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Agricultural Research, Volume 22 (1998-1999), p. 3-12
Fitting and evaluation of methods for more accurate heat units calculations
G. Spanomitsios
Agricultural Research Center Macedonia-Thrace, N.AG.RE.F.
Abstract
The heat units
(degree days) above 5, 8 and 10°C for the individual months of the period August
1992-July 1995 were calculated by the simple formula Ó(Tm-T b) (a),
where Tm =(Tmax+Tmin)/2 the mean temperature of the day
and Tb the base temperature, under which no appreciable growth for a plant
occurs. The reduction or elimination of one or more error sources introduced by,
1. The negative terms of the heat units sum (a) caused by temperatures Tm <Tb,
which however do not retard plant growth and development,
2. The daily mean temperature approximated by the (Tmax+Tmin)/2
value,
3. The underestimation of the temperature accumulated above Tb during days with
mean temperatures near and maximum temperatures sufficiently above Tb and
4. The overestimation during days with temperatures above a temperature threshold (30 or
35°C, according to the crop variety) value, was tried by the study of the efficiency of
four other approximation methods for the thermal time calculation. The obtained values
were compared with the corresponding values, resulted by a fifth method, calculating
precisely the heat units from hourly mean temperatures. The first four methods eliminate
or reduce the first, the first and the second, the first and the third, the first, the
third and the fourth error, respectively.
The results showed that the standard error of the temperature accumulated above 5, 8 and 10°C, estimated by the four methods, was varied from 15 to 17, 12 to 13.5, 10.5 to 11.5 and 5 to 6 degree days (°Cd) per month, respectively. These standard errors can be considered timely independent due to the nearly stable year to year temperature conditions prevailing in the region, and this will remain a fact until a serious climatic change occurs.
The more accurate among the four methods needs for its application the daily minimum and maximum temperatures and its estimated standard error equals that produced by the use of a mean daily temperature differing from the actual by only 0.15-0.2°C.
Keywords: heat unit, base temperature, degree days
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Agricultural Research, Volume 22 (1998-1999), p. 13-20
In vitro shoot
regeneration from apical meristem explants
of some grapevine (Vitis sp.) cultivars and rootstocks
grown in Greece
A. G. Kanakis1 and M. N. Stavrakakis2
1. Vine Institute of Athens, N.AG.RE.F.
2. Viticulture dept. of Agricultural University of Athens
Abstract
Grapevine axenic apical meristematic explants, of the genotypes Liatiko, Soultanina, Cardinal, Mandilaria, Vilana, Xynomavro, 5BB, 420A, 41B, 99R, 110R, 1103P, 140Ru, and SO4, produced adventitious shoots at a frequency higher than 67% when they were cultured in vitro on Murashige and Skoog (MS) or Nitsch and Nitsch (N & N) medium supplemented with 1.0 to 3.0 mgl-1 6-benzylaminopurine (BAP). The genotypes were classified, according to the average shoot number (ASN) produced per explant as follows: a) Liatiko, Soultanina and 5BB with an ASN higher than 12, b) Mandilaria, Vilana, Xynomavro, 140Ru and 1103P with an ASN between 7.42 and 8.32 and c) Cardinal, 420A, 41B, 110R and SO4 with an ASN between 2.03 and 4.25. The above classes were significantly different from each other at the 5% level. Finally, the genotype 99R with an ASN = 6.70 was classified between the second and third class and did not significantly differ from each one of them. With such a high proliferation rate (4.25 - 12.79 shoots per explant) can theoretically be produced some 30.000 to 40.000 plants per explant per year, which means that the proposed protocol could be used as a method for large scale in vitro propagation of grapevine. The regeneration of the adventitious shoots took place directly from the cells of the explant without any intermediate callus formation. This is very important since such a process can lead to the production of true-to-type plants. The basal N & N nutrient medium was better than MS in inducing more intensive adventitious shoot regeneration from meristematic explants.
Keywords: Vitis sp., merismatic explants, in vitro culture, adventitious shoot regeneration, ÂÁÑ
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Agricultural Research, Volume 22 (1998-1999), p. 21-26
Evaluation of the
adaptability of eight faba bean
varieties under eight environments
C. Podimatas1, C. Karamaligas2, E. Lazarou3 and G. Skipitaris4
1. Laboratory of Agriculture, Technological Educational Institution(TEI) of Larissa
2. N.AG.RE.F.- Agricultural Research Station of Palamas, Carditsa - Greece
3. N.AG.RE.F.- Cereal Research Institute – Thessalonike, Carditsa - Greece
4. N.AG.RE.F.- Ágricultural Research Station of Tripoli, Carditsa - Greece
Abstract
During the three year period 1990-93, a network of nine experimental fields was established in the environments of Larissa, Tripoli, Palamas and Serres, for the comparison of six new faba bean varieties and two other varieties as control.
The varieties studied were: Ku-188, Ku-189, Ku-191, Ku-192, Ku-193, new varieties of FCPRI which possess resistance to the fungus Sclerotinia spp, Ms-125, Italian variety of the Institute of Catania and the two old varieties of FCPRI Polycarpe and Tanagra, as control.
A randomized complete block design was used, with three replications. Each plot consisted of eight rows, spaced 50 cm apart. The four outer rows were used as discards (guard rows), providing a total plot area of 4m X 5m = 20 m2. The four internal rows were used for seed yield determination (providing a harvested area of 10 m2).
The sowing carried out in the beginning of November of each year, in a density of 30 plants / m2 and a basic fertilization of 6 units P2O5 was applied. No fertilisers with Potassium were applied, because the soil of the experimental field were sufficiently supplied with assimilable Potassium.
An evaluation of the adaptability of the above varieties was realized, using as criterion the seed yield of these varieties. Furthermore, the adaptability of each variety was expressed from the estimation of its average behaviour, in all environments tested and the slope of its regression line. The stability of its behaviour was measured with the standard error of its regression coefficient.
Better proven genotypes were these with high mean yield and small standard error of their regression coefficient, in all environments. In this experimentation it was found that the varieties Ku-188 or Ku-191 could be used for medium to high yielding environments, while the variety Tanagra, with a very good stability, for high and very high yielding environments.
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Agricultural Research, Volume 22 (1998-1999), p. 27-34
The Effect of
application of increasing doses of ammonium
nitrogen on growth, yield and fruit quality as well as
leaf N, P and K concentrations for orange (cv Tarroco).
D. Kotsias
Agios Saranta Pomology Research Station, Albania
Abstract
Nitrogen fertilizer experiments were carried out over a three year period (1989-1991) on 22 year old orange trees (cv Tarroco) at the Agios Saranta Pomology Research Station.
Six treatments with nitrogen in the form of ammonium nitrate were used at levels from 1 to 6 kg per tree to determine the effect on fruit yield and quality and hence the optimum fertilizer level.
The results show that an application of 3 Kg of NH4NO3 per tree increased yield by 17 kg compared to the control. Higher doses of nitrogen decreased yield while increasing overall shoot growth. Shoot length at the end of November was 20.22 cm (mean of three years) at 6 kg per tree compared to 11.16 cm for the control. The increase in yield observed with the 3 kg per tree application resulted from an increase in initial and final fruit set ( 17.90% and 10.8% respectively).
Leaf nitrogen increased with increasing nitrogen application; an application of 3 Kg per tree resulted in an nitrogen content of 2.41% and the greatest yield per tree.Higher leaf nitrogen content corresponded to lower yield.
Fruit colour change during ripening was delayed by 8-10 days at nitrogen levels of 5 and 6 kg per tree compared to the control and the other treatments. In contrast, all treatments had a positive effect on fruit storage as shown by the parameters investigated.
The results showed that 3 Kg ammonium nitrate can be recommended to producers for a greater, more economic yield and better fruit quality.
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Agricultural Research, Volume 22 (1998-1999), p. 35-44
Transgressive
segregation for morphological characteristics
of pods and seeds in peanuts (Arachis hypogaea L.)
S. Th. Kotzamanidis
Cereal Institute, Thessaloniki, N.AG.RE.F.
Abstract
The transgressive segregation for morphological characteristics of pods and seeds was studied in peanuts (Arachis hypogaea L.) during the years 1985-90 in the Cotton Research Institute. On the basis of the botanical type of the varieties four types of crosses were realized: Virginia X Spanish, where crosses Vrasna X Ispaniki, Vrasna X Sakania and Vergina X Sakania belong, Virginia X Valencia, where cross Lakonia X Seraiki belongs, Valencia X Virginia, where cross Seraiki X Karolina belongs and Virginia X Virginia, where cross Vergina X Vrasna belongs.
Pedigree selection was applied from F3 to F5 generation and the segregated material together with the parental varieties were evaluated on the basis of 100 pod weight, 100 seed weight, pod length, pod width, length and width of seed for the presence of transgressive segregation.
19 selections were evaluated, resulting from six crosses. In particular, the study involved 6 selections from the cross Vrasna X Ispaniki, 4 from cross Vrasna X Sakania, 2 from cross Vergina X Sakania, 4 from cross Lakonia X Seraiki, 2 from cross Seraiki X Karolina and 1 from cross Vergina X Vrasna.
The randomized complete blocks design with 5 replications was used in the evaluation trials. For the analysis of variance the F criterion was used, while for comparison of means the Duncan test.
Out of the 19 selections studied, 8 showed transgressive segregation for some characteristics and especially for 100 pod weight, 100 seed weight and pod width. The characteristic “seed length” has not shown any transgressive segregation. Most of the selections that showed transgressive segregation with Virginia type parents Vrasna and Vergina and Spanish type parents Ispania and Sakania belonged to the cross type Virginia X Spanish. Also, in this cross type, transgressive segregation was shown in all generations (F2, F3 and F4), more than the other cross types. In addition, selection IB-38-89 of cross Vrasna X Sakania showed transgressive segregation on all other characteristic except seed length. All previous observations show that yield and quality of peanuts can be improved by exploiting the phenomenon of transgressive variation occurring principally in crosses of varieties that belong to peanut types Virginia and Spanish.
Keywords: transgressive segregation, pod and seed traits
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Agricultural Research, Volume 22 (1998-1999), p. 45-52
Genetic study of
the grape cultivar Rhoditis
by Random Amplified Polymorphic DNA markers
M.N. Stavrakakis and K. Biniari
Agricultural University of Athens
Abstract
Ten decamer primers of arbitrary nucleotide sewuence were used to amplify genomic DNA by polymerase chain reaction (PCR-RAPD) in order to identify and discriminate between grape cultivar Rhoditis and the "types" Rhoditis white, Violento, Tourkopoula and Rhoditis "loose-berried", grown in different areas in Greece.
Grapivine DNA was extracted from young and fully expanded leaves.
Over 125 reproducible polymorphic fragments were generated by this method. Each primer showed a descried banding pattern with at least two bands. On the basis of the above results, the degree of genetic similarity was culculated and the dendrogram of the cultivars was constructed.
It was found that: a) there is genetic variation among the cultivars Rhoditis (red) and the types Violento and Tourkopoula, b) genetic variation is also detected between the grape cultivar Rhoditis (red) and the type Rhoditis white, but the high degree of the genetic similarity showed that the white type originated from Rhoditis red through mutation, c) the low degree of the genetic similarity between the types Violento and Tourkopoula means that these are different cultivars, d) genetic variation is also detected between the samples of the type Rhoditis red and Rhoditis white which originate from different geographical regions of Greece and e) there is genetic variation between Rhoditis red and Rhoditis "loose-berried".
These results show that RAPD methodology is reliable and very useful for the identification and genomic analysis of grape cultivars.
Keywords: cultivar identification, dendrogram, PCR, RAPD markers, similarity index, vitis vinifera
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Agricultural Research, Volume 22 (1998-1999), p. 53-60
Genetic study of
grape cultivar Phileri (V.vinifera L.) by
Random Polymorphic DNA markers
M.N. Stavrakakis1, K. Biniari1, G. Skipitaris2
1. Department of Viticulture, AUA
2. Ágricultural Research Station of Tripoli, N.AG.RE.F.
Abstract
Decamer primers of arbitrary nucleotide sequence were used to amplify genomic DNA by the polymerase chain reaction (PCR-RAPD) in order to identify and discriminate between grape cultivar Phileri and the "types" or synonyms Moscophilero, Xanthophilero, Asprophilero, Phileri Tripoleos and Phileri Attikis.
Over 120 reproducible polymorphic fragments were generated by this method. Each primer showed a banding pattern with at least two bands.
On the basis of the above results, the degree of genetic similarity was calculated and the dendrogram of the cultivars was constructed.
It was found that a) there was genetic variation between the cultivar Phileri (black) and the other types and synonyms b) The very low degree of the genetic similarity between the cultivar Phileri and Phileri Tripoleos and Phileri Attikis means that these cultivars are different c) the high degree of genetic similarity between the cultivars Phileri Tropoleos and Phileri Attikis indicates that these cultivars are related. d) the very high degree of the genetic similarity between the cultivar Phileri and the types Moscophilero, Xanthophilero and Asprophilero grown in Mantinia support the hypothesis that these cultivars originated from a a common stock through the accumulation of mutations. e) there was genetic variation between the cultivars Phileri, Moscophilero, Xanthophilero and Asprophilero which are grown in different regions.
The results of this study show that RAPD methodology is reliable and very useful for the identification and genomic analysis of grape cultivars.
Keywords: cultivar identification, dendrogram, PCR, RAPD markers, similarity index, vitis vinifera
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Agricultural Research, Volume 22 (1998-1999), p. 61-68
Employment and
production in the inshore fishery of Greece:
Seasonal integration and Granger causality
P. Fousekis, C.J. Pantzios
Karpenisi Institute of Rural Economy and Mountainous Regions
Abstract
The presence of sticky labor has important implications for efficient fisheries management since it affects the opportunity cost of labor employed in the fishing industry, a critical determinant of the optimal level of resources that should be devoted to a fishery. The objective of this paper is the analysis of the nature of employment in the inshore fishery of Greece. To this end, the concepts of seasonal integration and cointegration, and Granger causality are used along with a sample of seasonal (quarterly) observations on production and employment. The empirical results suggest that: a) The production series is integrated at the frequency è = 0 while the employment series is integrated at all frequencies of a cycle 2ð ; b) The production and the pre-filtered employment series are cointegrated at è = 0; c) The hypothesis that there is no Granger causality from output to employment cannot be rejected, implying that there is no employment accelerator. However, the hypothesis that there is no Granger causality from labor to employment is rejected. Overall, the empirical results support the notion that changes in employment in the inshore fishery of Greece are not easy and costless. An implication of the empirical results is that fish resource conservation policies involving output restrictions may turn out to be both economically inefficient and socially unequitable.
Keywords: fishing, production, employment, Granger causality
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Agricultural Research, Volume 22 (1998-1999), p. 69-74
A study on in vitro morphogenesis in grapevine cultivars
C.I. Siminis, K. Biniari, M.N. Stavrakakis
Laboratory of Viticulture, Agricultural University of Athens
Abstract
Genetic transformation techniques in grapevine are particularly desirable since conventional breeding is difficult and time consuming. The development of highly efficient plant regeneration systems is a prerequisite for the genetic transformation of grapevine. Plant regeneration has been obtained in some Vitis species and hybrids, but in few V. vinifera cultivars, by using embryogenic cultures in several cases. In this study the in vitro manipulations for morphogenesis induction from leaf explants in grapevine (Vitis vinifera L.) cultivars Athiri, Asyrtiko, Vidiano, Thrapsathiri, Mandilari, Soultanina and Fokiano are reported.
Plant regeneration via somatic embryogenesis and organogenesis was induced in young leaves (2-4 mm) from proliferating nodal cultures, while leaves from in vitro plants didn’t exhibit morphogenesis. Young leaves from nodal cultures consist a homogeneous explant population with significant morphogenic potential. For this reason in vitro shoot proliferation from axillary buds was examined in the above mentioned grapevine cultivars. Increased rate of shoot proliferation (15-30 shoots per explant) in nodal cultures was observed in B5 medium supplemented with BA. The better results were obtained in the presence of 2 mg/l BA. Somatic embryogenesis was induced in cultivars Athiri, Thrapsathiri and Soultanina in NN medium supplemented with 4 mg/l NOA and 0.8 mg/l TDZ. Direct shoot regeneration was observed in cultivars Athiri, Vidiano, Thrapsathiri, Mandilari and Soultanina in NN medium with 2.25 mg/l BA and 0.03 mg/l NAA.
Grapevine plant regeneration from young leaves represents a very interesting strategy since its very simple, leaf explants proved to be juvenile tissues adapted well to both organogenesis and embryogenesis and perhaps with very low frequency of somaclonal variation induced in the regenerants.
Keywords: embryogenesis, in vitro, morphogenesis, organogenesis, V. vinifera
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Agricultural Research, Volume 22 (1998-1999), p. 75-77
Short communication
The first
successful establishment of the insect Marchalina hellenica Gen.
(Coccoidea, Margarodidae) on the fir tree (Abies cephalonica)
N. Bacandritsos
Veterinary Institute of Athens, N.AG.RE.F.
Abstract
For many decades the insect Marchalina hellenica Gen.(Coccoidea, Margarodidae) has lived on the bark of Pinus spp, secreting honeydew which is collected by bees.
In 1993 and 1994 an attempt was made to establish the insect on the fir tree Abies cephalonica on Mt. Fteri. The attempt was repeated in 1995, 1996 and 1997 on the mountains Menalo and Helmos. The first observation of establishment of the insect on fir trees was carried out on mounts Menalo and Helmos in 1997.
There has as yet, however, been no observation of similar placement on Mt. Fteri.
Establishment of the insect Marchalina hellenica on a fir tree has been achieved for the first time worldwide.
Keywords: establishment, Marchalina hellenica, fir tree, Abies cephalonica
Copyright © 2000 National Agricultural Research Foundation