No abstract

Six populations; P1, P2, F1, F2, BC1 and BC2 of four bread wheat crosses were used in this study to determine quantitative genetic parameters for yield and its components characters under normal and water stress treatments. The means of the six generations were recorded for plant height, spikes number plant-1 , grains number spike-1 , 100-grain weight and grain yield plant-1 in four crosses namely; Line 1 × Sakha 93, Line 1×Sakha 94 , Sakha 93×Gemmiza 9 and Sakha 94 × Gemmiza 9 generated from four diverse parents. The experiment was carried out in 2006/2007 to 2008/2009 seasons at Sakha Agric. Res. Station, ARC. The means of the four crosses significantly decreased under the water stress treatments for yield and its components characters as the effect of water stress at most cases. The T-test of differences between parents of each cross under each treatment showed highly significant values in most cases in the four studied crosses under both treatments. The results showed the importance of additive gene effects in the inheritance of plant height and spikes number plant-1 , while, additive, dominance and epistasis were the important in the inheritance of grains number spike-1 , 100-grain weight and grain yield plant-1 at most cases under both normal and water stress treatments. Moreover, additive genetic variance played the greatest and the important role in the inheritance of plant height, spikes number plant-1 and grain yield plant-1 at most cases under both water treatments. On the other hand, dominance genetic variance was the greatest and the important in the inheritance of grains number spike-1 and 100-grain weight at most cases under both water treatments. On the other side, heritability in broad sense had medium to high percentages for all studied characters at all cases under normal and water stress treatments. Meanwhile, heritability in narrow sense had moderate to high values for yield and yield components characters at most cases under both water treatments, except grains number spike-1 which had low values at most cases under both water treatments. Genetic advance under selection was low for plant height at most cases under both water treatments. While, it was high for spikes number plant-1 and grain yield plant-1 at most cases under both water treatments. Also, it was founded to be low to high for plant height, grains number spike-1 and 100-grain weight at most cases under both water treatments.

The present study was carried-out at the Experimental Farm of Sakha Agricultural Research Station, during 2017/2018 and 2018/2019 seasons to evaluate eighteen bread wheat genotypes including fourteen promising lines and four cultivars namely; Sakha 93, Sakha 95, Giza 171 and Shandaweel 1 under normal irrigation and deficit conditions. Additionally, six selection indices were used to identify the best genotypes that might be grown under water deficit condition using different drought indices namely; Mean Productivity (MP), Harmonic Mean (HM), Geometric Mean Productivity (GMP), Stress Tolerance Index (STI), Yield Index (YI), and Modified Stress Tolerance Index (MSTI). The results indicated that, the effect of the irrigation treatments, genotypes and their interactions were significantly different in most studied characteristics. The means of all genotypes significantly decreased in all characters except for, proline content that was increased in the two growing seasons under water deficit conditions compared with to normal condition. Genotype 5 recorded the highest number of spikes /m², while the heaviest 1000-kernel weight was produced from Giza 171 under normal and water deficit condations. Sakha 95 gave the highest values for grain yield under both conditions. Based on drought indices HM, GMP, STI, YSI and MSTI, genotype 3 followed by Sakha 95, Shandweel 1, genotype 5 and Giza 171 were identified as suitable genotypes for water deficit conditions. The cluster analysis classified the tested genotypes into five main different groups, each group contained similar genotypes similar based on grain yield and stress tolerance indices. The fifes cluster consisted of one genotype (Sakha 95) that recorded high grain yield and stress tolerance degree followed by the third cluster which consisted of genotypes 3, 5, Giza 171 and Shandaweel 1 which had a moderate grain yield and tolerance to water deficit genotypes. So these genotypes might be used as parents in breeding programes to produce new genotypes with desirable characters related to drought tolerance.

The current study was conducted at the Experimental Farm of Sakha Agricultural Research Station (31o06 N,30o 56 E) during the two growing seasons of 2017-2018 and 2018-2019 to evaluate sixteen genotypes of bread wheat, such as ten promising lines from the local breeding program and six local cultivars, under normal, water deficit, and soil salinity conditions. The genotypes were arranged in three experiments representing the growing conditions. The used design was a randomized complete block design with four replications. Results appeared that there was significant decrease in all studied characters as result of water deficit and soil salinity conditions compared to the normal one, except 1000-kernel weight which increased under water deficit conditions. The effect of genotypes x growing conditions interaction was significant for days to heading, days to maturity and grain yield in both seasons while it was only significant in the 1st season for number of spikes m-2 and 1000-kerenl weight. The mean comparisons indicated that Line 7, Line 10 and Line 9 had moderate values of grain yield under both water deficit and soil salinity stresses with low grain yield reduction under those conditions. Therefore, Line 7, Line 10 and Line 9 may be applied in breeding program to generate new recombination with good soil salinity and water deficit tolerance characteristics. Meanwhile, the three cultivars; Misr 3, Sakha 95 and Giza 171 exhibited the highest grain yield under the three conditions with lowest grain yield reduction under both water deficit and soil salinity conditions indicating their good ability to tolerant difficult growing conditions. Therefore, these cultivars can recommend to be grown under water deficit or salt affected soil conditions. These results may be helpful to plan appropriate selection strategies to improve grain yield under water deficit and soil salinity in wheat crop in Egypt.

Water scarcity in Egypt and globally makes producing new varieties having high grain yield using less water requirements is an important goal for wheat breeders. The present research was conducted to assess the response of sixteen bread wheat genotypes under normal irrigation (five irrigations) and low irrigation (one irrigation, 25 days, after sowing irrigation.) during 2018/19 and 2020/21 seasons at the Experimental Farm of Sakha Agricultural Research Station, Egypt. A randomized complete block design with three replicates was used for each irrigation treatment separately. Results showed that the normal irrigation treatment had considerably higher mean values for all studied traits except, proline, malondialdehyde, activity of peroxidase and catalase enzymes,1000-kernel weight, protein content, wet and dry gluten which had significantly higher mean values under low irrigation treatment. Under low irrigation conditions, the four genotypes Sakha 95, Line 4, Line 8 and Misr 3 superior other genotypes in grain yield with insignificant difference among them. Sakha 95 and Line 8 had the highest chlorophyll a and b, proline content, chlorophyll florescence, activity of both catalase and peroxidase enzymes. While, Line 4 had the highest activity of catalase and peroxidase, heaviest 1000-kernel weight and high content of crude protein. In addition to Misr 3 recorded the best values of both wet and dry gluten. It could be recommended with cultivation Sakha 95 or Misr 3 to achieve high grain yield with less irrigation water. While Line 8 and Line 4 need more evaluation to use it in the regions which suffering from water shortage also it will be benefit for breeder to use these genotypes in wheat breeding program.