. Vii. Dry beans

Abstract: The effect of acidity factors of two Ultisols and one Oxisol on yield and foliar composition of cabbage was determined. On all soils, cabbage responded markedly in yield to liming, but response was stronger on the ultisols. All soil acidity factors correlated significantly with yields. On the Ultisols, yields increased with decreasing acidity up to the highest level of limiting, pH 5.6. Only 50% of maximum yield was obtained at 12-13%. AI saturation of the CEC and essentially no yields were produced at pH values below 4.5 with 50% Al saturation, a level of acidity common in Ultisols. About 50% of maximum yield was obtained at pH 4.7 with 25% Al saturation on the Oxisols compared with about 22% of maximum yield obtained at this level of acidity on the Ultisols. Density of the cabbage heads correlated positively with soil acidity on all soils. Soil acidity had no apparent effect on foliar composition of the basal leaves. Calcium content of the head leaves correlated negatively with soil acidity factors on the Ultisols. Basal leaves had a higher Ca content than head leaves and both had a higher Ca and a lower P content on the Coto soil than on the Corozal soils.

Whitefly-Transmitted Viruses in Puerto Rico

Abstract: The viruses transmitted by the Puerto Rican whitefly ( Bemisia tabaci Genn.), their vectors, and their main hosts are discussed in the present paper. The possible relationships between some of these viruses and certain foreign rugaceous viruses also are discussed. It seems that the Rhynchosia mosaic (Puerto Rico), the yellow mosaic of Phaseolus lunatus L. (India) and the yellow mosaic of Phaseolus longepedunculalus Mart. (Brazil) are related diseases. The Puerto Rican mosaic of Sida carpinifolia also seems related to the Brazilian chlorosis of Malvaceae. Five seemingly different rugaceous viruses have been studied in Puerto Rico.

Effect of chicken manure on chemical properties of a Mollisol and tomato production.

Abstract: An experiment was established on a San Anton soil (Cumulic Haplustolls) in southern Puerto Rico to evaluate the effect of chicken manure (0, 5, 10 and 15 t/ha) and nitrogen fertilizer (0, 56, 112 and 168 kg/h) on some soil chemical properties and tomato production. Chicken manure was broadcast and incorporated into the soil whereas urea, the nitrogen source, was applied by fertigation. A significant lineal effect was observed in exchangeable Mg 2+ and K + , electrical conductivity and Olsen available P with chicken manure applications. In the check treatment (no manure), exchangeable Mg 2+ was 2.54 cmol c /kg; exchangeable K + , 0.99 cmol./kg; electrical conductivity, 0.79 mmhos/cm; and available P, 52.58 mg/kg. The application of 15 t/ha of chicken manure increased exchangeable Mg 2+ to 2.70 cmol c /kg, exchangeable K + to 1.29 cmol c /kg, electrical conductivity to 2.22 mmhos/cm and available P to 83.98 mg/kg. Soil pH decreased significantly with the same treatment from 7.50 in the check treatment to 6.98 in the 15 t/ha chicken manure treatment. Chicken manure increased soil exchangeable NO 3 - at a depth of 20 cm, but did not increase exchangeable NH 4 + . Application of chicken manure did not increase tomato yield significantly; however, it increased significantly the number of large and medium fruits. It is suggested that an exchangeable NO 3 - content of about 15 to 20 mg/kg is adequate for optimum tomato production in a San Anton soil.

Root distribution of plantains growing on five soil types

Abstract: Plantain roots decreased sharply with depth and distance from the pseudostem on 5 soils typical of vast areas in the tropics. Primary roots in the upper 15 cm of all soils decreased from an average of 111 cm/1,000 cm 3 of soil at 0-30 cm from the pseudostem, to 29 cm/1,000 cm 3 of soil at 60-90 cm from the pseudostem. At 0-30 cm from the pseudostem, roots decreased from 111 cm/1,000 cm 3 of soil in the upper 15 cm of soil to 11 cm; 1,000 cm 3 of soil at the 30-45 cm depth. No roots were present below 45 cm in any soil.

Yam (Dioscorea spp.) response to fertilization in soils of the semiarid southern coast of Puerto Rico

Abstract: Yam ( Dioscorea spp) production in Puerto Rico is located in the central mountainous zone, but there is interest in expanding production to the southern semi-arid zone, where mechanization is possible, where irrigation is available and where soil pH is neutral or alkaline Two experiments were performed during 2000 (Experiment I) and 2001 (Experiment II) in a soil corresponding to the Pozo Blanco (Fine-loamy, mixed, superactive, isohypertermic Aridic Calciustolls) series with high exchangeable potassium and magnesium contents and with a good capacity to supply nitrogen Yam ( D alata cv Diamante and D rotundata cv Guinea Negro) response to the application of nitrogen, potassium, magnesium and micronutrients was evaluated In Experiment I, yam (cv Diamante) yields were severely affected by an uncharacterized tuber-root rot, and marketable production varied from 5,961 to 10,742 kg/ha In Experiment II, the disease incidence was less than in Experiment IThe application of micronutrients increased yields by as much as 100% There was a trend for greater marketable tuber production with the application of micronutrients and 75-12-250 kg/ha (N-P-K) for cv Diamante (18,787 kg/ha), and for cv Guinea Negro (10,492 kg/ha), with the application of micronutrients and 75-12-0 kg/ha (N-P-K) The results suggest that with good seed-quality, micronutrient foliar applications, and moderate application rates of nitrogen and potassium, adequate yam production can be achieved in these soils

Milling and Use of Okra Seed Meal at the Household Level

Abstract: Okra seed meal was produced at the household level by grinding seed in a corn seed mill, and sieving to remove most of the seed coat. The meal of about 33% protein and 32% oil was then used in various proportions as a substitute for wheat flour in cookies, cupcakes, sweet bread rolls and typical bread. Okra seed meal slowed the rising of dough in some cases. increased color, and added moisture and an unusual flavor, but was quite acceptable at substitution levels ranging from 25 to as much as 100% in some products. A vegetable curd made by extracting the protein of seeds with water and precipitating with magnesium sulphate was attractive and good-tasting . Thus, okra seeds serve as a potential new grain crop for the tropics.

Staining of substances adjacent to the sex bivalent in certain weevils of Puerto Rico.

Abstract: A nucleolar substance adjacent to early prophasic sex bivalents is observed and studied by cytochemical means in certain broad-nosed male weevils. The substance soon disintegrates, possibly because of an active nucleolus organizer. By early diplotene, the sex bivalent assumes a parachute shape (Xyp). An argyrophilous, fibrous substance appears first at the inner borders of X and y, then invades the whole space between them. Most commonly used nucleolus and protein stains leave it unmarked. RNA and histones seem to be excluded. Only AgNOR staining marks the substance clearly, especially if a formalin-containing fixative has been used.

Detecting endogenous growth regulators on the sarcotesta, sclerotesta, endosperm, and embryo by paper chromatography on fresh and old seeds of two papaya varieties.

Abstract: Sarcotesta, sclerotesta, endosperm and embryo of fresh and old (0 and 3 years, respectively) seeds of the P.R. 6-65 and P.R. 8-65 papaya varieties were separately analyzed by paper chromatography to determine the presence of natural growth inhibitor that might be responsible for the reduction in germination of papaya seeds during storage. The results showed that in the innermost seed parts (embryo and endosperm) endogenous growth promoters were found while the outermost structures (sarcotesta and sclerotesta) contained inhibitors. Therefore, it is possible that the natural growth inhibitors of this seed might be minimized by removing the sarcotesta (the gelatinous envelope) of the seed, which contains the most endogenous growth inhibitors, plus a careful washing to eliminate the soluble inhibitors of the sclerotesta during the extraction of seeds from the fruits.

Silvering of cucurbita moschata (duchesne) poir associated with bemisia tabaci genn. (homoptera: aleyrodidae) in puerto rico

Abstract: SILVERING OF CUCURBITA MOSCHATA (DUCHESNE) POIR ASSOCIATED WITH BEMISIA TABACI GENN. (HOMOPTERA: ALEYRODIDAE) IN PUERTO RICO

Germination of Two Papaya Varieties: Effect of Seed Aeration, K-treatment, Removing of the Sarcotesta, High Temperature, Soaking in Distilled Water, and Age of Seeds.

Abstract: Three experiments were conducted on the germination of fresh (0 years) and old (3 years) seeds of the P.R. 6-65 and P.R. 8-65 papaya varieties. The seeds of variety P.R. 8-65 had a better germination than those of P.R. 6-65, and the fresh seeds of both varieties had a higher percentage of germination than the old ones. Immersion of seeds in a nutrient solution containing KN0 3 and KH 2 PO 4 reduced significantly the germination in the 3-year-old seeds and increased germination in the 0-year seeds of the P.R. 6-65 variety, while in the P.R. 8-65, the 3-year-old seeds were not affected, and the germination of the 0-year seeds was reduced significantly. Air bubbles applied to fresh seeds of both varieties did not affect germination, while germination was significantly increased in old seeds of P.R. 6-65 but reduced in similar seeds of the P.R. 8-65. When air was applied to the two kinds of seeds of the two varieties the weight per seedling and the coefficient of germination velocity were significantly increased. Germination in the two kinds of seeds and varieties used in these studies may be increased by removing the sarcotesta (aril) of the seeds and/or by soaking the seeds in distilled water for 24 hours.

Early yield of five cacao families at three locations in Puerto Rico

Abstract: Five families of Theobroma cacao L. between three and eleven years of age were evaluated for yield at Gurabo, Corozal and Yabucoa. Parents involved in the combination of the families were such well-known clones as 'Pound-7', 'Scavina (SCA)-6', 'Scavina-12', and IMC, EET and UF selections which have been widely used to produce controlled-pollinated seed in Central America and elsewhere. Eight months after transplant, the temporary shade provided by plantains was removed, and the trees were grown under full sunlight and intensive management. Between 1986 and 1993 individual tree yield data were obtained. In September 1989, hurricane Hugo destroyed the Yabucoa experiment but the evaluation continued at Gurabo and Corozal until December 1993. At the termination of the first four-year evaluation period (1988 to 1989), families EET-400 x SCA-12 and SCA-6 x EET-62 were significantly superior yielders at Gurabo with an average total production of 5,538 kg/ha of dry beans. None of the families maintained superiority at Corozal and Yabucoa. The average total yield for all families was 5,950 and 5,225 kg/ha at Corozal and Yabucoa, respectively. The individual tree yield data showed that regardless of location only 2 or 3% of the trees within a family were high yielders and accounted for more than 60% of the total family production. At the termination of the eight-year evaluation period (1986- 1993), families EET-400 x SCA-12 and SCA-6 x EET-62 maintained their superior yielding ability at Gurabo, with an average total production of 14,368 kg/ha. All families performed similarly at Corozal with an average total production of 14,930 kg/ha.

Re-evaluation of pan evaporation coefficients at seven locations in Puerto Rico

Abstract: The goal of this project was to update pan evaporation coefficient (K P ) values for the seven University of Puerto Rico Experimental Substations, based on updated pan evaporation data and the Penman-Monteith reference evapotranspiration. As a part of the study, historical pan evaporation data were evaluated from seven experimental substations. Significant decreasing pan evaporation was observed at Lajas and Rio Piedras. Significant increasing pan evaporation was observed at Gurabo and Adjuntas, and no significant trends were observed at Fortuna, Isabela or Corozal. A significant difference was found to exist between the mean Kp values calculated with pan evaporation data from 1960 to 1980 and those with data from 1981 to 2000.

First report of a new invasive mealybug, the harrisia cactus mealybug hypogeococcus pungens (hemiptera: pseudococcidae)

Abstract: FIRST REPORT OF A NEW INVASIVE MEALYBUG, THE HARRISIA CACTUS MEALYBUG HYPOGEOCOCCUS PUNGENS (HEMIPTERA: PSEUDOCOCCIDAE)

Proper bunch management of the French-type superplantain (Musa acuminata x M. balbisiana, AAB) in Puerto Rico

Abstract: Soon after flowering, bunches of the Musa AAB clone 'Superplatano' (Superplantain) were trimmed to 4, 5 or 6 hands to determine the effect of pruning on fruit grade and marketable yields. Unpruned bunches of the horn-type 'Maricongo' plantain were included as control. Fruits in bunches pruned to 4 and 5 hands exceeded the mean weight of 270 g, a criterion used locally to render horn-type plantains marketable. 'Superplatano' bunches trimmed to 4 and 5 hands yielded 146,800 and 180,200 marketable fruits/ha, respectively, This represented a yield increase of about 26,000 and 59,400 fruits/ha, over the unpruned horn-type 'Maricongo' cultivar. The reduction of hands in the 'Superplatano' bunch significantly increased length, thickness and weight of fruits in the proximal and distal hands.