The horticultural interest of self-compatible fruit tree cultivars depends on their ability to reach the optimal fruit set by self-pollination, thus making superfluous cross-pollination and related problems. In Apulia region (southern Italy) the olive cultivation is spread on about 370,000 hectares. ‘Coratina’ is the most popular olive cultivar in the central part of the region, where actually it is grown in solid blocks on 60,000 hectares and characterized by high and constant productivity. ‘Coratina’ is generally considered to be a self-compatible olive cultivar, but its biological behaviour is a vexed question in the scientific literature. In order to ascertain the real biological behaviour of ‘Coratina’, a 3-year study was carried out on 10 representative monovarietal olive groves scattered on the area of main diffusion. Data concerning fruit set following open-pollination and unassisted self-pollination have been gathered. Among years and sites, an optimal fruit set (3.5%) was obtained from open-pollinated branches and a scarce fruit set (0.02%) from self-pollinated ones. These results assert the self-incompatibility of ‘Coratina’ and show its capacity to provide optimal production levels thanks to the abundant and natural sources of flying compatible pollen from neighbouring districts where different cultivars are spread.

Olive pollination is anemophilous and an adult olive tree can produce large amounts of pollen grains spread in the air during the flowering period. Viability of pollen grains can be checked by using different methods such as cytoplasmic stains, enzymatic reactions or germination. The aim of the work was to verify either if quality and number of pollen grains were similar in 'off' year with respect to 'on' year or differences occurred among olive cultivars. In 2006 and 2007, the viability and number of pollen grains per anther have been investigated in four Italian olive cultivars: 'Ascolana Tenera', 'Cazzinicchio', 'Cima di Melfi' and 'Coratina'. Grains viability was estimated by using three different techniques: acetic carmine, fluorescein diacetate and germination. The three techniques obtained statistically different data, with acetic carmine always showing the highest values but staining also heat-killed pollen grains. Fluorescein diacetate and germination were significantly correlated with a high R2 (0.862). The number of pollen grains significantly varied among the cultivars and between the two years. The average number of pollen grains per anther ranged from 65,722 ('Ascolana Tenera') up to 97,160 ('Cazzinicchio'). A significant difference was detected between the two years for the number of pollen grains per anther, ranging from 98,037 in 2006 ('on' year) down to 70,630 in 2007 ('off' year). The study also showed that the viability (with all the techniques) of the pollen grains was significantly higher in the 'off' year with respect to the 'on' one, with important consequences on the fertilization process.

In 2006 and 2007, the quality of pollen grains has been investigated in four Italian olive (Olea europaea L.) cultivars: ‘Ascolana Tenera’, ‘Cazzinicchio’, ‘Cima di Melfi’ and ‘Coratina’. Grains quality was estimated by using two different methods, acetic carmine (stainability) and fluorescein diacetate (viability), in comparison with germination. Acetic carmine and fluorescein diacetate gave statistically different data, i.e., 90.2 vs. 58.1%, whereas the mean germination value was only 48.0%. Acetic carmine always showed the highest values but also stained heat-killed pollen grains with a non-significant difference between heat-killed and stainable grains. Significant differences in acetic carmine and fluorescein diacetate values were observed among cultivars. ‘Cima di Melfi’ showed the highest percentage of stainable and viable pollen grains. Finally, fluorescein diacetate and germination were significantly correlated with a high R2 (0.862, P≤0.001).

Almond (Prunus amygdalus Batsch) is considered to be able to tolerate drought stress fairly well during all stages of fruit growth. Nevertheless, severe water stress together with high temperatures during summer can seriously reduce hull split and consequently promote the occurrence of hull-tight nuts. In this study we report the results of an investigation carried out in Apulia region (Southeast Italy) in order to evaluate the effects of the long, dry and warm 2012 summer on fruit quality of 23 almond cultivars. Cultivar sensitivity to water stress was expressed as hull-tight nut percentage. At harvest, the following measurements were performed: hull-tight nut percentage, kernel weight, percentage of well filled, empty and wrinkled kernels, both on normal and hull-tight nuts. Almost all cultivars showed fruits with adhering hulls, but with significantly different incidence. On average, hull-tight nuts showed lower kernel weight and higher percentage of empty and wrinkled kernels than normal fruits which, however, showed kernel weight values lower than those observed in standard years.

The prevailing environmental conditions, temperature in particular, drive seasonal changes both in leaf development and stomata! characteristics. In order to ascertain the effect of increases in climatic water deficit on some leaf and stomatal parameters under field conditions, a study was carried out on two sets of leaves (spring and summer) on a large sample of Amygdalus communis L. cultivars in comparison with several Amygdalus webbii Spach seedlings, a species more adapted to arid environments and probable ancestor of cultivated almonds. Observations were performed between spring and summer of a particularly hot season. The results showed a significant and general reduction of both leaf area and stomatal frequency and an increase in stomata! size. Nevertheless, there were evident differences between cultivated and wild almonds. A stronger reduction of leaf area was observed in A. webbii (-31%) with respect to A. communis (-14%); on the contrary, the latter reduced stomatal frequency more than the former (-25% and -19%, respectively). The examined cultivated almonds, in response to the increase in climatic water deficit, tended to arrange their stomatal structures like those of wild almonds. Finally, increasing the climatic water deficit, the slope of the linear regressions between stomatal frequency and size did not change in either species, leading to a better understanding of the mechanisms of almond acclimation to environmental stresses.

Abnormally developed pistils often occur in different apricot cultivars, as a consequence of physiological-biochemical factors and climatic conditions. Apricot is genetically prone to the formation of a high percentage of flowers morphologically hermaphroditic but physiologically unisexual due to pistil hypotrophy, atrophy and/or necrosis. The number of anthers, the amount of the total and stainable number of pollen grains per anther and per flower and flower (pistil) anomalies have been investigated in apricot (Prunus armeniaca L.) cultivars. Anthers and pollen were investigated for two years, 2004 and 2005, whereas flower bud differentiation and anomalies for three years, 2008, 2009 and 2010.Pistil hypo(a)-trophy anomalies occurred between the Baggiolini stages C and D and appeared to be significantly more frequent on the basal portion of long twigs with respect to either the apical portion or spurs and short twigs. All pollen characteristics taken into account varied significantly among the cultivars. The number of anthers per flower ranged from a maximum of 33.2 ('Rouge de Fournes') to a minimum of 22.6 ('Boccuccia Liscia'); the number of pollen grains per anther ranged from 2369 ('Kioto') to 1267 ('Ninfa'), and the pollen stainability was very high in all the examined cultivars (95.0-98.8%). The mean number of stainable pollen grains per flower was 57,149, ranging from 35,629 ('Boccuccia Liscia') up to 76,728 ('San Castrese'). These results indicate that cultivars both producing the greatest amount of stainable and compatible pollen grains per flower and bearing mainly on spurs or short twigs (lower flower anomalies) should be preferred either when planting new apricot orchards or for breeding programs.

The almond industry in Italy represents a high degree of structural variability that is determined and sometimes jeopardized by the coexistence of old, traditional orchards and new plantations that differ from each other not only in terms of age but also orchard systems. Apulia and Sicily remain the most important production areas where 90% of the almond orchards are concentrated. In this southern part of Italy, almond and its derivatives still remain very important. In the last two decades, the Italian almond industry did not show a regular trend, neither with respect to production nor to acreage. An innovative almond industry revealed its consistency year after year since 2000. Self-fertile cultivars, clonal rootstocks and new planting designs optimized for mechanization were the most important technical aspects which revealed a new way to set up almond orchards. As a matter of fact, the Italian almond industry is still characterized by two strongly different structures: a traditional one based upon old cultivars and orchard systems often with unsatisfactory yields, and an innovative one which is very interesting and appears to be able to partially renew the sector. Technical aspects on this new way to obtain innovative almond orchards and their perspectives are reported here primarily in terms of technical choices.

New apricot cultivars are yearly introduced in Italy by nurseries and growers. These cultivars come from both Italian and foreign breeding programmes and most of them have been selected in climatic and environmental conditions noticeably different from those of the main Italian apricot growing areas. So far, acquired experience on apricot has shown that environmental adaptability is hard to be foreseen and, for this reason, the introduction of cultivars in new areas often causes commercial failures. In order to reduce this problem and to help growers in choosing new cultivars, in 1992 a National Programme was launched to draw up an annual list of "Recommended fruit varieties" for fruit-tree growers. This means that each new apricot cultivar, bred in Italy or in other countries, enters the collection created by the 10 Operating Units and is assessed for its vegetative, pomological, horticultural and technological characteristics, according to a common evaluation protocol. Basing on the resulting features, lists with recommended/not recommended cultivars are filled in. In order to highlight the strong variability among Italian growing areas and the need for a proper collegial evaluation, a summary of some pomological and phenological features has been drawn up and discussed. Selected data have been collected on 10 sites all over Italy for two consecutive years (2006-2007) characterized by noticeably different climatic conditions. This last aspect could also lead to some considerations about the future adaptation of apricot cultivar to climatic changes.