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1.
Solanum gourlayi and Solanum spegazzinii, wild potatoes endemic to Argentina, possess desirable traits for breeding. In periodical regenerations of accessions, variability
was detected for morphology and breeding barriers. The persistence of these populations in nature was evaluated after more
than 20 years. Both species were observed in all visited sites, along with other wild and cultivated potatoes. Chromosome
numbers coincided with the originally reported, except for one population of Solanum gourlayi, with diploid and tetraploid cytotypes. The accompanying flora and environmental conditions revealed important alterations
as the result of road construction, excessive stocking rates and overgrazing. Principal coordinate and cluster analyses and
an AMOVA using AFLP data of three original accessions and the corresponding new accessions revealed high molecular variability
and extensive overlapping. Plant grouping of accessions occurred at a distance of 0.58 for S. gourlayi, 0.62 for S. spegazzinii and 0.67 for both species. The role of natural hybridization and sexual polyploidization in the evolution of sympatric populations
of wild potatoes is discussed.
相似文献
| Elsa L. CamadroEmail: |
2.
Aurélie Lécolier Pascale Besse André Charrier Thierry-Nicolas Tchakaloff Michel Noirot 《Euphytica》2009,168(1):1-10
Coffee is one of the main products on the international markets, in association with oil, corn, sugar, and paper pulp. The
history of coffee-tree cultivation is incompletely documented, both regarding its domestication in Africa, and its assisted
dispersal throughout the world. This review focuses on the coffee mutant, Coffea arabica ‘Laurina’ (Chevalier A in Encyclopedie Biologique. Vol 28, 1947), also named ‘Bourbon pointu’. This plant is generally acknowledged
to have been selected in the island of ‘Bourbon’ (La Réunion) from a field at the beginning of the 19th century. Compared
with the common ‘Bourbon’ variety, ‘Bourbon pointu’ trees are dwarf, with a characteristic Christmas-tree shape and the beans
have an excellent cup quality. Although cited many times in literature, the origin of this variety is ambiguous and is largely
discussed even today with increasing confusion, particularly in books and local newsletters. This article provides a thorough
historical and bibliographical review of coffee cultivation in La Réunion, which leads to an understanding of the bottleneck
responsible for the low genetic diversity of the ‘Bourbon’-type modern varieties. Complemented by a review of the scientific
studies conducted on this subject, confirmation of the veracity of the various historical accounts becomes possible, and appropriate
conclusions on the origin of the ‘Bourbon pointu’ are derived. Although historical texts provide important information and
represent priceless resources that give direction to scientific research, it is clear that this same research makes it possible,
in turn, to clarify and to interpret historical texts.
相似文献
| Michel NoirotEmail: |
3.
Evolution was measured over 16 years in a self-regenerating, bulk-hybrid subterranean clover population, consisting of F
2 seed from 253 crosses, sown at Nabawa and Mt Barker, short and long growing season sites, respectively, in south-western
Australia. Seed bank samples harvested annually were grown in a common garden. Experiment 1 measured flowering time in plants
from each year, while Experiment 2 measured 26 variables in the populations 3 and 16 years after sowing, in comparison with
the ancestral population. Changes in population means were observed in 20 characters and variability declined in 11 characters
at one or both sites, with much of this occurring within the first three years. Natural selection at Nabawa favoured early
flowering of long duration, thick peduncles, high harvest index and high hardseededness. At Mt Barker it favoured late flowering
of short duration, large leaves and long, thick petioles at flowering, thick stems with long internodes, long, thin peduncles
with a high burial angle, large plants at maturity, low hardseededness and high biochanin A and total isoflavone contents.
High seed production capacity, with high seed weight and seeds per burr, was important at both sites. The use of bulk-hybrid
populations is demonstrated as a low-input means of breeding and selecting well-adapted subterranean clovers.
相似文献
| P. G. H. NicholsEmail: |
4.
The standardization of environments (E) encouraged by modern society and by the productivist model of agriculture has resulted
in the standardization of genotypes (G) thereby reducing G × E interaction. New societal values call for the diversification
of agriculture to fit contrasted environments. This process can be depicted by four models defined by two axes, one socio-economic
(individual logics versus collective governance), and the other agro-ecological (reductionist versus systemic approaches).
These models differ in (i) their objectives (from improvement in yield to the empowerment of farmers), (ii) their specific
expectations with respect to genotypes (from inherited genetic resources to varieties that represent genetic, ethical and
social progress), (iii) their specific representations of the environment (E) (from a simple interaction between the bio-physical
environment (B) and the crop management (C), to a complex interaction including the competences of the actors (A), outlets
(O), regulations (R), society (S)), (iv) their particular relations between G and E (from G × E to G × B × C × A under evolving
constraints represented by R × O × S). Taking this diversity into account changes the way plant improvement is considered.
Thus, depending on the model, the order, interest and status of the five classic stages of plant improvement (setting objectives,
creating variability, selecting, evaluating and disseminating) may be called into question. Between the existing analytical
model (Model I) and a holistic model (Model IV) which remains to be developed, lies the challenge of ensuring the sustainability,
efficiency and acceptability of plant breeding and resulting innovations. From a simple “statistical parameter” that we, as
plant breeders, attempt to reduce, the G × E interaction is becoming an “objective” that we try to predict and valorize. Structuring
the different components of E, G and G × E, enables us to extend the basic concept of representivity to both the cultivation
conditions and the relational socio-economic positions of the actors involved.
相似文献
| D. DesclauxEmail: |
5.
In maize (Zea mays L.) breeding programs, selection among and within segregating progenies is based mainly on indirect selection criteria. A
better understanding of the environment influence on physiological attributes of maize inbred lines is important to the identification
and selection of superior inbred lines as well as to successful hybrid seed production. In this study, the size and form of
genotype (G) and genotype × environment (G × E) interaction effects for plant grain yield (PGY) and several physiological
attributes were examined for 12 maize inbred lines grown in four managed environments, represented by two seasons (Y) and
two nitrogen levels. Mixed model analysis revealed that the G effect was relatively high for attributes related to light capture,
phenology, early biomass production, and numerical components of PGY. The G × E interaction effect explained most of the variability
for PGY, harvest index (HI), and biomass production at maturity. Three-mode principal component analysis allowed us to: (1)
describe the associations among multiple attributes across environments, (2) reveal the form of the main patterns of G × E
interaction, (3) establish the importance of the genotype × year (G × Y) interaction for kernel number, HI, and biomass at
maturity in determining PGY, (4) identify promising genotypes of high-PGY across environments, and (5) detect genotypes of
similar response patterns for PGY but with a contrasting relative behavior for other attributes, which may permit the simultaneous
selection for grain yield and desired secondary traits. Such selection results would contribute greatly in the identification
of superior inbreds than selecting for grain yield alone.
相似文献
| Karina E. D’AndreaEmail: |
6.
Isatis tinctoria L. was cultivated until the 19th century to produce indigo, a natural blue pigment used principally for dyestuffs. The current
search for alternative crops and interest in natural products has led to reconsidering I. tinctoria as a crop to be grown in marginal areas to produce natural indigo. To reintroduce I. tinctoria into cultivation, its behaviour under different climatic conditions as well as its morpho-physiological and genetic diversity
must be assessed in order to evaluate the possibilities of future breeding work. To do this, a Eurasian collection of 15 accessions
was studied in a 2-year experiment. The study was carried out in four locations in order to assess plant performance at altitudes
ranging from 380 to 1,700 m a.s.l. A second experiment evaluated the morpho-physiological diversity of several traits (some
related to agronomic performances) of the collection. In a third experiment the genetic traits of the collection were characterised
by using eight AFLP and eight SAMPL markers. The species showed a wide adaptability to different mountainous conditions and
the populations showed high morphologic and genetic variability and differed according to their origins. Both morpho-physiological
and molecular characterisation allowed the accessions to be distinguished into groups of European and Asian origin. Future
breeding work is recommended because some accessions have good agronomic potential.
相似文献
| Valeria NegriEmail: |
7.
Wheat breeding is an economic activity that has provided high returns on past investments. Recent developments include technologies
that can lead to improved utilization of genetic resources, improved selection methods, more rapid fixed lines, improved statistical
analysis, and improved targeting of production environments. They have the potential to allow for the development of new varieties
more rapidly, and/or varieties with enhanced productivity in targeted environments, and varieties with novel characteristics.
To ensure that future breeding investments also have high returns, breeding programs need to assess these new technologies
to determine whether to incorporate them into their program. Clearly, given the extent of uptake by breeders, there are significant
perceived gains from incorporating some of the new technologies. However, not all programs will want to invest in all the
new technologies. This paper identifies the criteria needed to assess which technologies may be most gainfully utilized. In
some cases, the technologies can lower costs for a given operation. In other cases, they allow the selection program to be
restructured by providing additional information at an earlier stage of the program or by targeting specific traits. However,
several of the new technologies require significant investment, either in the infrastructure itself if the operations will
be conducted within the breeding organization, or funding for contracting if the operations are done by outside organizations.
Access to these facilities and the size of the necessary investment can be important issues for breeders considering incorporating
the new technologies in their programs. Where some significant gains can be achieved at relatively low cost, all programs
can adopt the new technology. Where the investment is large, only select breeding programs will be able to afford to incorporate
the new technology into their programs. Analysis of marker-assisted selection shows that some markers can enable some operations
to be carried out at a fraction of the cost of phenotypic evaluation. Similarly, analysis of the stomatal aperture-related
traits of leaf porosity and canopy temperature depression shows that both are low-cost options that can lead to significant
cost savings in selecting for yield. If the resources saved with such technologies are reinvested in the program, the restructured
programs are likely to produce markedly higher rates of gain from breeding, and consequently higher rates of return on the
investment in wheat breeding.
相似文献
| Peter J. MartinEmail: |
8.
Haiyan Zhang Shaoyu Yang Daryl C. Joyce Yueming Jiang Hongxia Qu Xuewu Duan 《Postharvest Biology and Technology》2010,55(3):154-159
Experiments were conducted to examine softening and quality responses of harvested banana fruit to cold shock treatment intended to extend shelf-life. Fruit were immersed in ice-water for 1 h, then treated with or without 100 μL L?1 ethylene for 24 h at 24 °C, and finally stored at 20 °C. Fruit firmness, chlorophyll content, ethylene production, respiration rates, contents of pectin, starch and sugar, and the activities of the cell wall modifying enzymes polygalacturonase (PG), pectin methylesterase (PME) and CMCase (cellulase, endo-1,4-β-glucanase) were analyzed. Total amylase activity was also measured. Immersion in ice-water for 1 h effectively inhibited ripening-associated processes, including peel de-greening and pulp softening during storage or ripening. The delay in ripening was also manifest in reduced ethylene production and respiration rates. The inhibition of softening by cold shock treatment was related to decreased PG and PME activities, that is, retardation of pectin solubilization/degradation. Reduced activities of CMCase and total amylase and conversion of starch to sugar by ice-water immersion also contributed to the delay in softening of harvested banana fruit. 相似文献
9.
X. Li J. Cai F. Liu T. Dai W. Cao D. Jiang 《Journal of Agronomy and Crop Science》2014,200(6):467-478
Low temperature seriously depresses seed germination and seedling growth in winter wheat (Triticum aestivum L.). In this study, wheat plants were sprayed with abscisic acid (ABA) and fluridone (inhibitor of ABA biosynthesis) at 19 days after anthesis (DAA) and repeated at 26 DAA. The seeds of those plants were harvested, and seed germination and offspring's seedling growth under low temperature were evaluated. The results showed that exogenous ABA application decreased seed weight and slightly reduced seed set and seed number per spike. Under low temperature, seeds from ABA‐treated plants showed reduced germination rate, germination index, growth of radicle and coleoptile, amylase activity and depressed starch degradation as compared with seeds from non‐ABA‐treated plants; however, activities of the antioxidant enzymes in both germinating seeds and seedling were enhanced from those exposed to exogenous ABA, resulting in much lowered malondialdehyde (MDA) and H2O2 concentrations and production rate. In addition, the maximum quantum efficiency of photosystem II was also enhanced in ABA‐treated offspring's seedlings. It is concluded that exogenous ABA treatment at later grain‐filling stage could be an effective approach to improve cold tolerance of the offspring during seed germinating and seedlings establishment in winter wheat. 相似文献
10.
Wheat of two strong high-protein and two weak low-protein cultivars from New Zealand and Australia were milled to commercial
specifications. All millstreams were tested for α-amylase, β-amylase, falling number, protein, starch, damaged starch, amylose,
amylopectin, pentosan and ash. The distribution of β-amylase in millstream flours was more variable among cultivars than α-amylase.
Generally, both enzymes had lowest activity in sizing and early reduction flours. α-Amylase was very high in the bran, pollard
and germ fractions, in which ash content was very high, whereas β-amylase was low in these fractions. These observations,
together with the moderate correlation of α-amylase and poor correlation of β-amylase to ash content, suggest that most α-amylasein
flour derives from contamination with bran, pollard and germ, whereas most β-amylase derives from the endosperm. Falling numbers
varied between the cultivars, but variation amongst millstreams for each cultivar was low, except for cv. Frame, which had
particularly high falling number values (834 and 1197) in second and third break flours. These two flours had some of the
highest α-amylase levels and lowest starch levels. However, they also had very high protein content (22 and 26%) and very
low starch damage (3.2 and 4.5%), which may contribute to the high falling numbers. When endogenous α-amylase in the flour
with the highest falling number was supplemented with high levels of barleyα-amylase, the flour withstood the detrimental
effects of α-amylasein baking (sticky crumb, poor crumb texture and loaf volume) better than flours of lower falling number,
but did not withstand the effects ofα-amylase on falling number.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
11.
12.
《Postharvest Biology and Technology》2010,57(3):209-215
Shiitake (Lentinus edodes) mushrooms were exposed to UV-C light (4 kJ/m2) and stored in modified atmosphere packaging (MAP) prior to 15 days at 1 ± 1 °C and 95% relative humidity plus 3 days at 20 °C. Mushroom firmness, total phenolics, total flavonoids, ascorbic acid and H2O2 contents, superoxide anion (O2−) production rate and activities of catalase (CAT), superoxide dismutase (SOD), ascorbate peroxidase (APX) and glutathione reductase (GR) were measured. UV-C treatment resulted in maintenance of a high level of firmness during 15 days at low temperature and reduced the decrease in firmness during shelf-life storage. Furthermore, treated samples showed higher total flavonoids, ascorbic acid, and delayed the increases in both O2− production rate and H2O2 contents. However, no clear treatment effects were seen in total phenolics contents. The treatment also increased the antioxidant enzyme activities of CAT, SOD, APX and GR throughout the storage period. These results indicate that postharvest application of UV-C radiation can delay softening and enhance antioxidant capacity in shiitake mushrooms. 相似文献
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14.
This study addressed the influence of high carbon dioxide and low oxygen levels on Pleurotus eryngii samples, stored at 20–25 °C and 90–95% RH for 5 d. Evaluations of sensory characteristics, malondialdehyde (MDA) content, superoxide anion (O2−) production rate and the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and cytochrome c oxidase (CCO) were made in the mushrooms in response to high carbon dioxide and low oxygen treatments. The results showed that 2% O2 + 30% CO2 significantly prolonged mushroom shelf-life when compared to the control. The 2% O2 + 30% CO2 mixture was better suited to maintaining mushroom sensory characteristics and delaying the MDA increase and O2− production rate during storage. The activities of SOD, POD, and CAT in 2% O2 + 30% CO2-treated mushrooms were significantly higher than those of the control. However, the CCO activity was not affected by the atmospheric treatment (2% O2 + 30% CO2). These results indicated that the 2% O2 + 30% CO2 treatment could alleviate lipid peroxidation and enhance antioxidant enzyme activities, but it exerted little influence on the CCO activity of Pleurotus eryngii. 相似文献
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N2 fixation, nitrate uptake, and tissue N levels werecompared in four novel self-fertile inbred lines (referred to as A, B,
C andD) of white clover (Trifolium repens L.) believed to differ markedly intheir nitrogen relations. Plants were inoculated
with a mixture of Rhizobiumstrains and grown in flowing nutrient solutions without mineral N for 18 dprior to supplying half
the plants with 20 μM
over a 36 d treatment period. Net uptakeof
was measured automatically on a dailybasis. The remaining plants constituted ‘controls’ solely dependent uponN2 fixation for acquisition of N. Total uptake of
over 36 days was 27.4 (A), 23.8 (B), 13.8(C) and 30.1 (D) mmol N/plant, compared with N2 fixation of7.2 (A), 16.9 (B), 26.2 (C) and 6.2 (D) mmol N/plant by the
-fed lines. Total N2 fixationby corresponding ‘control’ plants was 15.6 (A), 35.6 (B), 35.3 (C) and 2.2(D) mmol N/plant. Line D plants exhibited
a 3:1 segregation with respect toeither ‘nil’ or ‘partially impaired’ N2 fixation; thecorresponding ratio for line A was 1:3. Line C plants had a ‘low
uptake’ phenotype characterised by specific
uptake rates approximately half those ofthe other lines, higher N2 fixation in the presence of
, and low leaf + petiole concentrations of
, although concentrations of
in stolon and root fractions were similarin all lines. These inbred lines provide a tool for (1) the analysis of thegenetic
and physiological basis of variation in the efficacy with which
uptake down-regulates N2fixation, and (2) testing ecological hypotheses for temporal and spatialvariation in clover/grass coexistence in pastures.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献