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The performance of genotypes may vary under changed environments. For
instance, 100grain weight of small spelt (1.75g), wild emmer (3.13g),
cone (5.34g) and bread (3.89g) wheats reported previously (Holubee et
aL 1992), deviate from the present results. Having very shrivelled
grains, T. dicoccoides (No. 60) with 100-grain weight of 0.47g
had the protein content of 19.74% and lysine value of 3.89 (percent
protein). The accession No.60 could be regarded as an exception in T.
dicoccoides. High protein content in Aegilops accessions (19.1
to 34%), wild emmer (16 to 27%), emmer (14 to 21%), small spelt (
11.3 to 18.71%) and other wild/obsolete cultivars have been reported
(Dhaliwal 1977; Ciaffi et al. 1992; Damania et al. 1992; Holubee et
al. 1992; D'Egidio et al. 1993). Like protein percentage, lysine
content of diploids and tetraploids was also higher than that of
modern wheats (Rafl et al. 1992; Nevo and Beiles 1992). Grain weight,
protein and lysine content seem independent as far as their ploidy
level in the genome Triticum is concerned. The diploid species
Triticum monococcum (AA) had significantly similar grain
weight as the tetraploid species T. dicoccoides (No.53) and
T. dicoccum (AABB). Comparing the species of Aegilops,
Triticum and Hordeum, it was noted that the bread wheat,
Triticum aestivum had the lowest protein and lysine content.
The situation therefore demands concerted efforts for the improvement
of protein content and quality particularly in bread wheat
(Triticum aestivum).
Indeed simultaneous improvement in grain yield and protein content
has many limitations, yet positive breakthroughs have also been
documented. At Winnipeg, Canada, A.B. Campbell registered Neepawa
hard red spring wheat in 1969, with 7.6% more yield and 0.6% units
more protein than Thatcher (De Pauw and Townley-Smith 1988).
Similarly Lancota winter wheat also has both elevated yield and
protein content (Schmidt et al. 1979). Johnson et al. (1985) have the
opinion that because the negative correlations rarely exceed 0.6 and
variation in protein content was independent of yield, simultaneous
advances in both yield and protein content would be possible.
In the present study, we could not find any positive relationship of
grain weight with protein (Fig. 1a), protein
lysine (Fig. 1b) and flour lysine (Fig.
1c). The species T. aestivum (bread wheat), which is the most
widely cultivated species of genus Triticum possessed
intermediate 100-grain weight and the lowest protein and lysine
content. Two species T. turgidum and T. polonicum were
observed to have higher 100-grain weight, better protein and lysine
contents. Very strong positive relationships were obtained between
protein content and protein lysine (Fig.
1d), protein content and flour lysine (Fig.
1e) and between flour lysine and protein lysine (Fig.
1f).
The positive correlation between protein and lysine content observed
in present investigations clearly demonstrates that higher protein
content synthesized by wild grasses and old wheat grains was not
inferior in quality. This contention is further substantiated by
highly significant positive relationship observed between lysine
content of flour and protein of different cereals.
The preliminary screening studies provide significant evidence that
wild species of Triticum and Aegilops are bestowed with
particular traits such as grain weight (T. polonicum), protein
content (T. dicoccoides No.60, Ae. ovata,
Ae. kotschyi and Ae. tauschii), lysine
content (T. dicoccoides and Aegilops spp). One
accession No. 49 of wild emmer T. dicoccoides may be
considered to have simultaneously better grain weight, higher protein
and lysine content.
The best hope for future crop improvement lies in the conservation
and utilization of genetic diversity of wild species. Wild emmer
T. dicoccoides easily hybridizes with cultivated tetraploid
wheats, whereas gene transfer from wild to hexaploid cultivated
wheats is also possible after overcoming the genetic barriers.
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