Over the last decades, increasing natural disasters and climate change are considered as the major environmental problems facing the globe. Numerous studies have been indicated it would cause huge losses on agriculture, especially in the grain productivity. Therefore, several alternatives are suggested for boosting up productivity of wheat as one of the main human food crop. One of important strategy is proper management of inflorescence development and DELLA proteins have been elucidated to play pivotal roles in growth of many plant organs. In this study, putative negative regulator of DELLA protein, GAST (Gibberellic acids stimulated transcript) have been isolated to identify their role in the developing spike of wheat. Four genes were isolated from its gene family and designated as TaGAST1, 2, 3, 4. Genomic structure was analyzed to demonstrate chromosomal localization of TaGAST genes and evolutionary relationships were also verified with GAST genes in other plant species. RT-PCR was conducted to detect transcriptional changes of TaGAST genes on external phytohormone. Each of TaGAST genes showed considerable changes in transcription level after GA, ABA, PAC treatment, respectively. Through Yeast two-hybrid assay, one protein for TaGAST1, and four proteins for TaGAST2 was isolated as putative interactive proteins in wheat spikes just before and after emergence.

The direct use of mutation is a valuable approach to generate variability in crops. The electron beam, one of the ionizing radiations, has been applied to evaluate its effect on seed germination and early seedling growth of creeping bentgrass (Agrostis palustris Huds., cv Penn-A1). The mature dry seeds were irradiated with various electron beam energies (0.3, 1.0, 1.3, and 2 MeV) and current levels (0.03 and 0.06 mA). Although large variability was existed within each dose, distinct difference of germiability and seedling vigor were not found at 0.3 MeV / 0.03 mA and 0.3 MeV / 0.06 mA beam condition. However, 1.0 MeV / 0.06 mA application most effectively inhibited and retarded seed germination and most severely restricted cotyledon and root growth in early seedling growth. The direct use of electron beam would be a valuable supplementary approach to generate mutants suitable for breeding purposes.