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Morphological and anatomical development of fruits of two cultivars of olive (olea Europaea L.) grown under irrigated and rainfed conditions in southwestern Buenos Aires province

Rosetti, M. V., Flemmer, A. C., Hernandez, L. F.
Acta horticulturae 2014 no.1057 pp. 107-111
Olea europaea, cultivars, digital images, endocarp, fruit set, harvesting, irrigation, mesocarp, olives, rain, trees
This study compared the fruit development of the olive cultivars ‘Arbequina’ and ‘Nevadillo’ grown under irrigated and rainfed conditions in the southwest of Buenos Aires province (38°50’21”S; 61°06’46”W). From fruit set to harvest, seven fruit sampling dates were selected, measuring fruit volume and mesocarp and endocarp transverse area (TA). Digital images of histological sections of the mesocarp were analyzed by counting cell number and cell TA. During the experimental period, rain accounted for 511 mm (rainfed). Water supplied by irrigation totalized 222 mm. The fruit growth dynamics based on the volume and the TAfruit in both cultivars fit to a double sigmoid function with two phases of rapid growth connected by a plateau between January and March. Throughout the study, plant water status, monitored by the RWCleaf, was similar among water regimes. The TAendocarp was similar between cultivars and water regimes. At final fruit volume, TAfruit and TAmesocarp showed significant differences between cultivars, being of 2.48 cm3, 165 mm2 and 126 mm2 in ‘Nevadillo’ and 1.36 cm3, 129 mm2 and 93 mm2 in ‘Arbequina’, respectively. Final TAcell was similar in both cultivars averaging 6050 µm2. The mesocarp cell number was higher in ‘Nevadillo’, which may explain its higher TA(mesocarp). Fruits grown under rainfed had higher TAfruit, TAmesocarp, cell number and TAcell than those grown under irrigation. Lower crop load in rainfed trees compared to irrigated ones could explain this last result.