The objective of this study was to estimate the response to direct selection for grain yield/plant under normal and water stress conditions and study the correlated response of other studied traits. Two cycles of pedigree selection for grain yield/plant were practiced on a segregating population of wheat (Giza 168xSids 1) in the F₃-F₅ generations. Selection was practiced separately and over environments, at normal irrigation environment and drought stress irrigation environment. After the second cycle, the F_5-selected families were evaluated at the two environments. Pedigree selection for the two cycles at each environment showed 25.00 and 25.54% increase in grain yield/plant over the bulk samples for normal and drought stress selections, respectively, compared to 22.60% for selections over environments. The antagonistic selection was more efficient than synergistic selection in changing the mean. Selection for grain yield/plant was accompanied by late in heading date of 1.76, 4.07 and 0.13%, increase in plant height of 13.09, 9.79 and 7.38% and with decrease in 1000-grain weight of -2.01, -2.02 and -4.31% over the bulk sample when selection was practiced under normal, drought stress and over environments, respectively. Drought Susceptibility Index (DSI) was estimated for grain yield/plant. Four selected families i.e., No. 9 under normal environment, no. 71 under drought stress environment and no. 10 and 70 under over environments displayed DSI values less than one and the highest grain yield/plant. These families could be considered the best selected families resulted from selection for grain yield/plant. Pedigree selection for improving grain yield/plant was effective in isolating high yielding and drought tolerant genotypes.

drought stress --- drought susceptibility index --- Pedigree selection --- grain yield --- spring wheat

The knowledge of differences between weed species in their relative capacity to capture growth-limiting resources provides information which can be used to predict competitive ability of weed. A field study was conducted to compare weeds growth indices to evaluate weeds competitive ability. The experimental design was a Randomized Complete Block (RCBD) with 3 replications. Treatments were consisted of increasing durations of weed which were established by delaying weed Removal Time (RT) to different corn growth stages. Growth analysis was performed by determining weeds growth indices. In this trial different weed species exhibited marked differences in growth indices during growing season. Compare to other weeds, Barnyard grass had the greatest leaf area index and weed growth rate from the beginning to the middle of growing season. However, redroot pigweed achieved its maximum growth later from the middle of growing season to the end of season and became the dominant weed for that time. Redroot pigweed had by far the greatest relative growth rate compare with other weeds. It reveals that barnyard grass was the dominant weed for the beginning of growing season. However, from the middle of growing season till the end redroot pigweed became the dominant weed.

dominant weed --- competitive strategy --- growth indices --- Weed