THE WATER RELATIONS AND IRRIGATION REQUIREMENTS OF PAPAYA (CARICA PAPAYAL.): A REVIEW

Abstract

SUMMARYPapaya has never been found in the wild, but is believed to have originated in tropical America from where it has spread throughout the tropics and subtropics. This fruit crop is particularly important in India and Brazil. Most research on the water relations of papaya has been undertaken in Brazil and on the island of Guam (United States of America). Papaya is a short-lived large herb, growing to a height of up to 10 m. Leaves emerge from the upper part of the unbranched stem. After a juvenile period, lasting for about two months, flowers begin to develop in leaf axils. Flowering continues throughout the year as new leaves emerge. The plants, which are dioecious, begin to bear fruit within a year after planting, sustaining high yields for two years before yields decline. The ‘effective’ root depth varies with the method of irrigation, but can reach 0.55 m. The seedlings and the trees are susceptible to wind damage, a topic that has been well researched. Stomata are only found on the abaxial leaf surface. They are sensitive to changes in the saturation deficit of the air. Stomata also respond quickly to changing light conditions. On clear days, midday suppression of photosynthesis occurs as a result of partial closure of the stomata. In the morning, there is a time lag between water loss by transpiration and sap flow, as water is taken from storage in the hollow stem. Few attempts have been made to measure the actual water use of papaya, and there are no reliable published values for the crop coefficient. Limitations to the design of the papaya irrigation experiments reported so far make it difficult to reconcile the results in practical ways. Water productivities equivalent to 1.8 to 2.8 kg (fresh fruit) m−3 (irrigation water) have been obtained. Although papaya is generally considered to be drought sensitive and responsive to irrigation, there is a shortage of good experimental evidence to support this view. There is a need to establish practical irrigation schedules for this remarkable crop. A uniformity of approach to irrigation experimentation and a common, universally agreed nomenclature would facilitate this process.

Transcriptomic analysis reveals key transcription factors associated to drought tolerance in a wild papaya (Carica papaya) genotype

“…Commercial papaya is considered drought susceptible as, during dry periods, irrigation is necessary to increase their growth and fruit production [ 50 ]. In our study, WDS lead to decrease in various physiological parameters in the commercial genotype, as previously reported [ 50 , 51 ]. When the susceptible and tolerant genotypes were well-watered, both genotypes maintained Ψ values around -0.8 MPa, similar to those observed by [ 52 ] in well-irrigated papaya cv.…”

Brassinosteroid analogue affects the senescence in two papaya genotypes submitted to drought stress

“…Papaya (Carica papaya L.) is a semi-woody giant herb, and this species is considered to be drought sensitive and responsive to irrigation (Carr 2013), so soil water availability limits many physiological processes of papaya (Marler et al 1994, Clemente and Marler 1996, Mahouachi et al 2007. The irrigation of papaya plants is recommended during dry periods to increase growth and fruit production (Malo and Campbell 2006) whereas incorrect water management can adversely affect several physiological processes Glenn 2007, Campostrini et al 2010).…”

Distribución geográfica potencial de papaya silvestre cultivada en México

“…En adición, fue notorio que la precipitación pluvial fue una variable bioclimática relevante en la distribución potencial de cultivares de papaya. Para su cultivo la disponibilidad de agua es importante, dado que las plantas producen de 1.8 a 2.8 kg de fruta fresca por metro cúbico de agua aplicada (Carr, 2014). No obstante, el exceso de agua en el suelo, por lo menos durante un día, causa problemas por falta de oxígeno en el sistema radical (Thani et al, 2016).…”