Drought is one of the most important abiotic factors affecting wheat production and development of tolerant genotypes is limited by the lack of effective selection criteria. A genetic analysis of drought tolerance indices at seedling stage (i.e. root length, shoot length, root/shoot ratio and seedling dry weight) was performed for a seven-parent half diallel cross of bread wheat (Triticum aestivum L.) in Egypt. The parents and their F2 progenies were evaluated in the laboratory under osmotic stress induced by polyethylene glycol (PEG) with five treatments (i.e. 0, 5, 10, 15 and 20% PEG-6000). Grain yield per spike was also evaluated under drought stressed field conditions. The parent P7 had maximum root and shoot lengths under stress conditions, highest root/shoot ratio under 20% PEG and higher grain yield per spike than the other parents suggesting that P7 possessed stress tolerance genes. Grain yield/spike was significantly correlated with root length (r= 0.41, P0.05) and seedling dry weight (r= 0.46, P0.05) at 15% PEG. Both additive and non-additive gene effects were involved in the genetic control of all traits. Rather low to moderately narrow-sense heritability was obtained for root length (0.18 and 0.12) and shoot length (0.19 and 0.12) at 15 and 20% PEG, respectively; root/shoot ratio (0.15) and seedling dry weight (0.16) at 15% PEG. Moderate genetic advance was observed for root length (41.24%) and shoot length (29.96%) under stress conditions suggesting that selection could be practiced on both traits for improving drought tolerance in wheat breeding programs.

Drought is one of the most important abiotic factors affecting wheat production and development of tolerant genotypes is limited by the lack of effective selection criteria. A genetic analysis of drought tolerance indices at seedling stage (i.e. root length, shoot length, root/shoot ratio and seedling dry weight) was performed for a seven-parent half diallel cross of bread wheat (Triticum aestivum L.) in Egypt. The parents and their F2 progenies were evaluated in the laboratory under osmotic stress induced by polyethylene glycol (PEG) with five treatments (i.e. 0, 5, 10, 15 and 20% PEG-6000). Grain yield per spike was also evaluated under drought stressed field conditions. The parent P7 had maximum root and shoot lengths under stress conditions, highest root/shoot ratio under 20% PEG and higher grain yield per spike than the other parents suggesting that P7 possessed stress tolerance genes. Grain yield/spike was significantly correlated with root length (r= 0.41, P0.05) and seedling dry weight (r= 0.46, P0.05) at 15% PEG. Both additive and non-additive gene effects were involved in the genetic control of all traits. Rather low to moderately narrow-sense heritability was obtained for root length (0.18 and 0.12) and shoot length (0.19 and 0.12) at 15 and 20% PEG, respectively; root/shoot ratio (0.15) and seedling dry weight (0.16) at 15% PEG. Moderate genetic advance was observed for root length (41.24%) and shoot length (29.96%) under stress conditions suggesting that selection could be practiced on both traits for improving drought tolerance in wheat breeding programs.

The present study aimed to evaluate the impact of light source (Incandescent versus saving lamps) and the feed form (pelleted versus mash diets) on the growth performance and carcass traits of Ross broiler chicks during 42 days experimental period. Two hundred and forty one day-old chicks were equally assigned to four experimental groups, each comprised six equal replicates. Birds in groups 1 and 2 were exposed to yellow-reddish light produced from 60-watt incandescent lamps and fed on either mash or pelleted diets, respectively, while those in Groups 3 and 4 were subjected to white light by using 26 watt saving lamps and fed on either mash or pelleted diets, respectively. The light intensity for all experimental birds was 15 Lux during the first three days and 5 Lux thereafter. Chicks were housed and raised in two tiers-wire floor batteries, placed in a closed broiler house under controlled managerial and hygienic conditions. The studied traits included: body weight (BW), body weight gain (BWG), feed intake (FI), feed conversion ratio (FCR) and the carcass traits. The obtained results revealed that the highest Overallmeans of BW (2811.7g), DBWG (65.89g) and DFI (116.98 g) during the experiment were recorded in G4 (saving light + feed pelleted form), increasing significantly (P>0.5) than those of the other experimental groups. Both of light source and feed form had no significant effects on the mortality rate. In the same group, the use of saving lamps and feed pelleted diets increased significantly (P>0.5) the liver percentage as related to the carcass weight. Economically, the use of saving lamps as lighting source decreased the costs of the lighting program by about 56.7% than that of incandescent lamps. Therefore, it could be concluded that using both of saving lamps and pelleted diets is highly recommended in the broiler production to achieve the best possible profit, especially with the progressive increase in the prices of feed ingredients and power cost.

The effects of exposing Dandarawi fertile eggs to warm air before incubation on embryonic development, mortality and hatchability were studied. Seven hundred and fifty fertile eggs were used in this trial. Eggs were collected and stored at 16ºC for five days. Eggs were taken out the storage room and set for 12 hours in ambient air temperature (28ºC). Individual egg weights were recorded, then eggs were divided into five treatment groups (n=150 of each group). The first group (G1) was left for an additional 24 hours at room temperature and served as control. While, the other four groups (G2, G3, G4 and G5) were exposed to a temperature of (38-38.2ºC) for the respective durations of 6, 8, 10 and 12 hours, respectively, then to the ambient temperature (28ºC). After the 36 hours from taking the eggs out the storage room, all groups were set in the incubator. A sample of eggs from each group (n= 12 of each once) was cracked to record embryos’ relative weights at 6, 12 and 18 d of incubation. Eggs exposed (P0.05) to warm air prior to incubation had higher embryos weights at 6 and 12 d of incubation compared to the control. At hatch, no significant differences in hatchling weights were observed. Warming eggs before incubation decreased embryonic mortality, pepping chicks and improved hatchability (P0.05). In conclusion the pre-incubation warming for 10 or 12 hrs reduces embryonic mortality, pepping chicks and improves hatchability in Dandarawi eggs.

315-320