RICERCA ITALIANA     

VEGETATIVE GROWTH CONTROL MECHANISMS IN OLIVE (OLEA EUROPAEA L.)
GENOTYPES CHARACTERIZED BY DIFFERENT VIGOUR

Università degli Studi di Palermo

Abstract

Aim of the research project is the study of morphologic, hysto-anatomical, ecophysiological and molecular of processes involved in growth control in olive. Object of research will be two clones of cv. "Leccino" olive characterized by contrasting vegetative vigour: "Leccino Minerva", with standard vigour, and "Leccino dwarf", characterized by low vigour. Furthermore, to verify the level of control exerted by the environment on growth processes, the study will be performed under two different radiative regimes.
The structure of the research proposed finds its rationale in the importance, recognized in a number of species, of the mechanisms of regulation of plant water relations in the control of vegetative growth and dry matter partitioning processes. To this aim, a central role has been given to the integration of the information that will be gathered in studying plant hydraulic architecture and its regulation at a molecular level, with data on primary production and assimilate and nutrients partitioning within tree. This integration will be possible also due to the use of innovative methodologies that allow to evaluate "in vivo" important physiological parameters of plant water relations with high accuracy and on different scale levels.
In the research, particular emphasis will be dedicated to the processes contributing to the realization of primary production, such as water transport, photosynthesis, accumulation and partitioning of dry matter and mineral >>>

Principal Investigator

Tiziano CARUSO Università degli Studi di PALERMO

Research Objectives

In olive culture, the necessity to reduce costs of cultural practices and to obtain a fast return of investment costs, urges the integral mechanization of the cultivation techniques, namely harvest and pruning. The availability of small-sized trees is the fundamental prerequisite for the intensification of planting systems and the adoption of machinery with high operative efficiency. While in many fruit tree species, control of tree size has been obtained through the use of rootstocks, in olive, to date, the only way to control tree size is the use of low vigour genotypes. In recent years, some examples of high density hedge-row olive orchards have been setup, with the use of low-vigour genotypes, in which the integral mechanization of olive picking operations have been achieved through the use of the same overhead harvesting machines developed for the grapevine industry.
To date, within the world olive germplasm, only few genotypes have been recognized as suitable for high-density hedge-row systems. This could lead to an impoverishment of the diversity of olive cultivars which contribute to world oil production and, for this reason, a more extensive study of olive germplasm keeping into consideration the phenotypic characters related to tree growth and vegetative vigour is highly desirable. To this purpose, it becomes crucial a deeper knowledge on mechanisms of growth limitation.
Aim of the research project is the study of morphologic, hysto-anatomical >>>

Timescale

24 months

National and international background

As for large part of temperate zone fruit trees species, the olive, a species able to live in dry environmental conditions, the aspects related to the control of the vegetative growth of the tree, in the last thirty years, has become object of research activity at the more important scientific institution of the Mediterranean Countries (De Rio et al., 2000). The availability of rootstocks that reduce tree size represents, in fact, an important instrument, especially in the Mediterranean European Countries, in order to encourage a productive activity that today evidences signs of weakness. Similarly to what happened in fruit growing, also for olive it becomes necessary to renew the systems, intensifying planting densities to reduce the unproductive period, to increase yield and, in relation to the destination of the product, to mechanize integrally or, at least, to facilitate harvest (Tous et al., 1999). To give a new impulse to olive growing, it becomes therefore important to get new genotypes characterized by weak vegetative growth and early fructification.
Recently, the researchers attention on cultivar choices, moved towards on above mentioned characteristics instead to productivity and oil yield. In fact, the introduction of olive trees in new countries was done with cultivars like "Arbequina", "Koroneiki" e "Arbosana", in the past considered cultivars of minor importance.
The tendency to prefer cultivars of modest vigour and early fructification, is >>>