Genotypic and phenotypic correlations and path coefficient analyses for yield and its components in thirty hexaploid wheat varieties

Thirty bread wheat varieties with different genetic background were evaluated in this study. The analysis of variance indicated highly significant differences among genotypes for all studied traits. Mean values of traits manifested that variety Maxibak gave the highest values for 100-grain weight and grain yield per plant, while the varieties MD, Sakha 202, Sakha 60 and Golan showed the highest values for number of spikes per plant, spike length, number of spikelets per spike, and number of grains per spike, respectively. However, selection index revealed that Icarda 24 was the best variety in the combined values for the six studied traits. Highly significant positive phenotypic and genotypic correlation coefficients were found between grain yield per plant and each of number of spikes per plant, number of grains per spike and 100-grain weight. The direct phenotypic effect was moderately low for number of spikes per plant, number of grains per spike and 100-grain weight. On the other hand, the direct genotypic effect was slightly high for number of spikes per plant and 100-grain weight. The results indicated that the most important grain yield components were number of spikes per plant, number of grains per spike and 100-grain weight as estimated from phenotypic and genotypic correlations. 100-grain weight had the highest contribution to grain yield through its total direct and indirect effects at phenotypic and genotypic path analysis. Also, these effects were important for number of spikes per plant and number of grains per spike. Therefore, these three traits could be used as selection criteria in wheat breeding programs for increasing grain yield/plant

Effect of water stress on seedling protein and isozyme patterns in hexaploid wheat

Two hexaploid wheat varieties [Gizal68 and Sonalika] were used to study the changes in seedling leaf soluble proteins, peroxidase and esterase isozymes under drought conditions, and to detect molecular genetic markers related to drought stress. The seedling was treated with different concentrations of Poly Ethylene Glycol [PEG]. The variety Gizal68 manifested four new bands in its protein electrophoretic patterns after treatments comparing with the control, at relative front mobility [RF] 0.318, 0.457, 0.816 and 0.870. The treatments showed three new protein bands, in the variety Sonalika, with RF 0.318, 0.409 and 0.961, while one protein band more appeared at high concentrations of PEG. The peroxidase isozyme bands gave a clear variation between the control and PEG treatments. One new band was present in the drought stressed plants of Gizal68 variety. Concerning the variety Sonalika, only one band appeared in the electrophoretic pattern under control, while three bands appeared in the patterns of all PEG treatments. The variety Sonalika gave two bands of esterase in its electrophoretic pattern under control and three bands after PEG treatments, where band number 3 appeared only in the electrophoretic patterns of the treated plants. The peroxidase and esterase patterns could discriminate between the two wheat varieties Gizal68 and sonalika. The results indicated that the variety Gizal68 appeared more tolerance against the drought stress than Sonalika variety. The new protein and isozyme bands that were produced under drought stress can be used as molecular genetic markers related to drought stress

Effect of abscisic acid on some salt stressed Maize Inbreds

The effect of exogenous ABA treatment on eight maize inbred lines [Zea maysL.] differing in their salt tolerance, with regard to some yield-related traits was examined. Also, fingerprints for the two salt-tolerant and the two salt-sensitive inbreds using RAPD-PCR markers were identified. From 20 maize inbred lines, four were chosen as salt-tolerant genotypes [L123a, G251b, L113a and Rg25] and four as salt-sensitive genotypes [Rg5, G227b, Rg1 and G13]. These eight maize inbreds were treated with 10-5 M abscisic acid [ABA] under5000 and 7000 ppm NaCl conditions. The effect of exogenous ABA on salt tolerance was tested by estimating some yield-related traits [plant height, total root length, shoot fresh weight, shoot dry weight and root dry weight]. The two most salt-tolerant [L123a and G251b] inbreds and the two most salt-sensitive [Rg1 and G13] were selected for detecting some biochemical and molecular genetic markers associated with salt tolerance. SDS-PAGE banding pattern showed differential responses with respect to salt tolerance and ABA treatment, while esterase and peroxidase isozyme profiles were weakly or negatively correlated with salt tolerance and ABA treatment. RAPD-PCR analysis showed that four random 10-mer primers, out of six, succeeded in differentiating salt-tolerant [L123a and G251b] from salt-sensitive [Rg1 andG13] inbreds, some specific markers for maize inbreds across RAPD-PCR analysis were determined. Twenty-seven of 57 RAPD markers were found to be inbred-specific, phylogenetic relationships between these inbreds were studied on the bases of RAPD-PCR patterns. Dendrogram analysis showed that, the inbreds were divided into two main groups and the most dissimilar one was the most salt-sensitive