1,721,092 research outputs found
KIWIFRUIT YIELD EFFICIENCY, PLANT-DENSITY, AND BUD NUMBER PER SURFACE UNIT
No full textKiwifruit [Actinidia deliciosa (A. Chev.) C.F. Liang et A.R. Ferguson] crop response to variations in plant
density and bud number per surface unit of growing area was studied to determine optimum levels of these factors.
Five bud numbers per surface unit (50,000, 100,000, 150,000; 200,000, and 250,000 mixed buds/ha) and four plant
densities, obtained by varying the in-row spacings (1.5, 3.0, 4.5, and 6.0 m), were combined in a factorial design and
tested in a kiwifruit orchard during two growing seasons on the same vines. Kiwifruit yield increased from 7 to 24
t•ha —1 with increasing bud number per hectare according to a 2nd-order polynomial function. Both the reduction in
the mean fruit mass as well as the percentage budbreak caused a decrease in orchard efficiency. No differences
between 1.5- and 3.0-m in-row spacings were found; spacings wider than 3.0 m reduced crop efficiency principally
by decreasing fruit mass
MALE DENSITY AND ARRANGEMENT IN KIWIFRUIT ORCHARDS
No full textIn 1988 and 1989, flowers were removed before opening from all pollenizers (male vines) except that closest to the middle of an orchard block 76 m long and 24 m wide, containing 140 vines at 4 m X 4 m spacing. Fruit set decreased from 100% in vines nearest the central male to 17% in 1988 and to only 7% in 1989 in the most distant vines. Mean fruit weight for each vine decreased from 110 to 34 g in 1988 and from 113 to 37 g in 1989, fruit weight decreasing the further the vine was from the pollen source. As a consequence, yield progressively decreased from vines adjacent to the pollenizer (54.9 and 58.9 kg per vine in 1988 and 1989, respectively) to those most distant (3.7 and 1.9 kg per vine in 1988 and 1989, respectively). The area covered by a pollenizer, i.e. the area within which plants produce at least half the number of seeds of those closest to the pollenizer, was 229 m2 in 1988 and 103 m2 in 1989. Since pollen transfer, rather than its availability, is the main factor limiting pollination, to achieve full pollination about 118 pollen sources ha-1 must be provided in kiwifruit orchards, without regard to planting distances and canopy sizes. Male vines occupy too much canopy space and it is suggested that they be eliminated; instead, sectors of female vines at appropriate positions in the orchard should be grafted with male scionwood
Isozyme polymorphism in the genus Actinidia and the origin of the kiwifruit genome
No full textGenetic variation at fifteen putative loci in eight enzyme systems (aconitase, alcohol dehydrogenase, aspartate aminotransferase, phosphoglucose isomerase, phosphoglucomutase, shikimate dehydrogenase and uridine diphosphoglucose pyrophosphorylase) was studied in nearly 500 plants from 20 taxa of the genus Actinidia by means of starch gel electrophoresis. Eighty-two putative isozyme alleles were identified by analysing polymorphism within and among species, segregation in progeny from controlled crosses of Actinidia chinensis genotypes, and differences in banding patterns between shoot tip and pollen extracts. Cytosolic phosphoglucose isomerase was found to be duplicated in at least one diploid species, Actinidia chinensis. An agglomerative cluster analysis conducted on a genetic dissimilarity matrix did not correspond well with current taxonomic subdivisions of the genus and indicated that relationships between some Actinidia taxa should be reconsidered. For the enzyme systems studied, we identified 34 alleles in Actinidin deliciosa var. chlorocarpa, 39 alleles in Actinidia deliciosa var. deliciosa and 35 alleles in Actinidia chinensis. Actinidia deliciosa, the kiwifruit, (2n = 6x) and Actinidia chinensis (2n = 2x) share 34 of 40 alleles, and are consequently thought to be by far the most closely related species. Our results are consistent with the hypothesis that Actinidia deliciosa was derived by polyploidization solely from Actinidia chinensis without any other Actinidia species being involved
Indagini anatomiche sull'origine delle radici avventizie in talee di actinidia (Actinidia Chinensis Pl.)
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Kiwifruit (Actinidia spp.) in Italy: The history of the industry, international scientific cooperation and recent advances in genetics and breeding
No full textIn this review we give an account of the introduction of kiwifruit to Italy and the development of the industry, that in the 1990s became the world-leading player. Although kiwifruit were known in Italy since the 1930s as ornamental plants, the first kiwifruit orchards were established in Italy in the late 1960s, after several articles appeared in the French popular literature. Most kiwifruit plantings are still of the cultivar 'Hayward' but there are now orchards of several new cultivars, including the yellow-fleshed ones, while the baby kiwifruit (A. Arguta) plays a marginal role. The Italian kiwifruit industry makes up only a small part of Italian horticulture in general, but is nevertheless profitable and still expanding, after the small contraction in recent years owing to the spread of bacterial canker of kiwifruit. The orchard management has evolved as follows: the plant density has increased, owing mainly to the reduction of within row spacing from 6.0 to approx. 2.0 m; pergola and the T-bar has become in a few years the most popular training systems; the ratio of pollenizers: females has changed from 1:7-15 to 1:1-3, while artificial pollination is being generally adopted. Yields can vary from 30 to 60 t/ha according the cultivar, training and pruning and the use of plant growth regulators. The presence of leading kiwifruit scientists in New Zealand, the country that first domesticated the kiwifruit, led to an intense exchange of researchers between the two countries, promoted by the Plant & Food Institute of New Zealand and the Universities of Bologna and Udine, while the contact with Chinese scientists developed later, in some case encouraged by common research projects funded by the European Union (EU). Several Italian scientists have developed personal contacts with kiwifruit scientists of most kiwifruit growing countries. Studies on genetics of kiwifruit were initiated by the New Zealand breeders of DSIR and stimulated the development of breeding programs in New Zealand, followed on smaller scale in other countries, such as France, Italy, Japan, Korea and Chile. The development of linkage maps allowed the mapping of traits of interest and the development of the so-called marker-assisted selection (MAS). The release of EST database by the New Zealand scientists and the publication in 2013 of the kiwifruit genome sequence by Chinese scientists offered new tools for the MAS of agronomic traits and offered as well the opportunity to study biochemical pathways of the synthesis of flesh pigments, fruit aromas and other traits, now introduced into modern breeding programmes. In this review I give a brief account also of the success in promoting exchange of expertise and scientists within the kiwifruit community
Paternal inheritance of chloroplast DNA and maternal inheritance of mitochondrial DNA in the genus Actinidia
No full textPCR ampliÞcation of four chloroplast DNA
(cpDNA) and two mitochondrial DNA (mtDNA) regions
followed by restriction of the ampliÞed products
was used to identify restriction fragment length polymorphisms
in 21 Actinidia taxa. Subsequently, the
mode of organelle inheritance was investigated in both
interspeciÞc and intraspeciÞc controlled crosses made
between genotypes showing di¤erent cpDNA and/or
mtDNA haplotypes. Fifty-six seedlings produced from
three interspeciÞc crosses, including in one case the
pseudo reciprocal (di¤erent genotypes of the same
species used as opposite parents), were checked for
cpDNA inheritance, and 102 seedlings from the same
interspeciÞc crosses and 32 seedlings from two intraspeci
Þc crosses within the species A. deliciosa were
checked for mtDNA inheritance. In all cases, cpDNA
was inherited from the father and mtDNA was inherited
from the mother. Maternal inheritance of mtDNA
was expected, being the rule in plants, but A. deliciosa is
the Þrst genus in angiosperms for which a widespread
and strictly paternal inheritance of cpDNA has been
reported. Transmission of chloroplastic and mitochondrial
genomes through opposite parents provides an
exceptional opportunity for studying the paternal and
maternal genetic lineages of species in the genus
Actinidia
Osservazioni preliminari sulla differenziazione a fiore in gemme di actinidia (Actinidia Chinensis Pl.)
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