Suhas R. Ghate

Pecan drying with silica gel

Abstract High moisture in-shell pecans were dried by keeping them in direct and indirect contact with silica gel to investigate their drying characteristics. In-shell pecans were also dried with ambient air from a controlled environment chamber and with air dehumidified by silica gel. Direct contact and dehumidified air drying seemed feasible approaches.

Stand and yield of cucumber seeded with gel and fungicides in various tillage systems

Abstract A cucumber (Cucumis sativis L.) crop was established in various tillage systems from gel-sown germinated seed. Fungicides (flutolanil plus metalaxyl) were mixed with a gel or applied as a drench after seeding to control Rhizoctonia and Pythium seedling diseases. The benefit of mixing fungicides with a gel was similar to that of drenching the seeded area with fungicides. There was no advantage in using germinated seed for cucumber production in conservation tillage. Germinated seed was more susceptible to fungal diseases in the absence of fungicides. Crop yield was greater in conventionally prepared soil than in conversation tillage.

Water quality in catfish ponds subjected to high stocking density selective harvesting production practice

Abstract Nine 0·1-ha earthen ponds were stocked with 12500, 25000, and 37500 channel catfish ( Ictalurus punctatus ) fingerlings/ha in three replicates. Ponds were fed daily with a commercial feed at a rate up to 3% of the fish weight determined by sampling. They were periodically harvested to remove marketable fish weighing more than 0·25 kg. The harvested fish were replaced by fingerlings. Water quality of all ponds was monitored weekly by analyzing chemical parameters including nitrite-N, nitrate-N, total ammonia-N (TAN), total Kjeldahl nitrogen (TKN), total phosphorus, chloride, chemical oxygen demand (COD), and total and dissolved solids. Concentrations of nitrite-N, nitrate-N, TAN, and total phosphorus were not significantly different among stocking densities at any given time but were significantly different over time. The values of TKN and COD were significantly affected by treatments as well as time. The amounts of total solids were significantly higher for the highest stocking density treatment but the dissolved solids concentrations did not change significantly with stocking density or time. Ranges for chemical parameters were 7·0 to 8·4 for pH, 0·4 to 2·7 mg/litre for NH 3 N, 1·3 to 28·5 μg/litre for NO 2 N, 10·6 to 771·9 μg/litre for NO 3 N, 2·2 to 85·5 mg/litre for TKN, 28·2 to 150·0 mg/litre for COD, and 0·05 to 0·6 mg/litre for total phosphorus. The amount of total solids ranged from 105 to 262 mg/litre. The feed-to-weight-gain ratios were 1·66, 1·64, and 1·82 for high, medium, and low density treatments respectively.

Evaluation of a mass inoculation method of potatoes withPseudomonas solanacearum

Wounding of potato stems by the application of clean sand at a 45° angle at 550 kPa pressure followed by a spray-mist ofPseudomonas solanacearum proved to be the most reliable method of rapidly inoculating a large quantity of potato plants to incite bacterial wilt in the field. The technique was 100% efficient (320/320) and it was estimated that 10,000 plants/hr could be inoculated by using this method.Because of its hygroscopic nature, sand coated withP. solanacearum created too many mechanical problems to be of practical value for field use even though the amount of wilt after 21 days was not significantly different from that of the best treatment. In addition, viability of inoculum as a bacterial suspension in water was greater than as coated sand.ResumenEl herir tallos de plantas de papa aplicando arena limpia en un ángulo de 45° con una presión de 550 kPa y a continuación rociarlo conPseudomonas solanacearum, mostró ser el método más confiable de inocular rápidamente una gran cantidad de plantas de papa para provocar marchitez bacteriana en el campo. La técnica fue 100% eficiente (320/320) y se estimó que se podian inocular 10,000 plantas/hora con este método.Debido a su naturaleza higroscópica, la arena tratada conP. solanacearum creó demasiados problemas mecánicos para tener algún valor práctico en su utilización en el campo aunque la cantidad de marchitez, después de 21 días, no fue significativamente diferente de la del mejor tratamiento. Además, la viabilidad del inóculo en la forma de una suspensión bacteriana en agua fue mayor que como arena recubierta.

Engineering needs for potato production from true seed

Potatoes grown from true potato seed (TPS) are generally small and nonuniform in size and shape, compared to the ones produced conventionally from seed tubers. Potato production from TPS would be considerably less expensive than from seed tubers because of the negligible storage and handling costs of the TPS. Potato production from TPS would therefore have the greatest potential in the developing countries. In developed countries, this production method would have some potential in commercial production as well as in home gardening. Research related to the TPS potato production has been mostly directed toward investigating suitable cultural practices, screening breeding lines for higher yield and warm climate adaptability, weed control in the field, and other similar production areas. Research concerning mechanization of TPS potato production has been limited. Engineering input to the TPS potato production, handling and storage needs considerable attention to develop practical and economical practices. This paper highlights some research areas which the authors believe are worth investigating. Engineering research that is conducted at the Coastal Plain Experiment Station related to the TPS potato production has been outlined along with future plans.ResumenLas papas producidas a través de la semilla botánica (TPS) son generalmente pequeñas y desuniformes en tamaño y forma, en comparación con aquellas producidas convencionalmente a través de tubérculos-semillas. La producción de papa a través de TPS séria considerablemente menos costosa que cuando se utilizan tubérculos semillas debido al casi inexistente almacenamiento y a los costos mínimos de operación de la semilla botánica. La producción de papa a través de la semilla botánica tendría por lo tanto el mayor potencial en los países en desarrollo. En los países desarrollados este método de producción tendría algún potencial tanto en la producción comercial como en los huertos caseros. La investigación relacionada con la producción de papa a través de semilla botánica, ha estado mayormente orientada a investigar prácticas culturales adecuadas, a evaluar líneas de cruzamientos o mejoramiento para mayores rendimientos y su adaptación climas calurosos, al control de las malas hierbas en el campo y a otros aspectos similares de la producción. La investigación correspondiente a la mecanización de la producción de papa a través de semilla botánica ha sido muy limitada. El manejo y dirección de la producción de papa a través de semilla botánica, así como su manipulación y almacenamiento, requiere de considerable atención para desarrollar procedimientos prácticos y económicos. Este trabajo pone de relieve algunos aspectos de investigación que de acuerdo a los autores es importante investigar. Algunas investigaciones sobre el manejo de la producción de papa a través de semilla botánica que están siendo conducidas en la Estación Experimental de los Llanos Costeros, han sido descritos conjuntamente con algunos proyectos futuros.

Effect of storage temperature and duration on quality and survival of potato transplants

Potato transplants (Solanum tuberosum) were harvested and stored at 1.7, 7.2, 12.8, 15.6 and 18.3°C between 4 and 8 days. The transplants were evaluated after storage for leaf color and drop, wilt, tuberization, and stolonization. After transplanting, the plants were evaluated for survival. At 1.7 and 7.2°C storage, the leaves were greener with less drop than at the higher temperatures. During storage above 7.2°C, the development of tubers and stolons continued. Plant survival was generally higher at 1.7, 7.2 and 12.8°C than at 15.6 and 18.3°C.ResumenLas plántulas de papa (Solanum tuberosum) fueron sacadas del almácigo y mantenidas durante 4 a 8 días en 1.7°, 7.2°, 12.8°, 15.6° y 18.3°C. Luego fueron evaluadas por el color y la caída de sus hojas y por marchitez, tuberización y estolonización. Después del trasplante, las plántulas fueron evaluadas por su sobrevivencia. Con una exposición a 1.7° y 7.2°C, las hojas estuvieron más verdes y cayeron menos que a temperaturas más altas. Con una exposición a más de 7.2°C, el desarrollo de los tubérculos y de los estolones continuaba. En general, la sobrevivencia de las plantas fue mayor en las que habian estado expuestas a 1.7°, 7.2° y 12.8°C que en las expuestas a 16.6° y 18.3°C.

Growth of Pepper Seeds Planted with Gel Chemical Mixture

ABSTRACT GERMINATED pepper seeds were incorporated into three gels (Agro-Gel,* Laponite 508 and Water-Lock B 100) and treated with daminozide, gibberellic acid, diphenamid, metalaxyl and phenamiphos prior to being sown in the greenhouse. Germinated seeds were also fluid drilled in two soils with Laponite gel and then treated with two rates of the same five chemicals. Although some treatments affected seedling emergence rates, there was no adverse effect of any chemical on the dry weight, length, or diameter of the plants either in the greenhouse or in the field

Emergence and plant stand of pregerminated true potato seed in warm climate

Pregermination of true potato seeds obtained from open pollination of breeding lines and F1, hybrids improved the emergence and stand in a warm climate. Considerable differences in emergence existed within the breeding lines and F1 hybrids. With proper selection of breeding lines and pregermination of seeds, it would be possible to obtain a desirable plant stand in a warm climate.ResumenLa pregerminación de la semilla sexual de papa mejoró la emergencia y la densidad en muchas lineas avanzadas de mejoramiento y de híbridos F1 en un clima caliente. Hubo diferencias considerables en emergencia dentro de las líneas de mejoramiento y de los híbridos F1. Con una selección apropiada de lineas de mejoramiento y con la pregerminación de las semillas, séria posible obtener una densidad satisfactoria de plantas en clima cálido.

A Field Inoculator for Potatoes

ABSTRACT A device was developed for field inoculation of potato plants with Pseudomonas solanacearum E. F. Smith. A prerequisite wound induced by sand blasting, followed by a spray of bacterial suspension, produced severe wilt of potato even under suboptimal environmen-tal conditions.

Performance of Precooled Tomato Transplants

FIELD grown bare root tomato transplants packed in commercial shipping crates were precooled in a batch type precooler by forced air cooled with liquid carbon dioxide (L-C02). The precooled transplants were shipped via commercial truck from Tifton, GA to Fremont, OH. Some of the precooled and nonprecooled transplants were immediately planted in the field upon reaching destination and some were planted after 5 days of storage either at ambient or at 7°C temperatures. The technique of precooling using L-C02 was successful but there was nonuniform cooling between crates. The precooled transplants went through a heating and cooling cycle in transit because of the heat load of nonprecooled transplants. The survival and fruit yield data indicated that the performance of precooled and nonprecooled transplants was similar when they were not stored. The performance of stored transplants was worse than unstored transplants and the performance of precooled-stored transplants was worse than nonprecooled-stored transplants. Successive heating and cooling of precooled tomato transplants caused damage.