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Aminoacid composition and species
relationships in genus Triticum
D. LAFIANDRA, E. PORCEDDU, G. COLAPRICO
Germplasm Laboratory, CNR, Bari, Italy
The genus Triticum is composed of di- tetra- and
hexa-ploid species including both wild cultivated types.
Based on evidence from chromosome pairing in F1 hybrids and
on gross morphological and karyotype comparisons, three
basic genomes-A, B and D- have been recognised in the
cultivated types. Tetraploids - AABB - are thought to be
originated by amphiploidy between diploids AA and BB
(JENKINS, 1929 ; SARKAR and STEBBINS, 1956; SEARS, 1956;
RILEY, et al., 1958), probably before the advent of
agriculture, while exaploids - AABBDD - emerged later as a
result of amphiploidy between a tetraploid AABB and diploid
DD (KIHARA, 1944; MCFADDEN and SEARS, 1944).
The problem of confirming the parents of polyploid types is
intensified by the genetic heterogeneity accumulated by them
in centuries of evolution.
In recent times, numerous biochemical parameters, such as
phenolic compounds (Dass, 1972 ; FROST and HOLM, 1977),
proteins (JOHNSON and HALL, 1965, 1966), isoenzyme (NAKAI,
1973 ; MITRA and BHATIA, 1971 ; JAASKA, 1978) and
immunochemical methods (Bozzini et al. 1973) have
been used for studying the phylogenetic relationships in
wheats.
The present investigation on quantitative differences in the
aminoacids, from hydrolyzed proteins, of different species
of Triticum was undertaken in order to assess the
biochemical bases of the species relationships.
Material and Methods
33 samples of different species of Triticum - 3
samples of T. monococcum, 10 samples of T.
durum, 11 samples of T. aestivum, 1 sample of
T. speltoides, 2 samples of T. tauschii, 2
samples of T. longissimum and 4 samples of T.
dicoccoides - were included in the analysis.
Seeds were derived from a cultivation performed in the same
place during the same year. Protein content was determined,
by microkjeldahl method, as a crude nitrogen times 5.7;
aminoacid composition was determined by an ion exchange
chromatography on the hydrolized meals. Aminoacid content
was expressed as a % of protein content. Methionine and
cystine were not determined.
Analysis of variance was performed for each aminoacid ;
correlation coefficients and canonical analysis were
determined on mean values per species.
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