Selection for grain yield under normal and deficit irrigation regimes in bread wheat [electronic resource]

Includes bibliographic refrence

The objectives of the present research were to study the direct selection response for grain yield
planf1 under normal and deficit irrigation conditions and estimate the correlated response of other
studied traits. Two cycles of selection were practiced on a segregating populations of wheat cross (Sid
1 x Misr 2) in the F 3-F 5 generations. Selection was practiced separately under normal and deficit
irrigation conditions. The genotypic variance was slightly less than the phenotypic variance under both
environments and generally decreased from the base population (F 3) to the F 5 generation. Broad-sense
heritability estimates for grain yield planf1 after two cycles of selection were 65.66 and 59.95% under
normal and deficit irrigation, respectively. The realized heritability under normal irrigation was 47.94
and 53.66% compared to 34.90 and 58.64% under deficit irrigation conditions after the first and
second cycles of selection, respectively. The average observed gain for grain yield planf1 from
selection under normal and deficit irrigation groups, evaluated under normal irrigation were (13.92
and 15.48%) over the bulk sample and (9.27 and 10.78%) over the better parent, respectively. While,
from selection under normal and deficit irrigation, evaluated under deficit irrigation were (16.87 and
20.08%) over the bulk sample and (15.44 and 18.61%) over the better parent, respectively. Drought
susceptibility index (DSI) showed that six families selected under normal irrigation and five families
selected under deficit irrigation were superior for drought tolerance and had high grain yield under
deficit irrigation in F 5 generation. The antagonistic selection was better than the synergistic selection
in changing the mean and decreasing the sensitivity.

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