فهرست مطالب میر حسین پیمان

To study general and specific combining ability of some rice varieties for grain physical properties and milling quality، a diallel design with five parents (Hashemi، Vandana، Kadous، Shahpasand and IR36) was used. Parents and their F1 progenies (25 genotypes) were grown in a randomized complete blocks design with three replications in the Research Field of Rice Research Institute of Iran (RRII)، Rasht، Iran، during 2012، and nine different characteristics were recorded. Analysis of variance showed that there were significant differences among genotypes and also general and specific combining ability for all of studied traits، showing the role of additive and non-additive gene effects. Furthermore، the effects of reverse crosses for all studied traits except، degree of grains whiteness، were significant which indicated the role of maternal effects. The significance of MSGCA/MSSCA ratio، Baker ratio (genetic ratio) near to one and high narrow-sense heritability for physical characteristics showed that the additive gene effects controlling these traits were important than the non-additive gene effects، while non-significance of MSGCA/MSSCA ratio، Baker ratio (genetic ratio) less than one and low heritability for milling characteristics showed the role of non-additive gene effects. Results from graphical analysis based on Hayman method showed that all physical characteristics related to grain quality were controlled by partial dominance effect، while all milling properties were controlled by complete dominance to over dominance gene effect. The results of this research showed that the selection of elite progenies is suitable method to improve the physical characteristics in studied population، while hybrid production method will be suitable to improve milling quality in this population.

The effects of tillage methods and residual management on yield and yield components of rapeseed (Brassica napus L. CV. Hyola308) were evaluated after rice harvest. The experiment was carried out during 2004-2005 cropping season in a factorical arrangement of treatments at Rice Research Institute of Iran (RRII) in Rasht, in a Complete Randomized Block Design with three replications. Treatments included tillage in three methods a) conventional tillage b) minimum tillage, and c) no tillage, and rice residue management in two manners: a) removing residues, and b) not removing residues. Plant traits such as grain yield, oil percentage and yield, plant density, plant height, the lowest pody branch height from soil surface, number of pods per plant, plant and weed dry weight, leaf area index (LAI) and crop growth rate (CGR) were measured. Results indicated that grain yield was affected by the tillage type. Also, the effect of tillage type on plant height, number of pods per plant, the lowest pody branch height from soil surface, and oil yield was significant. The effect of residual management and residual management interaction and tillage were significant on none of the traits except for weed dry weight. Economic analysis indicated that rapeseed planting in a field with rice residual and minimum tillage had a relative advantage of less production cost in spite of nearly 15 percent yield decrease compared to other methods.