1Institute of Sciences of Food Production, CNR-ISPA, Via Amendola, 122/O, 70125 Bari, Italy.
2Mediterranean Agronomic Institute of Bari CIHEAM-IAMB, Via Ceglie, 9, 70010 Valenzano (BA), Italy.
3National Research Council of Italy, Institute for Agricultural and Forestry Systems in the Mediterranean (CNR–ISAFOM), Via Patacca, 85, 80056 Ercolano (NA), Italy.
4Consiglio per la Ricerca e la Sperimentazione in Agricoltura, Research Unit for Cropping Systems in Dry Environments (CRA-SCA), Via Celso Ulpiani 5, Bari, Italy.
Potato grown for early or off-season production plays a crucial role in the
economy of several areas in the Mediterranean countries. Irrigation is important for
determining yield and earliness, thus a better investigation of plant response under
various pedo-climatic conditions can help to improve resource use efficiency and
farmer income. A two-year field research (2009-2010) was carried out in Apulia
region, southern Italy, on cv Spunta grown under three irrigation regimes: full
irrigation (I100), 50% of full irrigation (I50) and rainfed (I0). Treatments were
arranged in a randomized complete block design with three replicates. Plant water
status, plant growth and, at harvesting, water use efficiency, yield and quality
parameters were quantified. Water stress significantly affected yield response: as
an average of the two years, a marketable yield decrement of 25.9 and 63.6% was
observed in I50 and rainfed compared with I100 treatment, respectively. On the
contrary, tuber dry matter and specific gravity increased moving from irrigated
treatments to the rainfed one and varied also as a function of experimental year.
The results confirmed that irrigation is required for early potato cultivation because
rainfall is not sufficient to meet crop water needs. In addition, the study indicated
that the irrigation regime reduced by 50% of crop water requirements was able to
furnish satisfactory yield, with tuber quality characteristics similar or even better
than those obtained under full irrigation. Keywords: Solanum tuberosum L.; Mediterranean climate; Leaf water potential;
Deficit irrigation; Yield components; Tuber quality.