Stefano Predieri

Mutation induction and tissue culture in improving fruits

This review describes in vitro mutation induction methods in fruits and the in vitro selection procedures available for early screening. Results obtained through in vitro mutation techniques, including somaclonal variation, are reviewed and compared with the current achievements and future prospects of transgenic breeding. Plant improvement based on mutations, which change one or a few specific traits of a cultivar, can contribute to fruit improvement without altering the requirements of fruit industry. Induced mutations have well defined limitations in fruit breeding applications, but their possibilities may be expanded by the use of in vitro techniques. Tissue culture increases the efficiency of mutagenic treatments for variation induction, handling of large populations, use of ready selection methods, and rapid cloning of selected variants. Molecular techniques can provide a better understanding of the potential and limitations of mutation breeding e.g. molecular marker-assisted selection, which can lead to the early identification of useful variants. The relatively high number of research reports compared with the low number of cultivars released suggests that mutagenesis in combination with tissue culture is either ineffective or has yet to be exploited in fruits. Positive achievement recorded in other species seem to support the hypothesis that in vitro mutation induction has high potential also for fruit improvement. The possible contribution of a well-pondered and coordinated use of the numerous mutation induction, mutant selection, and field validation procedures available to advances in fruit breeding is discussed.

High-frequency shoot regeneration from leaves of the apple rootstock M26 (Malus pumila Mill.)

Regeneration of shoots was achieved from in vitro leaves of M26 at frequencies close to 100% on a medium based on MS salts and LS vitamins, containing 4.4 μM BA and 0.5 μM NAA. Dark and red light gave the best results in inducing shoot regeneration. White light at high intensity helped development of regenerated shoots. Inorganic nitrogen could be reduced by 75% without negative effect, and the presence of NH4+ was necessary for regeneration. Leaves were able to regenerate after a 3 kR irradiation (gamma rays), not after 4 kR. Optimal dose should be between 1 and 2 kR.

Regeneration from in-vitro leaves of ‘Conference’ and other pear cultivars (Pyrus communis L.)

SummaryRegeneration of shoots from in-vitro grown leaf tissues of the pear cv. Conference was achieved at rates of up to 40%. The highest regeneration percentage was achieved using a phytohormone combination of benzylamino purine (5 mg 1−1) and 1-naphthalene acetic acid (1.0 mg 1−1) on a basal medium of Murashige and Skoog, to which had been added 200 mg I−1 of the antibiotic cefotaxime. The percentage regeneration was reduced when a higher concentration of cefotaxime (400 mg 1−1) was used. Cefotaxime had little beneficial effect on regeneration at a lower concentration of 1-naphthalene acetic acid (0.5 mg l−1). Regenerated shoots were easily micropropagated, rooted and transplanted to soil. To date, the plants have a true-to-type phenotypic appearance. Regeneration was also achieved with other cultivars—‘Abbe Fetel’, ‘Doyenne d’Hiver’, ‘Doyenne du Comice’ and ‘Passe Crassane’—but percentage regeneration was lower and, apart from ‘Passe Crassane’, the regenerated shoots were weak and could not be subcultured.

Vesicular-arbuscular mycorrhizal inoculation of micropropagated fruit trees

Micropropagated plantlets of OH x F 51 and GF 677, respectively pear (Pyrus communis L.) and peach (Prunus persica x Prunus amygdalus) clonal rootstocks were inoculated during an early weaning stage of acclimatization with Glomus sp. Both rootstocks were well colonized, although the infection of OH x F 51 spread more slowly. At the end of initial vegetative growth, mycorrhizal plants of both rootstocks showed a three-fold increase in shoot length over control plants. Mycorrhizal plants also had longer internode and greater fresh mass. The root/shoot ratio was especially altered by arbuscular mycorrhizal inoculation in OH x F 51 plants, which showed a greater increase in shoot rather than in root biomass. The growth-promoting ability of endomycorrhizal fungus persisted throughout the experimental period: Glomus sp. induced a greater development of both rootstocks in the second growing year, after overwintering. Colonization of micropropagated plants by arbuscular mycorrhizal fungus appears to alter the car...

Sensory evaluation and instrumental measurements to determine tactile properties of wool fabrics

Fabrics manufactured in Italy with 100% Sardinian sheep breed wool, traditionally named ‘Orbace’, and with local Tuscan wool from 50% Sardinian and 50% Comisana sheep breeds wool (Tuscan Cloth), were subjected to sensory evaluation, through descriptive analysis performed by a trained panel, and to an instrumental evaluation method, through FAST – Fabric Assurance by Simple Testing. The correlation between instrumental data and sensory attributes was investigated. Sensory evaluation indicated that Orbace fabrics, originated from 100% Sardinian wool, had higher grittiness, stiffness, force of compression and hand friction and lower softness and tensile stretch, as compared to the fabrics obtained from mixed wool. Principal component analysis (PCA) indicated a high correlation for grittiness, stiffness and force of compression in one direction, tensile stretch, softness, warmth and fullness in the opposite, clearly discriminating in this dimension Orbaces from Tuscan fabrics. This discrimination appears to be an effect of the wool used for the different fabrics. Differences in key sensory traits were also recorded among fabrics derived from the same raw material, but differing in weave. Thickness, as the key attribute of the second PCA dimension, provided discriminations within groups and is reasonably perceived as an effect of different weaves. Canonical Correlation Analysis indicated that measurements performed with FAST were correlated with a number of basic touch traits, including softness, stiffness, force of compression and tensile stretch. Orbace and Tuscan Cloth handle definition, on the basis of sensory and instrumental measures, will be of use to describe and protect original products.

In vitro Mutagenesis and Mutant Multiplication

Induced mutations technique is a valuable tool not yet fully exploited in fruit breeding. Tissue culture makes it more efficient by allowing the handling of large populations and by increasing mutation induction efficiency, possibility of mutant recovery and speediness of cloning selected variants. Some vegetatively-propagated species are recalcitrant to plant regeneration, which can be a limit for the application of gene transfer biotechnology, but not for mutation induction breeding. Mutagenesis offers the possibility of altering only one or a few characters of an already first-rate cultivar, while preserving the overall characteristics. Traits induced by mutagenesis include plant size, blooming time and fruit ripening, fruit color, self-compatibility, self-thinning, and resistance to pathogens (Predieri, 2001). The combination of in vitro culture and mutagenesis is relatively inexpensive, simple and efficient (Ahloowalia, 1998). The availability of suitable selection methods could improve its effectiveness and potential applications. The molecular marker technology available today already provides tools to assist in mutation induction protocols by investigating both genetic variation within populations and early detection of mutants with desired traits. However, cost still represents a major limitation to their application. Among the techniques and sources of genetic variation available for tissue culture mutation induction, physical mutagens have already shown potential for application in fruit breeding. The types of radiation suitable for mutagenesis are ultraviolet radiation (UV) and ionizing radiation (X-rays, gamma-rays, alpha and beta particles, protons, and neutrons). X-rays and gamma-rays are the most convenient and easiest types of radiation to use with regards to application methods and handling (Sanada & Amano, 1998), and have been both the most widely used ionizing radiation types and the most effective for fruit breeding purposes. Furthermore, physical mutagens

Effect of potassium humate on apple cv. Golden Delicious cultured in vitro

The effects of humic substances on in vitro culture of ‘Golden Delicious’ apple are reported. Potassium humate (KH) when used in proliferation showed a negative interaction with BA while it enhanced rooting when IBA was not present in the culture medium. In the presence of IBA, KH increased root number and reduced root growth. The highest concentration tested, 500 mg l-1, caused a drastic reduction in root system development. 50 mg l-1 KH hastened rooting and plants grew more rapidly when transferred to soil.

Older adults involvement in developing satisfactory pasta sauces with healthy ingredients

Purpose The third age can be a period of major food consumption changes. Either voluntary or imposed by health issues, they may be accompanied by alterations in sensory acuity. This research investigated how lifelong food habits, health-age issues affect food choice at a later age, with the aim of developing strategies to direct aged people towards healthier food habits. Design/methodology/approach A survey, aimed to investigate differences between current and past food habits, was carried out in a group of 170 Italian older adults. Questions focused on the composition of the main meal, asking participants to describe its actual structure and to highlight differences in previous years’ food habits. A Discrete Choice Experiment (DCE) was planned, during which participants were asked to help formulating innovative pasta sauces with healthy ingredients. Findings This survey clearly illustrated gender-related differences: women were characterized by a higher consumption of vegetables, while men revealed a mor...

Senior Consumers Involvement in Developing New Fish-Based Foods Through Sequential Hedonic Tests

Older population needs specific food, adequate to age and health requirements, and acceptable from the sensory point of view. To develop functional products the involvement of senior assessors was experimented. A panel of 35 seniors evaluated fish-burgers and fish-sausages through sensory tests adapted to their cognitive capacities. A model of sequential discrimination, ranking and tetrad tests, was applied with the aim to define the shape (burger vs. sausage), The species and relative percentage of fish, the addition of vegetables, and the presence of potato. The panel indicated a preference for sausage, while ranking tests indicated tuna alone or with mackerel to be preferred. The addition of tomato and artichoke improved acceptance. The acceptance scores showed that progressive discrimination tests successfully supported the development products. This study focusing on age related sensory perception, demonstrated how elderly are able to perform not only simple paired comparisons, but also more demanding ranking tests. There are mainly two practical applications in this work: a methodological one and an applicative one. The methodological is related to the evidence that quite complex and up to date sensory studies, if well structured, can be correctly executed by elder consumers. The applicative output is a preliminary recipe of healthy food for elder people that can be used as milestone in future studies. article History Received: 21 March 2017 Accepted:11 July 2017