ZmOCL1 is the founding member of the ZmOCL (Outer Cell Layer) family encoding putative transcription factors of the HD-ZIP IV class. It is expressed in the L1 cell layer of the embryo and several other tissues of maize. After determination of the intron/exon structure a mutator insertion was isolated in the upstream region. No notable phenotypes and wildtype levels of ZmOCL1 transcript were observed in homozygous mutant plants. In contrast transgenic plants carrying a fusion of the repressor domain of the Drosophila Engrailed gene with the DNA binding and dimerisation domains of ZmOCL1 showed a transient reduction of embryo, endosperm and kernel size that was most obvious around 15 DAP. An inverse relationship was observed between the degree of size reduction and the expression level of the transcript. In reciprocal crosses the size reduction was only observed when the transgenic plants were used as females and no expression of male transmitted transgenes was detected. Smaller kernels resembled younger kernels of wild-type siblings indicating that interference with ZmOCL1 function leads to an overall slow-down of early kernel development. Based on marker gene analysis ZmOCL1 may act via a modification of gibberellin levels. Phylogenetic analyses based on the intron/exon structure and sequence similarities of ZmOCL1 and other HD-ZIP IV proteins from maize, rice and Arabidopsis helped to identify orthologues and suggested an evolution in the function of individual genes after the divergence of monocots and dicots.

Genetic variability and identification of some molecular markers were studied in twenty promising lines of wheat using agronomic traits, ISSR (inter simple sequences repeats) and RAPD (random amplified polymorphic DNA) markers. Significant variation was evidenced in all agronomic traits. The lines proved to be superior to the check cultivar Sahel1 in yield and its component traits. Lines L2, L7 and L8 were the best in most yield component traits in both seasons. Moreover, Lines L2, L4, L5, L7 and L8 showed drought tolerance by which they displayed high performance in agronomic traits as well as a low drought susceptibility index. The percentage of polymorphism was 39.3% and 53.2% for ISSRs and RAPDs, respectively. UBC-881 belonged to penta-nucleotide repeat sequences (GGGTG) that produced the highest level of polymorphism, while UBC-846 belonged to di-nucleotide repeat sequences (CA) that produced the lowest level of polymorphism. Genetic similarities among wheat lines based on ISSR and RAPD markers ranged from 0.81 to 1.00 and from 0.86 to 0.98, respectively. There was a low average of PIC (polymorphism information content) values which were 0.10 (ISSR) and 0.15 (RAPD). The RAPD technique exhibited a higher marker index (MI = 0.69) compared to ISSR (MI = 0.43). There was insignificant correlation between ISSR and RAPD data (0.168, p > 0.05). There were two markers (UBC-881450bp and OPF-10540bp), on each of which two traits regressed significantly. The associated markers each explained a maximum regression of 18.92–34.95% of the total available variation for individual associated traits.

Genetic stability and diversity are two of the key factors for the improvement of many crop plants. A major challenge for plant breeders is selection of high yielding genotype with wide adaptation. Therefore, thirty six wheat genotypes were evaluated under two locations (Sohag and Aswan, Egypt) on favorable and late sowing date during winter seasons of 2012/2013 and 2013/2014 to estimate its performance and stability parameters. The wide range of weather conditions resulted in a broad variation of mean yields, ranging from 6.59 t/ha in favorable sowing date to 4.99 t/ha in late sowing date as heat stress. The combined analysis of variance showed that the flag leaf area, days to heading, spike length, 1000-kernel weight and grain yield were significantly influenced by years, locations, sowing dates and genotypes. Mean environmental grain yield ranged from 2.70 t/ha to 9.27 t/ha. The results showed that sowing at the favorable date increased all studied traits. The 36 genotypes showed diversity for the slopes of the joint regression. Genotypes No. 5, 6, 14, 19, 20, 22, 24 and 32 exhibited stability for grain yield and useful in the breeding program in developing new wheat genotypes with tolerance to heat stress conditions. Positive correlation was found between bi and x for days to heading, spike length, number of kernels/spike, 1000-kernel weight and grain yield (0.89**, 0.50**, 0.07, 0.13 and 0.51**), respectively. This might be due to adaptation of these genotypes to wide differences in climatic conditions which prevailed at the two studied locations. The best genotypes in terms of both favorable and heat stress indicating that selecting for improved yield potential may increase yield in wide range of environments.

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