| dc.description | Triticale (xTriticosecale Wittmack) is a hybrid of wheat (Triticum) and Rye (Secale)
first bred in laboratories during the late 19" century. The grain was originally bred in
Scotland and Sweden. Commercially available triticale is almost always a 2™
generation hybrid, i.e. a cross between two kinds of triticale. As a rule, triticale
combines the high yield potential and good grain quality of wheat with the disease
and environmental tolerance of rye. Only recently it has been developed into a
commercially viable crop. Depending on the cultivar, triticale can more or less
resemble either of its parents. When crossing wheat and rye, wheat is used as the
female parent and Rye as the male parent. The resulting hybrid is sterile and thus has
to be treated with the alkaloid chemical colchicines to make it fertile and thus able to
reproduce itself. The triticale hybrids are all amphidiploid, which means the plant is
diploid for two genomes derived from different species, in other words triticale is an
allotetraploid. In earlier years most work was done on octoploid triticale. Different
ploidy levels have been created and evaluated over time. The tetraploids showed little
promise, but hexaploid triticale was successful enough to find commercial application.
(Oetler, 2005) | en_US |
| dc.description.abstract | Ten dual-purpose triticale genotypes were evaluated in four different locations of Bangladesh to determine
the genotype x environment interaction and phenotypic stability of six traits including yield and forage
biomass using the Eberhart and Russell's model and the AMMI model. Significant differences were
observed for genotypes, environment and genotype x environment interactions for all the six characters
studied. The G x E interaction was further partitioned into linear and non-linear components. The G x E
interaction (linear) was highly significant for all the traits revealed that there were considerable genetic
differences among the genotypes for their regression coefficients on the environmental index. Significant
pooled deviation (non-linear component) for G x E interaction for all the six traits suggested that the triticale
genotypes also differed considerably in respect of their stability. Considering stability parameters of the
Eberhart and Russell's model; phenotypic index greater than zero (Pi>0), regression coefficient around
unity (bi = 1) and least deviation from regression (non-significant S2di), the triticale genotype E-5 with low
mean yield was the most stable for grain yield, whereas the genotypes E-7, E-4 and E-5 were regarded as
the most stable for green forage weight. Similarly, the genotypes E-1, E-7 and E-8 for days to maturity, the
genotypes E-4 and E-8 for plant height, the genotypes E-6 and E-2 for grains per spike and the genotypes
E-4 and E-10 for thousand grain weight were regarded as the most stable triticale genotypes. The
genotypes E-5, E-4 and E-7 were regarded as the most stable considering their overall stability
performances. Similarly, the genotypes E-6 and E-10 were highly responsive to environmental changes and
were considered suitable for favorable environments. Whereas the genotypes E-2, E-3 and E-8 were least
responsive to environmental changes and were considered suitable for poor environments. According to
the AMMI model, E-5 with low mean yield and E-4 with higher mean yield than grand mean yield were the
most stable triticale genotype for grain yield, whereas E-5 and E-7 were regarded as the most stable
genotypes for green forage weight. Similarly, the genotypes E-8 and E-1 for days to maturity, the genotypes
E-4 and E-8 for plant height, the genotypes E-6, E-1 and E-8 for grains per spike and the genotypes E-4
and E-7 for thousand grain weight were regarded as the most stable genotype. With overall ranking, the
genotypes E-5, E-4 and E-7 were regarded as the most stable triticale genotypes considering their overall
stability performances. Similarly, the genotypes E-9 and E-3 were the most unstable genotype with higher
grain yield and green forage weight. However, these genotypes showed high performance in favorable
environments. A comparison of the stability analysis for the triticale genotypes with the above mentioned
two models gave the similar stability ranking of the genotypes. With both models, the triticale genotype E-5
with low mean yield and the triticale genotype E-4 with higher mean yield than the grand mean with average
green forage biomass were regarded as the most stable dual-purpose triticale genotypes considering
overall stability performances. Comparatively, the AMMI analysis model was found more suitable for
accurate estimate and meaningful interpretations in analyzing the G x E interaction vis-a-vis in estimating
the phenotypic stability of some dual-purpose triticale genotypes across the environments. | en_US |
