Jain, SunitaYadav, Deepak2016-10-242016-10-242015http://krishikosh.egranth.ac.in/handle/1/81419ADP-glucose pyrophosphorylase (AGPase) play a key role in starch biosynthesis in higher plants and is heterotetramer, consisting of two large subunits and two small subunits with different functions. Much of the ADPGlc required for starch synthesis in the plastids of cereal endosperm is synthesized in the cytosol and transported across the plastid envelope. In the present investigation, AGPase activity and grain growth rate (GGR) were determined in developing grains of four wheat cultivars viz. WH1105 and WH1124 (newly released high yielding) WH542 (small grain) and HD2967 (bold grain) at 14, 21, 28, 35 and 42 days after anthesis (DAA). Data on yield and yield attributes were recorded on maturity. In addition, homology modeling of the three-dimensional structure of the LS and SS from wheat (Triticum aestivum L.) was carried out to obtain the best orientation of large and small subunits of the enzyme. AGPase activity increased till 28 th DAA in three wheat cultivars both in field and net house except in WH542 where AGPase activity increased till 21 st DAA and declined thereafter. At 28 th DAA, the highest AGPase activities of 340.1 nmoles min -1 g -1 fresh weight and 183.1 nmolesmin -1 g -1 fresh weights were observed in WH1105 and HD2967 grown in the field and net house, respectively. GGR also had similar pattern as AGPase activity. The maximum number of spikes per plant (10.2), spike length (10.3cm), grain weight per spike (1.66g), thousand grain weight (41.2g) and yield (16.8g) were observed in WH1105 in field. Similar performance for WH1105 was observed in net house although the number of spikes and yield by itself was less. Positive correlation (r 2 = 0.79 at p= 0.05) was observed between AGPase activity at 28 th day and yield in all the varieties. For homology modeling, the SS (1YP2A) from the crystal structure of potato tuber was taken as the template for both large and small subunits of wheat AGPase. The models were build using Modeller 9v7 and Swiss Model Server. Based on Qmean Score, Z-score, Dfire–energy and Gromos the models build with Swiss Model Server were further evaluated from SAVES Server that included PROCHECK, VERIFY3D and ERRAT. Best 3D orientations of large and small subunits obtained by Swiss Model Server were superimposed on the template 1YP2A using UCSF Chimera and RMSD of 0.190 A ° and 0.695 A ° , respectively were observed.enStarch, AGPase, Homology modeling, Swiss modelThesis