Evaluation of rice cultivats based on pre-harvest sprouting tolerance

Pre-harvest sprouting is one of the main factors that reducing the rice grain yield and quality in wet ýweather condition with raining in harvest time. 34 local and improved rice varieties were evaluated ýfor pre-harvest sprouting and some related ýcharacters to this trait at in vivo conditioný. Results of ýanalysis of variance indicated that the difference between genotypes were ýsignificant for pre-ýharvest sprouting and some other traits of grain. Genotypic and phenotypic correlation coefficients ýof pre-harvest sprouting ýwith alpha amylase activity were positive, this result showed that the ýalpha amylase enzyme had significant effect on pre-harvest sprouting. All varieties divided into ýthree groups by cluster analysis using ward method. First groups included 24 varieties and second ýand third groups included 4 and 6 varieties respectively. In total, varieties of the first and second ýgroups had the lowest of pre-harvest sprouting ýpercentage so they were resistance to germination ýbefore harvesting and the varieties of third group had the highest of pre-harvest ýsprouting ýpercentage so they were sensitive to germination before harvesting. Results of this ýresearch showed some local varieties with high resistance to pre-harvest sprouting had good ýpotential for using in breeding programs.