THE RESPONSE OF TWO SHORT-DAY ONION CULTIVARS TO CURING WITH SOLAR RADIATION IN PLASTIC TUNNELS

Short-day onion (Allium cepa L) production in Florida is limited mainly by poor keeping quality associated with inadequate curing. Curing is a drying process which removes about 5% of the water. A plastic tunnel accumulated heat from solar radiation, which raised air temperatures, lowered relative humidity, promoted drying and protected the bulbs inside the tunnel from rain. Curing efficiency was determined by weight loss, shelf life and quality of bulbs of 'Yellow Granex 33' ('Granex') and 'Texas Grano 502' ('T.G. 502') grown in organic (muck) and mineral (sand) soils and cured in windrows and plastic tunnels. Both 'Granex' and 'T.G. 502' had good appearance and quality after curing, particularly when grown in sand. Weight loss of 'Granex' was 5.5% and 'T.G. 502' 7.5% after 25 days of curing. 'Gran ex' had 6.4% and 'T.G. 502' 24.3% decay after 51 days of room temperature storage. Muck and sand grown onions had the same weight loss during curing, but after 51 days of storage, onions grown in sand had less weight loss and decay than those grown in muck. Windrowed onions lost 9.2% weight and tunnel cured onions 3.8% in 25 days curing. Tunnel cured onions had significantly more decay than windrowed onions at the end of 51 days of storage. Interactions among cultivars x soils x methods of curing were found to be significant. Yield, keeping quality and appearance were maximized when 'Granex' was grown in sandy soil and cured in plastic tunnels or windrows when no rain occurred. Regression analysis indicated a relationship between weight loss and time. 'Granex' required 11 days and 'T.G. 502' six days of windrow curing to attain 5% weight loss. 'Granex' reached 5% weight loss in 22 days and 'T.G. 502' in 11 days when cured in the tunnel. This suggests that a monitoring process is needed to ascertain when 5% weight is attained. ----- La produccion de cebolla (A. cepa LJ de corto dfa en Florida se limita mayormente por la corta vida poscosecha asoseiada con curaci6n inadequada. Curaci6n es un proceso desecativo que elimina alrededor de 5% del agua, Un tunel. de polictileno acumukf calor de radiacidn solar, que subid las ternperaturas del aire, baj<5 la humedad relativa, foment6 secamiento y protejd los bulbos dentro del tunel de la lluvia. Eficiencia de curacion fue determinado por disminuci6n de peso, duraci6n de vida poscosecha y calidad de bulbos de 'Yellow Granex 33' ('Granex') y 'Texas Grano 502' ('T.G. 502') cultivados en suelos organicos (muck) y minerales (arena) y curados en amontonamientos a aire libre 0 en tuneles de plastico. 'Granex' y 'T.G.. 502' tenian buena apariencia y calidad despues de curacion, partlcularrnente cuando fueron cultivados en suelo arenoso, Despues de 51 dias de curacion la disrninucidn de peso de 'Granex' era 5.5% y la de 'T.G. 502' era 7.5%. Despues de 51 dias de alrnacenamiento a temperaturas medianas, 'Granex' sufn6 6.4%· de pudricicn, y 'T.G. 502' sufri6 24.3% de pudricion. Cebollas cultivadas en suelos organicos y suelos arenosos tenian la misma dlsminucion de peso durante curacidn, pero despues de 51 dias de almancenarniento, las cebollas de suelo arenoso sufrieron menos disminuci6n de peso y pudricion que las de suelo orgJlnico. Cebollas en amontonarnientos perdieron 9.2% del peso y cebollas en tuneles perdieron 3.8% del peso en 25 di'3.s de curacion. Despues de 51 dias de almacenamiento, las cebollas curadas en tuneles sufrieron significa tivarnente mas pudrici6n que las cebollas curadas en amontonamientos. Se encontro interacciones significantes entre variedades y suelos y metodos de curacidn, Rendimiento calidad en almacenamiento y apariencia fueron mayores cuando 'Grauex' fue cultivado en suelo arenoso y curado en tuneles de plastico 0 en amontonamientos sin lIuvia. Analisis de regresion indic6 una relacion entre disminucion de peso y tiempo. 'Granex' exigio 11 Mas y 'T.G. 502' exigio 6 dras de curaci6n en arnontonarnientos para obtener un 5% disrninucion de peso cuando fueron curados in tuneles, Los datos sugieren que se precisa un metodo para determinar cuando se obtiene la disminuci6n de 5% del peso.


Issue Date:
Sep 08 1985
Publication Type:
Conference Paper/ Presentation
Language:
English
Total Pages:
9




 Record created 2017-08-03, last modified 2017-08-29

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